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The agri-food industry, produces organic residues that could be reused as fertilizer, thereby allowing the recycling of nutrients for crops and the replacement of mineral fertilizers. In this context, here we examined the capacity of anaerobic digestates and mixed residues (digestates plus spent mushroom substrates) to supply nutrients to lettuce (Lactuca sativa L.) grown in a greenhouse experiment. Moreover, the potential leaching of nutrients into the soil was evaluated in a column assay. The results obtained from organic residues treatments were then compared to those achieved in soil treated with mineral fertilizer and in untreated soil. Digestates treatments minimized the potential risk of nitrate (NO3−) leaching by allowing the slow release of NO3− maintaining crop yield. Given our observations, this type of organic residues emerges as an alternative to mineral fertilizer. The loss of NO3−-N from the total amount of N applied reached ∼3% in the mixed residues treatments, 36–46% in the digestate treatments, and 68% in the mineral fertilizer treatment. The mixed treatments showed low available N content as a result of immobilization in the soil, which is a limiting factor for crop production. Moreover, the organic residues treatments had no negative effect on lettuce seed germination or plant growth with respect to parameters such as chlorophyll, total polyphenols, and heavy metals in aerial biomass. The findings reported herein contribute to a better understanding of nutrient availability provided by organic residues materials and the capacity of these amendments to replace mineral fertilizers and avoid nutrient loss by leaching. Digestate treatments showed a similar capacity to maintain lettuce production as mineral fertilizer. Mixed treatments did not provide mineral N for the crop by N immobilization in soil. Nitrate loss when organic residues were applied was lower than for the mineral fertilizer treatment. Soil amendment with organic residues has no negative effects on lettuce yield. Digestates emerge as an alternative to mineral fertilizers for lettuce production, reducing soil nutrient loss. [ABSTRACT FROM AUTHOR]

Leonardite is an important source of organic fertilizers and soil amendment. The objective of this study was to determine the effects of increased doses of leonardite (control (L0), 20 (L20), 40 (L40), 60 (L60), and 80 (L80) t ha−1) on soil properties at different incubation times (control (T0), 15 (T15), 30 (T30), 45 (T45), 60 (T60), and 90 (T90) days). Analysis results of soil samples taken during six different incubation periods. Results showed that application of leonardite significantly improved soil organic matter (SOM), total nitrogen (N), exchangeable calcium (Ca) and, available iron (Fe), manganese (Mn) and zinc (Zn), especially with L40 and L60. Prolonged incubation time was significantly increased N, P, K, Ca, Fe, Zn concentrations especially T60 and T90. The nutrient concentration of the tomato plants was not affected by increased doses of leonardite, except for total N, Fe and Cu. By the way, prolongation of the incubation period resulted in fluctuating nutrient concentrations of the plant. As a result, it was determined that leonardite improved the chemical properties of the soils but it was not sufficient in the feeding of the tomato plant. Therefore, leonardite must be used with chemical fertilizers for plant growing. [ABSTRACT FROM AUTHOR]

Soil salinity is a major challenge in agriculture, particularly in calcareous soils with high calcium carbonate levels. Biochar, produced from biomass pyrolysis, is being considered as a potential solution for mitigating salinity effects. A greenhouse pot experiment was conducted using calcareous soil from a saline field to investigate the effects of sugarcane biochar applied at different rates (0.0%, 2.0%, and 5.0%) on soil properties and wheat (Triticum aestivum L.) growth. Results showed that both Low Rate (2.0% biochar) and High Rate (5.0% biochar) treatments significantly improved soil pH, reduced electrical conductivity (EC), and increased soil organic matter (SOM) content. Plant growth indicators such as plant height, stem diameter, and leaf chlorophyll content also showed significant improvement with biochar application. High Rate had more pronounced effects compared to Low Rate. The analysis confirmed the significant effects of biochar on soil properties and plant growth, indicating its potential as a beneficial soil amendment. Sugarcane biochar has the potential to mitigate salinity stress and enhance crop productivity in calcareous soils. Further research is needed to explore the long-term effects of sugarcane biochar application and its interactions with other soil management practices in different crop systems. These findings highlight the promising role of biochar as a sustainable approach for mitigating salinity stress in agriculture and improving soil quality for crop production. The study's findings highlight the potential industrial applications of sugarcane biochar in addressing soil salinity issues prevalent in calcareous soils, particularly in agriculture. The research underscores the positive impact of biochar on soil attributes, plant growth, and nutrient availability. With its ability to improve soil pH, reduce salinity, increase soil organic matter, and enhance plant growth, sugarcane biochar emerges as a promising soil amendment for agricultural use. This presents an opportunity for industries involved in sustainable agriculture, soil management, and crop enhancement to explore the integration of biochar into their practices. Additionally, the study emphasizes the need for further research and field trials to optimize biochar application rates, assess economic feasibility, and ensure environmental sustainability. The insights gained from this study offer a pathway for industrial stakeholders to explore biochar's role in enhancing soil quality, promoting plant growth, and ensuring sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Salinity is a major environmental problem that adversely affects plant growth by increasing soil osmotic pressure and disrupting plant nutrition. Using organic amendments is a viable tool for reducing physiological and morphological effects of excessive soil salinity on plants. To show the impacts of tea waste, compost and biochar on nutrient status and growth parameters of spinach (Spinacia oleracea L.) raised in salinity conditions, this study has employed factorial CRD with two treatments involving soil salinity (2.5 and 8 dS m−1) and organic materials (spent tea waste (STW), spent tea waste compost (STWC) and spent tea waste biochar (STWB)) at 0 and 3% w/w in three replications. As soil salinity increased from 2.5 to 8 dS m−1, fresh weight and dry matter production decreased by 31.5% and 30.4%, respectively. Phosphorous and potassium concentrations in plant tissue also decreased significantly due to the increase in salinity. Organic amendments (except STW) due to their physicochemical properties increased the nutrients uptake and growth parameters of the plant. Compared to other amendments, biochar reduced salinity effects on plant growth more effectively, which is possibly due to its high nutrient adsorbing and water holding capacity. In saline conditions, the highest potassium to sodium ratio belonged to the biochar treatment, which was 3.22 and 2.78 times greater than spent tea waste and compost, respectively. Therefore, it was preferred to change the spent tea waste into biochar before being used as soil amendment. [ABSTRACT FROM AUTHOR]

Sandy and acidic soil conditions are the major factors limiting the production of some vegetable crops in acidic soils. This study aims to examine the effect of various amendments on the growth, yield and mineral nutrients uptake of stem amaranth. Two pot experiments were conducted separately in two generic soils. Six treatments viz. T0 = control (without amendment), T1= lime, T2 = lime + wetland bottom sediment, T3 = lime + vermicompost, T4 = lime + rice straw biochar (RSB) and T5 = RSB were used for both experiments following CRD with four replications. Results revealed that plant heights (45.96 and 50.33 cm) of amaranth grown in alluvial and hill soils, respectively, were the highest in T4 treatment. Similarly, treatment T4 showed the highest fresh (118.53 and 116.11 g pot−1, respectively) and dry biomasses (16.98 and 19.54 g pot−1, respectively) for both soils. For both soils, treatment T4 resulted better nutrient uptake of N, P, K, S, Zn, Fe and Mn by edible stem, while non-amended soil gave the lowest result at all parameters. Analytical values of post-harvest soils indicated that T4 and/or T5 treatments resulted in an improvement in soil pH, organic carbon, total N, exchangeable K and extractable P, S and Zn. Treatment T3 showed elevated concentrations of extractable soils Fe and Mn. The amendment RSB combined with lime can be preferably used in strong acidic soils for cultivation of stem amaranth. [ABSTRACT FROM AUTHOR]

Phaseolus vulgaris is one of the most widely consumed legumes across the globe. It is rich in protein, carbohydrates, fiber, bioactive compounds, and mineral contents. Occurrences of drought under changing climate have posed a challenge to the quality and quantity of the crop yield. Our study, taking Phaseolus vulgaris as a test legume, reports that as a soil amendment, biochar and farmyard manure mitigated drought-induced damage in the plant. The experiment was set up in a greenhouse with 1 m2 blocks together arranged in factorial randomized block design. Water withdrawal was done for 15 days in either vegetative or reproductive stage of the crop to simulate drought conditions. Biochar or Farmyard manure was applied at the rate of 10t ha−1 as soil amendment and each treatment was replicated thrice. Higher photosynthesis (up to 23% and 16%, respectively), leaf protein (41% and 30%, respectively), grain protein (4% and 19%, correspondingly), and in-vitro protein digestibility (60% and 254%, respectively) were noted under application of both the amendments. Grain quality in terms of protein content, in-vitro protein digestibility, and protein fractions of Phaseolus vulgaris was improved under drought due to the addition of biochar and farmyard manure. However, the application of those amendments at the rate of 10t ha−1, especially farmyard manure, had a negative impact on the antinutritional factor (phytic acid) and mineral bioavailability. Between the two amendments studied, farmyard manure proved to be more efficient in promoting the overall grain quality of P. vulgaris, but its inimical effects must be concorded. [ABSTRACT FROM AUTHOR]

Agroecology is gaining increased attention by experts and global organizations; however, it's practical application in the field remains understudied, particularly in developing countries. Here, we aimed to evaluate common agroecological practices at three sites in Tanzania, including organic soil amendments, intercropping, and biological pest control – individually, in pairs, or in three-way combinations at each site. Information Communication Technology tools – the AgroEco Research and AgroEco Analysis application – were used for data gathering & storage and data visualization & statistical analysis, respectively. We found that high maize kernel weights (as proxy for yield) can be obtained from nutrient-poor soils specifically when grown with a combination of organic soil amendments and intercropped with legumes – ranging from 3 to 4.5 t/ha (with a maximum of 7 t/ha on one occasion) and exceeding national maize yields of 1–2 t/ha in Tanzania. However, intercropping and biological pest control individually and in combination did not affect maize yield. Under flood or drought conditions, only plots with soil fertility amendments produced some harvestable maize kernels. Our results provide a substantial reference for recommending and advocating agroecological methods to smallholder farmers, farmer training organizations, and policy makers. [ABSTRACT FROM AUTHOR]

Recycling of phosphorus (P) from feedstocks to soils can provide sustainability in agriculture. In our incubation study, we investigated the effects of adding cow manure-derived vermicompost (CMV), cow manure (CM), sugarcane trash biochar (STB), and triple super phosphate (TSP) to extractable P in a sandy loam soil. P was added to the soil at rates of 0, 50, 100, 200, and 300 mg kg−1 based on their total P contents. The amended soils were incubated for 1, 4, 8, and 16 weeks (wk) at room temperature and extractable P samples were measured (by water, Olsen, Mehlich-3 and Bray and Kurtz) and soil pH was monitored. After 1 wk of incubation, the extractable P values were 1.4 mg kg−1 with STB at the smallest while the highest was 79 mg kg−1 with TSP. The corresponding P values in the CMV and CM amended soils were 33 mg kg−1 and 31 mg kg−1. The reductions of extractable P from 1 to 16 wks of incubation were 40%, 35%, and 80% in the CMV, CM and TSP amended soils, respectively, while they increased from 1.43 mg kg−1 to 6.05 mg kg−1 ((320%) in the STB amended soil. Among the amendments, a significant positive relationship was observed between extractable P and the pH in soils amended with STB. The findings revealed that varying P extractability in soils depends on amendment types and duration of incubation. Sugarcane trash biochar did not exhibit an ability to substitute inorganic P fertilizer for assessing bioavailable P. [ABSTRACT FROM AUTHOR]

Biochar is widely used as a good soil amendment, while knowledge of modified biochar application in tea garden soils contaminated by fluoride (F) and cadmium (Cd) is insufficient. The tea seedling (Camellia sinensis L.) growth assay was performed to evaluate interaction of soil Cd and F and the improving effect of aluminum trichloride-modified corn stalk biochar (Al-BC) on their speciation, phytoaccumulation and phytotoxicity. Results showed that soil F speciation ratio sequence was as follows: residual > exchangeable > organic-bound > water-soluble > Fe/Mn oxide-bound. Soil exchangeable Cd was the largest Cd speciation (>35.6%), probably due to the low pH values in the acid tea gardens. Root F contents showed a strong significant relationship with soluble F contents (r = 0.92, P <.01) and similarly root Cd highly connected with exchangeable Cd (r = 0.86, P <.01). Seedling height, fresh and dry weight, root surface area, length, and photosynthetic pigment showed different sensitivities to F or Cd oxidative stress and toxicity effects, and only root F contents significantly inversely correlated with them (r = 0.74–0.80, P <.01). The interaction of Cd and F, could influence their speciation distribution and antagonized each other in root accumulation. Meanwhile, joint simulation models showed that antagonistic effects were observed in the F and Cd mixture soils for most cases at Enshi. Biochar application reduced bioavailable F and Cd contents, and thus decreased F and Cd accumulation in tea roots and obviously alleviated toxicity effects. For instance, biochar application significantly reduced root F contents, which had 33.2% to 62.2% declines at Enshi and 39.7% to 77.2% declines at Huanggang. Meanwhile, the soil properties were improved as biochar added, with an increase in soil pH, EC, CEC and organic matter. Overall, Al-modified biochar was beneficial environmental materials for reducing both F and Cd bioavailability. [ABSTRACT FROM AUTHOR]

It has been proposed that the quality of acidic soils can be improved in the presence of alkaline byproduct amendments containing silicon (Si), calcium (Ca), magnesium (Mg), and potassium (K). In the present study, we aimed to explore the effect of byproduct amendments on ameliorating acidic soil in Jiaodong Peninsula of China in the existence of different types of low-molecular-weight organic acids (LOAs, such as malic acid, citric acid, oxalic acid, and succinic acid) that are usually excreted by plant roots. Therefore, a 60-day incubation test was carried out to assess the effect of byproduct amendments and LOAs on soil physicochemical properties, soil available Mg and Ca, cation exchange capacity (CEC), soil respiration, and enzyme activities. The results showed that in the presence of LOAs, the byproduct amendments could still increased the soil pH and decreased the soil exchangeable acid and exchangeable Al3+. Compared with the control group (CK), all byproduct amendment-containing treatments could increase soil available Mg and Ca, soil CEC, soil respiration, and soil sucrase (S-SC) activity. The addition of byproduct amendments could significantly improve the chemical and biological properties of the acidic brown soils in Jiaodong Peninsula of China. However, LOAs, especially the LOAs that could precipitate with Ca in byproduct amendments, negatively impair the ameliorating effect on acidic soil compared with byproduct amendments alone treatment. When using byproduct amendments to ameliorate acidic soil, the type of LOAs secreted by plant roots was an influencing factor that must be considered. [ABSTRACT FROM AUTHOR]

Soil application of treated sewage sludge is considered a beneficial management option for agriculture and environment. Sludge treated with clay minerals or biochar was evaluated as soil amendment, in comparison with limed or untreated sludge. Bentonite, vermiculite, biochar or lime was added to dewatered sewage sludge at 0 and 15% rates, in three replications and air-dried. Then, the treated and untreated sludge were added to two soils, one acid and one alkaline, at 0 (control), 1 and 3% rates, in three replications. The results showed that the pH of acid soil significantly increased compared to control upon addition of treated and untreated sludge at both rates, but remained acidic (<6.0) in all cases except for limed sludge. Upon addition of 3% treated or untreated sludge to both soils, organic carbon (OC) significantly increased compared to control. The same stands for soil available ammonium nitrogen (NH4-N), phosphorus (P), potassium (K), copper (Cu), zinc (Zn) and boron (B) for both soils and rates. Soil total heavy metals, which regulate sludge's agronomic use, were below the legislative limits. However, the 3% addition rate of all kinds of sludge, especially of untreated, to both soils increased the electrical conductivity of saturation extract (ECse >2 dS m−1) at unacceptable levels for sensitive crops and available P, B and Zn 2–3, 2–4 and 6–12 times above the initial, respectively. Consequently, sewage sludge treated with bentonite, vermiculite or biochar could be used as a soil amendment but at rates lower than 3% (≈120 Mg ha−1). [ABSTRACT FROM AUTHOR]

Ethylenediamine-N,N'-disuccinic acid (EDDS) has been studied extensively for its potential use as an amendment in agriculture due to its numerous beneficial properties. The widespread usage of microplastics (MPs) poses a growing threat to plant growth. This study investigated the effects of Polystyrene MPs (PSMPs) and EDDS on soil pH, EC, organic matter (OM), available nutrients, and maize (Zea mays L.) growth in a calcareous soil. Results showed that both PS and EDDS had significant effects on soil pH, with higher concentrations leading to a decrease in pH. PSMPs negatively impacted soil health by increasing EC and decreasing OM, nitrogen (N), phosphorus (P), and potassium (K). EDDS had potential applications in soil remediation and phytoremediation by decreasing EC and increasing N, P, and K. The interaction between EDDS and PSMPs suggests that their effects on soil pH may be modulated by each other. The study highlights the potential negative impacts of high concentrations of PS on soil health and the potential benefits of using EDDS at lower concentrations in soil remediation and phytoremediation. However, further research is needed to understand the mechanisms and environmental impacts of EDDS and the combined effects of EDDS and PSMPs on soil properties and plant growth. Plastic pollution is a serious environmental issue affecting soil health worldwide, and this study sheds new light on the potential benefits of using EDDS at lower concentrations for soil remediation and phytoremediation. The findings reveal that EDDS can mitigate the negative impacts of PS on soil health and maize growth by improving nutrient availability, enhancing soil structure, and water retention. The study is the first to investigate the interactive effects of EDDS and PS on maize growth parameters across different levels of PS contamination. The results provide critical insights into the mechanisms underlying the mitigating effects of EDDS and highlight the need for further research on the environmental impacts of plastic pollution and effective management practices. Overall, this study presents a novel approach to mitigating the negative impacts of plastic pollution on soil health and crop production, with important implications for sustainable agriculture and environmental preservation. This study shows that EDDS, at lower concentrations, can mitigate the negative impacts of PSMPS on soil health and maize growth. It is the first to examine interactions between EDDS and PSMPS across varying levels of contamination. The results point to the potential benefits of EDDS as a soil amendment to remediate MPs pollution, revealing insights into its mechanisms of action. Findings suggest possible solutions for MPs pollution in agriculture but call for more research to balance environmental goals. Both EDDS and PSMPs impacted soil pH, EC, OM, and nutrient levels. PSMPS caused pH decrease, increased EC, and reduced OM, N, P, and K levels, negatively affecting soil health. EDDS showed potential for soil remediation, increasing N, P, and K levels, and decreasing EC, with optimal concentrations. Interaction between EDDS and PSMPs influenced soil pH modulation, revealing interplay between their effects. PSMPs had significantly negative effects on maize growth parameters, including root and shoot dry weight, chlorophyll content, leaf area, and plant height. EDDS amendment mitigated PSMPs's adverse impacts on maize growth, especially chlorophyll content and leaf area. Interaction between PSMPs and EDDS improved soil and plant health, possibly via chelation, property alteration, and enhanced nutrient availability. EDDS demonstrates promise as an environmentally friendly strategy to counteract the effects of PSMPs contamination on agricultural soils and crop productivity. Further research is essential to understand EDDS mechanisms and environmental impacts, as well as the combined effects of EDDS and PSMPs on soil and plant properties. [ABSTRACT FROM AUTHOR]

The pollution of soils and groundwater by heavy metal pollutants is a widespread environmental problem, particularly in Iran. One cost-effective method to remediate the polluted soils is phytoremediation, in which different plants are used to extract the heavy metals from soil and accumulate them in their organs. In this study, the phytoremediation potential of native plants of Southwestern Iran in removing nickel and lead from polluted soil was assessed separately and in combination with organic amendments of compost and biochar.Hence, the pot experiments were conducted in the greenhouse using soil gathered from the Pazanan oil refineryin Gachsaran, located at Kohgiluyeh and Boyer-Ahmad Province. Then, the hierarchical cluster analysis was applied to classify the different treatments of amendments.The results indicated that the phytoremediation strength of three native species for Ni uptake was C. procera> St. Plumosa > M. sativa; and for Pb uptake was St. Plumosa > C. procera> M. sativa. Also, the utilisation of organic materials originated from urban waste caused to increase in the Ni and Pb accumulation in root and shoot of these species as well as the residual concentration of the metals in soil. Based on the cluster analysis, the treatment of biochar 2% showed the most effect on the residual concentration of heavy metals in soil (1128.00 mgkg−1);the treatment of biochar 1% represented the highest accumulation of metals at the root (158.82 mgkg−1), while all treatments of different amounts of amendments have the same effect on the accumulation of heavy metals in the shoot (151.38 mgkg−1). In general, cluster analysis showed that the organic amendments, especially biochar even at low amounts can improve the phytoremediation capability of the studied native species in removing Ni and Pb from polluted soil. [ABSTRACT FROM AUTHOR]

Spent coffee grounds (SCG) and derived products have characteristics (high content of carbon and nutrients) that make them potentially useful as soil amendments. To evaluate the impact of SCG and derived products on soil functionality, an incubation (30 days) was performed with a soil amended with different doses (0.5, 1 and 1.75%) of SCG, a biochar produced from SCG at 270 °C (B270) and a hydrochar produced from SCG at 200 °C (H200). During incubation, the following parameters were measured: CO2 and N2O emissions, extractable organic Carbon (EOC), extractable Nitrogen (EN), NO3− and NH4+, microbial biomass Carbon (BC) and Nitrogen (BN). Soil amended with the most degradable materials (SCG and H200) showed greater amounts of CO2, BC and EOC, but also N immobilization. B270 was the most efficient amendment for the retention of added C and led to less N immobilization when compared with SCG and H200. SCG derived amendments can fulfil different functions in soil: SCG and H200 are more indicated for increasing C mineralization and microbial pool, while B270 is more effective at enhancing organic C levels. Higher rates of application generally led to more positive impacts on soil functioning, with the only limitation being short-term N immobilization. [ABSTRACT FROM AUTHOR]

A major obstacle to the creation of efficient biobased disease management practices continues to be the poor integration of traditional agricultural practices and cutting-edge technical approaches. The present review will expand the understanding of organic amendments and metabolites-mediated microbial community metabolism and their mechanistic aspects in disease-suppressive soil (DSS). Organic amendments have been shown to promote the biocontrol potential of resident soil microbiota. Organic amendments positively affect the labile carbon, cation exchange content (CEC) and microbial enzymatic activity. DSS is considered a rich source of beneficial soil microbial community that produces a plethora of antibacterial metabolites. Multiple gene clusters associated with known metabolites offer mechanistic insights associated with disease-suppressive phenotypes. Organic amended soil has higher abundance of chemotaxis genes. Several strains of Bacillus and Pseudomonas produce key metabolites, phenazines, 2,4-diacetylphloroglucinol, pyoluteorin, pyrrolnitrin, cyclic lipopeptides and volatile organic compounds in DSS. High-resolution metagenomics combined with bioinformatics tools would be instrumental in the identification of biomarkers associated with suppressive soils. The integration of traditional and genomic approaches can be employed to infer the untapped potential of resident soil microbiomes. [ABSTRACT FROM AUTHOR]

Soil aggregate is important to soil quality. Straw return is beneficial for soil amendment, but the effects of straw and straw-derived biochar on aggregate formation and stability in paddy soil are unclear. This study carried out a field experiment for 2 years in Northeast China with four treatments: conventional fertilization (CF), straw (ST, 7.5 t ha−1 year−1), biochar (BC, 2.5 t ha−1 year−1), and biochar-based fertilizer (BCF, 0.75 t ha−1 year−1). Compared with the CF and BCF, BC and ST improved the macroaggregates and significantly increased soil total carbon and aggregate organic carbon, indicating a sustained positive role in promoting the formation and stability of aggregates. BC significantly improved aggregate stability. Correlation analysis showed that macroaggregates (2–0.25 mm) can be increased by increasing the heavy fraction organic carbon (HFOC), BC and ST significantly increased the HFOC, and BC had a greater effect. Scanning electron microscopy (SEM) showed that the combination of biochar and soil particles can be captured with strong water scouring. BCF showed an increasing trend in the formation and stability of soil aggregates. In comparison, biochar had a greater effect on promoting the formation of macroaggregates and the stability of soil aggregates with a significant sustainable effect. [ABSTRACT FROM AUTHOR]

Use of saline-sodic irrigation water degrades soil health and reduced mustard yield, particularly in India's low-rainfall regions. This research was conducted to assess the effect of sodic water and nitrogen sources on soil organic carbon (SOC), microbial biomass, soil enzymatic activities, and interaction effects on mustard seed yield. The experiment was laid out in split-plot design comprising four levels of sodium adsorption ratio (SAR) of water (6, 10, 20, and 30) and six nitrogen sources [(control, 125% recommended dose of nitrogen (RDN) through urea, 75% RDN+50% RDN through farm yard manure (FYM), 75% RDN through urea+50% RDN through vermicompost (VC), 50% RDN through urea+75% RDN through FYM, 50% RDN through urea+75% RDN through VC]. The use of high SAR irrigation water caused a significant reduction in soil fertility and microbial parameters. The combined use of chemical fertilizers, FYM, and vermicompost significantly increased microbial activities (64.9% SMB-C), SOC (23.5%), soil enzyme activity (dehydrogenase and alkaline phosphates), and mustard seed yield (49%). The use of 50% RDN via urea+75% RDN via VC was suggested as a better technology for minimizing the adverse effect of high SAR water on crop yield. [ABSTRACT FROM AUTHOR]

Soil amendments are a broad class of materials that enhance physical, chemical or biological characteristics in croplands, pastures, or rangelands. While organic soil amendments such as manure, mulch and seaweed have well established agronomic benefits, there has been renewed private and governmental interest in quantifying and incentivizing their role in mitigating climate change. Likewise, biostimulants and biopesticides, which are intended to target specific plant or microbial processes, are emerging with claims of improved soil health, crop yields, soil organic carbon sequestration, and greenhouse gas emission reductions. We conducted a literature review to address the climate mitigation potential of organic soil amendments, including biostimulants and biopesticides. In doing so, we identify three elements of climate mitigation through the use of soil amendments: soil organic carbon sequestration, soil greenhouse gas emission reductions, and life cycle emission reductions. We review common soil amendment classes in detail, addressing the empirical evidence (or lack thereof) in which they meet these three elements of climate mitigation. We conclude by suggesting priorities for government and private investment. [ABSTRACT FROM AUTHOR]

The current investigation depicts the individual and synergistic effects of two important plant growth promoting microbial groups viz. Plant Growth Promoting Rhizobacteria (PGPR) and Phosphate Solubilizing Bacteria (PSB) in alleviating the phytotoxic impacts of chromium in Vigna radiata (L) R. Wilczek (green gram) seedlings. Cr6+ (100 ppm) treatment caused a stiff decline of about 44%, 72%, 68%, and 49% reduction in root and shoot length as well as leaf number and leaf area respectively as compared to control after 90 d of exposure. However, combined amendment with PGPR and PSB causes a significant amelioration of Cr toxicity though doubling the shoot length and leaf area with a 4 times increase in root length and leaf number after 90 d of growth. Total chlorophyll synthesis showed a 68% reduction in Cr6+ (100 ppm) which was ameliorated by combined treatments of PGPR and PSB. It showed a 123% increased total chlorophyll content than Cr6+ (100 ppm) whereas individual application of PGPR and PSB showed a 46% and 27% increase respectively. Combined application of PGPR and PSB with a toxic dose of Cr showed significant boosting alleviation ability and indicates its ameliorative role for abatement of Cr-induced toxicity. The present research work suggests the combined potential of PGPR and PSB in agriculture and can be adopted as a sustainable strategy for the alleviation of Cr toxicity stress in mining soil The present invitro hydroponic study is an novel alternative phytotechnological approach of using a combined application of PGPR and PSB for remediation/mitigation of Cr pollution. The synergistic role of PGPR and PSB in developing Cr-induced stress tolerance in green gram seedlings is depicted. The implication of these two tools significantly alleviates the Cr toxicity stress in green gram and effectively increased the growth of the plant in a stressed condition. The combined treatment of PGPR and PSB represents an improved strategy for the amelioration of chromium toxicity in green gram. The present research work suggests the combined potential of PGPR and PSB in agricultural and can be adopted as a sustainable strategy for the alleviation of Cr toxicity stress in mining soil. This suggest the possible application of PGPR and PSB as an effective tool for the bioremediation of Cr and growing green gram crops in chromium-contaminated areas. In this way, it can also contribute some plantation practices for the growth and survival of plants in contaminated sites and minimizing the perilous impact of chromium on the soil. [ABSTRACT FROM AUTHOR]

The present investigation was carried out in an on-going long-term fertilizer experiment, initiated during 1972 at experimental farm of Department of Soil Science, CSK HPKV Palampur, to study the long-term effect of fertilizers and amendments on soil aggregate stability and carbon dynamics in an acid Alfisol under maize-wheat cropping system. The experiment comprised of eleven treatments. The soil of the experimental site was silt loam and classified taxonomically as "Typic Hapludalf" (subgroup). Soil samples were collected from surface (0–0.15 m) layer after the harvest of wheat (rabi, 2019–2020) and were analyzed for different aggerate size and their carbon fractions. The addition of FYM enhanced the macroaggregates (>0.25 mm) as compared to microaggregates (<0.25 mm). Incorporation of FYM alone or in combination with chemical fertilizers enhanced the accumulation of different C pools in all aggregate fractions over unfertilized control. Among the macroaggregates, 1–0.5 mm fraction had higher total organic carbon (TOC), organic carbon (OC), labile carbon (LC) and non-labile carbon (NLC) as compared to microaggregates. Aggregate-associated carbon is less susceptible to physical, microbiological, and enzymatic degradation, and is a potential carbon reservoir that is protected from mineralization. Addition of FYM along with 100% NPK recorded highest SOC stocks, SOC sequestration rate and highest carbon buildup. Different aggregate fractions of TOC, OC, LC and NLC were found to be positively and significantly correlated with available N, P and K and negatively and significantly correlated with bulk density whereas, positively and non-significantly correlated with soil pH and electrical conductivity. Different aggregate fractions of TOC, OC, LC and NLC were positively and significantly correlated with grain and straw yield of wheat. [ABSTRACT FROM AUTHOR]

If produced in large quantity, spent mushroom wastes/compost (SMW/SMC) could constitute an environmental problem due to its leachate contaminating surface and groundwater. It could be re-used as soil amendment due to its rich nutrient composition. The suitability of SMC derived from sawdust cultivation of Pleurotus ostreatus K. for production of Celosia argentea L. in pots (5 kg of topsoil, 1:1 top soil by weight and 5 kg of SMC alone (corresponding to 0, 5 and 10 t∙ha−1, respectively); sole SMC and 100 kg∙ha−1 NPK as control) and field trials (0, 5, 10, and 15 t∙ha−1, with NPK at 60 kg∙ha−1 as control) were examined. The top soil used was of the Alfisol group of the basement complex which is locally classified as Ibadan series. Yield increased significantly with increase in SMC rates in pot and field-trials, relative to control, indicating SMC derived from sawdust cultivation of P. ostreatus as a potential fertilizer. [ABSTRACT FROM AUTHOR]

Soil salinization is a major threat to crop production. Biochar and aluminum sulfate as soil amendments are critical for improving rice (Oryza sativa L.) productivity under saline-sodic conditions. This study explored the effects of rice-husk biochar and aluminum sulfate on rice growth, biomass, yield, and soil properties under saline-sodic conditions. The experiment was carried out in an experimental field located at the Jilin Agricultural University, China. Five treatments, viz., T0 (no biochar, no aluminum sulfate, no nitrogen), T1 (no biochar, no aluminum sulfate, with NPK), T2 (aluminum sulfate and NPK), T3 (biochar and NPK), and T4 (biochar, aluminum sulfate, and NPK), arranged in a completely randomized design with five biological replicates, were assessed. Compared to T0, plant height, tiller number, leaf dry weight, panicle dry weight, sheath dry weight, stem dry weight, and total dry biomass significantly increased by 14.67%, 56.39%, 60.13%, 59.53%, 39.00%, 58.36%, and 55.99%, respectively, with T1. Compared to T0, the grain yield significantly increased by 82.79% with T1. Additionally, biochar and aluminum sulfate applications significantly decreased the Na+ concentration in different rice organs and considerably increased the K+ concentration and consequently, the K+/Na+ ratio. Moreover, compared to the control, the soil pH, Ca2+, Mg2+, CO32-, and Cl- concentrations under T1, T2, T3, and T4 treatments were substantially improved. Therefore, biochar and aluminum sulfate applications can alleviate saline-sodic stress, improve soil health, and increase rice productivity on saline-sodic soils. The study findings are anticipated to help develop new management strategies for improving rice production under saline-sodic conditions. [ABSTRACT FROM AUTHOR]

Amelioration of salt affected soils aims to reduce exchangeable sodium percentage (ESP), improve crop growth and yield. A field study was conducted with soybean-mustard cropping system for four consecutive years (2016–2019) to study the effect of soil amendments on crop yield, nutrient use efficiency and soil properties in degraded vertisol of North Western India. Treatments consist of various combinations of gypsum, farm yard manure (FYM) and crop residue (CR) with recommended fertilizer doses (RNPK), were laid in random block design with three replications. Application of gypsum alone and combined with organic amendments, showed pronounced decrease in ESP, slight reduction in pH, increased bioavailability of nutrients, as reflected by higher nutrient uptake and crop yields. Grain yield improvement in soybean (37–41%) and mustard (58–63%) was recorded in plots receiving RNPK + Gypsum + CR + FYM, RNPK + Gypsum + CR or FYM over only chemical fertilizer treatments. Combined application of gypsum with organic amendments increased N, P, K and S uptake by 75, 76, 84 and 114%, respectively over RNPK alone in soybean-mustard system. Highest values of apparent recovery efficiency and agronomic efficiency of N, P, K, S was registered under RNPK + Gypsum and RNPK + Gypsum + CR/FYM. Highest physiological and internal efficiency of nutrients was registered under RNPK and decreased with amendment application. This study revealed the combined use of FYM (10 t ha−1), CR (3 and 1.5 t ha−1), gypsum (2.5 t ha−1) with fertilizers as a sustainable technology for reclaiming soil sodicity, improving nutrient use efficiency and crop productivity under soybean-mustard system. [ABSTRACT FROM AUTHOR]

In the era of observed climatic changes that contribute to the emergence of soil moisture deficiency, effective ways to retain and rationally manage water are being sought. One of the ways to make water available during periods without rain is the use of a superabsorbent. The aim of the study was to identify the response of two soybean cultivars (Glycine max (L.) Merrill) to different doses of a superabsorbent polymer (SAP). The effect of the SAP on seed yields, selected elements of the yield structure and the chemical composition of seeds were evaluated. The study was carried out during 2016–2018, based on a two-factor field experiment, in a split-plot design, where the dose of SAP (0, 20, 30 kgha−1) and legume cultivar (Aldana, Merlin) were the factors. The results of the research showed that SAP application significantly increased the yield of soybean, but did not affect the quantitative traits and chemical composition of seeds. Genetic factors differentiated the seed yields and chemical composition of the soybeans. A significantly higher yield was obtained for the Merlin cultivar compared to Aldana (by 31.0% on average). The Merlin cultivar accumulated more total protein in seeds, but contained significantly less crude ash and potassium compared to Aldana. [ABSTRACT FROM AUTHOR]

There is little information on the impact of soil amendments on lead absorption by ornamental plants as phytoremediation and the antioxidant system. The experiment was set up in a factorial based on completely block design with three replications on Zinnia elegans. [Pb (NO3) at (0, 40, 80, and 120mg kg-1), soil amendment (control, diethylene trinitrilo pentaacetic acid (DTPA) 2.5 mM, DTPA 5mM, humic acid 200mg. L-1, and HA 400mg. L-1)]. Increased Pb concentration resulted in a significant rise in antioxidant enzymes, as well as an increase in Pb absorption by Z. elegans. DTPA 5mM and HA 400mg. L-1 application lead to significantly higher shoot dry weight (49 and 56%), root dry weight (62 and 63%), catalase (CAT) (18 and 19%), peroxidase (POX) (63 and 67%), superoxide dismutase (SOD) (10 and 14%), and shoot Pb (36 and 33mg.kg-1) in the contaminated soil, respectively. With the application of DTPA and HA, the residual Pb in soil fell in a negative association with the remediation factor. Z. elegans growing in polluted soils treated with DTPA 5mM and HA 400 mg. kg-1 showed Pb tolerance by inducing an effective antioxidative response to Pb toxicity and enhancing Pb absorption for phytoremediation purposes. [ABSTRACT FROM AUTHOR]

The major issue in modern agriculture is long-term sustainability. Nutrient management by integrating organic manures and inorganic fertilizers may play a vital role in improving and sustaining crop productivity. A long-term field experiment (since 1984) comprising 11 treatments with different combinations of inorganic and organic fertilizers such as farm yard manure (FYM), wheat cut straw (WCS) and Dhaincha (Sesbania aculeata L.) as green manure (GM) was conducted to evaluate their effects on crop yield, nutrient accumulation and soil fertility status under a rice – wheat cropping system. The maximum grain yield of wheat was recorded in T6, i.e. 50% recommended dose of fertilizers (RDF) + 50% nitrogen through FYM in rice and 100% RDF in wheat (4291 kg ha−1) as compared to chemically fertilized plots T5, i.e. 100% RDF in both rice and wheat (3441 kg ha−1). The application of organic manures in combination with chemical fertilizers reduced soil pH and bulk density from 7.40 to 7.23 and 1.49 to 1.37 g cm−3, respectively. Soil organic carbon (SOC), available soil nutrients and nutrient accumulation by crop were higher in integrated nutrient management-treated plots as compared to control. A positive and significant correlation was observed between SOC and available soil nitrogen (r = 0.987), phosphorus (r = 0.913) and potassium (r = 0.921). The results clearly suggest that integrated use of chemical fertilizers and organic manures on a long-term basis improves soil fertility and crop productivity with the potential to enhance soil sustainability [ABSTRACT FROM AUTHOR]

Both quality and quantity of medicinal plant production is influenced by the physico-chemical properties of soil. It has been demonstrated that different soil amendments can affect the production of plants. The aim of this study was to determine the effect of soil amendments on the soil bulk density (SBD), porosity (SP), pH and potassium (K), phosphorus (P) contains and its effects on Matricaria recutita growth, yield and essential oil (EO) quality. A field experiment was carried out using three common soil amendments: compost (C), manure (M) and sand (S) compared with the native soil in the littoral oases of Gabes, Tunisia. C, M and S were incorporated up to a depth of 10–15 cm at a rate of 440 Kg ha−1. A randomized complete block experimental design was used and the plots planted with Matricaria recutita. Results shown that the different fertilization systems affected chamomile yield and improved its EO quality and composition. The amendment with S ameliorated the quality of the EO and enhanced the accumulation of α-Bisabolol oxide, while the application of M and C fertilization improved the quantity of Chamazulen and the antioxidant activity. However, the overall results of this study revealed that soil amended with organic fertilizers could be a potential dose for maximum growth yield and better quality of EO extracted from capitula of chamomile. Thus, the introduction of chamomile culture into the Tunisian oases could be of great interest. [ABSTRACT FROM AUTHOR]

Organic and inorganic amendments are routinely applied to ameliorate soil conditions in semi-arid regions. This study aimed to examine the unsaturated transport of nalidixic acid-resistance Escherichia coli (E. coli NAR) in soil amended by cow manure (CM) and natural zeolite (NZ). Two levels of NZ (5 and 15% w/w) were added to a loam soil containing 5% w/w CM and incubated for 60 days. Then, the soil mixtures were poured into cylinders (3.6 × 15 cm) and a pulse (0.1 pore volume) of bacteria suspension (106 Cell mL−1) was added on top of the soil columns and leaching experiments were conducted at a steady-state, unsaturated flow condition and filtration coefficient (λf), relative adsorption index (SR), maximum depth of bacteria transport (Zmax), average (Cav) and cumulative cell density (Ccum) were calculated. CM and NZ application significantly increased the peak density, Zmax, Cav, and Ccum of E. coli NAR. The Cav, and Ccum of E. coli NAR in both 5 and 15% NZ containing mixtures were about 1 and 2-fold higher compared to the control. CM and NZ addition to soil decreased the filtration coefficient (λf) and relative adsorption index (SR) compared to the control. According to our results, we should conclude that the presence of NZ and CM, separately or together, can significantly increase the risk of groundwater contamination and it should be used with prudence. [ABSTRACT FROM AUTHOR]

Salinity continues to be a key factor limiting food security and agricultural sustainability in arid and semi-arid countries. Biochar has been promoted to reduce the risk of saline irrigation. In a controlled study, physiological and morphological growth factors of kochia plants that were irrigated with tap water (S1) and saline water (S2) were assessed to identify the ameliorative effects of biochar amendment to the soil at different levels (B1: 0%, B2: 2%, B3: 5%, and B4: 10%. According to our findings, salinity stress negatively affected morphological and physiological growth parameters of kochia plants by decreasing the fresh and dry weight (25% and 28%, respectively), plant height (30%), circumference (46%), total chlorophyll (51%), and relative water content (29%) when compared to the controls. Furthermore, electrolyte leakage increased considerably (19%) due to salt stress. Significant morphological and physiological growth enhancements were seen at all biochar levels in comparison to the control treatment, with the highest level increasing plant height by 55%, circumference by 76%, total chlorophyll concentrations by 121%, and relative water content by 28%. Furthermore, it resulted in a 36% reduction in the stressed plants' electrolyte leakage. The findings demonstrated biochar's benefits in reducing salinity's negative effects on kochia plants. • This study provides new data about the specifying the impact of using biochar on salinity concentration and the growth parameters of kochia plants. This investigation demonstrated a significant results in terms of that the salinity stress relative to using biochar. • Biochar is crucial for stimulating and activating biochemical defensive mechanisms against salt stress; yet, research in this area is lacking. • Biochar has shown that it is crucial to stimulate biochemical defense mechanisms against salinity stress • It was found that using biochar as a soil supplement improved morphological, physiological, and biochemical characteristics of the kochia plant by increasing fresh and dried weight per plant, plant height, plant circumference, chlorophyll concentrations, and relative water content while lowering electrolyte leakage in stressed kochia plants. This research will aid in increasing kochia's early development and stand establishment in saline circumstances. [ABSTRACT FROM AUTHOR]

Tomato is a demanding crop in fertilizers, fungicides, and pesticides. Therefore, producing food with limit use of chemical farm inputs became essential to reduce the harmful effects of these chemicals in agro-ecosystems. Green manures have great potential to limit the dependency on chemical inputs and preserve the soil fertility. Two fodder radish cultivars, used as green manure, were tested, during three consecutive cropping years, for their effects on soil properties and fertility, tomato growth and production, soilborne diseases' severity, and rhizosphere microbial community. Control treatment consisted of bovine manure and a commercial bio-activator of plant and soil systems i.e. biocat−15Ⓡ. All amended soils showed enhancement in their total nitrogen and available potassium and phosphorus levels. The highest increment in the soil organic matter and the soil carbon biomass noted using radish cv. Defender material. Before tomato planting, the monitoring of the soil microbial community structure revealed that the two green manures had increased the soil richness in actinomycetes communities but only cv. Defender had enhanced the bacterial population. For tomato growth and soilborne disease severity parameters, organic amendments had enhanced tomato growth by 17.8 to 41.7% and decreased disease severity by 46.6 to 97.3% at the second cropping year compared to the first one. The present results indicate that the four organic amendments tested would be an effective approach for improving the soil ecological environment for sustainable tomato cropping with significant enhancements of the majority of tested parameters recorded using fodder radish cv. Defender as green manure. [ABSTRACT FROM AUTHOR]

A field experiment was carried out to elucidate the effect of elevated carbon dioxide (eCO2 – 550 ± 30 ppm) on soil enzymes (dehydrogenase, β-glucosidase, fluorescein diacetate, urease, acid and alkaline phosphatase), soil carbon pool (Soil Organic Carbon (SOC), Microbial Biomass Carbon (MBC), oxidizable carbon, humic acid (HA), fulvic acid (FA) fractions), microbial population dynamics (heterotrophs, fungi, actinobacteria, diazotrophs, methanotrophs, and total anaerobes), carbon sequestration and yield in a flooded paddy soil in open top chambers (OTCs) in relation to rhizospheric and bulk soil. Responses of most of the observed parameters to eCO2 with biochar application in rhizosphere soil were significantly higher. The carbon (C) sequestration potential was found higher in the biochar applied plot under eCO2 with 0.59 Mg C sequestered ha−1. The same recorded the highest biomass yield and grain yield which is 12.8 and 30.8% higher than the control. Principal Component Analysis (PCA) recognized soil dehydrogenase, β – glucosidase, SOC, FA, Substrate Induced Respiration (SIR), metabolic quotient (qCO2) and counts of heterotrophs as key drivers of variability. The current study thus provides some dependable biological indicators to assess the paddy ecosystems, vis-à-vis anticipatory climate change. [ABSTRACT FROM AUTHOR]

Organic farming has emerged as a sustainable approach for increasing crop production while maintaining soil fertility. This eco-friendly practice relies on the use of various living microbes such as Rhizobia, arbuscular mycorrhiza fungi (AMF) and partially or fully decomposed biological materials like manure, compost, litter, coir, moss, and similar products used as soil supplements and/or conditioners for augmenting soil fertility. The present study was designed to evaluate the effect of these amendments on soil physico-chemical characteristics, and on germination and growth of marigold (Tagetes erecta) seedlings raised on these soils. The experiment was carried out in pots filled with garden soil amended with compost, moss, coir and NPK while un-amended garden soil served as control. Analysis of soil samples with organic materials show a slight change toward basic pH while inorganic fertilizer made the soil acidic. All the amendments led to increase in electrical conductivity while modulation of soil texture resulted in change in percolation rate. Amendments also resulted in changes in the soil nutrient content (organic C, N, P, K, Mg, Cu and Zn). However, coir and moss amendments did not bring about much change in nutrient status of the soil. There were notable changes in growth of marigold expressed in increased fresh weight, root length, shoot length as well number of nodes and number of leaves in amended soils. The study indicates that though coir and moss did not bring much change in nutrient status of soil but they altered the particle size for improved percolation. [ABSTRACT FROM AUTHOR]

A 32-year fertilizer experiment was conducted to investigate mineral and organic fertilization impacts on soil P forms by P K-edge X-ray absorption near edge structure and solution 31P nuclear magnetic resonance spectroscopy. The experiment included six treatments: control without fertilization, mineral fertilizers (NPK), pig manure at 30,000 (M1) and 60,000 kg ha–1 (M2), M1 plus NPK, and M2 plus NPK. The predominant P compounds were hydroxyapatite (up to 51.3% of soil total P) and orthophosphate and orthophosphate monoesters (up to 85.7% and 57.0% of soil NaOH-EDTA extractable total P, respectively). Compared with the control, the concentrations and proportions of monocalcium phosphate and orthophosphate increased following mineral fertilizers alone. Manure application, especially high rate manure combined with mineral fertilizers, further increased the concentrations and proportions of monocalcium phosphate and orthophosphate relative to mineral fertilizers alone. Moreover, manure amendment also generally increased the concentrations of other inorganic and organic P compounds. Manure application improve soil P availability by adding high concentrations of bioavailable inorganic P compounds to soil, similar to the addition of mineral fertilizers. This study contributes to the understanding of applied fertilizers and residual soil P dynamics and provides insights for sustainable P management in agricultural ecosystems. [ABSTRACT FROM AUTHOR]

The biodegradation of polycyclic aromatic hydrocarbons in soil is enhanced by chemical constituents of various plant species that support the growth and activity of PAH degrading bacteria in the rhizosphere. Here, we investigated the phytochemical effects of celeriac (Apium graveolens var. rapaceum) root tissues, a known stimulator of PAH degradation, on the copy numbers of nahAc, xylE, and 16S rRNA genes to determine the relative contributions of growth-linked degradation versus selective enrichment of PAH degraders. Real-time quantitative PCR analysis showed that the copy numbers of 16S rRNA genes, as a reporter of general bacterial population size, increased approximately 2- to 5-fold in soil amended with celeriac, but were not affected by exposure to naphthalene alone. In contrast, copy numbers of two functional genes (nahAc and xylE), commonly used as reporters for monitoring the population size of PAH degraders, were significantly increased following exposure to naphthalene but were differently affected by soil amendment with celeriac. As compared with the copy numbers of nahAc gene in unamended control soil, the nahAc copy numbers were increased by 460-fold in soil amended with naphthalene alone and by 610-fold in soil amended with both naphthalene and celeriac after 10 days of incubation. The copy numbers of xylE were increased by 20-fold in soil amended with naphthalene alone and increased by 200-fold in soil amended with both naphthalene and celeriac after 10 days of incubation. The result suggests that increased degradation rates of PAHs in the presence of celeriac involves both growth linked processes and selective enrichment of the degrader population. [ABSTRACT FROM AUTHOR]

Integrated nutrient management (INM) practice with farmyard manure (FYM), wheat straw (WS) and green leaf manuring (GLM) augments aggregate formation in soils. However, soil aggregation regulating several soils biological activities has been proven to be intricate with both positive and negative interactions across studies. We studied the distribution of soil organic carbon (SOC), microbial biomass carbon (MBC) and soil enzymes across three aggregate classes (>2000 µm, 2000–250 µm and <250 µm) from a long-term rice-wheat cropping system. Integrated nutrient management practices significantly influence the fraction of soil macro-aggregates; whereas suboptimal level of fertilization was dominated by micro-aggregates. Application of inorganic fertilizer with FYM over long-term improves SOC to the tune of 12.78% when compared with 100% recommended dose of fertilizers (RDF); whereas WS as an amendment improves MBC to the tune of 51.80% over RDF. Activities of the studied soil enzymes (Acid phosphatase, Alkaline phosphatase, Dehydrogenase, Fluorescein Diacetate Hydrolysing Capacity and Urease) were found to be higher when associated with large macro-aggregates fraction of size >2000 µm as compared to micro-aggregates. In conclusion, large macro-aggregates improve and regulate all the soil biological indicators after a long-term integration of organic amendments with inorganic fertilizers. [ABSTRACT FROM AUTHOR]

Iron-impregnated filter paper (Fe-Pi) was evaluated as phosphorus (P) extractant in four soils of Ogun state, southwest Nigeria in a screenhouse experiment. The experiments lasted for 8 weeks. Soil P contents were extracted at 0, 4, and 8 weeks after the incorporation of amendments (cattle manure, poultry manure, and wood ash) using Fe-Pi, Bray-1, Bray-2, Mehlich-1, Hunter, and Olsen extractant. Agronomic variables were taken fortnightly from grown maize plants and later harvested at 8 weeks, residual effects of the treatments were also evaluated. Maize dry matter weight (DMW) and P uptake were also measured. Results indicated that a linear relationship existed among the extractants with significant coefficient at p ≤.001. Fe-Pi established a strong relationship with the conventional extractants in the following order: Bray-1 (R2 = 0.99) > Bray-2 (R2 = 0.98) > Hunter (R2 = 0.96) > Mehlich-1 (R2 = 0.86) > Olsen (R2 = 0.82). Fe-Pi had a significant relationship with P uptake and DMW. Phosphorus uptakes under the animal manure amendments were statistically higher than uptake in control and woodash amended soils. Therefore, the study concluded that Fe-Pi was a good predictor of plant available P and had significant relationship with Bray-1, thus it could be considered for the estimation of soil available P in soils of southwest Nigeria. [ABSTRACT FROM AUTHOR]

Improving soil fertility by adopting several sustainable management practices that are a prime concern for plant growth. Organic waste addition to agricultural soil is becoming a common practice that improves physical, chemical and hydrodynamic properties and minimizes environmental impact. The use of some alternative nutrition sources as biochar and compost has been tested on two-year-old olive varieties 'Chemlali' and 'Koroneiki.' Three treatments were established "Cont" soil didn't amended, "Comp" soil amended with Compost (90% soil+10% compost), and "Bioc" soil amended with biochar (90% soil+10% biochar). All treatments were conducted under deficit irrigation receiving 50% of daily evapotranspiration. We evaluated soil–plant water status and relationships between all studied parameters. Results showed that soil water content was the lowest in non-amended treatments and did not exceed 10%. During experiment, compost amendment induced a better water plant status for both studied varieties less than −2 MPa for mean seasonal leaf water potential, while the biochar amendment induced a weak stress level indicated by the lower potential that reached a minimum value equal to −2.9 MPa. Crop Water Stress Index on biochar-amended soil was more important than that measured on other treatments which confirms the sensitivity of biochar treatment to hard conditions. High negative relationships have been found between soil water statuses and plant water statuses. The highest determination coefficient was between crop water stresss index and leaf water potential was about 0.85. In conclusion, the use of organic amendment is an approach for sustainable olive orchards under low water avaibility. [ABSTRACT FROM AUTHOR]

This work investigated the effect of soil amendments on the mobility of heavy metals and P in acidic and calcareous heavy metal polluted soils after incubated for one year. Compared to phosphate alone, the phosphate+bentonite amendment had lower available P concentrations (13.1 and 16.3% in the acidic and calcareous soils, respectively) and similar heavy metal immobilization capacity. The lime amendment increased soil P availability possibly by increasing the negative charges of soil particles in both soils. Lime amendment greatly reduced the DTPA-extractable concentrations of Cd, Cu, Mn, Ni, Pb and Zn in both soils; greater reductions were observed with higher rate compared to the lower rate and in the acidic soil compared to the calcareous soil, especially for Cd, Mn, Ni and Zn (23.9–95.3% lower than the control). The bentonite in the phosphate+bentonite treatment may have reduced soil P availability by adsorption of soluble P. Based on the results, phosphate+bentonite instead of phosphate alone may be used to reduce heavy metal and P availability in heavy metal contaminated soil. When only lime is used, caution should be taken with respect to potential soil P losses and subsequent off-site degradation in water and environmental quality. [ABSTRACT FROM AUTHOR]

Parthenium hysterophorus is an invasive weed, produces a lot of non edible biomass that is hazardous to humans. This study provides an insight to its beneficial use by converting the biomass into value-added materials like compost and biochar and subsequent amendment in soil as fertilizer. The biochar was prepared in a locally fabricated charcolator while the compost was prepared in a rolling tumbler. Two-year field experiment was set up using different combinations of biochar (BC), compost (C) and commercial fertilizer (CF) in the rice-wheat cultivation system in Lahore, Pakistan to assess soil health and crops performance after characterizing the products using advanced analyses. GCMS analysis has revealed the presence of stigmasterol and campesterol (plant growth promoters) in prepared compost. Field data showed that the combined application of compost and biochar in rice and wheat fields significantly improved the characteristics of soil like SOM and CEC. Agronomic characteristics such as the number of grains per tiller, grain weight and biological yield were significantly higher in C + CF (half dose of each) and almost equal to CF in the first year. In the second year, both crops agronomic performance was considerably more evident and pronounced following the same pattern. All other agronomic features also followed the same pattern. Thus, mixed application of organic and inorganic fertilizer on recurrent basis is recommended to improve yield of wheat and rice along with soil amelioration in the rice wheat cultivation system. [ABSTRACT FROM AUTHOR]

The combined remediation of cadmium (Cd) and arsenic (As) in paddy soils faces many challenges due to their opposite behavior. A pot study was conducted to evaluate the impact of biochar (BC), goethite (G), and goethite modified biochar (GBC) at a 1% application rate on the Chinese cabbage growth, uptake and immobilization of Cd and As in co-contaminated paddy soil. GBC composites were prepared at two different initial mass ratios (1:1 and 2:1) of iron/biochar (Fe/BC). Goethite modified biochar composite at Fe/BC initial mass ratios of 1:1 and 2:1 were labeled as GBC1 and GBC2, respectively. The results showed that GBC amendments significantly improved Chinese cabbage growth, chlorophyll content, and gas exchange attributes compared to BC and G applied singly. Biochar decreased Cd uptake by Chinese cabbage shoots and roots while increased As uptake by shoots and roots. The GBC1 amendment reduced Cd and As uptake by Chinese cabbage shoots (47.27% and 35.20%) and roots (36.80% and 41.12%), respectively, and reduced Cd and As bioaccessibility by 40.09% and 39.35%, respectively, compared to unamended soil. GBC is generally simple to synthesize from crop residue and is an environmentally acceptable material when used for Cd and As remediation in co-contaminated paddy soil. [ABSTRACT FROM AUTHOR]

Soil amendments and critical agronomic practices like biochar (B) and poultry manure (PM) change soil characteristics and have a direct impact on soil sustainability and crop productivity. Hence, a two-year field trial was conducted in the forest-savanna transition zone of southwest Nigeria at two locations (Owo – site A and Obasooto – site B) to examine the impacts of different levels of biochar (B) and poultry manure (PM) on soil physical and chemical qualities, sweet potato (Ipomoea batatas L.) growth, and yield. The experiment consisted of a 2 × 4 × 3 factorial layout with three replicates. The treatments applied at two locations were: four levels of biochar (B) (0, 10.0, 20.0 and 30.0 t ha−1) and three levels of poultry manure (PM) (0, 5.0 and 10.0 t ha−1). The biochar (B) and poultry manure (PM) significantly (p =.05) improved both soil physical and chemical properties, sweet potato growth and yield with their rates of application when compared to the control. In comparison to Owo (site A), Obasooto (site B) had significantly higher sweet potato growth and yield, and better soil properties. Application of 30.0 t ha−1 biochar (B) and 10.0 t ha−1 poultry manure (PM) had the best sweet potato growth and yield parameters of all the biochar (B) combined with poultry manure (PM) treatments. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of cypress cone biochar (RB) and its modifications (chitosan-coated biochar (CB), acid-modified biochar (AB), alkali-modified biochar (ALB), humic acid-coated biochar (HB), walnut shell residue extraction-coated biochar (WB), ball-milled biochar (BMB)) on the behavior of nickel (Ni) in Ni-spiked calcareous soil. The biochars were added separately to the soil at the rates of 1.5% and 3%, and the Ni behavior was investigated using methods of desorption kinetics and sequential extraction. The modification process significantly changed the specific area and functional groups of BMB, CB and HB compared to RB. Application of CB (26.3%), HB (28.7%), ALB (28.8%), BMB (30.7%), AB (31.9%) and RB (32.6%) showed the most effects on reduction of Ni mobility factor compared to control soil sample (38.8%). The results of Ni desorption showed high effectiveness of CB, BMB, ALB and HB, in reducing the Ni release compared to the control soil sample. Overall, our findings indicated that among the modified biochars, BMB, CB and HB showed a good performance in Ni stabilization, due to the simple and low-cost process of physical modification. BMB can be suggested as a suitable amendment for soil Ni immobilization. [ABSTRACT FROM AUTHOR]

A 3-year field experiment was conducted to determine the impact of corn residue-derived biochar on soil organic matter (SOM), soil nutrients, corn yield and partial factor productivity of synthetic fertilizer in Hetao Irrigation District, Inner Mongolia of China. Three rates of biochar, 15 (B15), 30 (B30) and 45 (B45) t ha−1, and a non-biochar control (B0) were applied to a corn field one time at the first crop growing season under film-mulched with drip-irrigation. Relative to B0, the B30 led to a significant increase in SOM at top 30 cm soil layer (15.3%) and partial factor productivity of fertilizers (12.8%) as averaged across 3 years. Amendment in B30 also increased the available nutrients in the soil (nitrogen, phosphorus and potassium), corn yield and economic benefit. In contrast, the first year showed the largest improvements for corn yield and economic benefit for B30, followed by the second year and the third year. The corn grain yield has potentially increased when the SOM and the available phosphorus were increased when compared to the available nitrogen and potassium. A single biochar amendment at the rate of 30 t ha−1 can be adequate for the corn production in 3 years under dry climatic conditions. [ABSTRACT FROM AUTHOR]

Root-knot nematodes, Meloidogyne spp., are among the most polyphagous and ubiquitous plant-parasitic nematodes. Among other management strategies, organic soil amendments and biological control agents are proposed. In this study, potential synergistic benefits of co-application of chitin and Streptomyces nigrescens (AMV1033) against M. incognita were determined. Hypothetically, chitinolytic activity of these microbes deteriorates nematode eggshells reducing nematode numbers. Additional chitin could enhance actinobacteria activity for nematode suppression. In in vitro and greenhouse bioassays, suppressive capacities of M. incognita by chitin amendment at 50 mg/g of soil (chitin-low) and at 500 mg/g of soil (chitin-high; only tested in the greenhouse), Streptomyces nigrescens (AMV1033) and the co-application of AMV1033 with the two chitin rates were tested. After four weeks of in vitro egg incubation, the number of extractable second-stage juveniles (J2s) was significantly reduced after co-application of chitin-low plus AMV1033, and less so after sole application of AMV1033. In a similar 2-week in vitro assay with M. incognita egg masses, the numbers of J2s were similarly reduced after the same treatments. In a watermelon greenhouse bioassay with M. incognita, root infection was decreased after co-application of AMV1033 plus chitin-high or chitin-low compared to the non-treated control. After these treatments, plants grew similarly as in the control, whereas sole chitin-high addition led to severe plant damage. Some amelioration of phytotoxicity of chitin-high by the co-application of AMV1033 was found. The results of the study demonstrated the potential to enhance suppression of M. incognita by S. nigrescens by co-application of chitin. [ABSTRACT FROM AUTHOR]

The utilization of sewage sludge (SS) as a fertilizer for agricultural land is increasingly seen by many as the best option for recycling. This study investigates the effects of SS-derived compost (SSC) or biochar (SSB) amendments on N, P, K, Ca, Mg, Na, Fe, Mn and Mo uptake by Chinese cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) from terra rossa and rendzina soils. A two-factorial experiment was performed under greenhouse conditions whereby elemental concentrations (substrate, leachates and plants), edible tissue uptake (ETU), concentration ratios (CR) and soil characteristics were determined. The pH (7.03 to 7.32) and P content (286 to 421 mg/kg d.w.) in SSC- and SSB-amended soils increased, while EC (450 to 253 μS/cm) decreased. Phosphorous levels were higher in SSB-amended soils, although P leaching indicates a low environmental risk in both soils. In leaves, P (1.02 to 4.15 g/kg d.w.), K (12.8 to 21.8 g/kg d.w.), Mg (1.05 to 1.55 g/kg d.w.), Na (660 to 1350 mg/kg d.w.), and Mo (1.20 to 2.65 mg/kg d.w.) levels increased with amendment rate and were higher in SSC-amended soils. Nutrient bioavailability also increased with amendment rate, while cabbage biomass production increased proportionally to the dose. The P, K, and Mg levels were higher in leaves, while roots contained more Ca, Fe, and Mn. Despite amendment rates 10x the permitted dose of SS, they did not affect soil leachate, plant growth and biomass yield. Overall, adopting the cautionary principle is advised until the long-term effects are better understood. [ABSTRACT FROM AUTHOR]

The evaluation of the impact of wood ash, on metal uptake and transfer factor of lettuce grown on soil amended with poultry litter, digestate and its fraction was carried out. Positive (inorganic fertilizer) and negative (unamended soil) fertilization controls were included and impacts on soil fertility and crop productivity, as well as potential toxic elements' levels, were assessed at pre and post planting period. Soil properties (e.g., plant available N and P, and water soluble elements), plant morphometry, elemental composition (e.g., total nitrogen, total carbon, total phosphorus) and nutrient uptake were determined using standard methods. There was higher nutritive content of the soil amended with whole digestate than fiber digestate resulting in its largest weight of lettuce. Ash significantly improved the impact of the amendments on the properties of the soil which was reflected in better lettuce productivity and was most applicable to the poultry litter. Based on the transfer factor and uptake of the trace metals, results show lower potential toxicity in the lettuce from the organic treatments in comparison to the inorganic fertilizer. Wood ash had positive ameliorative effects on the amended soils which makes it a suitable nutrient booster for organic fertilizers and alternative to inorganic fertilizers for leafy vegetables. [ABSTRACT FROM AUTHOR]

Subsoil fertilization can help agricultural sustainability, but this is not a widely adopted practice. Here, we conducted a pot experiment to study the response of microbial community diversity and topsoil/subsoil properties to cow manure amendment. Our results show that amending subsoil with cow manure (SM) increased available phosphorus (AP) and humic acid (HA) content and the ratio of humic acid to fulvic acid (HA/FA) by 22.2%, 17.7%, and 49.3%, respectively, relative to manure-amended topsoil (TM) (p < 0.05). SM was also more favorable for organic matter degradation and had 61.9%, 21.7%, and 85.3% higher relative abundances of the bacterial phyla Bacteroidetes and Actinobacteria and the order Cytophagales, respectively, relative to the TM treatment (p < 0.05). Compared with that of unamended subsoil (S), the Chao1 index, operational taxonomic units, and Shannon index of fungi were increased but bacterial diversity was decreased by SM treatment (p < 0.05). The only significant difference of the TM-treated soil with the unamended topsoil (T) was a lower bacterial Shannon index (p < 0.05). In conclusion, soil physicochemical properties and subsoil microbial communities were sensitive to cow manure amendment, which has the potential to improve the productivity of subsoils. [ABSTRACT FROM AUTHOR]

Evaluation of liming and fertility properties of biochar on acid soil was studied in this work. Selected soil properties such as pH, electrical conductivity (EC), exchangeable acidity (Ex Ac), exchangeable Al (Ex Al), exchangeable Fe (Ex Fe), available P and, soil organic carbon (SOC) were examined under the effect of biochar amendments. The acid soil was treated with biochar issued from coffee husk (CH) and cocoa pods (CP) pyrolyzed at 350°C and 550°C for 4 hours at amendment rate of 0, 20, 40 and 80 g kg−1 and an incubation time of 7, 14, 30, 40 and 60 d. Biochar amendments significantly increased soil pH, soil EC with respect to control and decrease in exchangeable acidity was observed. Results show that biochar improved available P in acid soil, though re-adsorption occurred with increasing incubation time. A significant increase in SOC is observed as compared to control. The impact of biochar on these acid soil chemical properties is due to the properties which are dependent on the biochar type and pyrolysis temperature. Thus, biochar can play the dual role of a liming agent and a source of P fertilizer nutrients. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) is the most important factor that affects soil quality. In arid areas, lack of SOM causes a major problem and farmers need to add organic amendments to restore the soil quality. Organic waste composting is an efficient and sustainable way to produce organic resource for soil amendment. The main objective of this study was to evaluate the effectiveness of compost derived from co-composting of date palm residues with goat manure to ameliorate soil quality in arid region in the southeast of Tunisia. Palm tree wastes were co-composted with goat manure (1/3 v:v) for 120 days. Chemical properties and structural changes of humic acids (HA) during the composting process were investigated using physicochemical and spectroscopic analyses: spectroscopic ultraviolet/visible (UV) analysis and Fourier Transform Infrared (FTIR) Spectroscopy. HA fractions extracted from different steps of composting process were monitored by measuring humification ratios CHA/CFA and E4/E6. Soil was amended with produced compost and manure during 3 months, and soil property evolution was evaluated using chemical and spectroscopic analyses. Results revealed that the date palm compost displayed neutral pH, a C/N ratio of about 12 and high levels of nutrients. FTIR spectra of HA extracted from produced compost and manure showed the abundance of aromatic structures with a high condensation and polymerization confirmed by a low E4/E6 ratio related to the increase in polymerization and polycondensation and a high CHA/CFA humification rate that improved the elevation of the humification degree. The application of the produced palm compost in soil improved soil quality by increasing levels of SOM and nutrients and showed a marked improvement of humification rate. The FTIR spectra of soil HA showed a clear increase in aromatic structures that improved soil stability. The input of palm compost is an efficient way to ameliorate arid soil quality by supplying highly humified organic matter restitution. [ABSTRACT FROM AUTHOR]

Eucalyptus plants are found to be located in a variety of places such as low rainfall areas, schools, colleges, and government hospitals. The leaves remain fallen beneath the plants for several months, as they contain a variety of phenolic compounds and terpenes, which are responsible for its multipurpose properties, such as antifungal, antibacterial, analgesic and anti-inflammatory. Out of this 1.8 cineol is found to be major constituent and responsible for inhibiting microbial growth, which is a prime requirement of biological waste degradation and composting. To fasten the degradation process, the phenolic compounds were isolated smoothly by grinding the eucalyptus leaves, followed by extraction with hot boiling water, precomposting of residue with available garden soil and water from bio-reactor of effluent treatment plant (ETP), instead of cow dung and then vermicomposting. This process was found to be cost-effective, giving better quality of vermicompost with good carbon-to-nitrogen (C/N) ratio, macro- and micronutrients for valuable soil amendment and sustainable agriculture growth. The process was found to be user-friendly, eco-friendly, sustainable and could be used for available substrates with possible pre-treatment. The process could be converted from conventional batch process to continuous process by the technique of precomposting with carbon- and nitrogen-rich biodegradable substrates. Physico-chemical analysis techniques such as electrical conductivity, pH, humification index, FT-IR spectroscopic technique and C/N ratio are found to be comparatively easy, fast, and effective techniques for monitoring vermicomposting process as well as determining completion, quality, and stability of vermicompost produced. [ABSTRACT FROM AUTHOR]