Lead (Pb) is a highly toxic contaminant that is ubiquitously present in the ecosystem and poses severe environmental issues, including hazards to soil-plant systems. This review focuses on the uptake, accumulation, and translocation of Pb metallic ions and their toxicological effects on plant morpho-physiological and biochemical attributes. We highlight that the uptake of Pb metal is controlled by cation exchange capacity, pH, size of soil particles, root nature, and other physio-chemical limitations. Pb toxicity obstructs seed germination, root/shoot length, plant growth, and final crop-yield. Pb disrupts the nutrient uptake through roots, alters plasma membrane permeability, and disturbs chloroplast ultrastructure that triggers changes in respiration as well as transpiration activities, creates the reactive oxygen species (ROS), and activates some enzymatic and non-enzymatic antioxidants. Pb also impairs photosynthesis, disrupts water balance and mineral nutrients, changes hormonal status, and alters membrane structure and permeability. This review provides consolidated information concentrating on the current studies associated with Pb-induced oxidative stress and toxic conditions in various plants, highlighting the roles of different antioxidants in plants mitigating Pb-stress. Additionally, we discussed detoxification and tolerance responses in plants by regulating different gene expressions, protein, and glutathione metabolisms to resist Pb-induced phytotoxicity. Overall, various approaches to tackle Pb toxicity have been addressed; the phytoremediation techniques and biochar amendments are economical and eco-friendly remedies for improving Pb-contaminated soils.

Irrigation has been pivotal in sustaining wheat as a major food crop in the world and is increasingly important as an adaptation response to climate change. In the context of agricultural production responding to climate change, improved irrigation management plays a significant role in increasing water productivity (WP) and maintaining the sustainable development of water resources. Considering that wheat is a major crop cultivated in arid and semi-arid regions, which consumes high amounts of irrigation water, developing wheat irrigation management with high efficiency is urgently required. Both irrigation scheduling and irrigation methods intricately influence wheat physiology, affect plant growth and development, and regulate grain yield and quality. In this frame, this review aims to provide a critical analysis of the regulation mechanism of irrigation management on wheat physiology, plant growth and yield formation, and grain quality. Considering the key traits involved in wheat water uptake and utilization efficiency, we suggest a series of future perspectives that could enhance the irrigation efficiency of wheat.

Several agroforestry systems prevail in different agro-ecological zones of Pakistan, and cover a remarkable area of 19.3 million hectares. They not only play an important role in slowing down CO₂ emissions, but also contribute to mitigating climate change. However, in many regions, the relevant effect of agroforestry systems on overall carbon (C) stock and their reliance on various factors are quite unidentified. This study was planned to assess the biomass accumulation and C stocks of different commonly practiced agroforestry systems (boundary, bund, scattered, agri-horticulture) and their constituent land use types (tree + cropland) through a non-destructive approach (allometric equations) in a semi-arid region of Punjab, Pakistan. The results showed that the highest plant biomass (87.12 t ha⁻¹) increased by 46%, 17%, 78%, and 339%, and C stock (42.77 t ha⁻¹) increased by 49.51%, 20%, 82%, and 361% in the boundary planting system compared to the bund, scattered, agri-horti and sole cropland, respectively. The soil organic carbon (SOC) stock at all three depths, 0–15 cm, 15–30 cm & 30–45 cm, was found in the following order: boundary planting system > bund planting system > agri-horti system > scattered planting system > agricultural system, with a maximum in the boundary planting system and minimum in the sole cropping system at all three depths. Overall, the total C stock of the ecosystem’s vegetation + soil C (0–30 cm) in the forested area was 275 t ha⁻¹, equating to 37 t ha⁻¹ in the agricultural system alone. Our results highlighted that agroforestry systems have the highest potential for C sequestration. We suggest that research and investment in agroforestry systems can be a successful way for Pakistan to achieve some of its climate change mitigation goals.

Drought is one of the major environmental stresses, resulting in serious yield reductions in wheat production. Silicon (Si) has been considered beneficial to enhancing wheat resistance to drought stress. However, few studies have explored the mediated effects of foliar supplementation of Si on drought stress imposed at different wheat growth stages. Therefore, a field experiment was carried out to investigate the effects of Si supplementation on the physiological and biochemical responses of wheat to drought stress imposed at the jointing (D-jointing), anthesis (D-anthesis) and filling (D-filling) stages. Our results showed that a moderate water deficit markedly decreased the dry matter accumulation, leaf relative water content (LRWC), photosynthetic rate (Pn), stomatal conductance (Sc), transpiration rate (Tr) and antioxidant activity [peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT)]. On the contrary, it remarkably increased the content of osmolytes (proline, soluble sugar, soluble protein) and lipid peroxidation. The grain yields of D-jointing, D-anthesis and D-filling treatments were 9.59%, 13.9% and 18.9% lower, respectively, compared to the control treatment (CK). However, foliar supplementation of Si at the anthesis and filling stages significantly improved plant growth under drought stress due to the increased Si content. Consequently, the improvement in antioxidant activity and soluble sugar, and the reduction in the content of ROS, increased the LRWC, chlorophyll content, Pn, Sc and Tr, and ultimately boosted wheat yield by 5.71% and 8.9%, respectively, in comparison with the non-Si-treated plants subjected to water stress at the anthesis and filling stages. However, the mitigating effect of Si application was not significant at the jointing stage. It was concluded that foliar supplementation of Si, especially at the reproductive stage, was effective in alleviating drought-induced yield reduction.

Silicon (Si) enhances maize resistance to drought. While previous studies have mainly focused on the seedling stage, the mediation of drought stress by Si imposed at the vegetative and reproductive stages has been rarely investigated. A soil-column experiment was thus conducted under a rainproof shelter to quantify the effect s of Si application on the physiological and agronomic responses of maize to drought stress imposed at the 6-leaf (D-V6), 12-leaf (D-V12), and blister (D-R2) stages. The observed parameters included plant growth, photosynthesis, osmolytes, antioxidant activity, and grain yield. The results showed that drought stress strongly decreased the leaf area, leaf water content, photosynthetic rate, chlorophyll content, and antioxidant activity (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)) and markedly increased lipid peroxidation. D-V6, D-V12, and D-R2 decreased grain yields by 12.9%, 28.9%, and 44.8%, respectively, compared to the well-watered treatment (CK). However, Si application markedly increased leaf area, chlorophyll content, photosynthetic rate, osmolyte content, and enzymatic antioxidant activities (SOD, POD, and CAT), and decreased malondialdehyde (MDA) and superoxide radical accumulation, ultimately improving maize yields by 12.4%, 69.8%, and 80.8%, respectively, compared to the non-Si treated plants under drought stress at the V6, V12, and R2 stages. Furthermore, maize yields had a significant positive correlation with chlorophyll content and SOD and POD activity during the three stages. Our findings suggest that Si-induced changes in chlorophyll content and antioxidant activity might constitute important mechanisms for mitigating drought stress. In conclusion, this study provides physico-biochemical evidence for the beneficial role of Si in alleviating drought-induced yield reduction in maize, particularly during the late vegetative or early reproductive stages. Thus, Si application constitutes an effective approach for improving maize yield in rain-fed agricultural systems.

Soil microbial activity (SMA) is vital concerning carbon cycling, and its functioning is recognized as the primary factor in modifying soil carbon storage potential. The composition of the microbial community (MC) is significant in sustaining environmental services because the structure and activity of MC also influence nutrient turnover, distribution, and the breakdown rate of soil organic matter. SMA is an essential predictor of soil quality alterations, and microbiome responsiveness is imperative in addressing the escalating sustainability concerns in the Himalayan ecosystem. This study was conducted to evaluate the response of soil microbial and enzyme activities to land conversions in the Northwestern Himalayas (NWH), India. Soil samples were collected from five land use systems (LUSs), including forest, pasture, apple, saffron, and paddy-oilseed, up to a depth of 90 cm. The results revealed a significant difference (p < 0.05) in terms of dehydrogenase (9.97–11.83 TPF µg g⁻¹ day⁻¹), acid phosphatase (22.40–48.43 µg P-NP g⁻¹ h⁻¹), alkaline phosphatase (43.50–61.35 µg P-NP g⁻¹ h⁻¹), arylsulphatase (36.33–48.12 µg P-NP g⁻¹ h⁻¹), fluorescein diacetate hydrolase (12.18–21.59 µg g⁻¹ h⁻¹), bacterial count (67.67–123.33 CFU × 10⁶ g⁻¹), fungal count (19.33–67.00 CFU × 10⁵ g⁻¹), and actinomycetes count (12.00–42.33 CFU × 10⁴ g⁻¹), with the highest and lowest levels in forest soils and paddy-oilseed soils, respectively. Soil enzyme activities and microbial counts followed a pattern: forest > pasture > apple > saffron > paddy-oilseed at all three depths. Paddy-oilseed soils exhibited up to 35% lower enzyme activities than forest soils, implying that land conversion facilitates the depletion of microbiome diversity from surface soils. Additionally, reductions of 49.80% and 62.91% were observed in enzyme activity and microbial counts, respectively, with soil depth (from 0–30 to 60–90 cm). Moreover, the relationship analysis (principal component analysis and correlation) revealed a high and significant (p = 0.05) association between soil microbial and enzyme activities and physicochemical attributes. These results suggest that land conversions need to be restricted to prevent microbiome depletion, reduce the deterioration of natural resources, and ensure the sustainability of soil health.