Benefits of organic manure combined with biochar amendments to cotton root growth and yield under continuous cropping systems in Xinjiang, China

Optimizing biochar application for enhanced cotton and sugar beet production in Xinjiang: a comprehensive study

BACKGROUND

Optimizing biochar application is vital for enhancing crop production and ensuring sustainable agricultural production. A 3-year field experiment was established to explore the effects of varying the biochar application rate (BAR) on crop growth, quality, productivity and yields. BAR was set at 0, 10, 50 and 100 t ha-1 in 2018; 0, 10, 25, 50 and 100 t ha-1 in 2019; and 0, 10, 25 and 30 t ha-1 in 2020. Crop quality and growth status and production were evaluated using the dynamic technique for order preference by similarity to ideal solution with the entropy weighted method (DTOPSIS-EW), principal component analysis (PCA), membership function analysis (MFA), gray relation analysis (GRA) and the fuzzy Borda combination evaluation method.

RESULTS

Low-dose BAR (≤ 25 t ha-1 for cotton; ≤ 50 t ha-1 for sugar beet) effectively increased biomass, plant height, leaf area index (LAI), water and fertility (N, P and K) productivities, and yield. Biochar application increased the salt absorption and sugar content in sugar beet, with the most notable increases being 116.45% and 20.35%, respectively. Conversely, BAR had no significant effect on cotton fiber quality. The GRA method was the most appropriate for assessing crop growth and quality. The most indicative parameters for reflecting cotton and sugarbeet growth and quality status were biomass and LAI. The 10 t ha-1 BAR consistently produced the highest scores and was the most economically viable option, as evaluated by DTOPSIS-EW.

CONCLUSION

The optimal biochar application strategy for improving cotton and sugar beet cultivation in Xinjiang, China, is 10 t ha-1 biochar applied continuously. © 2024 Society of Chemical Industry.

Biochar and Dairy Manure Amendment Effects on Cynodon dactylon Performance and Soil Properties

Studies have determined the separate effects of biochar (BC) and manure application on forage species and soil, but few examined the effects of BCs made from different feedstock applied along with dairy manure. We compared the effect of wood- and manure-derived feedstock BC as well as dairy manure amendment application on Cynodon dactylon performance and soil properties in sandy loam and clay loam soils in a greenhouse pot study. Plant samples were assayed for herbage and root dry weight as well as herbage and root N and C percent and yield. Soil samples were assayed for macronutrients, micronutrients, metals, pH and conductivity. Data analyses involved variance analysis and Tukey's tests using R in RStudio (the IDE). In general, C. dactylon yields or mineral content were not affected by either manure or BC. However, an increase in the total herbage dry weight (30%) and in herbage N% (55%) was observed for clay loam and sandy loam soil, respectively, due to manure amendment application. There were no alterations in clay loam NO3-N and P due to any treatment; however, in sandy loam, these nutrients were not altered only when wood BC was applied. In sandy loam soil, NO3-N and P increased when manure BC along with dairy manure and when manure BC alone were applied, respectively. Thus, wood BC application should be considered to avoid these nutrient buildups when dairy manure is used as a soil amendment. This research shows a neutral (BC) or positive (dairy manure amendment) impact on C. dactylon performance. BC incorporation increases soil total C, showing potential for C sequestration. Long-term field trials could corroborate plant performance and soil parameters.

Compost and humic acid amendments are a practicable solution to rehabilitate weak arid soil for higher winter field pea production

Arid soils are often weak, low in fertility, and lack essential plant nutrients. Organic amendments might be a feasible solution to counter the detrimental impact and rehabilitate weak arid soil for the growth of legumes. The study aimed to investigate how organic amendments of compost and humic acid may affect winter field pea productivity in arid soil. Over 2 years of field experiments, a range of treatments were applied, including different amounts of compost and humic acid. The results showed higher microbial carbon (C), and nitrogen (N) biomass, root length, shoot length, grains pod-1, and grain yield of pea, gained from the collective application of 8 Mg ha-1 compost and 15 kg ha-1 humic acid compared to all other treatments. Organic amendments increased soil microbial C density by 67.0 to 83.0% and N biomass by 46.0 to 88.0% compared with the control. The combined application of compost and humic acid increased soil microbial N biomass by 57.0 to 60.0% compared to the sole applications of compost-only and humic acid-only. It was concluded that organic amendments of 8 Mg ha-1 compost and 15 kg ha-1 humic acid in arid soil modulated microbial density, resulting in improved winter field pea productivity. This study suggests organic amendments of compost and humic acid might be a practicable solution to rehabilitate weak arid soil to grow legumes.

Effects of biochar coupled with chemical and organic fertilizer application on physicochemical properties and in vitro digestibility of common buckwheat (Fagopyrum esculentum Moench) starch

Common buckwheat starch, a functional ingredient, has wide food and non-food applications. Excessive chemical fertilizer application during grain cultivation decreases quality. This study examined the effects of different combinations of chemical fertilizer, organic fertilizer, and biochar treatment on the physicochemical properties and in vitro digestibility of starch. The amendment of both organic fertilizer and biochar was observed to have a greater impact on the physicochemical properties and in vitro digestibility of common buckwheat starch in comparison to organic fertilizer amendment solely. The combined application of biochar, chemical, and organic nitrogen in an 80:10:10 ratio significantly increased the amylose content, light transmittance, solubility, resistant starch content, and swelling power of the starch. Simultaneously, the application reduced the proportion of amylopectin short chains. Additionally, this combination decreased the size of starch granules, weight-average molecular weight, polydispersity index, relative crystallinity, pasting temperature, and gelatinization enthalpy of the starch compared to the utilization of chemical fertilizer alone. The correlation between physicochemical properties and in vitro digestibility was analyzed. Four principal components were obtained, which accounted for 81.18 % of the total variance. These findings indicated that the combined application of chemical fertilizer, organic fertilizer, and biochar would improve common buckwheat grain quality.

Cigarettes butt littering: The story of the world's most littered item from the perspective of pollution, remedial actions, and policy measures

Cigarettes butt (CB) is one of the most littered items on the planet. This paper critically analyzes the factors responsible for CB littering, and associated environmental ramifications, and reviews all the possible technical, behavioural, and policy-based solutions. Even while smoking has declined globally, middle-income nations have seen an increase in consumption, which may be related to increased affordability and a lack of public awareness. The smokers' individual beliefs and habits, environmental ignorance, covert littering as a result of social taboos associated with smoking, and behavioural gaps between intention and action might all be contributing factors to CBs' littering behaviour. The low biodegradability of cellulose acetate filters and toxic chemical leaching from CBs are the most important aspects of CB environmental toxicity. The small size and low economic value of CB contribute to the inefficiencies of current waste collection and management systems. The current research on CB valorisation includes fired-clay bricks, asphalt concrete, biofilms, sound absorber, cellulose pulp, pesticides, and insecticides as downstream mitigation strategies. This study highlights the urgent need for policymakers to enforce regulations enabling innovative cigarette designs, the creation of deposit-refund schemes, extended producer responsibility and stringent waste collection mechanisms. Adopting gentler marketing strategies and non-confrontational behavioural nudges could result in an overall reduction in CB pollution.

The critical role of biochar to mitigate the adverse impacts of drought and salinity stress in plants

Drought stress (DS) is a potential abiotic stress that is substantially reducing crop productivity across the globe. Likewise, salinity stress (SS) is another serious abiotic stress that is also a major threat to global crop productivity. The rapid climate change increased the intensity of both stresses which pose a serious threat to global food security; therefore, it is urgently needed to tackle both stresses to ensure better crop production. Globally, different measures are being used to improve crop productivity under stress conditions. Among these measures, biochar (BC) has been widely used to improve soil health and promote crop yield under stress conditions. The application of BC improves soil organic matter, soil structure, soil aggregate stability, water and nutrient holding capacity, and the activity of both beneficial microbes and fungi, which leads to an appreciable increase in tolerance to both damaging and abiotic stresses. BC biochar protects membrane stability, improves water uptake, maintains nutrient homeostasis, and reduces reactive oxygen species production (ROS) through enhanced antioxidant activities, thereby substantially improving tolerance to both stresses. Moreover, BC-mediated improvements in soil properties also substantially improve photosynthetic activity, chlorophyll synthesis, gene expression, the activity of stress-responsive proteins, and maintain the osmolytes and hormonal balance, which in turn improve tolerance against osmotic and ionic stresses. In conclusion, BC could be a promising amendment to bring tolerance against both drought and salinity stresses. Therefore, in the present review, we have discussed various mechanisms through which BC improves drought and salt tolerance. This review will help readers to learn more about the role of biochar in causing drought and salinity stress in plants, and it will also provide new suggestions on how this current knowledge about biochar can be used to develop drought and salinity tolerance.

Poultry manure gleaned antibiotic residues in soil environment: A perspective of spatial variability and influencing factors

The antibiotics released by human and animals end up in the environmental sinks like soil and water to cause contamination and induce resistance in the microflora. The knowledge of fate and behavior of antibiotics in diverse geographical, climatological, and physicochemical is limited. Therefore, present study investigated the spatial distribution of antibiotics and their relationship with various factors and the source-sink relationship between soil and poultry manure. This was achieved by employing spatially constrained hierarchical clustering, global and local spatial autocorrelation, and spatial regression techniques. Most of the antibiotics co-occurred in both soil and poultry manure matrices, however antibiotic concentration in soil (1.20 μg kg^-1 < antibiotics ≤21.38 μg kg^-1) was lower than that in the poultry manure (7.05 μg kg^-1< antibiotics ≤60.2 μg kg^-1). Majority of the antibiotics showed spatial independence in both poultry manure and soil, except for sulfadiazine, sulfanilamide and sulfapyridine with Moran's I > - 0.111. Local indicator of spatial association indicated localized spatial clustering and outlier behavior of antibiotics. The underlying reasons for spatial heterogeneity of antibiotics resolved by spatial regression models indicated elevation, S%, C%, pH and mean annual temperature as the major factors. The influence of antibiotic concentration in poultry manure as a source was significant but marginal compared to the other predictors of spatial heterogeneity.

Potential of Biochar-Based Organic Fertilizers on Increasing Soil Fertility, Available Nutrients, and Okra Productivity in Slightly Acidic Sandy Loam Soil

Reducing chemical fertilizers is critical for maintaining soil health and minimizing environmental damage. Biochar-based organic fertilizers reduce fertilizer inputs, improve soil fertility, increase crop productivity, and reduce environmental risks. In this study, a pot experiment was conducted in a greenhouse to assess the potential of biochar-based organic and inorganic fertilizers to improve soil fertility and Okra yield. Seven treatments with three replicates were arranged in a completely randomized design (CRD). Three treatments included biochar-blended formulations (i) biochar mixed with mineral NPK fertilizer (BF), (ii) biochar mixed with vermicompost (BV), and (iii) biochar mixed with goat manure (BM); two treatments included biochar enrichment formulations (iv) biochar enriched with cow urine (BCU) and (v) biochar enriched with mineral NPK fertilizer in aqueous solution (BFW), and the remaining two included control treatments; (vi) control (CK: no biochar and no fertilizers) and (vii) fertilized control (F: only recommended NPK fertilizer and no biochar). Mineral NPK fertilizers in BF, BFW, and F were applied at the recommended rate as urea, di-ammonium phosphate (DAP), and muriate of potash (MOP). Organic fertilizers in BV, BM, and BCU treatments were applied in equal quantities. All biochar-amended treatments showed improved soil chemical properties with higher pH, organic carbon, total N, and available P and K compared to the two non-biochar control plots (CK and F). Biochar blended with goat manure (BM) showed the highest effect on soil fertility and fruit yield. BM (51.8 t ha−1) increased fruit yield by 89% over CK (27.4 t ha−1) and by 88% over F (27 t ha−1). Similarly, cow urine-enriched biochar (BCU) (35 t ha−1) increased fruit yield by 29% and 28% compared to CK and F, respectively. Soil pH, OC, and nutrient availability (total N, available P, and available K) showed a significantly positive relationship with fruit yield. The study suggests that using biochar-based organic fertilizers, such as BCU and BM, could outperform recommended mineral fertilizers (F) and produce higher yields and healthy soils, thereby contributing to mitigating the current food security and environmental concerns of the country.

Biochar Stimulated Actual Evapotranspiration and Wheat Productivity under Water Deficit Conditions in Sandy Soil Based on Non-Weighing Lysimeter

The major climate-related hazard to worldwide agricultural productivity is drought, which is becoming more common because of ongoing climate change, especially in the arid and semi-arid regions. Herein, we investigated the influence of biochar soil application at 0, (B1), 7.5 ha^-1 (B2), and 15 t ha^-1 (B3) on the productivity and drought-tolerance indices of wheat (Triticum aestivum L., cv. Sakha 93) grown in sandy soil under irrigation levels of 100 (I1), 80 (I2), and 60% (I3) of crop evapotranspiration (ETc), as well as soil properties based on non-weighing lysimeter units. Increasing water deficiency significantly decreased the actual evapotranspiration (ETa) values. A growing biochar rate caused a significant increase in ETa values, water use efficiency, and wheat productivity compared to the untreated control. Additionally, biochar supplementation revealed an improvement in soil quality as measured by the reduction in the bulk density and hydraulic conductivity with an increase in the total porosity and void ratio of the experimental soil. The correlation analysis exhibited a highly significant and positive correlation (0.98 **) between biological yield and grain yield traits. Therefore, it may be stated that these traits are the most significant components of the evaluated grain yield in wheat plants. The productivity of I1 plants was not significantly different and slightly higher than that of I2 plants. Therefore, it can be recommended that exposed wheat plants cultivated in sandy soil with I2 × B3 treatment significantly provide the highest yield while saving 20% of the irrigation water.

Mitigation of tobacco bacteria wilt with microbial degradation of phenolic allelochemicals

Long-term continuous monoculture cropping of tobacco leads to high incidence of tobacco bacterial wilt (TBW) caused by Ralstonia solanacearum, which threatening world tobacco production and causing great economy loss. In this study, a safe and effective way to control TBW by microbial degradation of phenolic allelochemicals (PAs) was explored. Eleven kinds of PAs were identified from continuous tobacco cropping soil. These PAs exhibited various effects on the growth, chemotaxis and biofilm formation of R. solanacearum. Then we isolated eight strains of Bacillus, one strain of Brucella, one strain of Enterobacter and one strain of Stenotrophomonas capable of degrading these PAs. The results of degradation assay showed that these isolated strains could degrade PAs both in culture solutions and soil. Besides, the incidence of TBW caused by R. solanacearum and deteriorated by PAs were significantly decreased by treating with these degrading strains. Furthermore, six out of eleven isolated strains were combined to degrade all the identified PAs and ultimately sharply reduced the incidence of TBW by 61.44% in pot experiment. In addition, the combined degrading bacteria could promote the plant growth and defense response. This study will provide a promising strategy for TBW control in tobacco production.

Dissolved organic matter-assisted phytoremediation potential of cotton for Cd-contaminated soil: a relationship between dosage and phytoremediation efficiency

Dissolved organic matter (DOM) is a novel Cd-contaminated soils amendment for phytoremediation. However, the phytoremediation efficiency for different DOM doses has been insufficiently investigated. In this study, we investigated the effect of five DOM doses (v/w, 0%, 1%, 2%, 4% and 8%) on the phytoremediation efficiency of cotton in Cd-contaminated soil through pot experiment. The results showed that bioavailable Cd concentrations and organic matter in the soil increased with the increased of DOM dosage. The DOM dose increased the chlorophyll content, photosynthesis, and the total biomass of cotton. In addition, the DOM application increased the Cd content in cotton roots and changed the Cd uptake in cotton shoots, increasing shoot Cd extraction efficiency by 8.53-20%. Simultaneously, soil Cd phytoextraction efficiency significantly increased. Furthermore, applying a 1% DOM dose resulted in safeguarding fibre biomass and maximising the efficiency of shoot extraction. Redundancy analysis showed that the Mn content in leaves is critical for increasing cotton biomass, anti-oxidation competence and phytoremediation efficiency under 1% DOM dose. In conclusion, DOM enhanced cotton remediation in Cd-contaminated soils and applying DOM at 1% was a suitable choice for Cd-contaminated soils.

Enriched-biochar application increases broccoli nutritional and phytochemical content without detrimental effect on yield

BACKGROUND

Soil fertility is a major concern during vegetable production. Conventional versus organic fertilization has been studied in order to conserve soil properties. While some reports point out an increase in food nutritional properties, the loss of crop yield under organic conditions continues to be a problem. Thus, an experiment with broccoli in the field was carried out, comparing crop management under conventional fertilization (CF) and two soil amendment treatments: manure pellet (M) and an enriched-biochar (EB) supplemented by an organic fertilizer (AND) applied alone (M + CF; EB+AND) or in combination (M + EB + AND). Crop yield and the nutritional properties in the flowering heads (mineral content, phenolic compounds and glucosinolates (GSLs)), were determined.

RESULTS

Enriched-biochar and manure as a standalone amendment resulted in higher crop yield regarding CF, but not when they were applied in combination. The number of flowering heads with no-commercial characteristics was lower after enriched-biochar soil application. Finally, enriched-biochar treatment enhanced NO3 - , PO4 3- and SO4 2- levels in the flowering heads, and some of the ion contents can be associated with mineral changes in the soil after the biochar amendment. Also, the contents of phenolic compounds and indole GSLs were higher after enriched-biochar application compared with the other treatments, GSL increase being due to the higher percentage of sulfur in the plant rather that an adequate N/S ratio.

CONCLUSION

Application of enriched-biochar amendment in the cultivation of broccoli is appropriate, since there are no losses of yield and an increase in nutritional compounds in the flowering heads. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Responses of transcriptome and metabolome in the roots of Pugionium cornutum (L.) Gaertn to exogenously applied phthalic acid

BACKGROUND

The yield and quality of Pugionium cornutum (L.) Gaertn., a healthy, green vegetable with low sugar and high protein contents and high medicinal value, is severely affected by autotoxicity, which is a leading factor in the formation of plant disease. To help characterize the autotoxicity mechanism of P. cornutum (L.) Gaertn., we performed transcriptomic and metabolic analysis of the roots of P. cornutum (L.) Gaertn. response to phthalic acid, an autotoxin from P. cornutum (L.) Gaertn.

RESULTS

In this study, high-throughput sequencing of nine RNA-seq libraries generated from the roots.of P. cornutum (L.) Gaertn. under different phthalic acid treatments yielded 37,737 unigenes. In total, 1085 (703 upregulated and 382 downregulated) and 5998 (4385 upregulated and 1613 downregulated) DEGs were identified under 0.1 and 10 mmol·L^- 1 phthalic acid treatment, respectively, compared with the control treatment. Glutathione metabolism was among the top five important enriched pathways. In total, 457 and 435 differentially accumulated metabolites were detected under 0.1 and 10 mmol·L^- 1 phthalic acid treatment compared with the control, respectively, of which 223 and 253, respectively, increased in abundance. With the increase in phthalic acid concentration, the accumulation of ten metabolites increased significantly, while that of four metabolites decreased significantly, and phthalic acid, dambonitol, 4-hydroxy-butyric acid, homocitrulline, and ethyl β-D-glucopyranoside were 100 times more abundant under the 10 mmol·L^- 1 phthalic acid treatment than under the control. Seventeen differentially expressed genes significantly associated with phthalic acid content were identified. In addition, the L-histidinol content was highest under 0.1 mmol·L^- 1 phthalic acid, and a total of eleven differentially expressed genes were significantly positively correlated with the L-histidinol content, all of which were annotated to heat shock proteins, aquaporins and cysteine proteases.

CONCLUSIONS

Accumulation of autotoxins altered the metabolic balance in P. cornutum (L.) Gaertn. and influenced water absorption and carbon and nitrogen metabolism. These important results provide insights into the formation mechanisms of autotoxicity and for the subsequent development of new control measures to improve the production and quality of replanted plants.

Profitability and agronomic potential of cotton (Gossypium hirsutum L.) under biochar-compost-based amendments in three agroecological zones of northern Benin

Low land productivity is a major constraint facing agriculture in sub-Saharan Africa, which severely affects crop yields, particularly cotton which is main export agricultural produce of Northern Benin. To overcome this situation, the hill-placement of microdose biochar-compost-based amendments was carried out at two research stations and on farmer's fields in three agroecological zones of northern Benin. The study aims to evaluate the agronomic and economic performance of cotton under two types of compost and biochar-based amendments. On stations, the experimental design used was a complete randomized block with one factor and ten treatments replicated four times as follows: (i) absolute control without any amendment (Ck), (ii) mineral fertilizer (MF) at 200 kg/ha, (iii) cow dung-based compost at 200kg/ha (CP1_200) and (iv) 300kg (CP1_300), (v) household waste-based compost at 200kg/ha (CP2_200) and (vi) 300 kg (CP2_300), the combination of CP1 and 15% biochar designated Terra preta (TP) applied at 200kg/ha (vii, TP1_200) and 300kg/ha (viii, TP1_300), the combination of CP2 and 15% biochar applied at 200kg/ha (ix, TP2_200) and 300kg/ha (x, TP2_300). On-farms, the experimental design was a randomized complete block with one factor and six optimal treatments extracted from the on-station experiments with three replicates installed in four farmers' fields from each location studied. The six treatments were: Ck, MF, CP1_200, CP2_200, TP1_200 and TP2_200. Cotton growth (Plant height, number of vegetative and reproductive branches and total bolls per plant) and yield data were collected. The treatment TP1_300 yielded higher cotton seed with 2.53 t/ha, i.e., 86% more than the absolute control. However, the highest plant growth parameters were obtained with MF which were similar to those obtained with TP1_300 (P &gt; 0.05). Likewise, at farms, the highest plant growth parameters and yield were observed with MF followed by TP1_200 (with a cotton seed yield increase of 146% compared to the control, P &lt; 0.05). In addition, no significant differences were observed between organic fertilizers treatments for growth variables. However yield differences occurred. To resume, TP1_300 kg/ha performed best in terms of growth and yield in on-station experiments, while on-farms, TP1_200 kg/ha produced the highest responses of cotton. Value Cost Ratio (VCR) and Benefit Cost Ratio (BCR) values were generally as good or even better for MF treatment and treatments involving CP1 at both on station and on farm, compared to Ck. Although applying mineral fertilizer (MF) alone as currently done by many farmers appears to make economic sense, this practice is unlikely to be sustainable in the long term. Applying TP1_200 and TP1_300 are two possible strategies that are affordable to farmers and provide returns on investment at least as good as the current practice of sole application of MF. However, a long-term study to assess the effect of compost-activated biochar on crop productivity and soil quality is advised.

Impacted Application of Water-Hyacinth-Derived Biochar and Organic Manures on Soil Properties and Barley Growth

The biochar application can improve the physiochemical properties of both sandy and clayey loam soils and is considered a potential adaptation tool toward climate change. Therefore, the current study is novel in combining water-hyacinth-derived biochar with organic manures as a suggested effective way of treating the soil with biochar under arid and semiarid conditions. Water hyacinth weeds were slow pyrolyzed at a temperature of 300 °C, which resulted in nonalkaline biochar with a pH value of 6.31, which is suitable for alkaline soils. A pot experiment was established to study the impact of the solo application of nonalkaline water-hyacinth-derived biochar (WHB) and its combined application with farmyard (WHB/FM) and poultry manure (WHB/PM) at a rate of 1.5 and 3%, respectively, on some chemical and physical properties of sandy and clay loam soils and some barley’s growth parameters. WHB, WHB/FM, and WHB/PM significantly affected the soil pH at different application rates (1.5 and 3%) in sandy soil. A considerable alteration in water-stable aggregates (WSA), dispersion ratio (DR), available water content (AWC), and cation ratio of soil structural stability (CROSS) index resulted from combining manures (FM and PM) with biochar better than the solo application of biochar. WHB/PM treatments had a superior effect in improving barley’s growth. Relative increases were by 37.3 and 11.0% in plant height and by 61.6 and 28.5% in the dry matter in sandy and clayey loam soils, respectively. Under the conditions of this study, we can conclude that treating the soil with WHB/PM at a rate of 1.5 and 3% is the most effective application. The current study may have a vital role in Egyptian agriculture sustainability by enhancing the soil characteristics of the old agricultural and the newly reclaimed lands.

Transcriptome analysis provides novel insights into the soil amendments induced response in continuously cropped Codonopsis tangshen

Codonopsis tangshen Oliv (C. tangshen) is an important Chinese traditional medicinal plant with various health benefits. However, the growth of C. tangshen are seriously affected by continuous cropping, which led to the decrease of the yield and quality. A field experiment was conducted to learn the effects of soil amendments on the growth of C. tangshen under continuous cropping condition, and the biological events which occurred at molecular level were investigated. The results indicated that the content of chlorophyll a (Chl a), chlorophyll b (Chl b), and carotenoid (Car) was significantly higher in SCPM (silicon-calcium-potassium-magnesium fertilizer), SCPMA (SCPM combined with azoxystrobin) and SCPMAOM (SCPM combined with azoxystrobin and organic manure) treatments. Moreover, the yield and the levels of alkaloid, polysaccharide, flavone and total protein in the treatments of SCPM, SCPMA and SCPMAOM were significantly higher than those in the control, and these indexes were all highest in the SCPMAOM treatment. RNA-sequencing (RNA-Seq) is an economical and efficient method to obtain genetic information for species with or without available genome data. In this study, RNA-Seq was performed to understand how continuously cropped C. tangshen responded to the soil amendments at the transcriptome level. The number of differentially expressed genes (DEGs) were as follows: CK vs. SCPM (719 up- and 1456 down-), CK vs. SCPMA (1302 up- and 1748 down-), CK vs. SCPMAOM (1274 up- and 1678 down-). The soil amendments affected the growth of C. tangshen mainly by regulating the genes involved in pathways of 'photosynthesis,' 'plant hormone signal transduction,' 'biosynthesis of unsaturated fatty acids,' 'phenylpropanoid biosynthesis,' and 'starch and sucrose metabolism,' etc. qRT-PCR was performed to validate the expressions of 10 target genes such as CP26, PsaF, and POX, etc., which verified the reliability of RNA-Seq results. Overall, this study revealed the roles and underlying mechanisms of the soil amendments in regulating the growth of continuously cropped C. tangshen at transcriptome level. These findings are beneficial for improving the continuous cropping tolerance and may be valuable for future genetic improvement of C. tangshen.

Overview of the use of biochar from main cereals to stimulate plant growth

The total global food demand is expected to increase up to 50% between 2010 and 2050; hence, there is a clear need to increase plant productivity with little or no damage to the environment. In this respect, biochar is a carbon-rich material derived from the pyrolysis of organic matter at high temperatures with a limited oxygen supply, with different physicochemical characteristics that depend on the feedstock and pyrolysis conditions. When used as a soil amendment, it has shown many positive environmental effects such as carbon sequestration, reduction of greenhouse gas emissions, and soil improvement. Biochar application has also shown huge benefits when applied to agri-systems, among them, the improvement of plant growth either in optimal conditions or under abiotic or biotic stress. Several mechanisms, such as enhancing the soil microbial diversity and thus increasing soil nutrient-cycling functions, improving soil physicochemical properties, stimulating the microbial colonization, or increasing soil P, K, or N content, have been described to exert these positive effects on plant growth, either alone or in combination with other resources. In addition, it can also improve the plant antioxidant defenses, an evident advantage for plant growth under stress conditions. Although agricultural residues are generated from a wide variety of crops, cereals account for more than half of the world's harvested area. Yet, in this review, we will focus on biochar obtained from residues of the most common and relevant cereal crops in terms of global production (rice, wheat, maize, and barley) and in their use as recycled residues to stimulate plant growth. The harvesting and processing of these crops generate a vast number and variety of residues that could be locally recycled into valuable products such as biochar, reducing the waste management problem and accomplishing the circular economy premise. However, very scarce literature focused on the use of biochar from a crop to improve its own growth is available. Herein, we present an overview of the literature focused on this topic, compiling most of the studies and discussing the urgent need to deepen into the molecular mechanisms and pathways involved in the beneficial effects of biochar on plant productivity.

Effects of Cotton–Peanut Intercropping Patterns on Cotton Yield Formation and Economic Benefits

Intercropping has been widely adopted by farmers because it often enhances crop productivity and economic returns. However, to increase the comprehensive production benefits of agricultural cultivation and increase the economic benefits of cotton in Northwest Shandong Province, a set of green, ecological, and efficient intercropping mode suitable for Northwest Shandong Province was preliminarily formed. A 2-year intercropping experiment was conducted in Xiajin and Dongping counties in Shandong Province, with six alternative intercropping patterns proposed. After analyzing the experimental data, it was determined that the traditional cotton–peanut intercropping method is not mechanized and that a new intercropping mode has been proposed: four rows of cotton and six rows of peanut. We selected the appropriate intercropping mode for Xiajin and Dongping counties. The production efficiency of 4:4 cotton intercropping in Peanut Ridge was the best in Dongping and Xiajin counties, which was 28–123% higher than that of monoculture. This planting pattern is suitable for demonstration and promotion in the two counties, as well as in the traditional cotton area of the old Yellow River in Northwest Shandong.

Soil properties, root morphology and physiological responses to cotton stalk biochar addition in two continuous cropping cotton field soils from Xinjiang, China

Long-term and widespread cotton production in Xinjiang, China, has resulted in significant soil degradation, thereby leading to continuous cropping obstacles; cotton stalk biochar (CSB) addition may be an effective countermeasure to this issue, with effects that are felt immediately by root systems in direct contact with the soil. In this study, we assess the effects of different CSB application rates on soil nutrient contents, root morphology, and root physiology in two soil types commonly used for cotton production in the region. Compared with CK (no CSB addition), a 1% CSB addition increased total nitrogen (TN), available phosphorus (AP), and organic matter (OM) by 13.3%, 7.2%, and 50% in grey desert soil, respectively , and 36.5%, 19.9%, and 176.4%, respectively, in aeolian sandy soil. A 3% CSB addition increased TN, AP, and OM by 38.8%, 23.8%, and 208.1%, respectively, in grey desert soil, and 36%, 13%, and 183.2%, respectively, in aeolian sandy soil. Compared with the aeolian sandy soil, a 1% CSB addition increased TN, OM, and AP by 95%, 94.8%, and 33.3%, respectively, in the grey desert soil , while in the same soil 3% CSB addition increased TN, OM, and AP by 108%, 21.1%, and 73.9%, respectively. In the grey desert soil, compared with CK, a 1% CSB application increased the root length (RL) (34%), specific root length (SRL) (27.9%), and root volume (RV) (32.6%) during the bud stage, increased glutamine synthetase (GS) (13.9%) and nitrate reductase (NR) activities (237%), decreased the RV (34%) and average root diameter (ARD) (36.2%) during the harvesting stage. A 3% CSB addition increased the RL (44%), SRL (20%), and RV (41.2%) during the bud stage and decreased the RV (29%) and ARD (27%) during the harvesting stage. In the aeolian sandy soil, 1% CSB increased the RL (38.3%), SRL (73.7%), and RV (17%), while a 3% caused a greater increase in the RL (55%), SRL (89%), RV (28%), soluble sugar content (128%), and underground biomass (33.8%). Compared with the grey desert soil, a 1% CSB addition increased the RL (48.6%), SRL (58%), and RV (18.6%) in the aeolian sandy soil, while a 3% further increased the RL (54.8%), SRL (84.2%), RV (21.9%), and soluble sugar content (233%). The mechanisms by which CSB addition improves the two soils differ: root morphology changed from coarse and short to fine and long in the grey desert soil, and from fine and long to longer in the aeolian sandy soil. Overall, a 3% CSB addition may be a promising and sustainable strategy for maintaining cotton productivity in aeolian sandy soil in the Xinjiang region.

A critical review on performance indicators for evaluating soil biota and soil health of biochar-amended soils

Amendment of soil with biochar has been widely investigated for soil quality improvement in terms of biotic and abiotic functionalities. The performance of biochar-based amendment varies according to the site characteristics, biochar properties, and soil management targets. There is no existing review that summarizes a broad range of performance indicators to evaluate the health of biochar-amended soil. Based on the latest studies on soil amendment with biochar, this review critically analyzes the soil health indicators that reveal the potential impact of biochar amendment with respect to physicochemical properties, biological properties, and overall soil quality. It is found that soil pH, soil aggregate stability, and soil organic matter are the basic indicators that could influence most of the soil functions, which should be prioritized for measurement. Relevant functional indicators (e.g., erosion rate, crop productivity, and ecotoxicity) should be selected based on the soil management targets of biochar application in agricultural soils. With this review, it is expected that target-oriented performance indicators can be selected in future studies for field-relevant evaluation of soil amendment by biochar under different situations. Therefore, a more cost-effective and purpose-driven assessment protocol for biochar-amended soils can be devised by using relevant measurable attributes suggested in this review.

Biochar induced improvement in root system architecture enhances nutrient assimilation by cotton plant seedlings

BACKGROUND

Raising nitrogen use efficiency of crops by improving root system architecture is highly essential not only to reduce costs of agricultural production but also to mitigate climate change. The physiological mechanisms of how biochar affects nitrogen assimilation by crop seedlings have not been well elucidated.

RESULTS

Here, we report changes in root system architecture, activities of the key enzymes involved in nitrogen assimilation, and cytokinin (CTK) at the seedling stage of cotton with reduced urea usage and biochar application at different soil layers (0-10 cm and 10-20 cm). Active root absorption area, fresh weight, and nitrogen agronomic efficiency increased significantly when urea usage was reduced by 25% and biochar was applied in the surface soil layer. Glutamine oxoglutarate amino transferase (GOGAT) activity was closely related to the application depth of urea/biochar, and it increased when urea/biochar was applied in the 0-10 cm layer. Glutamic-pyruvic transaminase activity (GPT) increased significantly as well. Nitrate reductase (NR) activity was stimulated by CTK in the very fine roots but inhibited in the fine roots. In addition, AMT1;1, gdh3, and gdh2 were significantly up-regulated in the very fine roots when urea usage was reduced by 25% and biochar was applied.

CONCLUSION

Nitrogen assimilation efficiency was significantly affected when urea usage was reduced by 25% and biochar was applied in the surface soil layer at the seedling stage of cotton. The co-expression of gdh3 and gdh2 in the fine roots increased nitrogen agronomic efficiency. The synergistic expression of the ammonium transporter gene and gdh3 suggests that biochar may be beneficial to amino acid metabolism.

Rethinking Manure Application: Increase in Multidrug-Resistant Enterococcus spp. in Agricultural Soil Following Chicken Litter Application

The current study investigated the impact of chicken litter application on the abundance of multidrug-resistant Enterococcus spp. in agricultural soil. Soil samples were collected from five different strategic places on a sugarcane farm before and after manure application for four months. Chicken litter samples were also collected. Enterococci were enumerated using the Enterolert^®/Quanti-Tray 2000^® system and confirm and differentiated into species using real-time PCR. The antibiotic susceptibility profile of the isolates was determined using the disk diffusion method following the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The overall mean bacterial count was significantly higher (p < 0.05) in manure-amended soil (3.87 × 10⁷ MPN/g) than unamended soil (2.89 × 10⁷ MPN/g). Eight hundred and thirty-five enterococci (680 from soil and 155 from litter) were isolated, with E. casseliflavus being the most prevalent species (469; 56.2%) and E. gallinarum being the least (16; 1.2%). Approximately 56% of all the isolates were resistant to at least one antibiotic tested, with the highest resistance observed against tetracycline (33%) and the lowest against chloramphenicol (0.1%); 17% of E. faecium were resistant to quinupristin-dalfopristin. Additionally, 27.9% (130/466) of the isolates were multidrug-resistant, with litter-amended soil harbouring more multidrug-resistant (MDR) isolates (67.7%; 88/130) than unamended soil (10.0%; 13/130). All isolates were susceptible to tigecycline, linezolid and gentamicin. About 7% of the isolates had a multiple antimicrobial resistance index > 0.2, indicative of high antibiotic exposure. Although organic fertilizers are regarded as eco-friendly compared to chemical fertilizers for improving soil fertility, the application of untreated animal manure could promote the accumulation of antibiotics and their residues and antibiotic-resistant bacteria in the soil, creating an environmental reservoir of antimicrobial resistance, with potential human and environmental health risks.

Improving growth and photosynthetic performance of drought stressed tomato by application of nano-organic fertilizer involves up-regulation of nitrogen, antioxidant and osmolyte metabolism

Organic fertilizer usage is been introduced into agricultural practices for preventing the damaging effects of chemical fertilizers. Present study investigated the beneficial role of organic fertilizer (nano-vermicompost) on the growth, oxidative stress parameters, antioxidant and nitrogen metabolism, osmolyte accumulation and mineral elements in tomato under drought stress. Drought stress resulted in reduced growth and biomass accumulation by triggering oxidative stress due to excess accumulation of reactive oxygen species (ROS) and reduced mineral uptake. Application of nano-vermicompost proved significantly beneficial in improving growth and mitigating the drought induced growth decline. Nano-vermicompost increased growth and dry matter content and ameliorated the decline in chlorophyll contents, photosynthesis and PSII activity more significantly at higher concentration (100 mg kg-1 soil). ROS accumulation was significantly reduced by nano-vermicompost application thereby enhancing the membrane stability under normal as well as drought conditions. Furthermore, lipid peroxidation and activities of protease and lypoxygenase were significantly reduced. Drought up-regulated antioxidant system and application of nano-vermicompost further enhanced the activities of antioxidant enzymes and the contents of non-enzymatic antioxidant components. Accumulation of osmolytes including proline, glycine betaine and sugars increased significantly due to nano-vermicompost application. Besides, decline in the activity of nitrate reductase and content of essential mineral elements like nitrogen, potassium and phosphorous was also ameliorated by nano-vermicompost application.

Compost mixed fruits and vegetable waste biochar with ACC deaminase rhizobacteria can minimize lead stress in mint plants

High lead (Pb) concentration in soils is becoming a severe threat to human health. It also deteriorates plants, growth, yield and quality of food. Although the use of plant growth-promoting rhizobacteria (PGPR), biochar and compost can be effective environment-friendly amendments for decreasing Pb stress in crop plants, the impacts of their simultaneous co-application has not been well documented. Thus current study was carried, was conducted to investigate the role of rhizobacteria and compost mixed biochar (CB) under Pb stress on selected soil properties and agronomic parameters in mint (Mentha piperita L.) plants. To this end, six treatments were studied: Alcaligenes faecalis, Bacillus amyloliquefaciens, CB, PGPR1 + CB, PGPR2 + CB and control. Results showed that the application A. faecalis + CB significantly decreased soil pH and EC over control. However, OM, nitrogen, phosphorus and potassium concentration were significantly improved in the soil where A. faecalis + CB was applied over control. The A. faecalis + CB treatment significantly improved mint plant root dry weight (58%), leaves dry weight (32%), chlorophyll (37%), and N (46%), P (39%) and K (63%) leave concentration, while also decreasing the leaves Pb uptake by 13.5% when compared to the unamended control. In conclusion, A. faecalis + CB has a greater potential to improve overall soil quality, fertility and mint plant productivity under high Pb soil concentration compared to the sole application of CB and A. faecalis.

Critical review on soil phosphorus migration and transformation under freezing-thawing cycles and typical regulatory measurements

Freezing-thawing period plays an important role in the soil nutrient cycling. The frequency of freezing-thawing cycles (FTCs) can directly affect the supply of effective soil nutrients, further influences the growth and development of crops. Phosphorus is one of the essential nutrients for crop growth, and almost no compounds in gas form in nature, which is non-renewable resources. In modern agricultural production, phosphorus required by plants is mainly from the soil, but the utilization rate of phosphorus fertilizer in soil is generally only 10%-25%. Therefore, it is of great significance to study phosphorus migration and transformation behavior of soil in the non-growth period and related interfacial processes for improving the utilization efficiency of phosphorus fertilizer, increasing crop yield, reducing excessive application of phosphorus fertilizer, and subsiding environmental pollution. This paper systematically concludes key interfacial process of soil phosphorus in freezing-thawing soil system and relative mechanisms describing migration and transformation behavior of soil phosphorus. Besides, it summarizes the mediating effects of widely used soil conditioner on phosphorus cycling. The results show that freezing- thawing will destroy the structure of the soil, causing phosphorus to migrate along with runoff, soil water and heat movement. It also affects the types of microorganisms, the activity of microbial communities and the oxidation-reduction reaction of related minerals, making the phosphorus in soil from an unstable form to an active form. Biochar and humic substances can improve the physical and chemical properties of the soil, and have favorable effects on soil during freezing-thawing period. This review has important significance for the rational utilization of existing phosphorus resources, the maintenance of soil phosphorus cycle balance and the sustainable development of agriculture, meanwhile, has guiding significance for the reasonable utilization of agricultural wastes.

Cadmium Immobilization in the Rhizosphere and Plant Cellular Detoxification: Role of Plant-Growth-Promoting Rhizobacteria as a Sustainable Solution

Food is the major cadmium (Cd)-exposure pathway from agricultural soils to humans and other living entities and must be reduced in an effective way. A plant can select beneficial microbes, like plant-growth-promoting rhizobacteria (PGPR), depending upon the nature of root exudates in the rhizosphere, for its own benefits, such as plant growth promotion as well as protection from metal toxicity. This review intends to seek out information on the rhizo-immobilization of Cd in polluted soils using the PGPR along with plant nutrient fertilizers. This review suggests that the rhizo-immobilization of Cd by a combination of PGPR and nanohybrid-based plant nutrient fertilizers would be a potential and sustainable technology for phytoavailable Cd immobilization in the rhizosphere and plant cellular detoxification, by keeping the plant nutrition flow and green dynamics of plant nutrition and boosting the plant growth and development under Cd stress.

Potential role of compost mixed biochar with rhizobacteria in mitigating lead toxicity in spinach

Consumption of heavy metals, especially lead (Pb) contaminated food is a serious threat to human health. Higher Pb uptake by the plant affects the quality, growth and yield of crops. However, inoculation of plant growth-promoting rhizobacteria (PGPR) along with a mixture of organic amendments and biochar could be an effective way to overcome the problem of Pb toxicity. That’s why current pot experiment was conducted to investigate the effect of compost mixed biochar (CB) and ACC deaminase producing PGPR on growth and yield of spinach plants under artificially induced Pb toxicity. Six different treatments i.e., control, Alcaligenes faecalis (PGPR1), Bacillus amyloliquefaciens (PGPR2), compost + biochar (CB), PGPR1 + CB and PGPR2 + CB were applied under 250 mg Pb kg^-1 soil. Results showed that inoculation of PGPRs (Alcaligenes faecalis and Bacillus amyloliquefaciens) alone and along with CB significantly enhanced root fresh (47%) and dry weight (31%), potassium concentration (11%) in the spinach plant. Whereas, CB + Bacillus amyloliquefaciens significantly decreased (43%) the concentration of Pb in the spinach root over control. In conclusion, CB + Bacillus amyloliquefaciens has the potential to mitigate the Pb induced toxicity in the spinach. The obtained result can be further used in the planning and execution of rhizobacteria and compost mixed biochar-based soil amendment.