• Energy Research

Sustainable agricultural production is critically antagonistic by fluctuating unfavorable environmental conditions. The introduction of mineral elements emerged as the most exciting and magical aspect, apart from the novel intervention of traditional and applied strategies to defend the abiotic stress conditions. The silicon (Si) has ameliorating impacts by regulating diverse functionalities on enhancing the growth and development of crop plants. Si is categorized as a non-essential element since crop plants accumulate less during normal environmental conditions. Studies on the application of Si in plants highlight the beneficial role of Si during extreme stressful conditions through modulation of several metabolites during abiotic stress conditions. Phytohormones are primary plant metabolites positively regulated by Si during abiotic stress conditions. Phytohormones play a pivotal role in crop plants’ broad-spectrum biochemical and physiological aspects during normal and extreme environmental conditions. Frontline phytohormones include auxin, cytokinin, ethylene, gibberellin, salicylic acid, abscisic acid, brassinosteroids, and jasmonic acid. These phytohormones are internally correlated with Si in regulating abiotic stress tolerance mechanisms. This review explores insights into the role of Si in enhancing the phytohormone metabolism and its role in maintaining the physiological and biochemical well-being of crop plants during diverse abiotic stresses. Moreover, in-depth information about Si’s pivotal role in inducing abiotic stress tolerance in crop plants through metabolic and molecular modulations is elaborated. Furthermore, the potential of various high throughput technologies has also been discussed in improving Si-induced multiple stress tolerance. In addition, a special emphasis is engrossed in the role of Si in achieving sustainable agricultural growth and global food security.

Rice is the principal food grain crop of the world, grown on over 164 million hectares. Water is an important production constraint in food crops. Till recently, crop breeding efforts have mainly focused on the shoot, whereas most of the major drivers of the yield gap directly influence the root system, thereby implicating the plant's resource acquisition efficiency. Despite the substantial experimental evidence for the importance of root traits in drought tolerance, lesser efforts have been directed towards drought-adaptive root traits based on the selection index in rice. The above-ground components are easy to phenotype, and lesser efforts towards root traits stem mainly from the phenotyping bottlenecks of reliable recovery and evaluation of root traits. Moreover, greater phenotypic plasticity of root traits in response to changes in soil resource status, and lack of less costly screening techniques for roots is still a challenge, leading to comparatively lesser information about the potential role of roots in developing drought-resilient rice varieties. Root phenes are not as high in number as is the huge shopping list of above-ground traits and exploring the natural variation of root traits could assist rice improvement programs in developing varieties with desired root phenes for target environments. More importantly, elucidation of the relationship of root traits with the physiological and biochemical responses contributing to grain yield is also imperative. In this paper, we discuss the potential role of roots in determining the resilience of rice varieties for future farming systems based on evidence from root phenotyping, the relationship of root phenes with physiological efficiency and yield under water stress in rice.

Food security and environmental health are directly linked with soil carbon (C). Soil C plays a crucial role in securing food and livelihood security for the Himalayan population besides maintaining the ecological balance in the Indian Himalayas. However, soil C is being severely depleted due to anthropogenic activities. It is well known that land use management strongly impacted the soil organic carbon (SOC) dynamics and also regulates the atmospheric C chemistry. Different types of cultivation practices, i.e., forest, plantations, and crops in the Kashmir Himalayas, India, has different abilities to conserve SOC and emit C in the form of carbon dioxide (CO2). Hence, five prominent land use systems (LUC) (e.g., natural forest, natural grassland, maize-field-converted from the forest, plantation, and paddy crop) of Kashmir Himalaya were evaluated to conserve SOC, reduce C emissions, improve soil properties and develop understanding SOC pools and its fractions variations under different land use management practices. The results revealed that at 0–20 cm and 20–40 cm profile, the soil under natural forest conserved the highest total organic carbon (TOC, 24.24 g kg−1 and 18.76 g kg−1), Walkley-black carbon (WBC, 18.23 g kg−1 and 14.10 g kg−1), very-labile-carbon (VLC, 8.65 g kg−1, and 6.30 g kg−1), labile-carbon (LC, 3.58 g kg−1 and 3.14 g kg−1), less-labile-carbon (VLC, 2.59 g kg−1, and 2.00 g kg−1), non-labile-carbon (NLC, 3.41 g kg−1 and 2.66 g kg-1), TOC stock (45.88 Mg ha−1 and 41.16 Mg ha−1), WBC stock (34.50 Mg ha−1 and 30.94 Mg ha−1), active carbon pools (AC, 23.14 Mg ha−1 and 20.66 Mg ha−1), passive carbon pools (PC, 11.40 Mg ha−1 and 10.26 Mg ha−1) and carbon management index (CMI, 100), followed by the natural grassland. However, the lowest C storage was reported in paddy cropland. The soils under natural forest and natural grassland systems had a greater amount of VLC, LC, LLC, and NLC fraction than other land uses at both depths. On the other hand, maize-field-converted-from-forest-land-use soils had a higher proportion of NLC fraction than paddy soils; nonetheless, the NLC pool was maximum in natural forest soil. LUS based on forest crops maintains more SOC, while agricultural crops, such as paddy and maize, tend to emit more C in the Himalayan region. Therefore, research findings suggest that SOC under the Kashmir Himalayas can be protected by adopting suitable LUS, namely forest soil protection, and by placing some areas under plantations. The areas under the rice and maize fields emit more CO2, hence, there is a need to adopt the conservation effective measure to conserve the SOC without compromising farm productivity.