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The World Health Organization (WHO) states that in developing nations, there are three million cases of agrochemical poisoning. The prolonged intensive and indiscriminate use of agrochemicals adversely affected the soil biodiversity, agricultural sustainability, and food safety, bringing in long-term harmful effects on nutritional security, human and animal health. Most of the agrochemicals negatively affect soil microbial functions and biochemical processes. The alteration in diversity and composition of the beneficial microbial community can be unfavorable to plant growth and development either by reducing nutrient availability or by increasing disease incidence. Currently, there is a need for qualitative, innovative, and demand-driven research in soil science, especially in developing countries for facilitating of high-quality eco-friendly research by creating a conducive and trustworthy work atmosphere, thereby rewarding productivity and merits. Hence, we reviewed (1) the impact of various agrochemicals on the soil microbial diversity and environment; (2) the importance of smallholder farmers for sustainable crop protection and enhancement solutions, and (3) management strategies that serve the scientific community, policymakers, and land managers in integrating soil enhancement and sustainability practices in smallholder farming households. The current review provides an improved understanding of agricultural soil management for food and nutritional security.

Micronutrient silicon (Si) is receiving increasing attention in agriculture for its benefits to plant growth and stress tolerance. Plants have developed a highly efficient Si-transport mechanism that entails the localization of Si-transporter proteins such as Low silicon1 (Lsi1), Low silicon2 (Lsi2), Low silicon3 (Lsi3), and Low silicon6 (Lsi6), as well as the expression profiling that establishes a highly coordinated network between these proteins, facilitating Si uptake and accumulation. It has also been discovered that silicon (Si) can promote plant growth and alleviate a variety of biological and abiotic stressors. In this review paper, the effects of Si on plant–pathogen interactions are analyzed from physical, biochemical, and molecular perspectives. The addition of silica improves the plant’s physiological and chemical characteristics, including its defence mechanisms, hormonal modulation, and gene expression patterns. Si activates defence-related enzymes, promotes the production of antimicrobial compounds, regulates signal pathways, and induces the expression of defence-related genes. This results in combined resistance that dominates the biochemical/molecular resistance during plant–pathogen interactions. Furthermore, Si alleviates the toxic effects of abiotic stresses such as salt stress, drought, and heavy metals. Silicon’s ability to manage various plant stressors, the mechanisms of silicon-enhanced resistance and silicon’s inhibitory effects on pathogens in vitro are also discussed in this review paper. By integrating the information presented, a clear relationship between silicon treatments and plant growth promotion can be established. This information is valuable for understanding the role of Si in agriculture and improving the utilization of Si fertilizers and sources for agricultural production.

Mobilization of unavailable phosphorus (P) to plant available P is a prerequisite to sustain crop productivity. Although most of the agricultural soils have sufficient amounts of phosphorus, low availability of native soil P remains a key limiting factor to increasing crop productivity. Solubilization and mineralization of applied and native P to plant available form is mediated through a number of biological and biochemical processes that are strongly influenced by soil carbon/organic matter, besides other biotic and abiotic factors. Soils rich in organic matter are expected to have higher P availability potentially due to higher biological activity. In conventional agricultural systems mineral fertilizers are used to supply P for plant growth, whereas organic systems largely rely on inputs of organic origin. The soils under organic management are supposed to be biologically more active and thus possess a higher capability to mobilize native or applied P. In this study we compared biological activity in soil of a long-term farming systems comparison field trial in vertisols under a subtropical (semi-arid) environment. Soil samples were collected from plots under 7 years of organic and conventional management at five different time points in soybean ( ) -wheat ( ) crop sequence including the crop growth stages of reproductive significance. Upon analysis of various soil biological properties such as dehydrogenase, β-glucosidase, acid and alkaline phosphatase activities, microbial respiration, substrate induced respiration, soil microbial biomass carbon, organically managed soils were found to be biologically more active particularly at R2 stage in soybean and panicle initiation stage in wheat. We also determined the synergies between these biological parameters by using the methodology of principle component analysis. At all sampling points, P availability in organic and conventional systems was comparable. Our findings clearly indicate that owing to higher biological activity, organic systems possess equal capabilities of supplying P for crop growth as are conventional systems with inputs of mineral P fertilizers.

The soil rhizosphere pH, enzymatic activities (dehydrogenase, β-glucosidase, and arylsulfatase), microbial respiration rates, soil microbial biomass-C, soil microbial biomass-N and soil microbial biomass-S were used to monitor the impact of nitrogen (N) and sulfur (S) applications. The randomized block design experiment was conducted comprised fourteen treatments, varying N and S applications in timing and quantity at specific growth stages, with three replications. The results showed a significant increase in soil enzymatic and microbial activities after incorporation of N and S in the soil. The research highlights the efficacy of N and S (25 N kg ha − 1 as basal + 25 N kg ha − 1 at the R 2 stage + 12.5 S kg ha − 1 as basal + 12.5 S kg ha − 1 at the R 2 stage) in enhancing crucial variables, dehydrogenase, β-glucosidase, and aryl sulfatase activities, alongside microbial respiration and microbial biomass-C, N, and S during soybean growth at R 2 and R 5 stages. Notably, N treatments consistently lowered rhizosphere pH, with significant decreases observed, and combined N and S treatments also contributed to pH reductions compared to controls, while sulfur-only treatments maintained similar or slightly lower pH levels. Incorporating N and S boosted soil enzymatic and microbial activities while decreasing pH, with split dosing of N and S enhanced key variables in soybean, underscoring the intricate interactions between nutrients and soil dynamics. These findings provide valuable insights into optimizing nutrient management practices for improved soil health and crop productivity.

Arbuscular mycorrhizal (AM) fungi are being used as a new generation of biofertilizers to increase plant growth by improving plant nutrition and bio-protection. However, because of the obligatory nature of the plant host, large-scale multiplication of AM propagules is challenging, which limits its applicability. This study evaluates the ability of Burkholderia arboris to increase AM production in soybean mill waste and vermicompost amended by soil–sand mixture planted with sorghum as a host plant. The experiment was conducted in a nursery using a completely randomized design with four inoculation treatments (B. arboris, AM fungi, B. arboris + AM fungi, and control) under sterilized and unsterilized conditions. AM production was investigated microscopically (spore density and root colonization), and biochemically (AM-specific lipid biomarker, 16:1ω5cis derived from neutral lipid fatty acid (NLFA), and phospholipid fatty acid (PLFA) fractions from both soil and roots). Integrating B. arboris with AM fungi in organically amended pots was found to increase AM fungal production by 62.16 spores g−1 soil and root colonization by 80.85%. Biochemical parameters also increased with B. arboris inoculation: 5.49 nmol PLFA g−1 soil and 692.68 nmol PLFA g−1 root and 36.72 nmol NLFA g−1 soil and 3147.57 nmol NLFA g−1 root. Co-inoculation also increased glomalin-related soil protein and root biomass. Principal component analysis (PCA) further supported the higher contribution of B. arboris to AM fungi production under unsterilized conditions. In conclusion, inoculation of AM plant host seeds with B. arboris prior to sowing into organic potting mix could be a promising and cost-effective approach for increasing AM inoculum density for commercial production. Furthermore, efforts need to be made for up-scaling the AM production with different plant hosts and soil-substrate types.

Nitrogen (N) and sulfur (S) are essential nutrient elements, and their deficiency affects crop growth, productivity, and nutrient uptake due to their multifaceted role in plant metabolism, which has been well documented. Therefore, agricultural management strategies that can overcome these deficiencies are the need of the hour. In this context, a study was undertaken with the objective to assess the impacts of N and S applications, either basally or through split application (12.5, 25 and 50 kg ha−1), on the nutrient uptake, productivity, use efficiency, and micronutrient content status in soybean seeds, and also the change in soil nutrient zinc (Zn) and iron (Fe) content at different critical stages of soybean crop growth. The field trial was conducted utilizing a randomized complete-block design, and comprised fourteen treatments with varying N and S quantities. N and S were applied through basal and split applications in different combinations. The salient findings indicated that the highest seed, straw yield, N, and S uptake were obtained with the application of N25+25, S25+25, and did not significantly vary with N25+25, S12.5+12.5, N50, and N25+S50. The highest N use efficiency was recorded with the application of N25+S50, and S use efficiency with the application of N25+25, S25+25. The split application of N and S as N25+25, S25+25 significantly increased soil Zn and Fe content at R2 and R5 stages of soybean crop growth, as well as seed Zn and Fe uptake. It can be concluded that the basal and split application of N and S at the rate of 25 kg ha−1 can improve soybean productivity through increased mobilization and assimilation by plants. The findings indicated that applying N and S separately, with 25 kg ha−1 each basally and at the R2 stage resulted in the highest nutrient uptake, and seed and straw yields. The nutrient use efficiencies, along with Zn and Fe uptake by seeds, exhibited noticeable improvements with this split application approach compared to the control. Furthermore, the soil Zn and Fe contents also experienced enhancements due to the split application of both Nand S fertilizers. These results underscore the potential benefits of temporally adopting optimized fertilizer application strategies to maximize agricultural productivity while ensuring efficient nutrient utilization and soil health maintenance. Further research and field trials could provide deeper insights into the long-term impacts and scalability of this approach across different crop varieties and environmental conditions.

To ensure the sustainability of crop production and ecosystem functioning, a thorough understanding of the mechanisms governing soil carbon (C) sequestration and soil health is essential. This study examined the effects of three nutrient management practices (organic, inorganic, and integrated) and two cropping systems (soybean-wheat and soybean-chickpea), on arbuscular mycorrhizal fungi (AMF) and soil C-sequestration in a long-term (12 years) field experiment. We measured the stocks of soil organic carbon, total glomalin-related soil protein, pertinent soil quality parameters such as microbial biomass carbon, and β-glucosidase activity along with AMF biomass [microscopic parameters and 16:1ω5cis phospholipid fatty acid (AM PLFA) and neutral lipid fatty acid (AM NLFA)]. It was observed that the measures of AMF biomass were positively correlated with the soil organic carbon stocks, total glomalin-related soil protein stocks, and soil quality parameters. Organic practice recorded significantly higher AMF spores, mycorrhizal colonization percentage, AM PLFA (2.58 nmol g soil), AM NLFA (7.95 nmol g soil), soil organic carbon stocks (15.78 Mg ha ), total glomalin-related soil protein stocks (2.10 Mg ha ), and soil quality parameters such as microbial biomass carbon, and β-glucosidase activity than inorganic and integrated practices. In comparison to soybean-chickpea, C-sequestration was higher in soybean-wheat. Principal component analysis validated the said results and differentiated soybean-wheat under organic practice from the rest of the treatments. In conclusion, our results suggest that organic management in conjunction with soybean-wheat crop rotation enhances AMF and can be recommended for improving soil quality and C sequestration without compromising crop yield.

Increasing high temperature (HT) has a deleterious effect on plant growth. Earlier works reported the protective role of arbuscular mycorrhizal fungi (AMF) under stress conditions, particularly influencing the physiological parameters. However, the protective role of AMF under high-temperature stress examining physiological parameters with characteristic phospholipid fatty acids (PLFA) of soil microbial communities including AMF has not been studied. This work aims to study how high-temperature stress affects photosynthetic and below-ground traits in maize plants with and without AMF. Photosynthetic parameters like quantum yield of photosystem (PS) II, PSI, electron transport, and fractions of open reaction centers decreased in HT exposed plants, but recovered in AMF + HT plants. AMF + HT plants had significantly higher AM-signature 16:1ω5cis neutral lipid fatty acid (NLFA), spore density in soil, and root colonization with lower lipid peroxidation than non-mycorrhizal HT plants. As a result, enriched plants had more active living biomass, which improved photosynthetic efficiency when exposed to heat. This study provides an understanding of how AM-mediated plants can tolerate high temperatures while maintaining the stability of their photosynthetic apparatus. This is the first study to combine above- and below-ground traits, which could lead to a new understanding of plant and rhizosphere stress.

The changing global climate affects the agroecosystem making it challenging to achieve the world’s sustainable development goals. Among the facets of belowground microbial communities, the arbuscular mycorrhizal fungi (AMF) hold an important place. They represent the most common symbiont phylum colonizing more than 80% of the plant families and are likely to be affected by global climate change. These fungi facilitate plant’s mineral acquisition, improving growth and protecting them from biotic and abiotic stresses. The elevated carbon dioxide (eCO 2 ) level, temperature, increased nitrogen and phosphorus deposition influences the plant phenology and AMF functioning through changes in diversity and community composition of AMF. The interaction effects of soil management practices due to climate change affect the system productivity and perturb mineral cycling. Understanding the carbon and nitrogen cycling of an agro-ecosystem and its associated AMF communities concerning ecosystem productivity is the need of the hour. Plant-fungal associations require a more environment resilient approach to ameliorate the effect of anthropogenic changes in carbon and nitrogen cycles. Since AMF communities alter due to local environmental conditions and land-use changes, the most adapted community may help in predicting the mycorrhizal responses to chemical fertilizers, eCO 2 , temperature and drought. In this review, we aimed at investigating (i) the diversity and community composition of AMF in relation to the change in crop and soil management practices, and (ii) how the adapted AMF communities may perform in maintaining the ecosystem resilience of these agroecosystems under climate change conditions. Hence, AMF-plant symbiosis can be effectively integrated into global climate change models. Eventually, the ecosystem resilience will be better understood to exploit the resident AMF communities to offset some of the detrimental effects of anthropogenic environmental change.

Microbial bio-products are becoming an appealing and viable alternative to chemical pesticides for effective management of crop diseases. These bio-products are known to have potential to minimize agrochemical applications without losing crop yield and also restore soil fertility and productivity. In this study, the inhibitory efficacy of 2,4-diacetylphloroglucinol (DAPG) produced by Pseudomonas fluorescens VSMKU3054 against Ralstonia solanacearum was assessed. Biochemical and functional characterization study revealed that P. fluorescens produced hydrogen cyanide (HCN), siderophore, indole acetic acid (IAA) and hydrolytic enzymes such as amylase, protease, cellulase and chitinase, and had the ability to solubilize phosphate. The presence of the key antimicrobial encoding gene in the biosynthesis of 2,4-diacetylphloroglucinol (DAPG) was identified by PCR. The maximum growth and antimicrobial activity of P. fluorescens was observed in king’s B medium at pH 7, 37 °C and 36 h of growth. Glucose and tryptone were found to be the most suitable carbon and nitrogen sources, respectively. DAPG was separated by silica column chromatography and identified by various methods such as UV-Vis, FT-IR, GC-MS and NMR spectroscopy. When R. solanacearum cells were exposed to DAPG at 90 µg/mL, the cell viability was decreased, reactive oxygen species (ROS) were increased and chromosomal DNA was damaged. Application of P. fluorescens and DAPG significantly reduced the bacterial wilt incidence. In addition, P. fluorescens was also found effective in promoting the growth of tomato seedlings. It is concluded that the indigenous isolate P. fluorescens VSMKU3054 could be used as a suitable biocontrol agent against bacterial wilt disease of tomato.