Although nitrogen (N) is the most limiting nutrient for agricultural production, its overuse is associated with environmental pollution, increased concentration of greenhouse gases, and several human and animal health implications. These implications are greatly affected by biochemical transformations and losses of N such as volatilization, leaching, runoff, and denitrification. Half of the globally produced N fertilizers are used to grow three major cereals—rice, wheat, and maize—and their current level of N recovery is approximately 30–50%. The continuously increasing application of N fertilizers, despite lower recovery of cereals, can further intensify the environmental and health implications of leftover N. To address these implications, the improvement in N use efficiency (NUE) by adopting efficient agronomic practices and modern breeding and biotechnological tools for developing N efficient cultivars requires immediate attention. Conventional and marker-assisted selection methods can be used to map quantitative trait loci, and their introgression in elite germplasm leads to the creation of cultivars with better NUE. Moreover, gene-editing technology gives the opportunity to develop high-yielding cultivars with improved N utilization capacity. The most reliable and cheap methods include agronomic practices such as site-specific N management, enhanced use efficiency fertilizers, resource conservation practices, precision farming, and nano-fertilizers that can help farmers to reduce the environmental losses of N from the soil–plant system, thus improving NUE. Our review illuminates insights into recent advances in local and scientific soil and crop management technologies, along with conventional and modern breeding technologies on how to increase NUE that can help reduce linked N pollution and health implications.

Clay–organic complexes (COC) impart chemical and physical protection to soil carbon (C). In the present study, the aim was to assess the long-term effects of different organic amendments on C stability in COC, distribution of the aggregates, C concentration in the aggregates and labile organic C fractions in the inceptisols located at the research farm situated in the semi-arid sub-tropical climate of India. The results showed that the COC, the percentage of large macroaggregates (LMA) (>2 mm) and the C associated with the aggregates decreased through the soil depths, whereas the other size fractions of soil aggregates (<2 mm) showed an increasing trend. The COC was significantly higher (4.4 times) in soil treatments where farmyard manures (FYM), green manure (GM) and biofertilizers (BF) were applied together (FYM + GM + BF). The organic amendments increased the proportion of LMA over control (no application of organic amendments) to a magnitude of 83 to 101% and the C associated with LMA to a magnitude of 0.48 to 9.8% over control in surface soil. On average, the combined application of FYM, GM and BF exhibited higher C accumulation in almost all soil aggregate fractions, except microaggregates (mA), i.e., (0.25–0.053 mm) size fractions, where application of FYM alone recorded the highest value. Averaged over soil depths, the particulate organic C (POC), dissolved organic C (DOC) and potassium permanganate oxidizable C (POXC) were significantly higher under integrated organic treatments than individual amendments. The significantly higher correlation between COC and the percentage of LMA and aggregate-associated C implied their direct role in soil aggregate formation and their stability. The carbon stability, i.e., retention time of humus in soil, was significantly correlated with soil organic carbon, dissolved organic carbon, particulate organic carbon, potassium permanganate oxidizable C, C mineralization (C_min), glomalin-related soil protein (GRSP), macroaggregate (MA)-associated C and rice equivalent yield (REY). Overall, the data suggest that the combined application of FYM + GM + BF promotes soil quality under rice–wheat rotation in inceptisols in semi-arid sub-tropical India.

Indiscriminate and injudicious application of inorganic fertilizers and irrigation, respectively, cause declines in crop productivity as well as environmental pollution. Therefore, judicious use of organic manures and proper scheduling of irrigation are required for sustainable production of wheat crops. A two-year (2014–2015 and 2015–2016) study was conducted to determine the wheat nutrient uptake, soil moisture, and grain yield as a result of organic manures and irrigation schedule. The experiment was set up with four treatments of organic manure in four subplots with repellents and five irrigation planning treatments in the main plot. The results showed that an irrigation/water ratio of 0.9 irrigation water depth/cumulative pan evaporation (I₂) increased grain yield, soil moisture content, and nutrient uptake of wheat (I₃) compared to 0.6 IW/CPE during the vegetative period and 0.8 IW/CPE during the reproductive period. According to statistics, it was found that the vegetative period is maintained at 0.8 IW/CPE, and the reproductive period is maintained at 1.0 IW/CPE (I₅). Applying 7.5 Mg ha⁻¹ of farmyard manure (FYM) plus 3 Mg ha⁻¹ of vermicompost while employing organic manure increases grain output, soil moisture content, and nutrient content and absorption compared to the control treatment. Therefore, it is concluded that irrigation either at I₂ or I₅ + FYM at 7.5 Mg ha⁻¹ + vermicompost at 3 Mg ha⁻¹ could be recommended for enhancing grain of wheat cultivation, particularly in the semiarid regions of northwestern India.

In order to support livelihoods, enhance food security, restore ecosystem services, and reduce pressure on forests, degraded land can be restored by utilising alternative land-use systems (ALUS), such as silviculture, silvipasture, and hortipasture techniques. ALUS significantly modify the dynamics of soil nutrients in both the surface and subsurface layers. Soils from the 0–15, 15–30, and 30–45 cm layers of Leucaena leucocephala (S)-, Hardwickia binata (H)-, Emblica officinalis (A)-, and Azadiracta indica (N)-based silviculture systems, Acacia nilotica-based silvipasture systems (SPS), natural grassland (NT), and fallow land (F) were sampled in order to better understand the nutrient dynamics of ALUS. Soils under S, H, and SPS had ~203%, 195%, and 129% higher organic carbon (SOC), respectively, than fallow land in the 0–15 cm soil layer. In the subsequent soil layer, those land-use systems had ~199%, 82%, and 110% higher SOC, respectively, than fallow land. Similarly, in the deeper layer, those land uses had ~232%, 23%, and 105% higher SOC, respectively, than fallow land. SPS and NT also improved the SOC concentration significantly over fallow land. Plots under S, H, and SPS had ~198%, 190%, and 125% higher available N, respectively, than fallow land in 0–15 cm soil layer. In the 15–30 cm soil layer, those land-use systems had ~19%9, 82%, and 110% higher available N, respectively, than fallow land. These systems also improved the P and K contents in subsurface soil. Micronutrient concentrations were also improved in soils under S, H, and SPS. Hence, ALUS’ adoption in degraded areas with trees provides a chance for C storage and improves the nutrient dynamics on degraded land.

The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in sediments of the Don River delta and the surrounding area of the Taganrog Bay of the Sea of Azov (Russia). The PTE content was determined in fifty-four collected samples using the WDXRF and assessed using geochemical and ecotoxicological indicators. The source of Cr, Mn, Ni and Pb is mainly river runoff, and Cu, Zn and Cd are from a variety of anthropogenic sources. As shown by the assessment of the geoaccumulation index (Igeo), single pollution index (PI) and contamination factor (CF), these elements are the priority pollutants. According to these estimates, high and very high contamination of sediments in the estuarine zone of the Don River with Cd and Pb was detected in 72–94% and 2–57% of samples, respectively. However, environmental risks are determined almost exclusively by the level of Cd. Total contamination as assessed by the Nemerow pollution index (NPI), modified degree of contamination (mC_d) and metal pollution index (MPI) is of concern in 83–98% of the samples studied. The most heavily polluted sediments are in the vicinity of residential areas of the Taganrog Bay. Despite the lower average pollution levels of deltaic sediments, freshwater biota are exposed to higher potential toxic risks of adverse effects by PTE, particularly from Ni and Pb. Thus, the complex hydrological regime and uneven anthropogenic impact predetermine the geochemical state of the sediments of the estuarine zone of the Don River.

In India, 700 million tons of agricultural waste generated annually is burned by farmers in the fields, which decreases biological activity in soil. The issue of handling the enormous amounts of crop residues that emerge from increased crop output might be resolved by composting. However, different crop residues improve soil physico-chemical and biological properties in different ways. Crop residue incorporation and fertilization (NPK) impact crop productivity due to changes in soil microbial biomass carbon, nitrogen, phosphorous, and the soil enzymatic activity. A field experiment was conducted for two years (2020–2021 and 2021–2022), which comprises five partially composted crop residues treatments viz., control, clusterbean straw, groundnut shell, pearlmillet husk, and sesame stover (added at rate of 5 t ha⁻¹), and four fertilization (NPK) treatments viz., control, 75% RDF, 100% RDF, and 125% RDF. The microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP), enzymatic activities in soil and wheat yield were studied under a semi-arid environment (India). Data showed that the continuous application of crop residues and fertilizer significantly affected MBC, MBN, MBP, and soil enzymatic activity after two years of experimentation in a semi-arid region environment. The highest levels of microbial biomass (viz, MBC, MBN, MBP) and enzyme activities were noticed in the sesame stover and 125% recommended dose of fertilizer (RDF) treatments. Therefore, this study highlights the need for restoring crop residue for effective soil management. The crop residue and NPK fertilization are more efficient in improving the soil’s microbial properties and the yield of wheat.