The Effect of Different Organic Fertilizers on Yield and Soil and Crop Nutrient Concentrations

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

The effect on the morpho-physiological parameters and yield of sorghum cultivated in a greenhouse with reclaimed water (RW) and (dehydrated sludge (DS) obtained in a sewage treatment plant, was evaluated. 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 W + DS (T3) was very suitable for the cultivation since an adequate nutritional supply was provided. The positive effects on the morpho-physiological parameters, plant height, stem diameter and stem length (in cm), were: T3 - 148.8, 1.50, and 103, respectively; T4 - 154, 1.70, and 107, respectively; and on the grain production in weight of 1000 seeds (g), and productivity in grains per plant: T3 - 6.97 and 1453, respectively; T4 - 6.81 and 1636, respectively. Both treatments showed for most of the parameters, no significant differences compared with those of T2 or T5 with supplementary fertilizers. A high production of metabolites (mg g-1) like free amino acids was also shown: T3 - 6.45; T4 - 8.43 and proline: T3 - 1.86; T4 - 1.77, known to be a good indication of a plant natural defence against stress conditions, and in soluble protein: T3 - 11.20; T4 - 13.51. Therefore, since the production of such grains with RW or DS can be environmentally and economically beneficial, their use is recommended for small and medium farmers in semiarid regions.

Nutritional Quality and Popability of Popcorn (Zea mays L. var. everta) in Response to Compost and NPK 20-7-3 Application under Dryland Condition of South Africa

The dietary value of popcorn, an important snack, depends on its proximate and nutritional constituents, while the economic worth is based on popability and expansion traits of the kernels. There is paucity of information on how soil fertility influences or relates with popping potentials as well as quality of popcorn kernel in semi-arid region. Therefore, the proximate composition and popping parameters of popcorn in response to organic and inorganic fertilizers were investigated. The field trial was conducted in 2017-2019, and it comprised five amendment rates including 90 and 180 kg ha^-1 NPK fertilizer and 4 and 8 t ha^-1 compost and unamended treatment as the control. The trial was arranged in randomized complete block design in triplicate. Data on kernel yield, biomass, and harvest index were evaluated. Kernels were analysed for proximate composition and popping indices using standard procedures. Across the two seasons, mean protein (8.1%) and fibre (10.2%) contents were highest in kernels from plots fertilized with NPK at 180 kg ha^-1, while grains from plots fertilized with 8 t ha^-1 compost had the highest moisture (19.3%) and starch (50.1%) contents. The highest kernel expansion of 54.18 cm³ g^-1 and 77.6% popped kernels were obtained in plots fertilized with 4 t ha^-1 compost. Most of the kernels (61%) were small-sized caryopsis. Popability is significantly associated with volume expansion (r = 0.696). Proximate components and popability improved greatly in compost-augmented field relative to the unfertilized plots. Application of 4 or 8 t ha^-1 sorted municipal solid waste compost to Luvisol enhanced growth and nutritional quality of popcorn. In view of promoting nutrient cycling towards improving soil fertility without compromising environmental health, compost is comparable and a good alternative to fossil-based mineral fertilizers.

Bioavailability and health risk assessment of potentially toxic elements in popcorn kernel from sandy loam Ferric Luvisol amended with municipal solid waste compost

Application of municipal solid waste compost (MSWC) to marginal soil enhances crop growth but could also serve as source of pollutants into agroecosystem. There is scanty report on bioavailability of potentially toxic element (PTE) and the health risk of consuming popcorn kernel harvested from field fertilized with MSWC. Field trial was carried out in 2017-2019 to evaluate bioavailability of PTEs in kernel of popcorn harvested from field fertilized with MSWC. The trial was conducted at the experimental field of North-West University, Mafikeng campus South Africa. The treatments comprised three rates of MSWC including 0 t/ha (unamended, control), 4 t/ha and 8 t/ha arranged in randomized complete block design and replicated four times. One seed of popcorn was sown at 20 × 70 cm spacing per hole of 3 cm depth in a 6 × 4.2 m plot size. Growth and yield data were collected at maturity. Ears were harvested at maturity and the kernels were dried to 12% moisture content. Air-dried kernels (50 g) samples were collected and analyzed for essential mineral nutrient and some heavy metal(loid)s using ICP-MS. Measured concentrations of these heavy metal(loid)s were then used to calculate the health risk for adults and children. The results showed that uptake concentration was in the order K⁺ > HPO₄^2- > Mg⁺² > Ca²⁺ > Fe²⁺ > Cr⁶⁺ > Zn²⁺ > Mn²⁺  > Cu²⁺(mg/kg). Uptake concentration of metalloids: Al and Pd was significantly higher in the unamended. Bioavailability of PTE was highest in unamended plots. The average daily intake of the PTEs was within the recommended permissible level. The risk index value for oral pathway was < 1 for both adult and children population. Amending Ferric Luvisol with 80 t/ha MSWC enhanced popcorn growth and, concentration of accumulated PTEs in kernels at this rate, cannot pose health risk to both adult and children population.

Portable X-ray Fluorescence Analysis of Organic Amendments: A Review

Portable XRF spectrometry (pXRF) has recently undergone significant technological improvements and is being applied in a wide range of studies. Despite pXRF advantages, this technique has rarely been used to characterize organic amendments and residues. This article reviews those studies undertaken to date in which pXRF is used to characterize these products. Published studies show that pXRF correctly measures elements such as Fe, Pb, Zn, Mn, Ca, and K but gives conflicting results for elements such as Cr, Ni, and As. Among the reasons that may cause the low performance of the technique with certain elements or under certain measurement conditions would be the inadequacy of the analytical comparison procedures used (i.e., digestion with aqua regia), the lack of knowledge of the interfering effects of organic matter, and sample moisture on the XRF signals and the need for a standardized protocol for performing the measurements. However, the speed and low cost of the procedure forecast a greater future use of this technique, especially in cooperation with other fast spectroscopic techniques based on near-infrared (NIRS) or mid-infrared (MIR) spectroscopies. Chemometric procedures based on one or more of these techniques will allow the prediction of elements below the detection limit of pXRF instruments (Cd, Hg), or other properties of organic amendments (organic matter, N, electrical conductivity, cation exchange capacity).

Agronomic Productivity and Organic Fertilizer Rates on Growth and Yield Performance of Cabbage (Brassica oleracea var. capitata L.) in Northwestern Ethiopia

Cabbage (Brassica oleracea var. capitata L.) is a popular leafy vegetable in Ethiopia. However, the production and productivity of the crop are often constrained by several factors, such as deprived soil fertility and poor agronomic practices. Thus, a study was conducted in two locations in the East Gojjam zone of northwestern Ethiopia during the 2021/2022 cropping season to evaluate the effect of bud numbers and farmyard manure fertilizer rates on the growth and yield components of cabbage. Three numbers of cabbage buds (1, 2, and 3) and four levels of farmyard manure (0, 2.5, 5, and 7.5 tons/ha) were laid out in a 3 × 4 factorial arrangement in a randomized complete block design with three replications. Data on yield and quality were recorded and subjected to analysis of variance. The results revealed that growth, yield, and quality components were significantly influenced by the interaction effects of bud number and farmyard manure fertilizer rate. In both locations, the highest marketable (41.8 tons/ha) and total (43.1 tons/ha) yields were attained from the combined effects of 2 buds of cabbage and 5 tons of farmyard manure. The highest medium-sized heads (31.8 tons/ha) of cabbage were also recorded from the combination of 2 buds with 5 tons of farmyard manure. Moreover, the combined effects of 2 buds and 5 tons of farmyard manure showed the highest net benefit (5,679.03 US dollars) over the other treatments at the two locations. Hence, based on the results of the study, the combination of 2 buds and 5 tons of farmyard manure fertilizer can be suggested for the economical production of cabbage in northwestern Ethiopia and similar environments.

Application of Sewage Sludge in a Rice (Oryza sativa L.)-Wheat (Triticum aestivum L.) System Influences the Growth, Yield, Quality and Heavy Metals Accumulation of Rice and Wheat in the Northern Gangetic Alluvial Plain

For a sustainable and profitable agriculture production system, balanced and integrated use of nutrients is a key strategy. In addition, partial replacement of chemical fertilizers with organics ones reduces both environmental concerns and economic costs and provides greater soil health benefits. With this hypothesis, an experiment was conducted to assess the yield and economic benefits of a rice-wheat cropping system (RWCS) as influenced by the joint application of sewage sludge (SSL) and fertilizer. The treatments comprised: without fertilizer or SSL; 100% recommended dose of fertilizers (RDF); 100% RDF + 20 Mg ha−1 SSL; 100% RDF + 30 Mg ha−1 SSL; 50% RDF + 20 Mg ha−1 SSL; 60% RDF + 20 Mg ha−1 SSL; 70% RDF + 20 Mg ha−1 SSL; 50% RDF + 30 Mg ha−1 SSL; 60% RDF + 30 Mg ha−1 SSL and 70% RDF + 30 Mg ha−1 SSL. The experiment was laid out in a randomized block design with three replications. The result of our study indicate that the highest percent increase in mean plant height i.e., ~14.85 and ~13.90, and grain yield i.e., ~8.10 and ~18.90 for rice and wheat, respectively, were recorded under 100% RDF + 30 Mg SSL ha−1 treatment compared to 100% RDF, while 70% RDF + 20 Mg ha−1 SSL produced a statistically equivalent grain yield of 100% RDF in RWCS. The application of 20 and 30 Mg SSL ha−1 along with recommended or reduced fertilizer dose, significantly increased the heavy metal content in plant and soil systems above that of 100% RDF, but this enhancement was found within permissible limits. Moreover, the reduced use of SSL i.e., 20 Mg SSL ha−1, resulted in lower heavy metal content in grain and soil than did the 30 Mg ha−1 SSL treatment, but significantly higher than in the absolute control or 100% RDF treatment. In summary, the use of 20 Mg ha−1 SSL along with 70% RDF provided a safer, profitable and sustainable option in a rice-wheat cropping system in the middle Ganegatic alluvial plain.

Does Climate Change Influence Russian Agriculture? Evidence from Panel Data Analysis

Agriculture is one of the economic sectors primarily affected by climate change. This impact is very uneven, especially for countries with large territories. This paper examines the contribution of climate change to the improvement in agricultural productivity in Russia over the past two decades. Several ensembles of fixed effects regressions on yields and gross harvests of grain, fruits, and berries, potato, and vegetables were evaluated for a sample of 77 Russian regions over the 2002–2019 period. In contrast to similar studies of the climate impact on Russian agriculture, we considered a larger set of variables, including both Russian and global climate trends, technological factors, and producer prices. Russian weather trends such as winter softening and increase in summer heat have a significant but opposite effect on yields. An interesting finding is a significant and mostly positive influence of global climatic variables, such as the CO2 concentration, El Niño and La Niña events on both harvests and yields. Although technological factors are the main drivers of growth in Russian agricultural performance over the past 20 years, we found a strong positive effect on yield and gross harvest only for mineral fertilizers. The influence of the other variables is mixed, which is mainly due to data quality and aggregation errors.

Monitoring and assessment of soil quality based on micronutrients and physicochemical characteristics in semi-arid submountainous Shiwalik ranges of lower Himalayas, India

Lower Shiwalik foothill ranges (Kandi regions) are dominated by different land use systems, varying in fertility status due to soil erosion owing to undulating topographical features. For assessment of soil nutrient status of study area, the soil sampling was conducted to investigate the variation in micronutrient status and physicochemical characteristics of soil. Long-range basis soil sampling was carried out in 11 blocks falling in the entire Shiwalik ranges of lower Himalaya under different land use systems (LUSs), viz., agriculture (AG), horticulture (HR), agri-horticulture (AH), grassland (GL), and agroforestry (AF) systems. A total of 440 soil samples were collected from two depths (0-15, 15-30 cm) for analysis. The results had reported that the soils were slightly acidic to slightly alkaline (6.61 to 8.10) in the whole range. Soil organic carbon (SOC) was found to be varying from very low to very high (2.43 to 10.43 g kg^-1). DTPA-extractable Fe and Mn were found to be in dominant concentrations in the soils whereas, the deficiency of Zn was found under all existing land uses. Interestingly, Fe (r = 0.62*), Cu (r = 0.44), and Mn (r = 0.35) micronutrients were positively correlated with clay content whereas Zn (r = - 0.02) was negatively correlated. Soil quality based on principal component analysis (SQI-PCA) reported clay, SOC, and Zn are major dominating parameters to be considered of soil in Shiwalik ranges.

Comprehensive nutrient analysis in agricultural organic amendments through non-destructive assays using machine learning

Portable X-ray fluorescence (pXRF) and Diffuse Reflectance Fourier Transformed Mid-Infrared (DRIFT-MIR) spectroscopy are rapid and cost-effective analytical tools for material characterization. Here, we provide an assessment of these methods for the analysis of total Carbon, Nitrogen and total elemental composition of multiple elements in organic amendments. We developed machine learning methods to rapidly quantify the concentrations of macro- and micronutrient elements present in the samples and propose a novel system for the quality assessment of organic amendments. Two types of machine learning methods, forest regression and extreme gradient boosting, were used with data from both pXRF and DRIFT-MIR spectroscopy. Cross-validation trials were run to evaluate generalizability of models produced on each instrument. Both methods demonstrated similar broad capabilities in estimating nutrients using machine learning, with pXRF being suitable for nutrients and contaminants. The results make portable spectrometry in combination with machine learning a scalable solution to provide comprehensive nutrient analysis for organic amendments.

Genetic and Metabolic Diversity of Soil Microbiome in Response to Exogenous Organic Matter Amendments

Loss of organic matter content of cultivated soils is observed in many regions of Europe. The possibility of using organic waste as a soil additive that enriches the soil with organic matter and essential components is important in soil quality protection and waste management. This research concerned the influence of six organic wastes—two industrial composts, three digestates and meat bone meal—on soil microbial properties. The study of functional microbial diversity concerns the determination of the catabolic capacity of bacterial, fungal and anaerobic communities in relation to carbon substrates in metabolic profiling plates (Biolog® ECO, FF, AN (Biolog Inc., Hayward, CA, USA)). The assessment of genetic diversity was made on the basis of analysis of the restriction profile of ammonia-oxidizing archaea. Additionally, soil dehydrogenases activity was determined. The research showed that the type of organic waste used had an influence on the microbiological parameters. The application of exogenous organic matter caused increases in functional and genetic microbial diversity. The nature of the noted changes was short term and periodic. The values of the microbiological parameters in soils with organic waste were similar to those of the control samples. This indicates an improved microbiological balance and stability of the soil environment after the application of exogenous organic matter.

Comparative Performance of Organic Fertilizers in Maize (Zea mays L.) Growth, Yield, and Economic Results

Maize is a major crop grown and consumed in Uganda and it requires a high fertilizer input. However, the existing inorganic fertilizers in the market are often not affordable especially to small scale farmers, which results in decreased maize yields in the country. On the other hand, there is an abundance of unutilized animal manure, which, when treated, can be used to increase maize yields. This study evaluated the response of maize to products of different cattle manure treatment methods as well as inorganic fertilizer. The treatments such as cattle manure stored under shade (T), cattle manure stored in the open (M), cattle manure slurry digestate (S), vermicompost (V), and an inorganic fertilizer, DAP (D) were all applied in completely randomized block plots at an equal application rate of 50 kg N ha−1 with four replications per treatment. Control plots (C) where no fertilizer was applied were also considered. The experiment was done for two planting seasons in 2018. Number of leaves, plant height, cob, and grain yields were used to evaluate the performance of different fertilizer treatments. Economic assessment of all the six treatments was also carried out to determine the economic viability of applying these fertilizers on maize. Maize growth parameters and yields were all significantly increased (p < 0.05) with an application of both organic and inorganic fertilizers when compared with the control. However, there was no significant difference (p > 0.05) in the maize yields under the different fertilizer treatments. Vermicomposting was the most economically viable manure treatment method due to low operating costs and higher returns on investment that are supplemented with the production of chicken fodder (earthworm biomass) and, thus, can be recommended to farmers for production of a fertilizer that increases maize yields with assurance of economic returns.