Mycorrhizae and plants have a well-established symbiotic relationship, and play an important role in better plant growth, disease protection, and improving soil quality. Arbuscular and ectomycorrhizae are the most common of the seven species of mycorrhizae described in the scientific literature (arbuscular, ecto-, ectendo-, arbutoid-, monotropoid-, ericoid-, and orchidaceous mycorrhizae). This chapter presents a summary of current knowledge of mycorrhizal interactions, processes, and potential benefits to society. The molecular basis for genetic exchange between arbuscular mycorrhizal (AM) fungi and host crops, the role of AM fungi in disease protection, in promoting plant growth, in reducing heavy metal load, and in increasing grain production, and their impact on sustainable agriculture are presented in this chapter. The impact of AM-fungal incorporation and beneficial saprophytic mycoflora on the promotion of plant growth and root colonization, the role of AM fungus in restoring indigenous ecosystems, and the impact of the mycorrhizosphere on multitrophic interactions have been summarized. The ways in which the mycorrhizae transform the disturbed ecosystem into productive land are discussed. The importance of restoring mycorrhizal systems in the rhizosphere is emphasized, and their impact on land reclamation and environmental remediation of polluted soils is also discussed. The importance of ectomycorrhiza in forest ecosystems, ectomycorrhizal association in tropical rain forests and their role in maintaining thermal monodominance, are briefly explained.

Context or problemThe extensive use of chemical fertilizers and pesticides in modern agriculture, particularly since the green revolution, has led to profound consequences for agricultural ecosystems. This approach, while initially boosting yields, has disrupted soil health, biodiversity, and environmental balance. Moreover, it contributes silently to global climate change by releasing greenhouse gases. These challenges underscore the urgent need for a shift towards sustainable agricultural practices to safeguard soil health, biodiversity, and human nutrition while mitigating the impacts of climate change. Objective or research questionThe primary objective of this study is to assess the impact of the long-term (seventeen years) application of organic nutrient management on the physicochemical properties of basmati rice soil and its nutritional quality. The study aims to understand the effectiveness of different organic nutrient management practices in mitigating the negative consequences associated with conventional agricultural practices. MethodsThe experiment used a strip-plot design with three replications, assigning two cropping systems (basmati rice-wheat-green gram and basmati rice-wheat-sesbania) to vertical strips. Seven nutrient management practices, including control, farmyard manure (FYM), vermicompost, farmyard manure + crop residues, vermicompost + crop residues, farmyard manure + crop residues + biofertilizers, and vermicompost + crop residues + biofertilizers [nitrogen-fixing Azospirillum, phosphorus-solubilizing bacteria (PSB), potassium-solubilizing bacteria (KSB), and a cellulolytic culture (Aspergillus awamori, Trichoderma viride, Phanerochaete chrysosporium, and Aspergillus wululens)] were applied to the horizontal strips. ResultsThe findings show that the cropping system with sesbania green manure significantly improved soil physicochemical attributes, nutritional content, and basmati rice yield compared to the green gram-based system. Continued application of organic manures, crop residues, and biofertilizers notably enhanced soil fertility, grain quality, and basmati rice productivity. The combined use of vermicompost, wheat residue, biofertilizers, and sesbania green manure treatment increased organic carbon content by 78.7% over the control, and soil available nitrogen, phosphorus, and potassium by 38.3–54.9%, 57.6–143.8%, and 27.9–64.1%, respectively. Additionally, it augmented diethylenetriamine pentaacetic acid extractable iron, zinc, manganese, and copper content by up to 44.2%, 28.5%, 57.9%, and 71.0%, respectively. Co-application of the above organic sources also significantly enhanced grain and straw yields by 74.5–80.1% and 46.1–50.0%, respectively, compared to the control. ConclusionsEnhancing Basmati rice yield and quality in the Indo-Gangetic Plains can be sustainably achieved through sesbania green manuring and organic practices. Positive correlations with key soil parameters emphasize the significance of organic farming for long-term sustainability. Implications and significanceThe study suggests that adopting organic practices, including sesbania green manuring and combining organic inputs, can alleviate the adverse effects of conventional farming on soil health, biodiversity, and climate change. This aligns with the broader goal of establishing sustainable production and consumption in basmati rice-based cropping systems.

Soil salinity is a major environment stress impairing crop production and accelerating soil degradation. Use of soil amendments are practical solutions for altering soil quality to enhance crop productivity in these soils. Hence, we systematically evaluated the impact of soil amendments practices on crop productivity, nutrient use efficiency, soil properties, soil quality index, economics and energetics on soybean-mustard cropping system in sodic Vertisol. In this study, eight treatments comprising of various combinations of soil amendments such as gypsum (@2.5 t ha−1), farmyard manure (FYM@10 t ha−1), crop residue (CR@1.5 t ha−1 of soybean residue during rabi and 3 t ha−1 of mustard residue during kharif season) with recommended fertilizer doses (RNPK) was evaluated in randomized block design with three replications for four consecutive years in soybean-mustard cropping sequences (2016–2019). Results demonstrated that application of gypsum with CR and FYM recorded a significant drop in exchangeable sodium percentage (ESP) (45–48 %), and bulk density (BD) (3–6 %) than that of control. Organic amendment in conjunction with gypsum and chemical fertilizer significantly improved soil chemical, physical and biological properties than that under control and inorganic fertilizer alone treatments. Based on principal component analysis and correlation matrix, minimum data set identified ESP, pH, BD, organic carbon, available nutrients, biomass carbon, calcium content, dehydrogenase as the most important properties controlling soil quality. Integration of RNPK+Gypsum+CR and RNPK+Gypsum+FYM are found superior leading to higher crop yield in soybean (1.23 and 1.21 Mg ha−1 respectively), mustard (1.43 and 1.39 Mg ha−1 respectively), better nutrient recovery efficiency (77 and 53 % respectively), improved soil quality index (0.90 and 0.93 respectively), and higher economic return (benefit: cost ratio-2.88 and 2.1 respectively).Therefore, this study findings highlighted the conjunctive use of gypsum with organic amendments is effective in reclaiming salt stress, improving soil health and crop productivity under oilseed cropping sequence in degraded soils of semi-arid tropics.

AbstractA long‐term experiment (1995–2021) was conducted on litchi (Litchi chinensis L.) with and without conservation practices, that is, litchi under clean cultivation (LCC) (recommended doses of fertilizers without intercrops and mulch) and litchi with conservation practice (LCP) (micro‐site improvement, intercrops, and organic mulching) on degraded lands. The study aimed to evaluate the long‐term impact of litchi‐based land uses on vegetative growth (plant height, canopy volume, fruit yield, and litter production), soil moisture, biomass production, carbon stocks (CS), and soil qualities (enzyme activities, microbial counts, and soil fertility). The results revealed that LCP improved vegetative growth, yields, and soil moisture over LCC. The total dry biomass was observed 91.6–103.9, stored CS; 43.6–49.4, emitted CS; 7.04–9.40, mitigated CS; 30.1–30.5, soil CS; 35.7–39.9, total CS (soil + vegetation); 65.9–70.5 Mg ha−1 and carbon dioxide mitigation; 88.3–112.1 Mg ha−1 in LCC and LCP land uses, respectively. Further, in LCP, beta‐glucosidase, acid phosphatase, alkaline phosphatase, and dehydrogenase activities increased by 17.2%, 20.4%, 19.8%, and 24.8%, respectively, in surface soil compared with LCC in 2021. Likewise, the microbial density of bacteria, fungi, and actinomycetes was also observed to be 20.2%, 41.4%, and 19.5% higher, respectively, in LCP land use in 2021 over 2015. Similarly, available N, P, and K increased by 19.9%, 75.3%, and 36.8% under LCP from 1997 to 2021. Hence, litchi‐based land use with conservation practices can be advocated to rehabilitate and improve the soil health of degraded lands and enhance ecosystem services in similar edaphoclimatic conditions.

Abstract The present study focuses on the deltaic region of West Bengal, which is one of the most dynamic natural regions in the state. The study area is a part of the moribund deltaic region of Nadia district. Bank erosion, channel shifting, siltation of channels, and the decay of oxbow lakes are common geomorphic hazards in the Bhagirathi-Jalangi interfluve and further south in the floodplain of the Hugli River. The study area is susceptible to various geomorphic hazards, including bank erosion, channel shifting, siltation of channels, and the decay of oxbow lakes. These hazards are prevalent in the Bhagirathi-Jalangi interfluve and the southern floodplain of the Hugli River. The primary aim of the study is to identify distinct patterns of fluvial geomorphic features on the floodplain using remote sensing and GIS techniques. For the analysis, data on river planform were collected from the Survey of India toposheets and a number of satellite images. Surveys were carried out to compare the present scenario with the past situation. The results revealed that fluvial geomorphological changes over a period of 45 years are considerably significant. Anthropogenic causes have a greater influence on changing the morphology and increasing the rate of bank erosion.

The 20-year study investigated the effects of conservation practices (CPs) and farmers' practices (FPs) on various soil quality parameters, yield, and economics of horticultural land use systems. CPs demonstrated significant improvements in soil organic carbon (SOC), available nitrogen (N), phosphorus (P), and potassium (K), compared to FPs. Horticultural systems exhibited higher SOC and available N and P contents than FPs, with substantial variations among different fruit species. CPs also enhanced soil quality index, functional diversity, culturable microbial populations, enzyme activity, and soil microbial biomass carbon (SMBC) compared to FPs. It was observed that the SMBC values were 25.0–36.6% and 4.12–25.7% higher in 0–15 cm and 15–30 cm, respectively, under CPs compared to FPs for all the land use systems. In CPs, dehydrogenase activities (DHAs) in surface soils were 9.30 and 7.50 times higher under mango- and citrus-based horticultural systems compared to FPs. The CPs adopted in aonla, guava, mango, litchi, and citrus-based horticultural systems increased SOC by ~27.6, 32.6, 24.4, 26.8, and 22.0%, respectively, over FPs. Canopy spread, fruit yield, litter yield, and soil moisture were significantly higher in fruit-based horticultural systems under CPs. Economic viability analysis indicated higher net present values (NPVs), benefit-cost ratio (BCR), and shorter payback periods (PBPs) for horticultural land use systems under CPs. Principal component analysis (PCA) revealed that CPs had a more positive influence on soil parameters, particularly DHA, acid and alkali phosphatase activity, available N, P, and K contents, soil microbial load, and organic carbon. The maximum ecosystem services were contributed through mango-based land uses among all land uses. Mango-based horticultural systems exhibited the least impact from both CPs and FPs, while peach-based systems were most affected by CPs. Overall, the findings highlight the benefits of conservation practices in improving soil quality, microbial populations, enzyme activity, and crop productivity in horticultural systems.

Although agro-geotextile (AGT) emplacement shows potential to mitigate soil loss and, thus, increase carbon sequestration, comprehensive information is scanty on the impact of using agro-geotextiles on soil organic carbon (SOC) sequestration, aggregate-associated C, and soil loss in the foothills of the Indian Himalayan Region. We evaluated the impacts of Arundo donax AGT in different configurations on SOC sequestration, aggregate stability, and carbon management index (CMI) since 2017 under maize-based cropping systems on a 4% land slope, where eight treatment procedures were adopted. The results revealed that A. donax placement at 0.5-m vertical-interval pea–wheat (M + AD10G0.5-P-W) treatment had ∼23% increase in SOC stock (27.87 Mg·ha−1) compared to the maize–wheat (M-W) system in the 0–30-cm soil layer. M + AD10G0.5-P-W and maize–pea–wheat treatments under bench terracing (M-P-W)BT had similar impacts on SOC stocks in that layer after 5 years of cropping. The total SOC values in bulk soils, macroaggregates, and microaggregates were ∼24, 20, and 31% higher, respectively, in plots under M + AD10G0.5-P-W treatment than M-W in the topsoil (0–5 cm). The inclusion of post-rainy season vegetable pea in the maize–wheat cropping system, along with AGT application and crop residue management, generated additional biomass and enhanced CMI by ∼60% in the plots under M + AD10G0.5-P-W treatment over M-W, although M + AD10G0.5-P-W and (M-P-W)BT had similar effects in the topsoil. In the 5–15-cm layer, there was no significant effect of soil conservation practices on CMI values. Under the M + AD10G0.5-P-W treatment, the annual mean soil loss decreased by ∼92% over M-W treatment. We observed that CMI, proportion of macroaggregates, aggregate-associated C, labile C, total SOC concentration (thus, SOC accumulation rate), and mean annual C input were strongly correlated with the mean annual soil loss from 2017 to 2021. The study revealed that the emplacement of an A. donax mat and incorporation of a legume in a cropping system (M-W), conservation tillage, and crop residue retention not only prevented soil loss but also enhanced C sequestration compared to farmers’ practice (M-W) in the Indian Himalayas. The significance of this study is soil conservation, recycling of residues and weeds, and climate change adaptation and mitigation, as well as increasing farmers’ income.

Land use change (LUC), alters the multifarious biodiversity hotspots directly and indirectly through the loss of soil quality. A comparative study on soil carbon status and soil microbiome in undisturbed natural forest ecosystems with that of other land uses which gradually altered over time can serve as a suitable indicator for understanding LUC impact on carbon cycles. With this aim, the current investigation was initiated to infer the cyclic effects of LUC on the soil carbon status under six major ecosystems viz., cropland (CL), deciduous forest (DF), evergreen forest (EF), forest plantation (FP), scrubland (SL) and tea plantation (TP) of the Nilgiri Hill Region (NHR) (India's first biosphere reserve). The total organic carbon (TOC) and carbon stocks were highest in evergreen forest (10.25 %, 322.06 t ha−1) and they decreased with increasing depth of the soil profile across the pools of varying carbon lability. The proportion of active carbon pools (AP) in total carbon was higher in crop land and tea plantation (57.47 %, 58.38 %), however, in the case of evergreen forest, deciduous forest, forest plantation and scrub land the passive carbon pools (PP) (54.99 %, 61.28 %, 59.43 % and 60.70 %) was higher. We discovered LUC has altered the proportion of soil carbon pools, and the efficiency of soil microbiome and has resulted in higher carbon dioxide (CO2) emissions in tea plantation (71.87 t ha−1) and crop land (82.39 t ha−1). However, the native ecosystems (evergreen forest and deciduous forest) with higher recalcitrant carbon pools (46.96 g kg−1 and 34.89 g kg−1) prevent such carbon degradation and thereby hinder the soil carbon emissions as recorded in evergreen forest (48.43 t ha−1) and deciduous forest (56.47 t ha−1). Conclusively, our study demonstrates that LUC has substantially influenced the carbon cycle by altering the carbon stocks and CO2 emissions in relation to soil microbes. Henceforth, in order to maintain carbon footprints and attain carbon net neutrality under the current climate change scenario, suitable carbon management measures must be implemented in carbon-degraded ecosystems (crop land and tea plantation) of NHR.