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Levels of toxic trace elements (TTE) are increasing in soil systems in the modern era of agricultural mechanization and industrial revolution via anthropogenic activities. TTE-contaminated soil does not only have adverse impacts on soil health but also on plants, higher animals, and humans via food-chain contamination, leading to crop failure and several kinds of human and animal diseases. To maintain soil health for future generations and sustainable crop production, keeping our soil alive and protecting its biological components are of utmost importance. Many technologies have been used in the recent past for the mitigation of soil TTE, but slow remediation processes and expensive remediation methods have raised concerns about their limitations. Some remediation methods may lead to further secondary contamination of the soil. Innovative approaches are needed, and the use of endophytes serves as a potential tool to reclaim TTE-contaminated soil by minimizing their toxic effects and maximizing benefits to crops via improved nutrient cycling. The present chapter highlights the significance of endophytes for soil health restoration in TTE-contaminated soil for optimizing crop growth and productivity.

Refereed/Peer-reviewed The phytoextraction with hyperaccumulator plant species has been found as a novel approach for cleaning up of arsenic (As)-contaminated soils. However, proper management strategy should be developed to enhance the phytoextraction potential of hyperaccumulator and minimize the bioavailability and As contamination to agricultural crops. A greenhouse study was evaluated to assess the effectiveness of phosphatic fertilisers viz. di-ammonium phosphate (DAP) and single superphosphate (SSP) with successive two growing cycles on As removal by Chinese brake fern (Pteris vittata L.) from the contaminated Typic Haplustepts soils of West Bengal, India. Present study evaluated the influence of phytoextraction by the fern (P. vittata) on redistribution of As in different fraction (water soluble, exchangeable, aluminium, iron and calcium bound) in soil as well as total and Olsen's extractable fraction in soil and its subsequent impact on rice crop. Among the five fractions, water soluble fraction and Fe-bound As was found in higher magnitude than the other As bound fractions viz. Al-bound, Ca-bound and exchangeable fraction. This fern was grown in As contaminated soils in successive two growing cycles (four months each), and the total As removal from the soil were measured. The removal values of As varied from 6.4 to 13.5% after the first growing cycle and from 10.6 to 23.9% after the second growing cycle. The phytoextracted soils were reused for rice cultivation to reveal the effect of phytoextraction on As accumulation in rice. In this enhanced process of phytoextraction by P. vittata, the phosphatic fertilizers, DAP was contributed greater than SSP in enhancing the more As uptake by the fern as confirmed by our previous study and followed by a significant decrease in available fraction of As in soil and reduced availability for accumulation in rice. Combining the process of two successive cycles phytoextraction with phosphate (DAP) management strategy leads to reduced bio-available fraction in the soil may serve better for soil with medium levels of As contamination. However, these cycles phytoextraction could be prolong with adjustable soil amendments for high As contaminated soil to attain safe limits of As in the soil and reduced the risk of rice consumption in the arsenic affected areas. Combining the process of two successive cycles phytoextraction with phosphate (DAP) management strategy leads to reduced bio-available fraction in the soil may serve better for soil with medium levels of As contamination. However, these cycles phytoextraction could be prolong with adjustable soil amendments for high As contaminated soil to attain safe limits of As in the soil and reduced the risk of rice consumption in the arsenic affected areas.

A study was conducted to assess soil health in a participatory mode whereby farmers were sensitized, involved, trained, and provided with low-cost tools for assessing the soil health of their fields. The study was carried out in two selected villages in the districts of Bhopal and Sehore. Management practices consisted of different nutrient management practices, namely organic manure-based farming, integrated (organic + inorganic) nutrient-based farming, and inorganic fertilizer-based farming. In this approach, both qualitative and quantitative assessments of soil parameters were done to characterize soil quality and enhance soil health and productivity. It helped farmers to assess their soil health periodically and prepare a Soil Health Card for their farm. About 12 soil parameters comprising of physical, chemical, and biological health indicators were selected for the study. Results revealed that different nutrient management-based farming systems significantly affected soil pH, electrical conductivity, soil organic carbon, aggregate stability, mean weight diameter, soil moisture retention, soil penetration resistance, and crop yield. In addition, results indicated that organic-based farming recorded ‘good’ Soil Health Card values compared to integrated and inorganic fertilizer-based farming, regardless of location. In Parwalia village, results indicated that high soil quality index (SQI) was observed under organic nutrient management (0.61), followed by integrated (0.52) and inorganic nutrient (0.34) management. In Vaidakhedi village, the corresponding values were 0.63, 0.50, and 0.33, respectively. The improvement in soil quality also influenced the crop yield significantly. Moreover, a significant relationship was observed between field assessed values to the laboratory values in this study. Thus, adopting either organic or integrated nutrient-based farming helps sustain soil health and improve crop yield compared to the application of inorganic fertilizers. Results also highlight the importance of low-cost tools for assessing soil health in a participatory mode, which helps in the efficient allocation of manures and fertilizer nutrients as per requirement. This study reinforces the importance of soil physical (i.e. MWD, aggregate stability and penetration resistance) and biological (macro-life diversity and earthworm counts) indicators for inclusions in Soil Health Card for making it a comprehensive assessment of soil health.

In recent decades, environmental pollution due to presence of toxic metal elements come across globally with severe threats to plants, soil, humans, and animals. The major causes behind this are rapid and injudicious industrialization, intensive farming, faulty mining activities, and wastes which get accumulated in the soil at higher toxic concentration after long term exposure. Even a slight upsurge in the heavy metal concentration beyond permissible limit causes harmful effects to all the living entities. The acquaintance of plants to metal contaminated growing media diminishes crop performance by altering vegetative and reproductive development that eventually affect sustainability of agricultural production. Silicon (Si) exhibits a significant key role in minimizing heavy metal poisonousness in plants. Amending soil with silicates reduces toxic effect of heavy metals by involving various mechanisms and stimulates crop development by lessening various stresses due to biotic and abiotic factors. Here, we reviewed the most recent research development using silicon as amendment for mitigation of adverse impacts of heavy metals in plants. The paper will be describing about the advanced technologies related to usage of silicon in crop cultivation to enhance sustainable crop production by altering and (or) improving metal contaminated soils.

TiO2 nano particles (NPs) are one of the most produced nanoparticles in the world which are increasingly being released in to the soil. Soils are exposed to various level of concentration of TiO2 NPs, which has raised concern over the adverse influence on soil microbial community, in turn on ecosystem functions. Although, increasing number of studies on ecotoxicological effect of TiO2 NPs are coming up recently, however, a common conscience has yet to be reached regarding the impact of TiO2 NPs on soil microbial community and processes. Moreover, very few studies have targeted soil enzymes which are being considered as sensitive indicator of soil health. Therefore, the present study has been carried out to estimate the ecotoxicological effect of various doses of TiO2 NPs (5, 10, 20, 40, 80, 100 mg kg−1 soil) on different soil enzymes and microbial community structure. Results revealed that soil enzyme activities and microbial biomass had a uniform trend where the value increased up to the dose of 20 mg TiO2 NPs kg−1 soil and there onwards reduced drastically up to 100 mg TiO2 NPs kg−1 soil dose. On the contrary, soil respiration and metabolic quotient kept increasing up to 100 mg TiO2 NPs kg−1 soil dose indicating sub-lethal stress on microbial community. Nevertheless, the structure of microbial community had slightly different trend where the biomass of total phospho lipid fatty acid (PLFA), Gram positive, Gram negative bacteria, fungi, actinomyctetes and anaerobes were found to be increased up to dose of 80 mg TiO2 NPs kg−1 soil, but, significantly declined at 100 mg TiO2 NPs kg−1 soil dose. Furthermore, temperature effect on TiO2 NPs toxicity had exhibited a less negative impact at 40 °C rather than at 25 °C. In addition alteration index (AI3), an integrated indicator of C, N, P cycling of soils as well as a well-documented indicator of soil pollution, has been found to be regulated by soil respiration, clay content, anaerobe and eukaryote for AI3-Acid Phos. and by fungi to bacteria ratio, soil respiration, microbial biomass and Gram positive bacteria for AI3-Alk. Phos. Overall, the study provided valuable information regarding ecotoxicological impact of environmentally relevant concentrations of TiO2 NPs in clay loam soils as well as improved our perception regarding the impact of NPs on soil functioning.

Zinc (Zn) deficiency prevails in different soils and crops of the world. Soil Zn deficiency adversely affects growth, yield and micronutrients (Zn, copper (Cu), iron (Fe) and manganese (Mn)) concentration in different crops including pigeonpea (Cajanus cajan L. Millsp.), a protein rich legume crop grown consumed in different parts of the world. Therefore, we carried out a 2-years field experiment on a Zn-deficient Vertisol with 20 different pigeonpea genotypes and 3 levels of Zn treatments in a split-plot design with 3 replications, to study the effect of Zn application on yield, micronutrients concentration and uptake by pigeonpea genotypes. The 3 levels of Zn treatments were no Zn (no Zn fertilizer was applied), soil Zn (20 kg Zn ha−1) and soil + foliar Zn. Compared to no Zn application, soil and soil + foliar application of Zn enhanced mean grain yield by 15 and 24%, stover yield by 13 and 29% and total biomass yield of pigeonpea genotypes by 13 and 29%, respectively. Soil + foliar application of Zn significantly increased mean grain Zn concentration by 33% compared to no Zn application. Soil and soil + foliar Zn application led to reduction in mean grain Cu concentration by 9 and 10%, respectively, and did not significantly increase or decrease grain Fe and Mn concentration. Soil and soil + foliar application of Zn significantly increased mean grain Zn, Fe and Mn uptake by pigeonpea genotypes compared to no Zn application. Soil + foliar application of Zn had significantly higher mean grain Zn, Fe and Mn uptake compared to soil Zn application. The grain, stover and total biomass yield, micronutrients concentration in grain and stover and micronutrients uptake by the genotypes were different under various treatments. The genotypes ICPL 87119, BDN 2, JKM 7, Virsa Arhar 1, DT 23 and AAUT 2007–10 under soil application of Zn and ICPL 87119, BDN 2, JKM 7 and Virsa Arhar 1 under soil + foliar application of Zn were found promising for cultivation to obtain higher grain yield and micronutrients uptake.

In the pursuit of higher food production and economic growth and increasing population, we have often jeopardized natural resources such as soil, water, vegetation, and biodiversity at an alarming rate. In this process, wider adoption of intensive farming practices, namely changes in land use, imbalanced fertilizer application, minimum addition of organic residue/manure, and non-adoption of site-specific conservation measures, has led to declining in soil health and land degradation in an irreversible manner. In addition, increasing use of pesticides, coupled with soil and water pollution, has led the researchers to search for an environmental-friendly and cost-effective alternatives to controlling soil-borne diseases that are difficult to control, and which significantly limit agricultural productivity. Since the 1960s, disease-suppressive soils (DSS) have been identified and studied around the world. Soil disease suppression is the reduction in the incidence of soil-borne diseases even in the presence of a host plant and inoculum in the soil. The disease-suppressive capacity is mainly attributed to diverse microbial communities present in the soil that could act against soil-borne pathogens in multifaceted ways. The beneficial microorganisms employ some specific functions such as antibiosis, parasitism, competition for resources, and predation. However, there has been increasing evidence on the role of soil abiotic factors that largely influence the disease suppression. The intricate interactions of the soil, plant, and environmental components in a disease triangle make this process complex yet crucial to study to reduce disease incidence. Increasing resistance of the pathogen to presently available chemicals has led to the shift from culturable microbes to unexplored and unculturable microbes. Agricultural management practices such as tillage, fertilization, manures, irrigation, and amendment applications significantly alter the soil physicochemical environment and influence the growth and behaviour of antagonistic microbes. Plant factors such as age, type of crop, and root behaviour of the plant could stimulate or limit the diversity and structure of soil microorganisms in the rhizosphere. Further, identification and in-depth of disease-suppressive soils could lead to the discovery of more beneficial microorganisms with novel anti-microbial and plant promoting traits. To date, several microbial species have been isolated and proposed as key contributors in disease suppression, but the complexities as well as the mechanisms of the microbial and abiotic interactions remain elusive for most of the disease-suppressive soils. Thus, this review critically explores disease-suppressive attributes in soils, mechanisms involved, and biotic and abiotic factors affecting DSS and also briefly reviewing soil microbiome for anti-microbial drugs, in fact, a consequence of DSS phenomenon.

Two experiments were conducted to determine the cotton plant’s tolerance to Pb and its remediation potential. In the first experiment, the phytoremediation potential was determined by exposing the plant to four levels of Pb (0, 500, 750, and 1000 mg kg−1). The cotton plant exhibited an excellent tolerance index at Pb 1000 mg kg−1 (root 78.65% and shoot 93.08%) and lower grade of growth inhibition (root 21.35% and shoot 6.92%). Pb stress resulted in higher leakage of electrolytes and increased the synthesis of higher proline, total phenol, and free amino acid contents to mitigate stress. The plant could not meet the criteria of a hyperaccumulator of Pb. The concentration of Pb in the shoot was a mere 96 μg g−1 dry wt (< the critical judging concentration of 1000 μg g−1 dry wt), and bioconcentration and translocation factors were

Safe disposal of huge quantity of fly ash is compulsory to avoid environmental problems, and contents of significant amount of plant nutrients, particularly phosphorus (P), make it a potential amendment in agriculture. A comparative assessment of P adsorption, release kinetics and enzymatic activities of weathered fly ash amended texturally different soils is yet to be explored. This article explores the influence of fly ash with or without FYM on P adsorption parameters and indices, release kinetics, P activity coefficient (PAC) and enzymatic activities in Inceptisol and Vertisol with the treatments comprising graded doses of weathered fly ash and FYM. Increased fly ash doses amplified the P adsorption in soils, which further increased with FYM application. Binding energy, adsorption maxima and P sorption index also augmented by increased doses of fly ash. Gibb’s free energy of adsorption indicated that P adsorption was due to chemisorption. However, rate of P release was 6–10 times higher at initial stages and increased concentration of P through fly ash and FYM quantified higher P diffusion rate. PAC was negatively influenced by higher quantity of fly ash, but FYM positively influences PAC. Enzymatic activities decreased in Inceptisol beyond 200 t ha−1 fly ash; however, 50 t ha−1 FYM nullifies the negative impact of fly ash and increased enzymatic activities in both the soils. Increased maximum P buffering capacity, PAC, enzymatic activities and liming effects on acidic soils suggested better management options of fly ash as slow release P source in crop production along with FYM.

An experiment was conducted to study the effects of co-composted products of municipal solid waste (MSW) and pigeon pea biochar (PPB) on heavy metal mobility in soil and its uptake by spinach. Application of municipal solid waste biochar co-compost (MSWBC) significantly (p ≤ 0.05) reduced the heavy metal content in spinach leaves and roots compared to municipal solid waste compost (MSWC) amended soil. The percent decrease in spinach leaf following the application of MSWBC-10% PPB compared to MSWC was 20.62%, 28.95%, 36.02%, 41.88%, 41.50%, and 41.23% for Cu, Cd, Pb, Cr, Ni, and Zn, respectively. The dry matter yield of spinach and soil organic carbon (SOC) content in soil amended with MSWBC-10% PPB was significantly increased by 32.75% and 47.73%; and 17.62% and 27.45% relative to control and MSWC amended soil. The study concludes that co-composted product, MSWBC, stabilized heavy metals in MSW, reduced their uptake by spinach and thus making it a viable option for safe disposal of MSW.

In the present study, we evaluated Furcraea foetida for the phytoremediation of cadmium (Cd)-contaminated soils. We selected F. foetida because it is a drought-resistant plant, produces high biomass, and needs minimum maintenance. It belongs to the leaf fiber group of plants and therefore has economic importance. Since it is a non-edible crop, there is no danger of food chain contamination. Despite possessing these ideal characteristics, surprisingly, to date, the plant is underutilized for phytoremediation purposes. Therefore, to evaluate the phytoremediation potential of the plant, we exposed it to five levels of cadmium (0, 25, 50, 100, and 200 mg Cd kg-1 soil) and studied its influence on growth, dry matter production, uptake, and translocation efficiency. The plant showed good tolerance to Cd 200 mg kg-1 soil without exhibiting any visible toxicity symptoms. The metal mainly accumulated in the roots (233 μg g-1dw), followed by leaf (51 μg g-1 dw). The bioconcentration factor was > 1, but the translocation factor was < 1. The plant was not classified as a hyperaccumulator of Cd; however, because of its high uptake (897 μ g-1 plant) and translocation efficiency (78%), we concluded that the plant could be utilized for phytoextraction of Cd from soils with low to moderately contaminated soils.

Agave americana was evaluated for its phytoremediation potential of the soils contaminated with Cd. This plant was selected because of its drought tolerance and high biomass. The pot culture experi...

The current experiment envisages estimating nitrification and elucidates the mechanistic processes of nitrogen mineralization in a long-term fertilizer experiment (LTFE) on a soybean-wheat cropping...

Due to declining soil quality and increasing climate change, resource conservation technologies are often advocated for the food production system. Conservation agriculture (CA) is one of the technologies that increase soil nutrient status without jeopardizing the soil health and quality. The effects of conservation tillage, residue retention, and cropping systems on soil physical, chemical, and biological properties within the irrigated agricultural system are well established. However, scanty information is available on the combined impact of tillage, residue, and cropping system available on the major and micro-nutrient in the rainfed farming systems. Thus, a field experiment was conducted to measure the short-term effect of CA practices on soil properties and major (N, P, and K) and micro (Fe, Mn, Zn, and Cu)-nutrients in a Vertisol of Central India. The field experiment was laid out in a split-plot design consisting of two tillage systems (TS), conventional tillage (CT) and reduced tillage (RT), as the main plots and six cropping systems (CS) as subplots. A total of 144 soil samples were collected after four crop cycles to assess soil properties and nutrient (major and micro-nutrient) status. Results demonstrated that in the surface soil layer (0–5 cm), the major and micro-nutrient concentrations were higher than subsurface layers, regardless of TS and CS. In the surface soils, soil organic carbon (SOC) varied from 0.58 to 0.60% under CT and from 0.60 to 0.62% under RT. Tillage and cropping systems had a significant effect (p

Aim: To study the combined effect of tillage and manure addition on bulk soil and aggregate associated carbon and nitrogen in Vertisol. Methodology: The study was conducted in a long-term tillage experiment having two tillage treatments (reduced tillage and no-tillage) together with100% NPK fertilizer without (T1) and with addition of farm yard manure (T2) @ 2.0 ton C ha-1 to soybean in a soybean-wheat cropping system in a Vertisol of Central India, with three replicates in a split plot design. The parameters studied were aggregate size distribution, mean weight diameter, water stable aggregates, bulk soil and aggregate associated organic carbon, available nitrogen and rate of carbon mineralization. Results: The results indicated significantly higher SOC in reduced tillage (0.87%) than no-tillage (0.71%) under100% NPK fertilization in the bulk soil for 0-15 cm depth. However, 100% NPK + FYM showed a significant increase in the bulk soil organic carbon in the no-tillage treatment only. Available nitrogen content in the bulk soil and aggregate fractions were significantly lower under no-tillage than the corresponding reduced tillage treatments. Manure addition led to significantly higher available N content and proportion of WSA in both the tillage practices. The carbon mineralization was significantly higher by 1.4 to 1.6 times under reduced tillage than no-tillage. Interpretation: Long-term tillage study in Vertisol of Central India indicated reduced tillage to be a better option than no-tillage in maintaining organic carbon and nitrogen availability in soil.

Glauconite is a potassium (K) bearing mineral, which generally contains 6–10% K2O and mostly available in various natural deposits in India. Glauconite mineral was converted to nano-particle form b...

Of late, intensive farming for higher food production is often associated with many negative implications for soil systems, such as decline of soil organic matter (SOM), increase in risks of soil erosion by wind and/or water, decline in soil biological diversity, increase in degradation of soil physical quality, lower nutrient-use efficiency, high risks of groundwater pollution, falling water tables, increasing salinization and waterlogging, in-field burning of crop residues, pollution of air and emission of greenhouse gases (GHG), leading to global warming, and decline in factor productivity. These negative implications necessitate an objective review of strategies to develop sustainable management practices, which could not only sustain soil health and ensure food security, but also enhance carbon sequestration, decrease GHG emissions, and offer clean and better ecosystem services. Conservation agriculture (CA), that includes reduced or no-till practices along with crop residue retention and mixed crop rotations, offers multiple benefits. Adoption of a system-based CA conserves water, improves and creates more efficient use of natural resources through the integrated management of available soil nutrients, water, and biological resources, and enhances use efficiency of external inputs. Due to apparent benefits of CA, it is increasingly being adopted and now covers about 180 million hectares (Mha) worldwide. However, in South Asia its spread is low (

Exploring diversity of endophytes from cultivated crop offers immense promise for plant growth promotion. Present study evaluated plant growth promoting efficiency, phosphorus, and potassium solubi...

Methane (CH4) consumption in agricultural soil is imperative for the mitigation of climate change. However, the effect of tillage and cropping systems on CH4 consumption is less studied. Experiments were carried out in Madhya Pradesh, India with soybean-wheat (SW), maize-wheat (MW) and maize-gram (MG) cropping systems under conventional tillage (CT) and no-tillage (NT). Soybean/maize was cultivated during the kharif season (July–October) and wheat/chickpea in the rabi season (October–March) for 9 years consecutively. Soil samples were collected during vegetative growth stages of soybean and maize from different cropping systems. Methane consumption, the abundance of methanotrophs as particulate methane monooxygenase (pmoA) gene copies, soil and crop parameters were estimated. Methane consumption rate was higher in NT and upper soil layer (0–5 cm) than CT and 5–15 cm depth. Methane consumption rate k ranged from 0.35 to 0.56 μg CH4 consumed/g soil/d in the order of MW>SW>MG in 0–5 cm. The abundance of pmoA gene copies ranged from 43 × 104/g soil to 13 × 104/g soil and was highest in MW-NT and lowest in MG-CT. Available nitrogen, phosphorus and potassium were higher in 0–5 cm than in 5–15 cm depth. Soil and plant parameters and abundance of pmoA genes correlated significantly and positively with CH4 consumption rate. No-tillage stimulated CH4 consumption compared to CT irrespective of cropping system and CH4 consumption potential was highest in MW and lowest in MG. However, the magnitude of the positive effect of NT towards CH4 consumption was higher in SW and MG than MW.

Soil aggregates govern soil organic carbon (SOC) sequestration. But, sparse understanding about the process leads to inaccuracy in predicting potential of soil to stabilize C in warming world. We appraised effects of 43 years of fertilization on relative temperature sensitivity of SOC decomposition (Q10) in soil aggregates to know whether SOC quality or quantity governs Q10. Treatments were: fallow, control, 100% recommended dose of nitrogen (N), N and phosphorus (NP), N, P and potassium (NPK), and NPK + farmyard manure (FYM) (NPK + FYM). Macroaggregates, microaggregates and silt + clay (s + c) fractions were incubated for 16 weeks at 25, 35 and 45 °C, SOC quality (R0) and Q10 were computed. SOC mineralization from macro- and micro- aggregates were 34 and 28% higher than s + c across the treatments. The s + c fraction of NPK + FYM had ~ 41, 40 and 24% higher C decay rate than NPK plots at 25, 35 and 45 °C, respectively. For s + c fraction Q10 increased over other aggregates. Mean Q10 of s + c fraction was ~ 18.3 and 17.5% higher than macro and micro-aggregate-C, respectively. R0 was the lowest for NPK + FYM, suggesting long-term manuring with balanced NPK significantly enhance recalcitrance of C. We observed Q10 of macroaggregates and s + c fraction is controlled by C quality but C quantity governs Q10 of microaggregates in Vertisol. Specifically, microaggregates of NPK + FYM were more temperature sensitive, and could be vulnerable to C loss. Hence, practices facilitating microaggregate formation should be avoided. Thus, we recommend manure application for facilitating C sequestration.

Biodegradation of chlorpyrifos under the influence of fertilizer application and climate factors such as elevated CO2, temperature and moisture was studied. Soybean was grown in control, inorganic, organic and integrated (both inorganic and organic) fertilized fields. Rhizospheric soils collected during the vegetative growth phase were amended with chlorpyrifos (10 μg/g soil) and incubated under different climate factors. The climate factors were CO2 concentration (400, 800 ppm), temperature (25, 45°C) and moisture-holding capacity (60, 100%). Chlorpyrifos degradation rate varied from 0.28 to 0.65 μg/g soil/d. The abundance of 16S rRNA gene copies of eubacteria varied from 13 × 106 to 7 × 105/g soil. Actinomycetes-specific 16S rRNA gene copies were in the range of 62.5 × 105 to 18.5 × 103/g soil. Microbial abundance was high in organic amended soil and low in control soil irrespective of climate factors. Elevated CO2 and high temperature inhibited (P < 0.05) chlorpyrifos degradation rate and the abundance of 16S rRNA genes of eubacteria and actinomycetes. Chlorpyrifos degradation followed as: organic > integrated > inorganic > control. The degradation rate was positively correlated (P < 0.01) with the soil organic C, available N, water-stable aggregates and mean weight diameter of the soil aggregates of soil. Principal component analysis denoted temperature and fertilizer as the major components of variation. The study highlights that elevated CO2 and temperature affect chlorpyrifos biodegradation; however, the effect can be alleviated by the amendment of organic fertilizer.

Global modernization, industrialization and urbanization have resulted in increased contamination of our environment by heavy metals. A long persistence of heavy metals in nature has lead to the development of metal resistant microbial strain. Microorganisms play a significant role in bioremediation of heavy metal contaminated soil. In this study, endophytic fungal isolates (EN1 and EN2) isolated from root of Amaranthus spinosus collected from contaminated site of Bhanpur, Bhopal, Madhya Pradesh have been studied for their tolerance and capacities to uptake heavy metals like cadmium (Cd) and lead (Pb). Among the two fungi, EN1 was found to have maximum tolerance for both Cd and Pb based on their growth on heavy metal supplemented potato dextrose agar medium. It also revealed that the maximum uptake of Pb and Cd was 85.7% and 82.6%, respectively at increasing concentration (0-20 ppm). Fungal isolate EN1 was identified to be Penicillum sp. based on morphological and molecular characteristics. This study indicated the potential of these endophytic fungi for bioaccumulation of higher concentration of Cd and Pb from contaminated site which make them potential candidate for bioremediation. Finally, the result indicated that Penicillium sp. could be a prospective candidate to increase the phytoremediation efficiency of plant and play an important role in the decontamination of polluted soil.

Adoption of conservation agriculture (CA) is very slow due to weed infestations. The application of herbicides is the only viable option to deal with problem of weed management to adhere with basic principles of CA. A field experiment was carried out for three years to evaluate the expediency of different herbicides and their sequential applications under CA. In this study, seven treatments comprised of either alone or sequential application of pre-emergence (PE) and post-emergence (PoE) herbicides, hand weeding and weedy check were tested in soybean. Result indicated that sequential application of glyphosate at 1 kg ai ha-1 + pendimethalin at 1 kg ai ha-1as PE followed by PoE application of imazethapyr at 100 g ai ha-1 at 30 days after sowing (DAS) proved to be the best economical option in terms of plant growth parameters, crop biomass, seed yield, weed index and carbon and nutrient recycling. Pearson’s correlation coefficients matrix revealed that grain yield was significantly (P2 value of 0.53, 0.99, 0.95 and 0.98, respectively. The fitted stepwise multiple regression model also revealed that N and P uptake in grain, weed density at 20 DAS and K uptake in weed were actual predictor for grain yield. We concluded that, effective and economical weed control under CA in soybean can be achieved through sequential application of glyphosate along with pendimethalin at 1 kg ai ha-1 each PE followed by PoE use of imazethapyr at 100 g ai ha-1 at 30 DAS.

Glycoproteins, e.g., glomalin related soil proteins (GRSP), are sticky organic substances produced by arbuscular mycorrhizal fungi (AMF). This review summarizes the information on i) the biochemical nature, physical state and origin of GRSP, ii) GRSP decomposition and residence time in soil, iii) GRSP functions, in particular the physical, chemical, and biochemical roles for soil aggregation and carbon (C) sequestration, and finally iv) how land use and agricultural management affect GRSP production and subsequently, organic C sequestration. GRSP augment soil quality by increasing water holding capacity, nutrient storage and availability, microbial and enzymatic activities, and microbial production of extracellular polysaccharides. After release into the soil, GRSP become prone to microbial decomposition due to stabilization with organic matter and sesquioxides, and thereby increasing the residence time between 6 and 42 years. Temperate soils contain 2-15 mg GRSP g-1, whereas arid and semiarid grasslands amount for 0.87-1.7 mg g-1, and GRSP are lower in desert soils. GRSP content is highest in acidic soils as compared to neutral and calcareous soils. Conservation tillage, organic fertilizers and AMF inhabiting crops (e.g. maize, sorghum, soybean, and wheat) increase GRSP production and transform C into stable forms, thereby sustaining soil health and reducing CO2 emissions. Crop rotations with non-mycorrhizal species (e.g. rapeseed) and fallow soils reduce AMF growth and consequently, the GRSP production. The GRSP production increases under nutrient and water deficiency, soil warming and elevated CO2. In the context of global climate change, increased C sequestration through GRSP induced aggregate formation and organic matter stabilization prolong the mean residence time of soil C. Protecting soils against degradation under intensive land use, stable aggregate formation, and prolonging the residence time of C calls for strategies that maximize GRSP production and functions based on reduced tillage, AMF-relevant crop rotations and organic farming.

Understanding the spatial spreading patterns of plant-available sulphur (S) (AS) and plant-available micronutrients (available zinc (AZn), available iron (AFe), available copper (ACu), available manganese (AMn) and available boron (AB)) in soils, especially in coastal agricultural soils subjected to various natural and anthropogenic activities, is vital for sustainable crop production by adopting site-specific nutrient management (SSNM) strategies. We studied the spatial distribution patterns of AS, AZn, AFe, ACu, AMn, and AB in cultivated soils of coastal districts of India using geostatistical approaches. Altogether 39,097 soil samples from surface (0 to 15 cm depth) layers were gathered from farm lands of 68 coastal districts. The analysis of soil samples was carried out for soil pH, electrical conductivity (EC), soil organic carbon (SOC) and AS, AZn, AFe, ACu, AMn, and AB. Soil pH, EC and SOC varied from 3.70 to 9.90, 0.01 to 7.45 dS m-1 and 0.02 to 3.74%, respectively. The concentrations of AS, AZn, AFe, ACu, AMn, and AB varied widely in the study area with their corresponding mean values were 37.4±29.4, 1.50±1.53, 27.9±35.1, 2.14±1.74, 16.9±18.4 and 1.34±1.52 mg kg-1, respectively. The coefficient of variation values of analyzed soil parameters varied from 14.6 to 126%. The concentrations of AS, AZn, AFe, ACu, AMn, and AB were negatively and significantly correlated with soil pH and positively and significantly correlated with SOC. The geostatistical analysis indicated stable, Gaussian and exponential best-fit semivariogram models with moderate to strong spatial dependence for available nutrients. The generated spatial spreading maps revealed different distribution patterns for AS, AZn, AFe, ACu, AMn, and AB. There were variations in spatial spreading patterns of AS, AZn, AFe, ACu, AMn, and AB in east- and west-coastal area. About 62, 35, 12, 0.4, 23 and 45% of the study area had deficiency of AS, AZn, AFe, ACu, AMn, and AB, respectively. The spatial spreading maps will be highly useful for SSNM in the cultivated coastal soils of the country. This study could also be used as a base for assessing spatial spreading patterns of soil parameters in cultivated coastal areas of other parts of the world.

The deficiencies of nutrient elements and inappropriate nutrient management practices in agricultural soils of the world is one of the reasons for low crop productivity, reduced nutritional quality of agricultural produce, and animal/human malnutrition. We carried out the present study to evaluate the single and multi-nutrient deficiencies of sulfur (S) and micronutrients (zinc (Zn), boron (B), iron (Fe), copper (Cu) and manganese (Mn)) in agricultural soils of India for their effective management to achieve sustainable crop production, improved nutritional quality in crops and better animal/human health. Altogether, 24,2827 surface soil samples (0 to 15 cm depth) were collected from the agriculture fields of 615 districts in 28 states of India and were analyzed for available S and micronutrient concentration. The concentration of available S and micronutrients varied widely. There were variable and widespread deficiencies of S and micronutrients in different states. The deficiencies of S, Zn and B were higher compared to the deficiencies of Fe, Cu and Mn. There were occurrences of two-nutrient (namely S + Zn, Zn + B, S + B, Zn + Fe Zn + Mn, S + Fe, Zn + Cu and Fe + B), three-nutrient (namely S + Zn + B, S + Zn + B and Zn + Fe + B) and four-nutrient (namely Zn + Fe + Cu + Mn and Zn + Fe + Cu + Mn + B) deficiencies in different extents. This information could be used by various stakeholders for production, supply and application of the right kind of fertilizers in different districts, states and agro-ecological regions of India for better crop production, crop nutritional quality, nutrient use efficiency and soil and environmental health. This will also help in a greater way to address the issue of malnutrition in human/animals.

Potassium (K) is one of the essential nutrients required by crops in large quantities; however, its use in agriculture by farmers is less than required in developing countries. This neglect...

Accelerated erosion removes fertile top soil along with nutrients through runoff and sediments, eventually affecting crop productivity and land degradation. However, scanty information is available on soil and nutrient losses under different crop covers in a vertisol of Central India. Thus, a field experiment was conducted for 4 years (2010–2013) to study the effect of different crop cover combinations on soil and nutrient losses through runoff in a vertisol. Very limited information is available on runoff, soil, and nutrient losses under different vegetative covers in a rainfed vertisol. Thus, the hypothesis of the study was to evaluate if different crop cover combinations would have greater impact on reducing soil and nutrient losses compared to control plots in a vertisol. This experiment consisted of seven treatment combinations of crop covers namely soybean (Glycine max) (CC1), maize (Zea mays) (CC2), pigeon pea (Cajanus cajan) (CC3), soybean (Glycine max) + maize (Zea mays) − 1:1 (CC4), soybean (Glycine ma x)) + pigeon pea (Cajanus cajan) −2:1 (CC5), maize (Zea mays) + pigeon pea (Cajanus cajan) − 1:1 (CC6), and cultivated fallow (CC7). The plot size was 10 × 5 m with 1% slope, and runoff and soil loss were measured using multi-slot devisor. All treatments were arranged in a randomized block design with three replications. Results demonstrated that the runoff and soil loss were significantly (p

Increasing lead (Pb) and nickel (Ni) pollution through geogenic and anthropogenic activities is a major concern to evolve a sustainable crop and to meet the food requirement of a growing population. Interaction effects of metal ions may affect the essential plant nutrients concentration and their uptake by crops. For this, a pot culture experiment was conducted with four levels (0, 100, 150 and 300 mg kg−1 dry soil) of each Pb and Ni in combinations that were spiked into black cotton soils (5 kg pot−1) of Central India. Spinach crop was raised as test crop. The essential plant nutrients and heavy metal concentration in spinach were measured. Experimental results showed that increasing the concentration of Pb in soil significantly (p = 0.05) reduced the concentration of micronutrients (Fe, Zn, Cu, Mn) as well as macronutrients (P, K, S) in the plant parts. Application of Ni did not significantly increase the concentration of plant nutrients in root and shoot of spinach. The magnitude of Pb toxicity was high as compared to the magnitude of Ni toxicity in both root and shoot. This type of research studies helps in the formulation of waste water management policies, mostly in developing countries to protect the natural resources with respect to sustainable crop management.

Nitrate (NO3−) and bicarbonate (HCO3−) are harmful for the water quality and can potentially create negative impacts to aquatic organisms, crops and humans. This study deals with the removal of NO3− and HCO3− from contaminated wastewater using Fe-exchanged nano-bentonite and Fe3O4 nanoparticles. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, surface area measurement and particle size analysis revealed that the adsorbents fall under the nano-scale size range with high specific surface area, and Fe was successfully exchanged in the nano-bentonite clay. The kinetics of adsorption was well defined by pseudo-first order and pseudo-second order kinetic models for both NO3− and HCO3−. The Fe-exchanged nano-bentonite was a better performing adsorbent of the oxyanions than Fe3O4 nanoparticles. According to the Sips isothermal model, the Fe-exchanged nano-bentonite exhibited the highest NO3− and HCO3− adsorption potential of 64.76 mg g-1 and 9.73 meq g-1, respectively, while the respective values for Fe3O4 nanoparticles were 49.90 mg g-1 and 3.07 meq g-1. Thus, inexpensiveness and easy preparation process of Fe-exchanged nano-bentonite make it attractive for NO3− and HCO3− removal from contaminated wastewater with significant environmental and economic benefits.

To accelerate the process of decomposition using consortia of thermophilic ligno-cellulolytic fungi, different crop residues viz. sorghum (SG), soybean (SS), maize (MS), sugarcane (SC), cotton (CS) and pigeon pea (PS) with a varied C:N ratio and sawdust (SD) having high lignin content were collected and used for decomposition process. Compost quality assessed by evaluating different maturity and stability indices at five succeeding stages [first mesophilic (M1), thermophilic (T), second mesophilic (M2), cooling (C) and humification (H)]. A significant reduction was observed in the C:N ratio, biodegradability index, nitrification index, ratio of water-soluble carbon to organic nitrogen (WSC/Org.N) with an increase in concomitant over time while Ash (%), organic matter loss (%), CEC/TOC ratio, cellulose biodegradation ratio (BR) and lignin/cellulose ratio were significantly increased with time. By correlation study, biodegradability index (BI) and fluorescein diacetate (FDA) hydrolysis emerged as the most suitable compost maturity and stability parameters, respectively. Principal component analysis (PCA) results confirmed that BI, BR, WSC/Org. N and FDA can be regarded as key indicators for assessing compost quality. Our findings conclude that fungal consortia of Tricoderma viride, Rhizomucor pusillus, Aspergillus awamori and Aspergillus flavus can accelerate decomposition time from 8 to 12 months (which is normal farming practice) to 120 days.

Rising carbon dioxide (CO₂) concentration causes fertilization effects resulting in enhanced crop biomass and yields and thus likely enhances nutrient demand of plants. Hence, this field study was carried out to investigate the effects of elevated CO₂ and N on biomass yield, nutrient partitioning, and uptake of major nutrients by soybean (Glycine max L.) using open‐top chambers (OTCs) of 4 m × 4 m size. Soybean was grown in OTCs under two CO₂ [ambient and elevated (535 ± 36.9 mg L⁻¹)] and four N levels during July to October 2016. The four N levels were N₀, N₅₀, N₁₀₀, and N₁₅₀ referring to 0, 50, 100, and 150% recommended dose of N. Both CO₂ and N significantly affected biomass and grain yield, though the interaction was non‐significant. CO₂ enrichment produced 30–65% higher biomass and 26–59% higher grain yield under various N levels. As compared to the optimum N application (N₁₀₀), the CO₂‐mediated increment in biomass yield decreased with either lower or higher N application, with the response being lowest at N₁₅₀. As compared to ambient concentration, elevated CO₂ resulted in significant reduction of seed P concentration at all N application levels but at N₁₅₀, an opposite trend was observed. The decrease in seed P was maximum at N₀ and N₅₀ (7–9%) and by 3% at N₁₀₀, whereas there was a gain of 7.5% at N₁₅₀. The seed N and K concentrations were not affected either by CO₂ or N application. Total N, P, and K uptake at harvest were significantly affected by CO₂ and N, but not by CO₂ × N interaction. Elevated CO₂ resulted higher uptake of N by 18–61%, P by 23–62%, and K by 22–62% under various N treatments.

Sewage sludge being a cheap source of plant nutrient is commonly applied by farmers and is being promoted for implementation of “waste to wealth” programme in India. It has diverse impact on soil microbial properties. The aim of this study was to assess the impact of application of sludge from three waste water treatment plants namely, Okhla (Sld-O), Keshopur (Sld-K) and Pappankallan (Sld-P) in National Capital Region (NCR), Delhi, India on various soil biological properties and bio-safety of crop produce. A pot culture experiment with eight treatment combinations (3 sludge × 2 doses [i.e. 11.2 mg kg−1 + 50% recommended NPK, 22.4 mg kg−1] + recommended dose of NPK + absolute control) was conducted. The sludge amendment significantly improved the microbial biomass carbon, potential mineralizable nitrogen, enzyme activities (dehydrogenase, acid and alkaline phosphatase) as well as yield of palak. However, excess nitrate concentration (∼100% higher than control) in post-harvest soils and contamination of palak leaves with Escherichia coli is a matter of great concern and should be monitored carefully for proper utilization of sludge in agriculture.

Available results on the evaluation of nitrogen (N) use efficiency in conservation agriculture (CA) are inconsistent and studies that cover all three components of CA are sparse, especially in tropical agro-ecosystems. Hence, CA effects on variations in total soil N (TSN) and aggregate-associated 15N on a sandy loam soil were evaluated after 15N urea (~5% atom excess) application at 120 kg ha−1 to wheat in the fourth year of an experiment in the Indo-Gangetic Plains (IGP). The cropping system during 2008–2011 was cotton (Gossypium hirsutum)-wheat (Triticum aestivum), that was changed to maize (Zea mays)-wheat in 2011–2012. Results revealed that plots under zero tillage with residue retention of both crops (ZT + R) had better topsoil (0–5 cm layer) aggregation and higher residual 15N in soils than conventionally tilled (CT) plots. The ZT + R plots also had higher macro-aggregates (0.25–8 mm) with less silt + clay sized particles than the CT plots in the 5–15 cm soil layer. Furthermore, both tillage and residue management had significant effects on TSN and aggregate-associated N stocks. The plots under ZT + R had ~9% higher TSN in topsoil than the CT plots and the ZT and ZT + R plots had about 48 and 34% higher large macro-aggregate associated N stocks than CT and CT + R plots, respectively. However, the potential N-mineralization data of the macro-aggregates of ZT + R (CA) and CT plots were similar. In addition, the fertilizer 15N use efficiency, the residual fertilizer 15N in soil (0–45 cm layer) and the calculated unaccounted fertilizer 15N data of both CA and CT plots were also similar after the fourth year of cultivation. In summary, although CA (ZT + R) adoption had better soil aggregation and with more TSN accumulation within macro-aggregates, it could not affect the fertilizer 15N use efficiency within a short period (4 years). Thus, with a short-term adoption of CA, fertilizer-N dose may not be reduced in a sandy loam soil of the IGP and similar agro-ecosystems.

Long-term sustainability concerns are growing in agriculture owing to over and under application of fertilizers and poor management of available resources which are resulting into soil health deterioration and declining crop productivity. Balanced and integrated use of organic and inorganic fertilizers is the most logical concept for managing and sustaining long term soil health and crop productivity. Hence, a long-term field experiment was conducted from 2012 to 2017 to develop integrated nutrient management (INM) practices for sustaining crop productivity and maintaining soil health under maize (Zea mays L.) chickpea (Cicer arietinum L.) cropping system in Vertisols of central India. Twelve treatments that comprised of various combinations of general recommended dose (GRD) of NPK, farmyard manure (FYM), poultry manure (poultry manure), urban compost (UC), maize residue (MR), glyricidia loppings (GL) and soil test crop response (STCR) based NPK with target yield 5.0 and 1.50 Mg ha1 in maize and chickpea, respectively were tested. The experiment was conducted following a Randomized Complete Block Design (RCBD) set up with three replications and Simple Random Sampling (SRS) technique of sampling. The results indicated that the grain yield and system yield were observed to be significantly higher with 75% NPK of STCR + FYM at 5 Mg ha1 treatment and recorded an increase of 20.9% and 13.08% in mean grain yield of maize and chickpea, respectively over GRD. The combined analysis results illustrated significant (P

The present research was conducted to study the potential of cotton for the remediation of soils contaminated with Cd, to understand the biochemical basis of its tolerance to, and to investigate the plant-microbe interaction in the rhizosphere for enhancement of phytoextraction of Cd. Cotton (Bt RCH-2) was exposed to four Cd levels (0, 50, 100, and 200 mg/kg soil) in a completely randomised design and found that the plant could tolerate up to 200 mg/kg soil. Cd stress increased the total phenol, proline, and free amino acid contents in the plant leaf tissue compared with control but inhibited basal soil respiration, fluorescein diacetate hydrolysis, and activities of several enzymes viz. dehydrogenase, phosphatases, and β-glucosidase in the soil over control. The concentration of Cd in the shoot was less than the critical concentration of 100 µg/g dry weight, and bioconcentration and translocation factors were 100 µg g −1dw beyond 600 mg Cd/kg soil, the bioconcentration and translocation factors were

Feeding the increasing global population, which is projected to increase between 8.9 and 10.6 billion by 2050, there has been increasing demands for more improved/sustainable agricultural management practices that can be followed by farmers to improve productivity and maintain environmental sustainability without jeopardizing the ecosystem. About 95% of our food directly or indirectly comes from soil. It is a precious resource, and sustainable soil management is a critical socio-economic and environmental issue. South Asia (SA) has been experiencing high economic growth but still suffering from extreme rate of poverty, hunger, and deterioration of natural resources including soil. In this region, the presence of a large rainfed area with its associated challenges urgently calls for cost-effective resource conservation technologies such as conservation agriculture (CA). The Indo-Gangetic Plains (IGP) of SA region is one of the hotspots for the adoption of no-till farming/CA. Although conventional tillage (CT)-based farming offers some important short-term benefits, long-term adoption of these practices may lead to the loss of soil organic carbon/fertility, poor soil health, and soil degradation. Conservation agriculture (CA) is being practiced globally approximately in 180 M ha of land, whereas in south Asia it remains less than 5 Mha. Thus, CA is one of the major sustainable soil/agricultural management systems that can meet the needs of farmers as well as offer numerous benefits to farmers as well as ecosystem services. CA is a multi dimensional approach that is studied not only for its positive environmental and ecological impacts but also as an alternative to reduce crop residue burning. In this chapter, issues, challenges, benefits, and future perspectives of CA have been discussed.

Crop residue burning is an emerging problem due to shortage of manual labor and mechanization of agricultural practices. It affects not only soil microbial community and nutrient transformation processes in soil but also human and animal health adversely. Soil is a medium for plant growth and a support system of millions of fauna and flora, greatly affected by repeated burning of crop residue in farms. Changes in microbial activity upon crop residue burning depend on soil temperature, length of burning, rain incidence after burning, dominant group of microorganisms, and time of sampling. The adverse effects of residue burning on soil biota and thus on soil health will continue for long term, and that eventually affects sustainable crop production. The increased soil temperature at the time of residue burning not only kills the soil microbes but also depletes soil organic carbon level, which is vital for keeping soil living. In short, adopting suitable location-specific technology is necessary to ensure proper residue management without harming the various life forms on earth. Also, encouraging and incentivizing the farming community for enriching the soil with carbon will help in discouraging the practice of crop residue burning.

To mitigate the changing climate due to the increase concentration of greenhouse gases (GHG) in the atmosphere, studies on carbon (C) sequestration potential of different agricultural management practices are receiving worldwide attention. Conservation agriculture (CA) is highly recommended for its high C sequestration capacity and the productive use of crop residues that are otherwise burnt and pollute the environment. The adoption of CA offers preservation of soil moisture by leaving at least 30% of the soil surface covered with crop stubble/leaf litters, thereby decreasing wind and water erosion. The amount of residue cover left on the field depends on the type of operation, availability of implements and the fragility of the residue. Under CA, if 1 ft of residue is left on the field, an additional amount of 1.6–2.0 t/ha of crop residue is being added in to the field compared to farmers’ practice that improves soil aggregation, infiltration, organic C status and enhanced biological properties. The C sequestration in CA is accomplished through the addition of carbon through residues, protection of soil organic carbon in soil aggregates under minimum soil disturbance and addition of soil organic carbon (SOC) to deeper soil layer due to the inclusion of legumes in the cropping system. In fact, practising CA can potentially sequester C at rates of 300–600 kg C/ha/year depending on the type of soil and climatic conditions. In addition, CA practices are widely adopted to increase soil productivity, revert soil degradation, improve C sequestration and also increase input use efficiency and crop yields. Therefore, location-specific CA must be developed and advocated. The challenges and bottlenecks in disseminating CA in a large scale must be addressed and overcome by further studies with policy initiatives and interventions.

Crop residue management is prime consideration in attempting fertility optimization in pulse-based cropping systems under soil-protective tillage technologies. Conservation tillage is a crucial element of conservation agriculture which has intended to support sustainable soil health and crop productivity. Conservation agriculture provides a new paradigm in agricultural research which primarily differs from conventional tillage and aimed to achieve specific production targets of food grains in India. Conservation tillage together with other supplementary practices such as soil cover with residue retention and crop diversity by including pulse crops was therefore emerged as a feasible way of ensuring sustainable production of food and helps in maintaining ecological integrity. Therefore, this book chapter reviewed how crop residue recycling is essential in achieving sustainable crop production in pulse-based cropping systems in Central India.