Salinity stress (NaCl) and heavy metals contamination (CdCl2) are the serious environmental constraints for decreased crop production worldwide. However, the interaction between NaCl and CdCl2 regarding sodium (Na), cadmium (Cd), and chloride (Cl) accumulation in plants has not been completely established. Therefore, the interactive effects of NaCl andCdCl2 on plant growth, Na, Cd, and Cl accumulation in plants, and wheat yield were evaluated. Wheat seeds were cultivated in clay loam soil under greenhouse conditions. After two weeks of sowing, plants were subjected to NaCl at the rate of 0, 50, and 100 mM either alone or in combination with CdCl2: 0, 1, and 2 mM, respectively. The results revealed that increasing NaCl and CdCl2 levels reduced Na and Cd concentrations, whereas enhanced Cl concentrations. Furthermore, moderate levels of CdCl2 and NaCl stresses enhanced the antioxidative enzymatic activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in addition to proline accumulation in wheat leaves. By contrast, 100 mM NaCl in combination with 2 mM CdCl2 enhanced H2O2 accumulation by 105%, which thus decreased the membrane stability index (MSI) by 49% and wheat yield by 27% as compared to 2 mM CdCl2. The reduced Cd toxicity by NaCl or Na accumulation in plant tissues by CdCl2 involved competition between Na and Cd at binding sites, however, enhanced Cl phytotoxicity in plants resulted in the overproduction of H2O2 that was not quenched by antioxidative enzymes, thereby decreased MSI and wheat yield.

Current agricultural production systems face challenges of poor economic returns, soil fatigue and negative environmental outcomes from excess use of nitrogenous fertilizers, especially in wheat production under middle gangetic plains. To overcome these challenges, the current study was conducted to optimize nitrogen management in different wheat genotypes with precision nitrogen management tools and approaches. The field experiment was laid out in split-plot design, with three genotypes assigned to the main plot and six nitrogen management practices to the sub-plot. The soil of the experimental field was sandy loam in texture, with low levels of organic carbon and available nitrogen, and medium levels of available phosphorus and potassium. Results revealed that the HD-2967 genotype outperformed others in terms of growth, grain yield (4.7 and 4.81 t ha-1), gross return (1417.41 and 1505.48 US$ ha-1), net return (953.43 and 1019.76 US$ ha-1), and B-C ratio (2.04 and 2.08) in 2015-16 and 2016-17, respectively. Among the nitrogen management practices, application of 150 kg N ha-1 in three equal splits demonstrated improved crop growth, grain yield (4.7 and 4.81 t ha-1), and economic returns (gross return, 1500.40 and 1607.65 US$ ha-1, net return, 1025.40 and 1110.38 US$ ha-1 and B: C ratio, 2.17 and 2.23) in 2015-16 and 2016-17, respectively. However, it resulted in higher nitrogen losses. Green seeker guided N application significantly reduced apparent nitrogen losses compared to all other nitrogen applied treatments. These findings provide valuable insights for optimizing wheat production by selecting appropriate genotypes and implementing precision nitrogen management techniques to enhance yield, profitability, and environmental sustainability.

Droughts cause significant economic damage worldwide. Evaluating their impacts on crop yield and water resources can help mitigate these losses. Using single variables such as precipitation, temperature, the soil moisture condition index (SMCI) and the vegetation condition index (VCI) to estimate drought impacts does not provide sufficient information on these complex conditions. Therefore, this study uses station-based and remote-sensingbased data to develop new composite drought indexes (CDIs), including the principal component analysis drought index (PSDI) and the gradient boosting method drought index (GBMDI). The first dataset includes historical observations of the standardized precipitation index (SPI), standardized precipitation evapotranspiration index (SPEI), and the self-calibrated Palmer drought severity index (SC-PDSI) at the 1-, 3-, 6-, and 12month timescales. The second dataset consists of remote-sensing-based data including the VCI, SMCI, temperature condition index (TCI), and precipitation condition index (PCI). We validated the results of PSDI and GBMDI by comparing them with historical drought events, in-situ drought indices, and annual winter wheat crop yield data from 2003 to 2022 using a regression model. Our temporal analysis revealed extreme to severe drought events during1990s and 2010s. GBMDI typically aligned with actual drought events and exhibited stronger correlations with in-situ drought indices than PSDI. We observed that drought intensity in winter were more severe than in summer. GBMDI was the most effective method, followed by PSDI, for assessing drought impacts on winter wheat yields. Thus, the proposed integrated monitoring framework and indexes offered a valuable and innovative approach to addressing the complexities of agricultural drought, particularly in evaluating its effects.

Intercropping is an alternative farming method that maximizes crop yield and resource usage effectiveness, especially in low-input agricultural systems. Legume-based intercropping systems can effectively boost the quality and wheat yield by promoting soil functions and microbial activities. However, changes in the types of legumes and field management can alter the response of crop functions. A three-year field study was conducted on intercropping cultivation of winter wheat variety (Butterfly and Lorien) and legume species (faba bean, incarnate clover, spring pea, winter pea) to assess grain yield and wheat quality in organic farming. Based on the results, Butterfly showed higher grain quality but lower grain yield and yield components than Lorien. Mixtures of legume crops with winter wheat did not significantly differ in wheat grain yield, but grain quality variables were significantly affected. Protein content (PC) was significantly higher in wheat and legume mixtures than in sole wheat by 4 %. PC in wheat + winter pea (Wheat + Wi) and wheat + faba bean (Wheat + Fa) were higher than wheat sown alone. Wet gluten (WG) was higher in Wheat + Wi than in sole wheat and wheat + incarnate clover mixtures (Wheat + In). The rheological parameters evaluated by the Mixolab showed greater wheat quality in Butterfly and legume mixtures. Mixed and row-row intercropping of wheat and legume species did not significantly influence rheological properties. To conclude, customizing wheat yield and grain quality under the effect of winter wheat and legume mixtures requires considering the optimal solution based on different cultivates, wheat varieties and legume species to achieve the desired response.

Context or problem: Lone-term application of chemical fertilizers in farmland ensure adequate or profitable crop yields but may damage soil structure. Cover crops (CCs) have great potentials to improve soil quality and promote sustainable crop production. However, the combined impacts of CCs with nitrogen fertilization on soil quality and crop yields are not clear. Objective or research question: We aimed to examine the effects of CCs combined with N fertilization rates on soil physical properties, C and N fractions in both bulk soils and aggregates, and crop yields, and to find the best management practice that improve both soil quality and crop yields synthetically. Methods: A 4-year summer CCs - winter wheat field experiment was conducted in the Loess Plateau of China. CCs with different species and combinations (CC) were soybean (SB), sudan grass (SG), a mixture of both (SS), and no cover crop (CK) and N fertilizer (NR) were applied to winter wheat at rates of 0 (N0), 60 (N60), and 120 (N120) kg N ha(-1). Soil physical properties and C and N fractions in both bulk soils and aggregates were evaluated at 0-10, 10-20, and 20-40 cm soil depths. Results: Soil total porosity (TP), saturated water content (SWC), capillary water capacity (CWC), and C and N fractions decreased while bulk density (BD) increased with the increase of soil depth. The CC, NR, and their interaction (CCxNR) had significant effects on soil BD, aggregate size distribution and stability (MWD), and C and N fractions and only CC and CCxNR had significant effects on other physical properties. The incorporation of CCs significantly increased the proportions of > 5 mm aggregates and C and N fractions in both bulk soils and aggregates, especially in 0-10 and 10-20 cm. And SB and SS improved soil other physical properties more than SG, especially in 0-10 cm, which decreased BD by 13.2% and 12.6% while increased TP by 6.5% and 8.3%, SWC by 14.3% and 15.3%, CWC by 13.9% and 14.2%, MWD by 16.6% and 14.4%, respectively, compared to CK. Additionally, soil physical properties improved more with N60 while the C and N fractions in both bulk soils and aggregates increased more with N120. However, BD increased by 2.6% and 3.3% in N60 and N120 than N0, respectively. The correlations between the proportion of macro-aggregates and soil C and N fractions at 0-10 and 10-20 cm indicated the positive effects of CCs on improving soil structure and fertility simultaneously. Aggregated-associated C and N fractions decreased firstly and then increased with the reduced aggregate sizes, and were higher in micro-aggregates than in other size classes. N60-SB increased wheat yields by 98.7% compared with N0-CK. Conclusions: Overall, the incorporation of soybean residue was the best management practice for winter wheat yield and soil fertility under the reduced N fertilization.