Tannery wastewater mainly comes from leather industries. It has high organic load, high salinity, and many other pollutants, including chromium (Cr). Tannery wastewater is generally used for crop irrigation in some areas of Pakistan and worldwide, due to the low availability of good quality of irrigation water. As tannery wastewater has many nutrients in it, its lower concentration benefits the plant growth, but at a higher concentration, it damages the plants. Chromium in tannery wastewater accumulates in plants, and causes stress at physiological and biochemical levels. In recent times, the role of micronutrient-amino acid chelated compounds has been found to be helpful in reducing abiotic stress in plants. In our present study, we used lysine chelated zinc (Zn-lys) as foliar application on maize (Zea mays L.), growing in different concentrations of tannery wastewater. Zinc (Zn) is required by plants for growth, and lysine is an essential amino acid. Maize plants were grown in tannery wastewater in four concentrations (0, 25%, 50%, and 100%) and Zn-lys was applied as a foliar spray in three concentrations (0 mM, 12.5 mM, and 25 mM) during plant growth. Plants were cautiously harvested right after 6 weeks of treatment. Foliar spray of Zn-lys on maize increased the biomass and improved the plant growth. Photosynthetic pigments such as total chlorophyll, chlorophyll a, chlorophyll b and contents of carotenoids also increased with Zn-lys application. In contrast to control plants, the hydrogen peroxide (H₂O₂) contents were increased up to 12%, 50%, and 68% in leaves, as well as 16%, 51% and 89% in roots at 25%, 50%, and 100% tannery water application, respectively, without Zn-lys treatments. Zn-lys significantly reduced the damages caused by oxidative stress in maize plant by decreasing the overproduction of H₂O₂ and malondialdehyde (MDA) in maize that were produced, due to the application of high amount of tannery wastewater alone. The total free amino acids and soluble protein decreased by 10%, 31% and 64% and 18%, 61% and 122% at 25%, 50% and 100% tannery water treatment. Zn-lys application increased the amino acids production and antioxidant activities in maize plants. Zn contents increased, and Cr contents decreased, in different parts of plants with Zn-lys application. Overall, a high concentration of tannery wastewater adversely affected the plant growth, but the supplementation of Zn-lys assertively affected the plant growth and enhanced the nutritional quality, by enhancing Zn and decreasing Cr levels in plants simultaneously irrigated with tannery wastewater.

Summer maize (Zea mays L.) is a widely cultivated crop in the arid and semi-arid Guanzhong region of China. However, due to the spatial and temporal variation in rainfall, the seasonal maize yield varies substantially and occasionally is not economical for poor farmers to produce. Recent water-saving agricultural practices were developed by the government to make it possible to apply supplementary irrigation at optimum sowing dates to maximize maize production under limited rainfall in the region. CERES (Crop Estimation through Resource and Environment Synthesis)-maize model was used to identify the appropriate irrigation strategies, crop growth stages and sowing dates for sustainable maize production. Model calibration process were carried out for full irrigation treatments of four growing seasons, (2012–2015). The data used for calibration included: Crop phenology, grain yield, aboveground biomass and leaf area index. The calibration phase model showed good agreement between simulated and observed values, with normalized root mean square error (nRMSE) ranging from 4.51% to 14.5%. The performance of the calibrated model was evaluated using the field data of grain yield, aboveground biomass, leaf area index and water use efficiency. The performance of the model during evaluation was satisfactory with acceptable nRMSE error ranging from 7% to 10%. Soil moisture content was evaluated for full irrigation treatments for both 2012 and 2013 seasons. With results showing that soil moisture content below 35 cm layer was well simulated with nRMSE, 0.57 to 0.86 respectively. Appropriate simulated sowing dates for higher production and water productivity were from 14 to 24 June. The proper amount and timing of irrigation water application was 100 mm at the flowering stage, and 100 mm at the grain filling stage respectively. Summer maize yield can be improved by adjusting the sowing date and applying supplementary irrigation when precipitation cannot meet the crop water demand in the Guanzhong Plain.

Wheat production under rainfed conditions is restrained by water scarcity, elevated temperatures, and lower nutrient uptake due to possible drought. The complex genotype, management, and environment (G × M × E) interactions can obstruct the selection of suitable high yielding wheat cultivars and nitrogen (N) management practices prerequisite to ensure food security and environmental sustainability in arid regions. The agronomic traits, water use efficiency (WUE), and N use efficiencies were evaluated under favorable and unfavorable weather conditions to explore the impacts of G × M × E on wheat growth and productivity. The multi-N rate (0, 70, 140, 210, and 280 kg N ha⁻¹) field experiment was conducted under two weather conditions (favorable and unfavorable) using three wheat cultivars (AUR-809, CHK-50, and FSD-2008) in the Pothowar region of Pakistan. The experiments were laid out in randomized complete block design (RCBD), with split plot arrangements having cultivars in the main plot and N levels in the subplot. The results revealed a significant decrease in aboveground biomass, grain yield, crop N-uptake, WUE, and N use efficiency (NUE) by 15%, 22%, 21%, 18%, and 8%, respectively in the unfavorable growing season (2014–2015) as compared to favorable growing season (2013–2014) as a consequence of less rainfall and heat stress during the vegetative and reproductive growth phases, respectively. FSD-2008 showed a significantly higher aboveground biomass, grain yield, crop N-uptake, WUE, and NUE as compared to other wheat cultivars in both years. Besides, N₁₄₀ appeared as the most suitable dose for wheat cultivars during the favorable growing season. However, any further increase in N application rates beyond N₁₄₀ showed a non-significant effect on yield and yield components. Conversely, the wheat yield increased significantly up to 74% from N₀ to N₇₀ during the unfavorable growing season, and there was no substantial difference between N₇₀–N₂₈₀. The findings provide opportunities for maximizing yield while avoiding excessive N loss by selecting suitable cultivars and N application rates for rainfed areas of Pothowar Plateau by using meteorological forecasting, amount of summer rainfall, and initial soil moisture content.

This study evaluated the effects of deficit irrigation strategies on wheat production, water productivity, and nitrogen dynamics in a semi-arid region of Pakistan. Field experiments were conducted over three crop seasons (2019–2022) with four irrigation treatments: 100% (I₁₀₀), 80% (I₈₀), 60% (I₆₀), and 40% (I₄₀) of crop evapotranspiration (ETc) requirements. Canopy cover dynamics exhibited quadratic relationships within days after sowing, attaining maximum covers of 95, 93, 89, and 75% under I₁₀₀, I₈₀, I₆₀, and I₄₀, respectively. Biomass accumulation followed similar quadratic trends, maximizing at 15.1 t ha⁻¹, 11.0 t ha⁻¹, 8.5 t ha⁻¹, and 6.0 t ha⁻¹ for the respective treatments. Irrigation significantly affected biomass yield (BY), grain yield (GY), and nitrogen uptake, with I₁₀₀ having higher values than deficit treatments. Relative to I₁₀₀, the BY decreases were 8% (I₈₀), 23% (I₆₀), and 48% (I₄₀), while the GY reductions were 7%, 23%, and 50%, respectively. Grain nitrogen uptake ranged from 123 kg N ha⁻¹ (I₁₀₀) to 59 kg N ha⁻¹ (I₄₀), mirroring yield trends. Water use efficiency based on biomass (WUE_b) and grain yield (WUE_g) remained consistent across I₁₀₀, I₈₀, and I₆₀ but dropped significantly under I₄₀. The yield response factor (K_y) analysis indicated that wheat exhibited moderate sensitivity to water stress, with K_y values of 1.25 (I₆₀) and 1.02 (I₈₀). These findings suggest that deficit irrigation at 80% ETc can optimize water conservation while sustaining wheat productivity and resource-use efficiency in semi-arid environments.

Nitrogen fertilization plays a critical role in promoting plant growth, improving physiological and biochemical traits, and enhancing wheat productivity. This study aimed to evaluate the effects of seven nitrogen (N) doses—0, 45, 90, 135, 180, 225, and 270 kg N ha⁻¹—on wheat performance under semi-arid subtropical conditions over three consecutive growing seasons (2015–2018). A randomized complete block design (RCBD) was used to assess a comprehensive set of agronomic, physiological, biochemical, and nutritional parameters. Key factors examined included grain yield, above-ground biomass, nitrogen harvest index, total nitrogen content in grains and straw, and physiological traits such as photosynthetic rate, stomatal conductance, transpiration rate, and the accumulation of soluble proteins, sugars, and amino acids. The study also incorporated multivariate statistical techniques, such as multi-trait genotype–ideotype distance index (MGIDI), principal component analysis (PCA), and descriptive statistics to identify the most effective nitrogen dose. Results indicated that 180 kg N ha⁻¹ (T₄) was the most effective treatment for improving wheat growth, physiological efficiency, and grain yield, with 135 kg N ha⁻¹ (T₃) also showing favorable outcomes. In contrast, higher doses (225 and 270 kg N ha⁻¹) led to diminished performance, suggesting a threshold beyond which nitrogen becomes counterproductive. These findings support 180 kg N ha⁻¹ as the optimal dose for maximizing yield and biochemical quality while contributing to more sustainable and profitable wheat production.

The current investigation emphasized the impact of various silicon (Si) application methods, including seed priming, fertigation, and foliar application, on the morpho-physiological and biochemical responses of two wheat cultivars, Nishan (drought-tolerant) and Faisalabad-2008 (drought-sensitive), under water-deficient conditions. The plants were cultivated under normal (100% field capacity) and drought-stressed (50% field capacity) regimes. Si application methods and water deficit significantly influenced growth, physiological performance, and biochemical traits. Foliar Si application emerged as the most effective strategy, enhancing shoot and root length, biomass accumulation, tiller production, spike length, and grain yield. Physiological parameters such as photosynthetic rate, stomatal conductance, and relative water content also improved notably with extrinsic silicon application, particularly under drought conditions. Biochemically, foliar-applied Si increased total soluble proteins and improved nitrogen metabolism while reducing the accumulation of drought-induced stress markers, including proline, total free amino acids, and total soluble sugars. Additionally, the chlorophyll and carotenoid contents were better preserved, indicating sustained photosynthetic efficiency. Antioxidant enzyme activities (SOD, POD, CAT, APX) were elevated under drought stress, with Si application reducing oxidative damage, especially in the sensitive genotype. Multivariate analyses, including principal component analysis (PCA), Pearson’s correlation, heatmaps, and the MGIDI index, consistently ranked foliar silicon (Si) as the most beneficial treatment in enhancing drought resilience. These findings demonstrate that foliar silicon application significantly improves the morphological and physio-biochemical tolerance of wheat to water deficit, offering a practical and efficient strategy to enhance crop performance and stability in water-limited regions.