Residual loads from tilapia farming on the sediment of a Brazilian reservoir

This study investigated the sediment geochemistry of a fish farming area in net cage tanks in the Rosário reservoir, Brazil. Three areas were investigated: reference (RA), fish farming (FFA), and dispersion (DA). The results were analyzed through correlation, similarity, principal component analysis, comparison with legislation, sediment quality guidelines, and sediment pollution indices. The mean concentrations for RA, FFA, and DA areas were respectively: Cu (mg.kg-1) 37.74, 62.23, and 71.83; Mn (mg.kg-1) 22.55, 66.48, and 55.90; Zn (mg.kg-1) 9.13, 114.83, and 94.27; Fe (%) 0.28, 0.40, and 0.43; OM (%) 15.84, 21.95, and 18.45; TOC (%) 1.86, 3.69, and 6.05; TN (mg.kg-1) 2365.00, 5015.00, and 3447.51; TP (mg.kg-1) 780.00, 6896.00, and 2585.50; ORP (mV) -95.50, -135.20, and -127.10; pH 6.60, 6.58, and 6.05; <63 μm 90.59, 78.68, and 87.30. Statistically, the influence of fish farming on sediment, organic matter, and pollutant sedimentation was demonstrated. Cu and Zn concentrations were below sediment quality guidelines. Regarding legal limits (resolution 454/2012/CONAMA), nutrients in the FFA area exceeded by 60% (TN) and 100% (TP), while in DA and RA areas they were 100% lower. TOC was 100% lower in all areas. Organic matter exceeded the limit by 100% in all areas. Pollution indices resulted in: low contamination factor 78%; unpolluted for 87% of pollution load and 83% of combined pollution; moderately polluted for 75% of the Nemerow index. The greatest impacts and influence of farming on pollutant sedimentation were more concentrated in the fish farming area. In terms of legal aspects and pollution indices, fish farming produced low levels of trace metal pollution and nutrient concentrations exceeded legal limits.

Mineral profile and histopathological findings in the liver of white-lipped frog (Leptodactylidae) from the morphoclimatic domain of the Caatingas, Brazil

This study aimed to investigate the mineral profile and histopathological findings in the liver of Leptodactylus macrosternum (white-lipped frog) and to assess the association between melanomacrophage areas and hepatic fungal granuloma with several factors such as weight, snout-cloacal length, sex, hepatosomatic index, season (dry and rainy), and condition factor K. A total of 135 frogs of different ages were collected from three areas in the city of Petrolina, Pernambuco, with varying land use (conventional agriculture, organic agriculture, and Caatinga stricto sensu). The liver of all specimens exhibited changes such as granulomatous lesions, inflammatory cell infiltrate, blood vessel congestion, and sinusoid dilation. The melanomacrophage areas were influenced by weight, snout-cloacal length, and hepatosomatic index. Our findings revealed a positive correlation between body size (weight and snout-cloacal length) and melanomacrophage/hepatic granuloma, while the hepatosomatic index showed a negative relationship. For the condition factor K, only age presents relationship. Eleven elements were quantified for the mineral profile, with aluminum (Al), iron (Fe), and zinc (Zn) being the most abundant in both liver and muscle. Although the histopathological findings and mineral profile of the liver and muscle in this study indicate an effect on the health of L. macrosternum in different collection areas, confirming the relationship between environmental characteristics and these findings requires future studies. Furthermore, long-term studies would be necessary to allow the monitoring of all stages of development of these populations, from tadpoles to adults, for a better evaluation of these effects in L. macrosternum.

Accessing the Health Risk of Ingestion of Surface Water from Lucrécia and Parelhas Dams in Northeast Brazil Using the Sentinel Organism Drosophila melanogaster

This study investigated the genotoxic risk of chronic exposure of hemolymph's cells of Drosophila melanogaster (Insecta, Diptera) to water samples from Boqueirão de Parelhas Dam and from Lucrécia Dam in the semiarid region of Brazil. The dams are located over the Pegmatite Province of Borborema, with rocks rich in uranium and thorium. Water samples hydrated a culture medium composed of mashed potatoes, where larvae of D. melanogaster fed for 24 h, before be underwent to the Comet assay. The same water was evaluated for the presence of dissolved Radon gas (222Rn) and concentrations of 11 toxic metals (Ag, Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). The results indicated a genotoxic effect resulting from exposure to the waters of the Parelhas dam, in the samples of August 2018; and in Lucrécia dam, in January 2019. D. melanogaster stood out for its high sensitivity to monitor the genotoxic effects of compounds dissolved in public dams. And unlike to other essentially aquatic sentinel organisms, this species stood out as a model to concomitant studies of air and water possible contaminated, in a scenario of natural environmental radioactivity present in semiarid of Brazil.

Cactus cladodes for dairy goats: what is the best fiber source?

This study evaluated the effect of different fiber sources supplied with cactus cladodes in diets on the intake and digestibility of nutrients, ingestive behavior, milk yield, and composition of dairy goats. The fiber sources were corn silage, sorghum silage, Digitaria pentzii Stent. hay, and sugarcane bagasse. Twelve Saanen goats with an average weight of 48.9 ± 7.3 kg and average production of 2.8 ± 0.7 kg of milk/day were assigned in three simultaneous 4 × 4 Latin squares (four animals, four treatments, and four experimental periods). There was no difference between the fiber sources for intake (P > 0.05) of dry matter (2.58 kg/day), organic matter (2.30 kg/day), crude protein (0.385 kg/day), neutral detergent fiber (0.895 kg/day), non-fibrous carbohydrates (0.858 kg/day), and metabolizable energy (5.66 Mcal/day). Also, the fiber sources did not influence dry matter and nutrient digestibility (P > 0.05). The association of cactus cladodes with silages, hay, and sugarcane bagasse did not change milk production, milk production corrected for 3.5% of fat and corrected for energy (2.78; 2.53 and 2,55 kg/day, respectively), in addition to milk composition (P > 0.05). No differences were observed in ingestive behavior (P > 0.05). Any fiber sources evaluated are recommended.

Levels of leucaena hay associated with cactus pear in diets for crossbred steers

Our hypothesis is that the total replacement of ground corn grain (GCG) by cactus pear (CP) in association with 70% of leucaena hay (LH) increases dry matter (DM) intake and digestibility and nitrogen metabolism and maintains the feeding behavior of cattle. The objective was to evaluate the effects of inclusion of these feeds on the nutritional parameters and nitrogen metabolism of cattle. Eight steers, average age of 12 months, weight of 267.5 ± 15 kg, were distributed into two simultaneous 4 × 4 Latin squares according to a 2 × 2 factorial scheme, in which the first factor evaluated was different proportions of inclusion of LH (50 or 70% DM basis), and the second factor was the total replacement of GCG with CP. There was lower DM intake in animals fed with 70% LH. There was an interaction between the factors for DM digestibility, in which the animals fed CP did not differ regardless of the inclusion of LH, but for animals without CP, the greater inclusion of LH decreases DM digestibility. The inclusion of CP decreased free water intake. There was an interaction for total water intake (WI), in which the animals fed without CP presented similarity for this, while in the inclusion of CP, the animals fed 70% of LH presented higher WI. Also, lower values of chewing were observed for animals fed with CP. The replacement of GCG with CP improves the efficiency of nitrogen utilization in the rumen. The inclusion of 70% LH depresses intake.

Thermal stress index for native sheep

The first objective of this study was to develop a thermal stress index for sheep based on environmental and animal data collected in a climate chamber under various environmental conditions. The second objective was to compare published indices of thermal comfort and the proposed index, testing them with the data from this study, with the objective of pointing out the most adequate index to be used by breeders when choosing management procedures. A total of 3024 data were obtained for the physiological variables of the sheep exposed to the eight thermal conditions in the climatic chamber and in ambient condition, kept three days in each thermal condition. A principal component analysis summarized the measurements of physiological variables into only one variable (y1). Using SigmaPlot software, multiple regression of y1 with the environmental variables and their combinations produced a number of indices. The equation chosen was the heat stress index for sheep, TSI = 24.153 - (0.0523*A_T) + (0.746*B_GT) + (4.104*Vp), with R² = 0.668. The correlations presented high values, where these correlation values were assumed to indicate the efficiency of each index as indicators of the animals' response to the environment. Thus, it was assumed that the TSI presents a high efficiency.

Effect of reclaimed water and dehydrated sludge on the morpho-physiology and yield of sorghum

Reclaimed water (RW) and dehydrated sludge (DS) have been used to improve plant nutrition. In this work, the effect on the morpho-physiological parameters and yield of sorghum cultivated with RW and DS was evaluated. The experiment was carried out in a greenhouse; RW and DS were obtained in a sewage treatment plant. The dewatering of the sludge occurred in drying beds. Six treatments (T), with five repetitions each, were carried out in entirely randomized blocks. Water (W) was used in T1 (W) (control), T2 (W+NPK), and T3 (W+DS); RW was used in T4 (RW), T5 (RW+P), and T6 (RW+DS). The results showed that irrigation with only RW (T4), or DS+W (T3) was very suitable for the cultivation since an adequate nutritional supply was provided. The positive effects were verified based on the morpho-physiological parameters (T3 - 148.8 cm of plant height, 1.50 cm of stem diameter, and 103 cm of stem length. T4 - 154 cm of plant height, 1.70 cm of stem diameter, and 107 cm of stem length), and grain production (T3 - the weight of 1000 seeds equal to 6.97 g and productivity of 1453 grains per plant. T4 - weight of 1000 seeds equal to 6.81 g and productivity of 1636 grains per plant). Both treatments showed for most of the parameters, no significant differences compared with those of T2 or T5 with supplementary fertilizers. T4 or T3 also showed a high production of metabolites like free amino acids (T3 - 6.45 mg g^-1; T4 - 8.43 mg g^-1) and proline (T3 - 1.86 mg g^-1; T4 - 1.77 mg g^-1), known to be a good indication of a natural defence that is used by plants against stress conditions, and soluble protein (T3 - 11.20 mg g^-1; T4 - 13.51 mg g^-1). Therefore, since the production of such grains in semiarid regions with RW or DS can be environmentally and economically beneficial, their use is recommended for small and medium farming operations in arid and semiarid regions.

Delineation of groundwater potential zones of the transboundary aquifers within the semiarid Bulal catchment, Southern Ethiopia

In the semiarid Bulal transboundary catchment of southern Ethiopia, groundwater is the only reliable drought-resilient water source. The central and southern parts of the catchment are dominantly overlain by the transboundary aquifers of the Bulal basalts, while the basement rocks outcrop in the eastern part. This study uses an integrated geographic information system (GIS), remote sensing (RS), and analytical hierarchal process (AHP) to identify and delineate the groundwater potential zones of the semiarid Bulal catchment within the Ethiopian territory. Based on their relative importance to groundwater occurrence and movement, ten input parameters were chosen. According to Saaty's AHP approach, the input themes and each of their distinct features were given normalized weights. A composite groundwater potential zone index (GWPZI) map was generated by integrating all the input layers employing the GIS-overlay analysis technique. The map was validated using the yield of wells from the catchment. The GWPZI map depicts four groundwater potential zones: high (representing 27% of the total area), moderate (20%), low (28%), and very low (25%). The geological feature has the greatest influence on the distribution of groundwater potential. Areas with high potential are mainly overlain by the Bulal basaltic flow, while low groundwater potential zones are in the regolith over the basement rocks. Unlike conventional methods, our novel approach is effective in identifying relatively shallow GWPZs throughout the catchment, and it can be applied in similar semiarid regions. The GWPZI map serves as a quick guide for effectively planning, managing, and developing the catchment's groundwater resources.

Functional threshold responses of benthic macroinvertebrates to environmental stressors in reservoirs

Reservoirs are aquatic ecosystems created by humans to supply water needs. They can impair aquatic diversity due to the lack of connectivity, reduced water volume, and pressures exerted by surrounding human activities. These changes are expected to produce abrupt fluctuations in the reservoirs' environment, thus influencing the structure and functioning of aquatic communities. Therefore, this study aimed to understand the impact of a range of environmental stressors in reservoirs on benthic macroinvertebrates by analyzing their functional threshold response. Biological data were collected in six reservoirs from the semi-arid region of Northeast Brazil, as case study. A total of 37.874 benthic macroinvertebrates belonging to 35 taxa were collected. Nevertheless, almost 90% of this abundance belonged to three species alone, considered generalists, with multivoltine reproduction and from the gatherer-collectors feeding group. Increases in environmental stressors such as salinity, nitrate, ammonia, and dissolved solids led to the selection of macroinvertebrates with specific traits (e.g., protected body, gill respiration, and large body size). These functional traits showed differences in their threshold response depending on the stressors and are indicators of the effects of these stressors on the reservoirs. Some of the potential sensitive traits (with a negative threshold response to the stressor) could also associate with other stressors, demonstrating that tolerance of benthic macroinvertebrates is defined by a set of functional characteristics. Overall, the increase in stressor' gradients selected functionally tolerant organisms with high resistance capacity, but these were represented by dominant species. This resulted in low diversity in the reservoirs, which may compromise ecosystem functioning, and raises concerns about adequate management of the systems.

Clinical, histopathological, and molecular findings for Mycobacterium avium subspecies paratuberculosis (MAP) in dairy goats under semiarid conditions

The objective of this study was to report the occurrence of Mycobacterium avium subspecies paratuberculosis (MAP) in dairy goats, via description of their clinical presentation, histopathological findings, and molecular identification of the infectious agent. Screening was performed using IS900 real-time PCR (qPCR) in milk samples from 179 properties in the semiarid of Northeast region of Brazil. Pooled milk samples from all lactating goats from processing plants were submitted to molecular diagnosis. One property had a positive result at qPCR. The production unit which had the positive sample for MAP was located, and an on-site visit to this property was performed to collect individual milk samples, seven of which tested MAP positive by IS900 qPCR. With permission from the owner, two goats (Animal 1 was positive and Animal 2 was negative on first qPCR for MAP) were acquired and euthanized. Animals 1 and 2 had milk and portions of the duodenum, ileum, colon, and mesenteric lymph nodes positive at qPCR for MAP. Animal 1 also had MAP DNA detected in part of the jejunum and cecum. In animal 2, the ileocecal valve tested positive. MAP was not detected in the blood or feces of either animal; however; it was confirmed for the association of clinical findings, histopathology, and qPCR. The gene IS900 from the positive samples were sequenced and showed a 99% similarity with MAP. The MAP was identified for the first time in the goat milk and tissues in the semiarid region of Northeast Brazil.

Towards large scale biocrust restoration: Producing an efficient and low-cost inoculum of N-fixing cyanobacteria

Dryland soil degradation is increasing due to global change and traditional restoration methods are not successful due to water scarcity. Thus, an alternative technology based on inoculating biocrust-forming cyanobacteria on degraded soils has emerged. Biocrusts are communities of mosses, lichens, cyanobacteria or fungi that colonize soil surface forming a stable and fertile layer. Previous studies have shown the benefits of inoculating cyanobacteria to restore soils at a small scale. However, to face field restoration projects, it is necessary to produce high quantities of biomass at an affordable cost. In this work, we analyze if the previously tested cyanobacteria Scytonema hyalinum, Tolypothrix distorta (heterocystous strains) and Trichocoleus desertorum (a bundle-forming one) can be produced with agricultural fertilizers. Different culture media were used: two containing pure chemicals (BG11 and BG11₀, this N-free medium was used just for heterocystous strains) and two containing fertilizers (BG11-F and MM-F). The performance of the cultures was monitored by measuring the biomass concentration and photosynthetic stress. Afterwards, we analyzed their capacity to induce biocrusts and improve soil properties by inoculating the biomass on a mine substrate indoors and measuring, three months later, the albedo, chlorophyll a and organic carbon content. Results show that the bundle-forming cyanobacterium was unable to grow in the media tested, whereas both heterocystous cyanobacteria grew in all of them and induced the formation of biocrusts improving the organic carbon substrate content. The best results for S. hyalinum were found using the MM-F medium, and for T. distorta using a medium containing pure chemicals (BG11). However, results were also positive when using a medium containing fertilizers (BG11-F). Thus, agricultural fertilizers can be used to undertake the production of heterocystous cyanobacteria for large scale restoration in drylands. On the other hand, more research is needed to find sustainable techniques to produce biomass of bundle-forming cyanobacteria.

Response of cbbL-harboring microorganisms to precipitation changes in a naturally-restored grassland

The impact of the long-term uneven precipitation distribution model on the diversity and community composition of soil C-fixing microorganisms in arid and semiarid grasslands remains unclear. In 2015, we randomly set up five experimental plots with precipitation gradients on the natural restoration grassland of the Loess Plateau (natural precipitation, NP; ± 40% natural precipitation: decreased precipitation (DP), DP40; increased precipitation (IP), IP40; ± 80% natural precipitation: DP80; IP80). In the third and fifth years after the experimental layout (spanned two years), we explored the cbbL-genes, which are functional genes in the Calvin cycle, harboring microbial diversity and community composition under different precipitation treatments. The results showed that the increase in mean annual precipitation significantly changed the cbbL-harboring microbial alpha diversity, especially when controlling for 40% natural precipitation. The response of the dominant microbial communities to interannual increased precipitation variation shifted from Gammaproteobacteria (Bradyrhizobium) to Betaproteobacteria (Variovorax). The structural equation model showed that precipitation directly affected the cbbL-harboring microbial diversity and community composition and indirectly by affecting soil NO₃^- (mg N kg ^-1), soil organic matter, dissolved organic N content, and above- and underground biomass. In conclusion, studying how cbbL-harboring microbial diversity and community composition respond to uneven precipitation variability provides new insights into the ecological processes of C-fixing microbes in semi-arid naturally-restored grasslands dominated by the Calvin cycle.

Understanding interactive processes: a review of CO2 flux, evapotranspiration, and energy partitioning under stressful conditions in dry forest and agricultural environments

Arid and semiarid environments are characterized by low water availability (e.g., in soil and atmosphere), high air temperature, and irregularity in the spatio-temporal distribution of rainfall. In addition to the economic and environmental consequences, drought also causes physiological damage to crops and compromises their survival in ecosystems. The removal of vegetation is responsible for altering the energy exchange of heat and water in natural ecosystems and agricultural areas. The fluxes of CO₂ are also changed, and environments with characteristics of sinks, which can be sources of CO₂ after anthropic disturbances. These changes can be measured through methods such as sap flow, eddy covariance, remote sensing, and energy balance. Despite the relevance of each method mentioned above, there are limitations in their applications that must be respected. Thus, this review aims to quantify the processes and changes of energy fluxes, CO₂, and their interactions with the surfaces of terrestrial ecosystems in dry environments. Studies report that the use of methods that integrate data from climate monitoring towers and remote sensing products helps to improve the accuracy of the determination of energy fluxes on a global scale, also helping to reduce the dissimilarity of results obtained individually. Through the collection of works in the literature, it is reported that several areas of the Brazilian Caatinga biome, which is a Seasonally Dry Tropical Forest have been suffering from changes in land use and land cover. Similar fluxes of sensible heat in areas with cacti and Caatinga can be observed in studies. On the other hand, one of the variables influenced mainly by air temperature is net radiation. In dry forest areas, woody species can store large amounts of carbon in their biomass above and belowground. The use of cacti can modify the local carbon budget when using tree crops together. Therefore, the study highlights the complexity and severity of land degradation and changes in CO₂, water, and energy fluxes in dry environments with areas of forest, grassland, and cacti. Vegetation energy balance is also a critical factor, as these simulations are helpful for use in forecasting weather or climate change. We also highlight the need for more studies that address environmental conservation techniques and cactus in the conservation of degraded areas.

Patterns of organic matter accumulation in dryland river corridors of the southwestern United States

We use Google Earth imagery, drone imagery, and ground-based field measurements to assess the abundance, spatial distribution, and size of accumulations of organic matter in perennial, intermittent, and ephemeral channels in drylands of the southwestern United States. We refer to these accumulations as organic matter jams (OMJs). We examine correlations between OMJ characteristics and indicators of spatial heterogeneity within river corridors. We hypothesize that OMJs occur primarily in association with obstacles such as living woody vegetation and that spatially heterogeneous river corridors have greater numbers of OMJs per surface area of river corridor. Using data from 19 river reaches across four areas in Arizona and Utah, we find that OMJs are preferentially associated with bars in the active channel and with living woody vegetation in the channel and floodplain. We also find that whether greater spatial heterogeneity corresponds to greater spatial density of OMJs can be influenced by downstream distance from major sources of large wood and organic matter and whether the river corridor is supply- or transport-limited with respect to organic matter. Consequently, the strongest influence on OMJ location and abundance can vary between individual reaches of a river corridor and between watersheds. The abundance and size of OMJs in river corridors of sparsely vegetated drylands fall within the ranges of values published for perennial river corridors in wetter climates. We suggest that management of dryland river corridors explicitly include protecting and restoring organic matter accumulations in these environments.

PARASITES OF THE BRAZILIAN ROCK CAVY, KERODON RUPESTRIS: REVEALING THEIR HISTORY IN THE BRAZILIAN SEMIARID REGION

Using microscopy and/or immunodiagnosis, the authors analyzed 284 fecal samples from the Brazilian rock cavy, Kerodon rupestris, that were collected between 1984 and 2015 in Serra da Capivara National Park for the presence of helminths and protozoa. Fourteen morphospecies of helminth eggs of the following taxa were found: Trematoda, Nematoda, Strongylidae, Lagochilascaris sp., Strongylida, Trichuris (2 species), Oxyuridae (3 species), Ancylostomatidae (2 species), and Ascarididae (2 species), along with 3 protozoan taxa: Coccidia, Cryptosporidium sp., and Balantidium sp. During the last 30 yr, the population of K. rupestris has increased in the region as a consequence of the creation and management of the National Park, and data from this study show a concurrent increase in the diversity of intestinal parasites in this host, including new reports. Some of these species have zoonotic potential, which suggests that K. rupestris may be in contact with domestic farm animals and/or human feces. These results show the importance of integrating different diagnostic approaches for the identification of protozoa in the region and indicate that further methods need to be employed to increase recovery. This work highlights the usefulness of parasite studies in assessing the health of ecosystems, especially in protected areas, which should be considered by park managers and health agencies.

The influence of trophic status and seasonal environmental variability on morpho-functional traits in tropical man-made shallow lakes

In the tropics, seasons are delimitated by the extent of rainfall resulting in seasonal differences in water parameters shaping phytoplankton community dynamics. Dry periods can intensify eutrophication and often result in seasonal or even perennial cyanobacterial dominance. This study was developed to evaluate phytoplankton response to trophic state and seasonal differences of environmental filters (dry and rainy periods) using the morphology-based functional groups (MBFG) approach. We also aimed at identifying environmental thresholds of each MBFG dominance in six man-made lakes located in the tropical semiarid region of Brazil. Our results showed clear MBFG association with lakes' trophic states. The dominant groups in mesotrophic conditions were members of MBFGs V (unicellular flagellates) and VI (non-flagellated with a siliceous exoskeleton), and in meso-eutrophic MBFG IV (medium size without specialized traits) dominated. Conversely, MBFG VII (with mucilage and aerotopes) and VIII (nitrogen-fixing cyanobacteria) dominated mostly under eutrophic conditions, though linked to shallower euphotic zones. Light and phosphorous were the most important environmental thresholds associated with MBFG's dominance. Overall, most of the lakes displayed seasonal differences in environmental filters. In contrast to what was expected, the rainy season was associated with higher nutrients, suspended solids, and reduced euphotic depth compared to the dry season. Our results, overall, show that the effects of seasonality varied across lakes and highlight eutrophication as the main environmental factor for MBFG selection suggesting reduced seasonality effects during dry years in the tropics.

Socioeconomic factors influencing knowledge and consumption of food plants by a human group in a mountainous environment in the semiarid region of Bahia, Northeast Brazil

BACKGROUND

The relationship of people with natural resources is guided by different sociocultural, ecological and evolutionary factors. Regarding food plants, it is not different. Studies around the world have evaluated the effects of socioeconomic factors, such as age, gender, income, profession, education level, time of residence, ethnic diversity, religion, festive rituals, access to urban areas and migrations. In this sense, the objective of the present study was to characterize the diversity of knowledge and use of food plants by people from Serra dos Morgados and evaluate if the socioeconomic factors influence knowledge and consumption of food plants in the community.

METHODOLOGY

This research was conducted in the village of Serra dos Morgados, municipality of Jaguarari, Bahia, with the purpose of evaluating the factors that influence in the knowledge and use of food plants. Socioeconomic data such as age, gender, time of residence, and monthly income were collected. The free list technique was applied during the collection of ethnobotanical data in order to analyze the preference of the plants based on the salience index (SI). To analyze the factors that influence knowledge and use forms, we used GLM Lasso.

RESULTS

A total of 33 people were interviewed, 8 men and 25 women; their age ranged from 30 to 82 years. People cited 98 species of plants, 41 species being identified of spontaneous occurrence. The plant with the highest salience index (SI) was "cheirosa" (Psidium ganevii) (SI = 0.5679), followed by "massaranduba" (Micropholis sp.) (SI = 0.4323); "araça" (Campomanesia guazumifolia) (SI = 0.3320); and "cambuí" (Siphoneugena sp.) (SI = 0.3144).

CONCLUSIONS

The main factors that influence knowledge and use forms in the locality were family income and the collection site, with homegardens cited as the preferred area for collection of food plants. This study provided an overview related to potentially important species for a community located in a region where there are few ethnobiological studies. The results presented here can be used in future studies, providing clues for investigations. Also, there is a contribution to the conservation of biocultural aspects related to the use of food plants in a community living in mountainous regions.

Evaluation of air temperature estimated by ERA5-Land reanalysis using surface data in Pernambuco, Brazil

This study aimed to analyze the average air temperature data estimated by ERA5-Land reanalysis over 10 years (01/01/2011 to 12/31/2020), based on data from 12 automatic weather stations located in different cities in the state of Pernambuco, northeast of Brazil. For more careful evaluation, the average air temperature data were stratified by mesoregions of the state. ERA5-Land reanalysis data were validated using statistical indices that evaluated the accuracy. The average air temperature estimated by ERA5-Land reanalysis agree well with weather stations in almost the entire state of Pernambuco. The highest accuracy of the average air temperature estimated by ERA5-Land occurred in the city of Ibimirim (R² = 0.98), while the lowest accuracy was measured in the city of Caruaru (R² = 0.57). Root-mean-square error (RMSE) generated by the ERA5-Land reanalysis was lower than 0.60 °C in most Pernambuco. The highest RMSE of ERA5-Land for average air temperature was calculated using data from the city of Caruaru (1.11 °C), whereas the lowest RMSE was obtained with data from the city of Recife (0.41 °C). According to mean bias errors, (MBE) the ERA5-Land underestimated the average air temperature data compared to automatic weather stations data, especially in Ouricuri, which had the highest underestimation (-0.80 °C). On the other hand, among the municipalities where ERA5-Land overestimated the temperature values, the highest overestimation was identified in Garanhuns (0.35 °C). Therefore, based on the results of this study, ERA5-Land reanalysis successfully estimated the average air temperature for the state of Pernambuco.

Microclimate and animal thermal comfort indexes in different silvopastoral system arrangements in Caatinga

The objective was to evaluate the microclimate and animal thermal comfort indexes in silvopastoral system in the Brazilian semiarid region with different woody cover levels within Caatinga trees. The experiment was carried out at the Teaching, Research and Extension Unit of the Federal Institute of Science and Technology of Ceará, Campus Limoeiro do Norte, in Chapada do Apodi, CE, in 2018. The treatments were forage grown under woody cover of 46.15% (SS46), forage grown under woody cover of 30.00% (SS30), and forage grown under woody cover of 17.64% (SS18). The evaluations were carried out during three consecutive days, in the vegetative, transition, and dormancy periods at 6 a.m.; 10 a.m.; 2 p.m. and 6 p.m.. First, the microclimate variables, relative air humidity (%), wind speed (m s^-1), dry bulb temperature (°C), wet bulb temperature (°C), black globe temperature (°C), and dew point temperature (°C), were obtained for subsequent calculation of black globe temperature and humidity index and radiant thermal load (W m^-2). SS46, SS30, and SS18 systems had no differences of black globe temperature and humidity index and radiant thermal load in the sun. There were significant reductions in black globe temperature and humidity index and radiant thermal load within the trees promoting improvement in the thermal environment at times of higher radiation load. The trees promoted better conditions of animal thermal comfort in all silvopastoral arrangements and periods of the year.

Mesquite pod (Prosopis juliflora) meal on meat quality of pasture-finishing lambs

This study was carried out to validate the inclusion of up to 750 g/kg of mesquite pod (Prosopis juliflora) meal in the diet and evaluate the effects on carcass characteristics and meat quality for lambs finished in pasture. Forty male, non-castrated, crossbred Santa Inês lambs, with an initial body weight (24.2 ± 3.1 kg), and approximately 120 days old were used. The animals were kept in a total area of 4 ha, divided in four paddocks of 0.62 ha each (10 animals/paddocks), on pastures of Massai (Panicum maximum cv. Massai) with drinkers and feeders during the finishing phase. Dietary treatments based on mesquite pod meal inclusion levels (g/kg of dry matter): CON, without mesquite pod meal; MPM25, 250 g/kg of mesquite pod meal; MPM50, 500 g/kg of mesquite pod meal; and MPM75, 750 g/kg of mesquite pod meal. No treatment effect were detected (P > 0.05) for carcass measures, carcass characteristics, chemical composition of longissimus thoracis muscle, tissue composition, and lipid oxidation. Lamb meat color values, such as lightness (L*) and yellowness (b*), were not affected (P > 0.05) by mesquite pod meal inclusion on the diets, whereas for redness (a*), HUE-angle, and chroma were influenced (P < 0.05). Palmitic acid had a quadratic effect, while oleic acid, eicosatrienoic acid, saturated fatty acids, monounsaturated fatty acids, and PUFA:SFA had a linear course (P < 0.05). In conclusion, the mesquite pod meal can be used as an energy feed source up to 750 g/kg of dry matter in the diet, without changing the carcass characteristics and meat quality of lambs finished in pasture.

Performance of richness estimators for invertebrate inventories in reservoirs

Biological inventories combined with the estimation of species richness represent a useful tool for the analysis of the pattern of species distribution in different regions. This study aimed to (i) comparatively evaluate the performance of non-parametric richness estimators for invertebrate inventories in reservoirs between ecoregions and (ii) to assess whether the efficiency (bias, precision and accuracy indices) of the estimators is altered when applied to sites from different ecoregions. The study was conducted in the ecoregions Central Pediplano of the Borborema Plateau (Paraíba River basin) and Northern Sertaneja Depression (Piranhas-Assu River basin), semiarid region of Brazil. Six reservoirs were selected and benthic macroinvertebrates were sampled at 141 sites distributed along the littoral zone, in 4 periods (June, September, December 2014 and March 2015). The organisms were identified to the family level, except for Chironomidae, identified to the genus level. We comparatively analyzed six non-parametric richness estimators: Jackknife 1, Jackknife 2, Chao1, Chao 2, ICE, and Bootstrap, and three performance indicators: bias, precision, and accuracy. ICE and Jackknife 2 had more stable results for total species richness, but with different performance between ecoregions for bias, precision, and accuracy. Variation in performance of the estimators may be associated with differences in species richness and frequency between ecoregions. ICE and Jackknife 2 proved to be the best estimators for biological inventories of aquatic invertebrates in reservoirs in studies comparing data from different ecoregions, due to accuracy and precision, while Bootstrap is the least indicated, given greater bias and less accuracy and precision.

Do essential oils from plants occurring in the Brazilian Caatinga biome present antifungal potential against dermatophytoses? A systematic review

The Caatinga is an exclusively Brazilian biome where semiarid climatic conditions promote singularities in adaptive biodiversity. Many aromatic species are found in this region possessing antifungal properties, which are attributed to their essential oils. Thus, we questioned whether essential plant oils found in the Caatinga present anti-dermatophytic potential. Dermatophytes are keratinophilic fungi that cause one of the most prevalent mycoses globally, skin infections known as dermatophytoses (tineas). Here, we provide a comprehensive report of the available published information, analyzing the methods used to evaluate the antifungal activity, verifying the quality of the evidence and possible clinical applications, and discussing research trends in this area. The plants studied concentrated in the genera Croton (Euphorbiaceae), Lippia (Verbenaceae), Piper (Piperaceae), and Mentha (Lamiaceae). All of the studies used in vitro tests to analyze antifungal potential, and little evidence was ascertained concerning the mechanism of antifungal action. In addition, the essential oils also evidenced drug modifying activity of conventional antifungal drugs (Ketoconazole and Terbinafine). We believe that the anti-dermatophyte potential of plant essential oils occurring within the Caatinga is underestimated and that this review will encourage future chemical-pharmacological investigations into the plants within this biome.Key points• The essential oils from plants occurring in the Caatinga Biome present unknown anti-dermatophyte potential.• The studies against dermatophyte fungi concentrate on the families Lamiaceae and Verbenaceae.• In vitro assays were used to assess the anti-dermatophyte potential of the essential oils.

Corn substitution by mesquite bean flour (Prosopis juliflora) maintains growth and improves protein metabolism of Nile tilapia juveniles (Oreochromis niloticus)

The objective of this study was to evaluate the potential of mesquite bean flour (Prosopis juliflora) as an energy ingredient in extruded diets for juvenile Nile tilapia (Oreochromis niloticus). Two experiments were carried out: the first consisted of a study to evaluate the chemical composition and digestibility of the energy and nutrients of MBF; the second consisted of a growth test, in which juveniles consumed diets containing different proportions of corn substitution by MBF, in which zootechnical, hematological, physiological, and metabolic variables were evaluated. It was observed that MBF has a chemical composition similar to corn, as well as the apparent digestibility of energy and nutrients. The higher sucrose/starch ratio of the ingredient stands out, as well as the difference in digestibility (p < 0.05) between the predominant carbohydrates 87.63 and 99.25% for starch and sucrose, respectively. In the growth assay, no difference was observed between zootechnical variables (p > 0.05), and sucrase and alkaline phosphatase activities were increased (p < 0.05), which was not observed for amylase and lipase (p > 0.05). The hematological variables did not change (p > 0.05). Metabolic variables indicate a reduction in gluconeogenesis from amino acids, as can be seen by the reduction in liver transaminase levels (ALT and AST) and glutamate dehydrogenase (GDH), as well as the greater availability of free amino acids in plasmas (p < 0.05). Thus, it can be said that MBF has a high nutritional value and can totally replace corn in diets for juvenile tilapia and the metabolic findings indicate a potential protein-sparing effect.

Arbuscular Mycorrhizal Fungal Community Structure in the Rhizosphere of Three Plant Species of Crystalline and Sedimentary Areas in the Brazilian Dry Forest

The Brazilian dry forest (Caatinga) is located in one of the world's largest tropical semiarid regions, and it occurs on two large geological environments named the crystalline and sedimentary basins. In order to determine the structure and the main drivers of the composition of communities of arbuscular mycorrhizal fungi (AMF) in the Caatinga, we collected soil samples from the rhizosphere of Jatropha mollissima, J. mutabilis, and Mimosa tenuiflora, species that occur in crystalline and sedimentary areas. Ninety-six AMF taxa were identified from soils collected directly in the field and trap cultures. Acaulospora, Glomus, and Rhizoglomus represented almost 49% of the taxon richness. The composition of the AMF communities differed between the crystalline and sedimentary areas and between the rhizospheres of the three plant species. Coarse sand, total sand, natural clay, calcium, soil particles density, flocculation, pH, and base saturation were the principal edaphic variables related to the distribution of these organisms. We registered nine and 17 AMF species classified as indicators, for the geological environments and plant species, respectively. Glomerospores of Glomerales predominated in crystalline basins, whereas glomerospores of Gigasporales prevailed in sedimentary areas; among the plant species, lower number of glomerospores of Archaeosporales and Glomerales was recorded in the rhizosphere of J. mollissima. The results show that the AMF community composition is shaped by geological environments and plant hosts. In addition, soil characteristics, mainly physical attributes, significantly influence the structure of Glomeromycota communities occurring in areas of the Brazilian semiarid.

Intake, digestibility, nitrogen balance and performance of crossbreed Boer goats fed with diets containing saltbush (Atriplex nummularia L.) and spineless cactus (Opuntia ficus-indica)

Saltbush and spineless cactus are adapted to arid and semiarid regions and used as an important forage resource in ruminants' diet. However, spineless cactus restricts production due to its low crude protein and NDF levels and high salt and oxalate contents, which can limit the digestibility and intake of dietary nutrients. Therefore, this experiment was conducted to evaluate the best ratio levels of saltbush associated with spineless cactus in diets for crossbreed Boer goats through ingestion, water balance, digestibility, nitrogen balance, growth and carcass weight. Twenty-four castrated crossbred Boer (Boer × Brazilian native) goats 6 months of age and average body weight of 20.28 kg were utilized. The animals were weighed and distributed in randomized blocks in four experimental diets with saltbush of 8.4, 18.8, 31.2 and 48.3%. The addition of saltbush hay promoted quadratic behaviour (P < 0.05) in intake of dry matter and nutrients. There was no effect (P < 0.05) from the addition of saltbush hay on the digestibility of organic matter, total carbohydrates, non-fibrous carbohydrates and neutral detergent fibre, whereas there was an increase in dry matter. The crude protein digestibility behaved quadratically (P = 0.06), where the maximum digestibility was obtained with the addition of 31.2% of hay. The balance and net nitrogen utilization presented a quadratic effect (P < 0.01). Saltbush in rations for goats presented promising results, the growth rate (0.15 kg/day) obtained in diet with a lower proportion of saltbush, would satisfy smallholders when considering that this species, associated with spineless cactus, may reduce the use of concentrate feeds; however, the diet with 31.2% of saltbush hay provided the biggest gain in body and carcass weight of the goats.

Dietary nutrient restrictions in the post-weaning period change Santa Inês ewe lamb nutritional metabolic profile

The objective of this study was to evaluate the metabolic profile of Santa Inês ewe lambs fed diets for early or late-maturing diets with or without nutrient restrictions. The experiment consisted of a 2 × 2 completely randomized factorial experiment with either early- or late-maturity feed formulation according to "Nutrient Requirements of Small Ruminants" with or without 15% crude protein (CP) and total digestible nutrients (TDN) restrictions in diets formulated, five replications, and 20 ewe lambs averaging 15.1±2.6 kg. Lambs on early-maturity diets consumed greater (P<0.05) dietary ether extract (EE), non-fibrous carbohydrates, and TDN than those on late-maturity diets. Lambs on early-maturity diets had 7.11% greater dry matter digestibility (DMD) compared to lambs fed late-maturity diets. Lambs fed late-maturity diets, in general, had greater intake (IN), excreted (EN), and retained (RN) N as well as greater RN/IN and EN/IN ratios. There were no differences in blood total protein or albumin among lambs fed for different finishing maturity targets. Diets designed for late-maturing lambs resulted in greater microbial N and CP as well as rumen and metabolizable, degradable, and undegradable rumen and metabolizable CP. The selection of diets for early or late maturity carcasses depends on the production system goals. Diets without restrictions are recommended for early-maturity carcass finishing while diets with 15% CP and TDN restriction are recommend for late-maturity finishing.

Effect of different blend levels of spineless cactus and Mombasa hay as roughage on intake, digestibility, ingestive behavior, and performance of lambs

This study aimed to determine the best level of the blend of spineless cactus (Nopalea cochenillifera) and Mombasa (Panicum maximum) hay as roughage in the diet of lambs based on intake, digestibility, ingestive behavior, and lamb performance. Forty-eight uncastrated crossbred Santa Ines breed lambs with an average age of 4 months old and an average initial BW of 20.5 kg ± 2.8 kg were distributed in two experiments using a completely randomized design: experiment 1: 16 lambs (four treatments and four replicates) for in vivo digestibility trial in metabolic cage; experiment 2: 32 lambs (four treatments and eight replicates) in feedlot to determine intake, ingestive behavior, and performance. As the amount of cactus in the roughage increased, there was a linear reduction (P <0.001) on intake (g/day) of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), non-fibrous carbohydrates (NFC) digestibility, time spent ruminating, feeding efficiency of NDF (P = 0.0153), NDF rumination efficiency rate (P = 0.032), final BW, TWG, and ADG of lamb. However, there was a linear increase (P <0.001) on the intake of the NFC and TDN, digestibility coefficient of DM, CP, total carbohydrates (TC) and NDF gross energy, metabolizable energy, and time spent idling when spineless cactus increased in the roughage blend. The least amount of cactus in the roughage (112-637 g/kg DM) promoted higher intake of DM and CP, improving lamb performance. However, the blend up to 450-300 g/kg DM improved digestibility and energy production as well as it did not affect the feed efficiency.

Effect of replacing forage sorghum silage with biomass sorghum silage in diets for F1 Holstein × Zebu lactating cows

The objective of this study was to evaluate the replacement of forage sorghum silage (FS silage) with BRS 716 biomass sorghum silage (BRS 716 silage) in diet of F1 ½ Holstein × ½ Zebu cows on their nutrient intake and digestibility, ingestive behavior, nitrogen balance, and milk yield and composition. The experimental design was in two 5 × 5 Latin squares, simultaneous, composed, each, by five animals, five treatments, and five experimental periods. The study included 10 cows with an initial body weight (BW) of 544 ± 12.84 and 88 ± 14 days of lactation at the beginning of the experiment. The treatments were defined by replacement FS silage at levels 0, 25, 50, 75, and 100% with BRS 716 silage. The roughage:concentrate ratio in the total dry matter (DM) of the diets was 75:25. The replacement of FS silage with BRS 716 silage reduced (p < 0.01) the dry matter intake and digestibility of dry matter, but it had not changed average milk yield (12.68 kg/day; p = 0.94), feed efficiency, body weight, the score of body condition, and the average daily gain of the cows. The milk composition was not changed except casein/total protein in milk that decreased and that increased linearly milk urea nitrogen. The inclusion of BRS 716 silage increased the activities of rumination and chewing and decreased the periods of feeding and idleness. The replacement of up to 100% of FS silage with BRS 716 silage in the diet of F1 Holstein × Zebu cows does not alter average milk yield, despite changing diet intake and digestibility.

Digestibility of spineless cactus meals in extruded diets for Nile tilapia (Oreochromis niloticus): energy, protein, amino acids, and carbohydrates

The aim of the present study was to determine the apparent digestibility coefficients (ADCs) of gross energy, dry matter, crude protein, amino acids, and different carbohydrate fractions of spineless cactus meals (SCMs) for Nile tilapia juveniles, fed with extruded diets. Fish were fed a reference diet or one of five test diets, each of which included 70% reference diet and 30% corresponding SCM. Fecal collection was performed in modified Guelph method. The ADCs for dry matter, gross energy, and soluble carbohydrates of the "redonda" spineless cactus meal (RSCM) were higher (P < 0.05) than those of either the "IPA 20" spineless cactus meal (ISCM) or "gigante" spineless cactus meal (GSCM), and the ADCs for crude protein of the RSCM and "Orelha de elefante africana" spineless cactus meal (OEASCM) were higher than those of the other cactus meals (P < 0.05). In addition, the ADCs for dry matter, crude protein, and gross energy of the SCMs were similar to wheat middlings. The digestibility of the less soluble fraction of the evaluated carbohydrates, the non-fibrous carbohydrates, varied between 58.32 and 73.04%, indicating efficiency in the digestion and absorption process. The data obtained in this article can be the basis for growth experiments, with the substitution of traditional ingredients for SCMs. The determination of zootechnical, physiological, metabolic, and health variables can indicate the potential for using SCMs in diets for Nile tilapia.

Bacteria from tropical semiarid temporary ponds promote maize growth under hydric stress

World climate change has triggered soil water stress and imposed limitations on agricultural production. Plant growth-promoting bacteria (PGPBs) have been an efficient strategy to improve the biological supply and growth of plants under distinct abiotic stress conditions. We hypothesized that the soils from a temporary pond may harbor PGPBs with potential strains which increase maize tolerance to water deficit. We studied rhizosphere and bulk soil of Mimosa bimucronata in a temporary pond from semiarid Northeast Brazil to access strains with characteristics to promote plant growth and mitigate abiotic stress for maize crop. We isolated 355 bacterial isolates, from which 96 were selected based on the morphophysiological characterization to assess IAA production (42 % produced over 50 μg mL^-1 of IAA), calcium phosphate solubilization (with one isolate achieving medium IS), biofilm and exopolysaccharides production (66 % and 98 % of isolates, respectively). Based on these mechanisms, the 30 most promising bacterial isolates were selected to assess biological nitrogen fixation (74 % of the isolates showed nitrogenase activity greater than 20 C₂H₄.h^-1.mg^-1), ACC deaminase activity (80 % of isolates) and growth in medium with reduced water activity (8 % of isolates grew in medium with water activity (A_w) of 0.844). We sequenced the 16S rRNA gene from the seven most promising isolates in in vitro and in vivo assays, which were identified as Staphylococcus edaphicus, Bacillus wiedmannii, Micrococcus yunnanensis, Streptomyces alboflavus, Streptomyces alboflavus, Bacillus wiedmanni and Bacillus cereus. In vivo, eleven isolates and three bacterial consortia did not differ from the control with nutrient solution, for total leaf area and root dry mass of maize. S. alboflavus (BS43) had the best in vivo results, not differing from the control with nutrient solution. We highlight the unpublished potential of Staphylococcus edaphicus and Streptomyces alboflavus in promoting the growth of plants under water stress. In addition, it is the first report of bacteria isolated from a temporary pond in the Brazilian semiarid which promoting plant growth attributes and development.

Drought impacts, social organization, and public policies in northeastern Brazil: a case study of the upper Paraíba River basin

The upper Paraíba River basin plays a key role in controlling the flow from the Epitácio Pessoa Reservoir, a major reservoir in the semiarid region of Paraíba state. The objective of this study is to analyze historical droughts and public policies and their impacts on the social organization in the upper Paraíba River basin, which is located in the semiarid region of Brazil. In this study, the following methodological procedures were used: (a) historical survey of drought occurrence and dam construction in the semiarid region of Brazil, (b) data processing of hydrologic records (rainfall and streamflow), and (c) field visits to collect and compare data on the changes in the volume of water stored behind dams. The results showed that state intervention in the semiarid region follows a trend based on the characteristics of each historical moment and the interests of the groups that comprise the state sector. It is also observed that the implementation of several public policies, such as social programs, construction of dams, and the transfer of water from the São Francisco River, has resulted in significant changes in the streamflow behavior in this semiarid region. These changes have differed in magnitude depending on the hydrological characteristics of each period (i.e., dry, rainy, or normal). Finally, the use of dams for water management in the semiarid region was identified as the main factor influencing water security and social organization.

Spatial variation and availability of nutrients at an oyster reef in relation to submarine groundwater discharge

Submarine groundwater discharge (SGD) is often an overlooked component of the solute budgets in coastal embayments and is not considered in oyster restoration, conservation, and management plans. A combination of spatial and temporal geochemistry (nutrients, trace metals, alkalinity components, stable isotopes, and major ions) of porewater and surface water combined with SGD-derived solute fluxes and turnover times was used to examine the significance of SGD in delivering nutrients to paleovalley systems in coastal embayments, thus sustaining the health and productivity of oyster reefs. A 1-km² area encompassing a paleovalley system, in Copano Bay, Texas, exhibited significant differences in the spatial and temporal hydrogeochemical characteristics (major ions, stable isotopes and nutrients) along the reef when compared to the other environments (i.e., paleovalley, estuary-wide). Solute fluxes (i.e., dissolved organic carbon (DOC), dissolved inorganic nitrogen (DIN), total alkalinity, DIC, etc.) are slightly larger at the reef, followed by the margin and shoreline. During dry conditions, SGD from the 1-km² area was estimated to supply anywhere between two-fold to one order of magnitude more nitrogen (in the form of DIN) than the riverine inputs to Copano Bay. During a wet year SGD equates the river input in the form of DIN. In addition, SGD-based turnover times, averaging <11 days for all nutrients, are significantly shorter than the average estuary flushing time (i.e., 38 days). Results from this study suggest that SGD within a paleovalley system is an important component in the estuarine nutrient budget through significant inputs and cycling processes between the subsurface and water column, particularly during low surface flows. Thus, estuarine environments such as paleovalley margins and interfluves provide favorable conditions to oysters through preferably enhanced SGD solute fluxes and should be considered in oyster restoration efforts.

Nitrogen and phosphorus retention budgets of a semiarid plain basin under different human activity intensity

Excessive nitrogen (N) and phosphorus (P) runoff from human activities results in degraded water quality. It is, therefore, crucial to quantitatively assess nutrient inputs over time and their impact on riverine nutrient exports. In this study, we estimated the long-term (1995-2015) nutrient inputs at the county scale by integrating Net Anthropogenic Nitrogen Input (NANI) and Net Anthropogenic Phosphorus Input (NAPI) methods, and nutrient exports into rivers by the Export Coefficient Model (ECM) for a semiarid plain basin, the Baiyangdian (BYD) Basin, China. The results showed that N and P input intensities in the year 2015 reached 18852 kg N km² yr^-1 and 2073 kg P km^-2 yr^-1, showing a 35% and 11% increase in comparison with 1995, respectively. About 60% of these nutrients were derived from fertilizer application. The multi-year averaged N and P exported to rivers was 548 kg N km^-2 yr^-1 and 79 kg P km^-2 yr^-1, respectively. Hotspots for nutrient budgets were found in the southeastern counties. Hotspots covered about 12% of the total land, but contributed by 38-52% of total nutrient budgets. The nutrient export ratios showed no significantly temporal variations, and only about 2.15-2.89% of NANI and NAPI were exported into rivers. The low nutrient export ratio was due to the low water discharge that limited the nutrient transportation in the semi-arid plain basin. As most of anthropogenic nutrient inputs were retained in the basin, their impacts on the pollution of soils and aquifers need to be considered and adequately addressed in the future. This study constructs the spatial quantitative nutrient budgets, which can provide effective information for region policy formulation.

Diets containing cunhã (Clitoria ternatea L.) hay and forage cactus (Opuntia sp.) meal on production and meat quality of Boer crossbred goat

The aim of this study was to evaluate the effect of association of forage cactus meal (CM) and cunhã hay (CH) on carcass traits, meat quality, and fatty acid (FA) profile of goats. Twenty-four goats were finished on diets composed with the association of CM and CH (83% CH + 17% CM, 67% CH + 33% CM, or 50% CH + 50% CM), corresponding to 60% of the total diet; the remainder was composed of 10% elephant grass and 30% concentrate. The control treatment consisted of 70% elephant grass and 30% concentrate. Carcass yield and commercial cut weight were higher in the animals fed CH and CM at any concentration (P < 0.05). Animals fed with intermediate and high CM content resulted in meat with better proportions of unsaturated FA (P = 0.0281), desirable FA (P = 0.0024), omega 6/omega 3 ratio (P = 0.0340), and hypo-/hypercholesterolemic index (P = 0.0140). The inclusion of CH and CM provided carcass yield and FA profile more favorable for consumer market and human health.

How does Spix's yellow-toothed cavy (Galea spixii Wagler, 1831) face the thermal challenges of the Brazilian tropical dry forest?

The aim of this work was to investigate the thermal biology of the Spix's yellow-toothed cavy (Galea spixii) from the hot and dry environment of the Brazilian Caatinga by infrared thermography and biophysical equations. We monitored the rectal temperature, as well as the non-evaporative (radiative and convective pathways) and evaporative heat exchanges of males and females. The mean rectal temperature of females and males was 37.58 ± 0.02 and 37.47 ± 0.02 °C, respectively. We identified thermal windows by infrared thermography. The surface temperatures and the long-wave radiation heat exchanges were higher in the periocular, preocular, pinnae and vibrissae regions, in that order. The surface temperature of the periocular and preocular regions correlated positively with rectal temperature. Convective heat exchange was insignificant for thermoregulation by G. spixii. Evaporative heat loss increased when the thermal environment inhibited the radiative pathway. Females showed higher evaporative thermolysis than males at times of greater thermal challenge, suggesting a lower tolerance to heat stress. Therefore, infrared thermography identified the thermal windows, which represented the first line of defense against overheating in G. spixii. The periocular and preocular surface temperatures could be used as predictors of the thermal state of G. spixii.

From waste to resource: Cost-benefit analysis of reservoir sediment reuse for soil fertilization in a semiarid catchment

Reservoir networks have been established worldwide to ensure water supply, but water availability is endangered quantitatively and qualitatively by sedimentation. Reuse of sediment silted in reservoirs as fertilizer has been proposed, thus transforming nutrient-enriched sediments from waste into resource. The aim of this study is to assess the potential of reusing sediment as a nutrient source for agriculture a semiarid basin in Brazil, where 1029 reservoirs were identified. Sedimentation was modelled for the entire reservoir network, accounting for 7 × 10⁵ tons y^-1 of sediment deposition. Nutrients contents in reservoir sediments was analysed and compared to nutrients contents of agricultural soils in the catchment. The potential of reusing sediment as fertilizer was assessed for maize crops (Zea mays L.) and the sediment mass required to fertilize the soil was computed considering that the crop nitrogen requirement would be fully provided by the sediment. Economic feasibility was analysed by comparing the costs of the proposed practice to those obtained if the area was fertilized by traditional means. Results showed that, where reservoirs fall dry frequently and sediments can be removed by excavation, soil fertilization with sediment presents lower costs than those observed for application of commercial chemical fertilizers. Compared to conventional fertilization, when using sediments with high nutrient content, 25% of costs could be saved, while when using sediments with low nutrient content costs are 9% higher. According to the local conditions, sediments with nitrogen content above 1.5 g kg^-1 are cost efficient as nitrogen source. However, physical and chemical analyses are recommended to define the sediment mass to be used and to identify any constraint to the application of the practice, like the high sodium adsorption ratio observed in one of the studied reservoirs, which can contribute to soil salinization.

Nutritional and performance viability of cactus Opuntia-based diets added to concentrate levels for Girolando lactating dairy cows

Objective

The aim of this research was to evaluate the effect of different concentrate levels in diets based on cactus Opuntia Stricta (Haw.) Haw cladodes on the performance of lactating Girolando cows.

Methods

The experiment involved 10 Girolando multiparous dairy cows at 512.6 kg of body weight (BW) and producing 13.2 kg milk/d, allocated into two 5×5 Latin squares. The experimental treatments consisted of control diet composed by cactus Nopalea cochenillifera. Salm-Dyck. cladodes (Nopalea), forage sorghum silage and concentrate at 20% on dry matter (DM) basis, and four concentrate levels diets (20%, 24%, 28%, and 32%) plus cactus Opuntia stricta (Haw.) Haw. cladodes (Opuntia) and forage sorghum silage.

Results

Regarding cows fed control diet, the nutrients intake were greater than for cows fed with cactus Opuntia and concentrate. Regarding concentrate levels, intakes of DM, organic matter (OM), crude protein (CP), non-fiber carbohydrates (NFC), and total digestible nutrients of cows increased linearly. Organic matter, CP, and NDF digestibilities were similar in between to control diet and cactus Opuntia-based diets. The digestibility of NFC increased linearly when the concentrate was inserted. The N balance was the same for control diet and cactus Opuntia-based diets, irrespective the concentrate levels.

Conclusion

For cows producing 14 kg/d with 3.5% of fat, it is recommended 32% of concentrate to be included in cactus Opuntia-based diets, and the increase in concentrate level promotes a linear increase in milk yield.

The impacts of porous rock check dams on a semiarid alluvial fan

Low-tech rock check dams are widely used to address land degradation; however, assessments of their impacts on runoff and sediment are lacking and are often limited to the first few years after construction. In 2008, two small (4.0 and 3.1 ha) instrumented watersheds located 300 m apart on an alluvial fan on the Santa Rita Experimental Range in southern Arizona were treated with 37 porous, loose rock check dams. Ten years after construction, the watersheds are experiencing contrasting responses to treatment. The ratio of runoff to precipitation was higher after check dam construction on one watershed and lower on the other, but not significantly in either case. Statistically significant changes in peak runoff rate are not detectable 10 years after construction at either watershed. However, a statistically significant reduction in sediment concentration was found on one watershed and no change was found at the other. The check dams have altered channel grades. However, backfilling of the dams is nearly complete on one watershed and the other has remaining capacity. The alluvial fan setting poses a complex restoration environment due to high sediment loads that deposit in response to vegetated areas of accumulated sediment creating conditions for channel avulsion and new incising concentrated flow paths. Check dams have a lesser impact on watershed outlet runoff and sediment than on internal watershed channel morphology and vegetation establishment. With monitoring and maintenance, check dams can be an effective tool for grade stabilization, but watershed restoration requires additional practices to address degraded interfluve areas.

When drought meets forest management: Effects on the soil microbial community of a Holm oak forest ecosystem

The growth and survival of plants in semiarid Mediterranean forests can be improved through the benefits conferred by thinning, a forest management practice that removes trees and reduces the competition between the remaining ones. Here, we evaluate the impacts of induced drought (the exclusion of 25% of the natural rainfall for 5 years) and thinning, and their interaction, with the objective of determining whether the thinning of Holm oak (Quercus ilex L.) modulates the resistance of the soil microbial community to drought. Sequencing of 16S rRNA and ITS amplicons revealed that drought, thinning, and their interaction influenced the composition of the bacterial community, while the fungal community was exclusively affected by thinning. Thinning consisted of the removal of the aboveground parts of the Holm oak trees, which were thereafter left in forest stand. Thinning contributed to the C and N contents, with parallel increases in microbial biomass, particularly in summer. Drought increased the amounts of total organic C and total N, likely due to the reduced enzyme activities. Indeed, the composition of the bacterial community was modulated primarily by the indirect and long-term effects of drought - the accumulation of soil organic matter - rather than by the direct effect of the lower water content imposed by the drought treatments. Thinning under drought conditions did not increase soil organic C (SOC) content. However, the resistance of the soil microbial community to drought was fostered by thinning, particularly at the functional level, as indicated by the enzyme activities related to C, N and P cycles. These responses were associated to variations in the composition of the microbial communities in thinned, drought-exposed plots, in comparison to unthinned, drought-exposed plots. In conclusion, the interaction between forest management and drought influenced the soil microbial community of a Holm oak-dominated Mediterranean ecosystem.

Investigation of ozone deposition to vegetation under warm and dry conditions near the Eastern Mediterranean coast

Dry deposition of ozone (O₃) to vegetation is an important removal pathway for tropospheric O₃, while O₃ uptake through plant stomata negatively affects vegetation and leads to climate change. Both processes are controlled by vegetation characteristics and ambient conditions via complex mechanisms. Recent studies have revealed that these processes can be fundamentally impacted by coastal effects, and by dry and warm conditions in ways that have not been fully characterized, largely due to lack of measurements under such conditions. Hence, we hypothesized that measuring dry deposition of O₃ to vegetation along a sharp spatial climate gradient, and at different distances from the coast, can offer new insights into the characterization of these effects on O₃ deposition to vegetation and stomatal uptake, providing important information for afforestation management and for climate and air-quality model improvement. To address these hypotheses, several measurement campaigns were performed at different sites, including pine, oak, and mixed Mediterranean forests, at distances of 20-59 km from the Eastern Mediterranean coast, under semiarid, Mediterranean and humid Mediterranean climate conditions. The eddy covariance technique was used to quantify vertical O₃ flux (F_tot) and its partitioning to stomatal flux (F_st) and non-stomatal flux (F_ns). Whereas F_st tended to peak around noon under humid Mediterranean and Mediterranean conditions in summer, it was strongly limited by drought under semiarid conditions from spring to early winter, with minimum average F_st/F_tot of 8-11% during the summer. F_ns in the area was predominantly controlled by relative humidity (RH), whereas increasing F_ns with RH for RH < 70% indicated enhancement of F_ns by aerosols, via surface wetness stimulation. At night, efficient turbulence due to sea and land breezes, together with increased RH, resulted in strong enhancement of F_tot. Extreme dry surface events, some induced by dry intrusion from the upper troposphere, resulted in positive F_ns events.

Nutritional evaluation and productivity of supplemented sheep grazing in semiarid rangeland of northeastern Brazil

Sheep production systems in Brazilian caatinga rangelands require supplementation adapted to changes in floristic and chemical composition as dry seasons progress. Meeting sheep nutritional needs in extensive semiarid systems is challenging because of sheep dietary preferences and habits. The objective of this trial was to evaluate the substitutive effect of concentrate supplementation on grazing sheep in the Brazilian caatinga rangeland and its consequences on performance in different seasons. The trial was conducted from March to August 2013 at Embrapa Goat and Sheep in Sobral, Ceará State, Brazil. Thirty-two Brazilian Somali multiparous ewes were submitted to estrus synchronization and controlled breeding. At the start of the trial, ewes averaged 30.45 + 2.60 kg body weight (BW). Ewes were divided into four groups and individually offered 0, 200, 350, or 500 g supplement head^-1 day^-1. Intake prediction and digestibility trials were evaluated at three periods: rainy season (April), transition rainy-dry (June), and dry season (August). Sheep weights were taken every 14 days to measure their performance from late gestation until weaning. Ewe BW and body condition score changes were determined too. Lamb BW changes were also measured every 14 days from birth through weaning. A completely randomized design with split plot arrangement using eight replications was used for intake and digestibility measurements. The differences between supplement offered (0, 200, 350, and 500 g sheep-1) and season (rainy, transition rainy-dry, and dry) were submitted to analyses of variance and multiple means were separated, where differences were detected, using the Tukey's test. During lactation up through weaning, ewes supplemented at 500 g day^-1 had greater BW than ewes without supplement. Ewes supplemented with 200 g concentrate head^-1 day^-1 had 9.1% greater (P ≤ 0.05) BW at weaning and their lambs had 19.7% greater birth and 16.6% heavier wean BW despite lower dry matter intake compared to unsupplemented animals. Supplementation with 200 g concentrate increased carrying capacity by 28.8% during the dry season and by 20.5% during the rainy season. This study confirmed that in the dry season, when quality of rangeland forages decreases, supplementation contributes to greater DMI, improves postpartum and lactation BW recovery of ewes, and contributes to greater lamb birth and wean weights. Moreover, supplementation leads to feed substitution effects that may increase rangeland resilience by mitigating overgrazing. Supplementation with 200 g concentrate can also prevent negative energy balance for grazing animals, improving longer postnatal recovery, longer intervals between parturitions, fewer double and is necessary to ensure a better BW at birth to lambs.

Markov chains and cellular automata to predict environments subject to desertification

The foremost objective of this study was to analyze the performance of a Markov chain/cellular automata model for predicting land use/land cover changes in environments predisposed to desertification. The study area is the Vieira river basin, located in Montes Claros (MG, Brazil). Land use/land cover prognosis was performed for the year 2005 so that this result could be compared with the ranked image for the same year, taken as ground truth. Kappa indices were used to evaluate the change level that occurred between these two cases. Results from cellular automata were evaluated from those of the Markov chain model. The latter proved to be efficient in the quantitative prediction of changes in land use/land cover. Regarding the cellular automata, an average performance was noted in the spatial distribution of classes. Specifically, with regard to desertification, the use of the CA-Markov model was effective at estimating the total area of the most susceptible class to this process, Bare Soil; however, it was inefficient in its spatialization. Even with the caveats related to the performance of cellular automata, the overall prediction capacity of CA-Markov models can be considered as good.

Transference of bioactive compounds from support plants to the termites Constrictotermes cyphergaster (Isoptera)

This study aims to investigate the microbiological potential of the termite species Constrictotermes cyphergaster (Silvestri, 1901) and its support plants. We collected five C. cyphergaster nests from three different support plant species. Microbiological assays were performed on these extracts using the serial microdilution method in triplicate to measure the minimum inhibitory concentration (MIC) of each microorganism for the analysed extract. The ethanol extracts of the termite C. cyphergaster showed no significant activity against strains of Staphylococcus aureus and Escherichia coli, with an MIC >1000 μg mL-1. Only the extracts of the nests and termites with the nest had the same MICs. These results were in contrast to the extracts of Spondias tuberosa (Umbuzeiro), Poincianella pyramidalis (Catingueira), and Amburana cearensis (Cumaru), which demonstrated significant activity against S. aureus with MICs <1000 μg mL-1. The modulating activity of the extracts tested in the present study demonstrated potentiation of most antibiotics across the bacterial strains tested when combined with the extracts for both S. aureus and E. coli. These results indicate that the extracts tested in the present study may be composed of animal and vegetable origins with the potential to modify the activity of antibiotics and thus may aid in antimicrobial therapy.

Prevalence of subclinical hypocalcemia in dairy cows in the Sousa city micro-region, Paraíba state

Subclinical hypocalcemia is a metabolic disorder characterised by a decrease in serum calcium (Ca) levels, with no clinical symptoms. The aim of this study was to determine the punctual prevalence of subclinical hypocalcemia in dairy cows, in the Sousa city micro-region, Paraíba state. Samples were collected from 29 dairy farms, consisting of 153 and 296 blood samples in the pre- and postpartum period respectively. In relation to the mineral supplementation profile, 89.25% of the properties use a commercial supplement. On average, 40.53% of lactating cows presented total serum Ca levels under the lower limit of 8.0 mg/dL, with an exclusive supplement of NaCl resulting in a higher percentage of cows, 61.11%, with the condition of subclinical hypocalcemia. For ionized Ca, the average prevalence of subclinical hypocalcemia was 21.16%. The prevalence of subclinical hypocalcemia for total serum Ca was 37.25 and 42.23% of cows in the pre- and postpartum period respectively. The type of mineral supplement did not influence (P > .05) total and ionized serum Ca levels in lactating cows. There was no significant difference (P > .05) for total and ionized serum Ca levels as a function of the reproductive period in lactating cows. Subclinical hypocalcemia was evident in the dairy cows under evaluation and occurred with an average punctual prevalence of 40.34%. Commercial supplement is the most common form of mineral mixture used; however, it was not able to promote an increase in the levels of total and ionized serum Ca levels due to errors in managing the supply.

An overview of nitrate sources and operating processes in arid and semiarid aquifer systems

Nitrate concentration in most aquifers in arid and semi-arid areas has increased in the past several decades as a result of human activities. Under the predominantly oxic conditions of these aquifers, denitrification is inhibited, allowing nitrate, a soluble and stable form of nitrogen (N), to accumulate. Because of its close association with municipal and agricultural wastes, nitrate is commonly used as an indicator of anthropogenic contamination. Aquifers affected by agricultural waste may contain salts from irrigation returns and herbicides in addition to nitrates. Preventing leakage from soil to deeper parts of the aquifer is thus a priority in the sustainable management of aquifers in arid and semiarid areas. Studies report a wide range of nitrate concentrations distributed non-uniformly within the aquifer, with roughly 40% and 20% of sampled wells exceeding 50mg/L nitrate in shallow and deep parts of the aquifer respectively. In aquifers at risk of becoming contaminated, nitrate isotopes (δ¹⁵N, δ¹⁸O, Δ¹⁷O) can be used to identify the source of nitrogen as mineral or organic fertilizer, sewage, or atmospheric deposition. A variety of mathematical models (crop, hydrological, geochemical, or a combination of them) have been successful in identifying best practices that minimize N leakage without negatively affecting crop yield. In addition, field research in crop management, e.g., conservation agriculture, has yielded promising results in determining the adequate dosage and time of application of fertilizers to reduce N losses. Examples of key dryland aquifers impacted by nitrate are discussed, and some of the most pressing challenges to achieve sustainability are presented.

Radionuclides as natural tracers of the interaction between groundwater and surface water in the River Andarax, Spain

The identification of specific aquifers that supply water to river systems is fundamental to understanding the dynamics of the rivers' hydrochemistry, particularly in arid and semiarid environments where river flow may be discontinuous. There are multiple methods to identify the source of river water. In this study of the River Andarax, in the Southeast of Spain, an analysis of natural tracers (physico-chemical parameters, uranium, radium and radon) in surface water and groundwater indicates that chemical parameters and uranium clearly identify the areas where there is groundwater-surface water interaction. The concentration of uranium found in the river defines two areas: the headwaters with U concentrations of 2 μg L^-1 and the lower reaches, with U of 6 μg L^-1. Furthermore, variation in the ²³⁴U/²³⁸U isotopic ratio allowed us to detect the influence that groundwater from the carbonate aquifer has on surface water in the headwaters of the river, where the saline content is lower and the water has a calcium bicarbonate facies. The concentration of ²²⁶Ra and ²²²Rn are low in the surface waters: <1.6 × 10^-6 μg L^-1 and <5.1 × 10^-12 μg L^-1, respectively. There is a slight increase in the lower reaches where the water has a permanent flow, greater salinity and a calcium-magnesium-sulphate facies. All this is favoured by the influence of groundwater from the detritic aquifer on the surface waters. The results of this study indicate the utility in the use of physico-chemical and radiological data conjointly as tracers of groundwater-surface water interaction in semiarid areas where the lithology of aquifers is diverse (carbonate and detritic) and where evaporitic rocks are present.

Spectral reflectance characteristics of soils in northeastern Brazil as influenced by salinity levels

In northeastern Brazil, large swaths of once-productive soils have been severely degraded by soil salinization, but the true extent of the damage has not been assessed. Emerging remote sensing technology based on hyperspectral analysis offers one possibility for large-scale assessment, but it has been unclear to what extent the spectral properties of soils are related to salinity characteristics. The purpose of this study was to characterize the spectral properties of degraded (saline) and non-degraded agricultural soils in northeastern Brazil and determine the extent to which these properties correspond to soil salinity. We took soil samples from 78 locations within a 45,000-km² site in Pernambuco State. We used cluster analysis to group the soil samples on the basis of similarities in salinity and sodicity levels, and then obtained spectral data for each group. The physical properties analysis indicated a predominance of the coarse sand fraction in almost all the soil groups, and total porosity was similar for all the groups. The chemical analysis revealed different levels of degradation among the groups, ranging from non-degraded to strongly degraded conditions, as defined by the degree of salinity and sodicity. The soil properties showing the highest correlation with spectral reflectance were the exchangeable sodium percentage followed by fine sand. Differences in the reflectance curves for the various soil groups were relatively small and were not significant. These results suggest that, where soil crusts are not present, significant challenges remain for using hyperspectral remote sensing to assess soil salinity in northeastern Brazil.

In vitro and in vivo action of Piptadenia viridiflora (Kunth) Benth against Haemonchus contortus in sheep

Anthelminthic resistant populations of Haemonchus contortus are a major problem in sheep rearing, but plant extracts may offer viable alternative treatments. In our preliminary studies, Piptadenia viridiflora was frequently selected by sheep grazing in the Cerrado. The present research evaluated its in vitro and in vivo anthelmintic activity. The HPLC chromatograms of P. viridiflora aqueous extract (AE) and ethanolic extract (EE) showed the presence of flavonoids. The total condensed tannin (proanthocyanidin) was 0.2 and 1.01% in AE and EE, respectively. In an egg hatching inhibition (EHI) test, the LC90 of AE was 2.4mg/mL, and, of EE, was 2.1mg/mL. After tannin extraction, higher EHI and lower LC90 were observed. In a larval development inhibition test, the LC90 of AE was 13.66mg/g of fecal culture. The highest dose of AE administered to mice (203.0mg/kg bw) was well tolerated, suggesting low toxicity. In vivo, AE was orally administered to lambs at 283mg/kg bw, and, at weeks one, two, and three post-treatment, the mean fecal egg count (FEC) was significantly lower than in untreated lambs (P<0.05). Blood parameters were normal and similar in untreated and treated sheep. For all lamb groups, the mean total serum protein was significantly higher at week two post-treatment than at other evaluated periods (P<0.05). Piptadenia viridiflora extracts had low condensed tannin content and exhibited high anthelminthic efficacy in vitro and significantly reduced FEC. Tannins were not shown to be the principal components affecting EHI, hence it is necessary to isolate and characterize the principal active P. viridiflora compounds, and to assess their possible synergism.

Thinning effects on litterfall remaining after 8 years and improved stand resilience in Aleppo pine afforestation (SE Spain)

Monthly litterfall was monitored over a 3-year period in afforested Aleppo pines in the Mediterranean semiarid SE Spain with the aim of determining the long-term response of pines to reductions in tree competition and how this forest practice might influence stand resilience. Three thinning intensities applied 5 years earlier were evaluated (T75 = 75% of the basal area removed, T60 = 60% and T48 = 48%), both at the stand and at the tree level. On average, the total annual litterfall varied between 1.30 Mg ha(-1) yr(-1) (±0.24 SE) in T75 and 3.28 Mg ha(-1) yr(-1) (±0.78 SE) in the unthinned control. At the stand level, monthly differences among the treatments were found over time in the needles (F = 11.09, df = 3, P = 0.0009) and woody fraction (F = 4.36, df = 3, P = 0.0269) following the thinning gradient: T0 (control)>T48 > T60 > T75, and for the total amount of needles (χ(2) = 9.33, P = 0.025) and twigs (χ(2) = 9.11, P = 0.027) recorded at the end of the study period. High amounts of twig and needle fall were recorded during summer and beginning of autumn, whereas the main miscellanea inputs were registered during the spring, coinciding with the fall of nests and frass from caterpillar outbreaks. At the tree level, the total litterfall fluctuated between 1.5 kg tree yr(-1) in T0 (2nd yr) and 7.0 kg tree yr(-1) in T75 (3rd yr), although mean annual statistical differences among the treatments were found only for the first year of monitoring. However, needle fall was higher for larger pines (T75) than for the smaller ones in control (T0) when the data were analysed over the 3-year-period (F = 3.64, df = 3, P = 0.0247), and the same happened for the woody fraction (F = 3.63, df = 3, P = 0.0250). By contrast, pine trees in the unthinned control registered needle-fall rates (measured as kg m(-2) tree(-1)) that were similar to or higher than those of pine trees in thinned stands, suggesting that defoliation processes took place at high tree densities, especially after a severely dry period. We propose thinning as a measure to adapt high-density plantations to alterations due to climate change, in order to prevent forest decline and mortality.

Net requirements of calcium, phosphorus, magnesium, and sulphur for growth of non-descript breed hair lambs of different sex classes in the Brazilian semiarid conditions

The aim of this study was to determine the net requirements of calcium (Ca), phosphorus (P), magnesium (Mg), and sulphur (S) for weight gain of non-descript breed hair lambs (NDBL) of different sex classes reared under Brazilian semiarid conditions. Sixty NDBL (20 intact males, 20 castrated males, and 20 females), with an average initial body weight of 18.1 ± 0.4 kg and average age of 5 months were used. The macromineral requirements were determined by the differences in body composition through comparative slaughter direct method. The animals were confined for 58 days, and the average fasting body weight (FBW) and average daily gain (ADG) of lambs fed ad libitum were 29.2 ± 0.6 and 0.19 ± 0.01 kg, respectively. The net requirements of macrominerals for gain of NDBL did not differ between sex classes (P > 0.05), and ranged from 1.83 to 1.46 g/day of Ca, 1.21 to 1.01 g/day of P, 37 to 30 mg/day of Mg, and 0.31 to 0.28 g/day of S, for lambs with an ADG of 0.200 kg and 15 or 30 kg of FBW, respectively (P < 0.05). The N to S net ratio reduced and increased, respectively, as the body weight and ADG increase. The net requirements of Ca, P, Mg, and S for gain of NDBL slaughtered young and at the same age did not differ between sex classes and decreased as the body weight increased. The net requirements for gain of Ca and P were similar to those recommended by NRC (2007).