Among the abiotic stresses, water stress is a key factor that limits agricultural productivity worldwide by reducing crop yield through numerous biochemical and physiological disruptions. The use of nanomaterials in commercially available products is rapidly expanding, with significant applications in agriculture and phytoremediation. Current advancements in nanotechnology have introduced iron nanoparticles (Fe-NPs) as a promising approach to enhance crop resilience against stress conditions. Iron (Fe) plays a critical role in photosynthesis, enzyme activation, chlorophyll synthesis, and oxidative stress management, which are pivotal to plant response against water stress. Due to high surface area, small size, and controlled reactivity, Fe-NPs exhibit exceptional advantages over traditional Fe sources, viz., improved bioavailability and nutrient uptake. The current review explores Fe-NP's potential to mitigate the adverse effects of water stress in crop plants by activating various beneficial mechanisms, including improvement in antioxidant defence, osmotic adjustment, and modulating stress related to phytohormones. Particularly, Fe-NPs improve water use efficiency (WUE) and root development, facilitating water and nutrient uptake under stress conditions. Moreover, Fe-NPs assist in antioxidant enzyme regulation, which reduces the accumulation of reactive oxygen species (ROS), thereby reducing oxidative damage and sustaining the metabolic activities of plants under limited water availability. However, FeNP use in agriculture poses potential health and environmental risks, including water and soil contamination, soil microbial alteration, and residues in edible crop plants, which require careful consideration. Furthermore, Fe-NP effectiveness may vary depending on factors, viz., size of nanoparticles (NPs), concentration, method of application, and crop type. The paper concludes by discussing potential research avenues, highlighting the necessity of sustainable application methods, optimal Fe-NP formulations, and thorough environmental effect evaluations. Fe-NPs are a promising element in creating next-generation, nano-enabled farming techniques meant to increase crop resistance to water stress, which could ultimately improve food security in the face of a changing climate.

Intensive agriculture development and achievement to higher profitability has inflicted permanent damage on agroecosystems. Rapid deterioration of structure and functional properties in agroecosystems has intensified the need for research on agroecosystem health and management. To assess the health status of wheat agroecosystems in the agricultural lands of Bandar-e-Turkmen county (Golestan province, Iran), we were used the variables of weed and natural enemies biodiversity, soil health (carbon and organic matter, microbial respiration, earthworm, soil salinity, and acidity), environmental indexes (environmental effects of pesticides (EIQ) and nitrate leaching) and vegetation indexes (RVI, cultivar type, and grain yield). In this study, thematic layers were prepared in ArcGIS and overlayed according to three scenarios. Then final layer was classified into three classes of health. Based on the results, only 8.47% (5 fields) were located in the first health class. These fields were characterized by high grain yield, low weed biodiversity, minimal pesticides use, optimal soil conditions, high RVI, and the presence of earthworms and natural enemies. Also, we found that 42 fields (71.19%) were placed in the second health class. Increase of biodiversity and population of weeds, lower grain yield, and reducing the quantity and quality of soil variables were important factors that reduced the health degree of these fields. Based on the results, 20.34% of the area (12 fields) in the central and western parts of the county was placed in the unhealthy class. It seems that increasing the environmental restrictions, including salinity higher than 6 ds/m, high weed diversity, increasing the consumption of harmful and dangerous pesticides with high environmental impact, and less grain yield than the potential of cultivars, were the main reasons for placing these fields in the unhealthy class. Also, the most important factors of decreasing the health degree of fields, frequency of weeds, increasing consumption of chemical pesticides, low soil organic matter, absence of earthworms, and decreasing grain yield were identified. Generally, management of weeds, implementation of crop rotation, preservation of plant residues on the soil surface, and development of conservation agriculture can help to improve the health indicators of wheat agroecosystems.

Soil salinity is represent a significant environmental stressor that profoundly impairs crop productivity by disrupting plant physiological functions. To mitigate this issue, the combined application of biochar and nanoparticles has emerged as a promising strategy to enhance plant salt tolerance. However, the long-term residual effects of this approach on cereal crops remain unclear. In a controlled pot experiment, rice straw biochar (BC) was applied in an earlier experiment at a rate of 20 t/ha, in conjunction with ZnO and Fe2O3 nanoparticles at concentrations of 10 mg L- 1 and 20 mg L- 1. Two rice genotypes, Jing Liang You-534 (salt-sensitive) and Xiang Liang You-900 (salt-tolerant), were utilized under 0% NaCl (S1) and 0.6% NaCl (S2) conditions. Results showed that, application of residual ZnOBC-20 significantly enhanced rice biomass, photosynthetic assimilation, relative chlorophyll content, SPAD index, enzyme activities, K+/Na+ ratio, hydrogen peroxide (H2O2) levels, and overall plant growth. Specifically, ZnOBC-20 increased the tolerance index by 142.8% and 146.1%, reduced H2O2 levels by 27.11% and 35.8%, and decreased malondialdehyde (MDA) levels by 33% and 57.9% in V1 and V2, respectively, compared to their respective controls. Residual of ZnOBC-20 mitigated oxidative damage caused by salinity-induced over-accumulation of reactive oxygen species (ROS) by enhancing the activities of antioxidant enzymes (SOD, POD, CAT, and APX) and increasing total soluble protein (TSP) content. Xiang Liang You-900 exhibited a less severe response to salinity compared to Jing Liang You-534. Additionally, residual of ZnOBC20 significantly enhanced the anatomical architecture of both root and leaf tissues and regulated the expression levels of salt-related genes. Residual of ZnOBC-20 also improved salt tolerance in rice plants by reducing sodium (Na+) accumulation and enhancing potassium (K+) retention, thereby increasing the K+/Na+ ratio under saline conditions. The overall results of this experiment demonstrate that, residual effects of ZnOBC-20 not only improved the growth and physiological traits of rice plants under salt stress but also provided insights into the mechanisms behind the innovative combination of biochar and nanoparticles residual impacts for enhancing plant salt tolerance.

The manuscript revealed the ameliorative effects of exogenous melatonin in two distinct reproductive stages, i.e., developing grains (20 days after pollination) and matured grains (40 days after pollination) in two contrasting indica rice genotypes, viz., Khitish (arsenic-susceptible) and Muktashri (arsenic-tolerant), irrigated with arseniccontaminated water throughout their life-cycle. Melatonin administration improved yield-related parameters like rachis length, primary and secondary branch length, number of grains per panicle, number of filled and empty grains per panicle, grain length and breadth and 1000-grain per weight. Expression of GW2, which negatively regulates grain development, was suppressed, along with concomitant induction of positive regulators like GIF1, DEP1 and SPL14 in both Khitish and Muktashri. Melatonin lowered arsenic bioaccumulation in grains and tissue biomass, more effectively in Khitish. Unregulated production of reactive oxygen species, leading to cellular necrosis caused by arsenic, was reversed in presence of melatonin. Endogenous melatonin level was stimulated due to up-regulation of the key biosynthetic genes, SNAT and ASMT. Melatonin enhanced the production of diverse antioxidants like anthocyanins, flavonoids, total phenolics and ascorbic acid and also heightened the production of thiol-metabolites (cysteine, reduced glutathione, non-protein thiols and phytochelatin), ensuring effective chelation and arsenic detoxification. Altogether, our observation, supported by principal component analysis, proved that melatonin re-programs the antioxidative metabolome to enhance plant resilience against arsenic stress to mitigate oxidative damages and reduce arsenic translocation from the soil to tissue biomass and edible grains.

Globally from abiotic stresses, salt stress is the major stress that limits crop production. One of them is wheat that has been utilized by more than 1/3 of the world population as staple food due to its nutritive value. Biochar is an activated carbon that can ameliorate the negative impacts on plants under saline conditions. The present study was conducted to examine the ameliorative impact of Biochar application to Triticum aestivum L. plant grown under salinity stress and evaluated on the basis of various growth, yield, physiological, biochemical attributes. Preliminary experiment was done to select the Triticum aestivum L. varieties with 90% germination rate for further experiment. The selected varieties, FSD08 and PUNJAB-11 of wheat were treated with two levels of sodium chloride (0 mM and 120 mM). Two varieties of wheat included FSD08 and PUNJAB-11 were treated with two levels of sodium chloride (0 mM and 120 mM). To address the impact of salt stress two levels of biochar 0% and 5% was used as exogenous application. A three way completely randomized experimentation was done in 24 pots of two wheat varieties with three replicates. The results demonstrated that salt stress affected growth, physiological attributes, yield and inorganic mineral ions (Ca2+ and K+) in roots and shoots parameters of wheat negatively while biochar overall improved the performance of plant. SOD, CAT, APX and POD activities enhanced during salt stress as the plant self-defense mechanism against salinity to minimize the damaging effect. Salt stress also significantly increased the membrane permeability, and levels of H2O2, MDA, Cl and Na ions. Biochar treatment nullified negative impacts of NaCl and improved the plant growth and yield significantly. Hence, biochar amendment can be suggested as suitable supplement for sustainable crop production under salinization.

Hydroclimatic stresses can negatively impact crop production via water deficits (low soil water supply and high atmospheric demand) or surpluses (high soil water supply and low atmospheric demand). However, the impact of both stresses on crop yields at regional scales is not well understood. Here we quantified yield sensitivities and corresponding spatio-temporal yield losses of US rainfed maize, soybeans, sorghum, and spring wheat to hydroclimatic stresses by considering the joint impacts of root-zone soil moisture and atmospheric evaporative demand from 1981 to 2020. We show that crop yields can be reduced similarly by two major hydroclimatic hazards, which are defined as the most yield damaging conditions over time: 'Low Supply + High Demand' and 'High Supply + Low Demand'. However, more exposure to 'Low Supply + High Demand' hazard led to the largest annual yield losses (7%-17%) across all four crops over time. Modeled yield losses due to these hazards were significantly associated with crop insurance lost costs. The extent of yield losses varies considerably by crop and location, highlighting the need for crop-specific and regionally tailored adaptation strategies.