• Energy Research

Although nitrogen (N) is the most limiting nutrient for agricultural production, its overuse is associated with environmental pollution, increased concentration of greenhouse gases, and several human and animal health implications. These implications are greatly affected by biochemical transformations and losses of N such as volatilization, leaching, runoff, and denitrification. Half of the globally produced N fertilizers are used to grow three major cereals—rice, wheat, and maize—and their current level of N recovery is approximately 30–50%. The continuously increasing application of N fertilizers, despite lower recovery of cereals, can further intensify the environmental and health implications of leftover N. To address these implications, the improvement in N use efficiency (NUE) by adopting efficient agronomic practices and modern breeding and biotechnological tools for developing N efficient cultivars requires immediate attention. Conventional and marker-assisted selection methods can be used to map quantitative trait loci, and their introgression in elite germplasm leads to the creation of cultivars with better NUE. Moreover, gene-editing technology gives the opportunity to develop high-yielding cultivars with improved N utilization capacity. The most reliable and cheap methods include agronomic practices such as site-specific N management, enhanced use efficiency fertilizers, resource conservation practices, precision farming, and nano-fertilizers that can help farmers to reduce the environmental losses of N from the soil–plant system, thus improving NUE. Our review illuminates insights into recent advances in local and scientific soil and crop management technologies, along with conventional and modern breeding technologies on how to increase NUE that can help reduce linked N pollution and health implications.

Peanut (Arachis hypogaea L.), being an energy-rich crop, is sensitive to nutrient deficiencies and a scavenger of nutrients from the soil. Optimum and integrated nutrient management (INM) improves productivity and the quality of seeds. The objective of this study was to identify suitable system-based INM (S-INM) options for peanut–wheat cropping sequence in the Saurashtra region of India. Results showed that peanut growth, yield attributing parameters, pod, and haulm yield, and NPK uptake were higher when 100% recommended fertilizer doses (RDFs) + farmyard manure (FYM) @5 t/ha + plant growth-promoting rhizobacteria (PGPR) were applied. However, application of 75% RDFs + FYM @5 t/ha + PGPR in peanut and 100% RDF in wheat was most effective to improve growth and yield attributes, yields and nutrient uptake by wheat. Further, this FYM- and PGPR-amended treatment was found to increase system productivity by 15.3 and 17.1%, system profitability by 17.0 and 22.6%, and net energy gain by 10.0 and 17.9% over the reference treatment and over farmers’ practice (FF), respectively. This sustainable system approach will be helpful for agronomists and farmers in identifying and practicing suitable field practices with further study on the residual effect of organic manures on the peanut–wheat based cropping system in the western region of India with light black soils.

With the growth of population, climate change is a threat to global food security. Understanding and identifying appropriate options of cropping systems and management practices at spatial (locations) and temporal (climate change) scale is important and required. A simulation study was carried out on 13 different locations of Senegal with the objectives of (i) assessing impacts of midcentury climate change scenario across different spatial scales and (ii) evaluating effects of crop management strategies (date of planting, planting density, nitrogen fertilizer management, irrigation, and crop rotations) to reduce risk under current and midcentury climates. Simulation results showed that N fertilization, planting date, and irrigation greatly affected sorghum and millet yield, which can be considered as suitable crop management options to reduce risks under the projected midcentury climate in Senegal although the impact varied by location. The response to N was highly related to water availability or rainfall. In contrast, peanut yield was not sensitive to N application. Early planting (01 to 10-June) improved yield for all three crops across 9 of the locations whereas yield of the three crops in the northern Senegal (Podor, Dagan, Louga and Kanel) remains low and thus was not improved by change in planting date. The length of growing season during the midcentury period decreased at least by up to three weeks due to late onset of rain for some locations, implying that shorter and high-yielding cultivar will be more suitable under future climate. Climate change slightly decreased sorghum yield during the midcentury (likely due to increased temperature and decreased rainfall) although response varied by location while millet yield was either improved or unchanged for most locations. Peanut yields decreased on average by 16 to 20% during the midcentury period regardless of all factors tested. Yield decreases for peanut might be due to increased duration of elevated temperatures and late initiation and shorter duration of rainy season, which implied breeding for heat and drought tolerance, and shorter season varieties might be beneficial. Of all crops evaluated, millet performed well under future climate compared to sorghum or peanut in Senegal although this may be affected by varietals factors. Changes in production systems, particularly focusing on tolerant crops as millet and sorghum will be critical.

Residue management has become a new challenge for Indian agriculture and agricultural growth, as well as environmental preservation. The rice-wheat cropping system (RWCS) is predominantly followed cropping system in the Indo-Gangetic plain (IGP), resulting in generating a large volume of agricultural residue. Annually, India produces 620 MT of crop residue, with rice and wheat accounting for 234 MT of the surplus and 30% of the total. Farmers are resorting to burning crop residue due to the short window between paddy harvest and seeding of rabi season crops, namely wheat, potato, and vegetables, for speedy field preparation. Burning of residues pollutes the environment, thus having adverse effects on human and animal health, as well as resulted in a loss of plant important elements. This problem is particularly prevalent in rice-wheat-dominant states such as Punjab, Haryana, Uttarakhand, and Uttar Pradesh. If we may use in situ management as residue retention after chopper and spreader, sowing wheat with Happy seeder/zero drill/special drill with full residue load, full residue, or full residue load incorporation with conventional tillage, burning is not the sole approach for residue management. In addition, off-farm residues generated are being utilized for animal feed and raw materials for industries. While there are regional variations in many mechanization drivers and needs, a wide range of mechanization components can be transported to new places to fit local conditions. This article focuses on innovations, methods, and tactics that are relevant to various mechanization systems in particular geographical areas. This article also stresses the need for a thorough analysis of the amount of residue generated, residue utilization using modern mechanical equipment, and their positive and negative effects on crop yield and yield attributes, weed diversity, soil physic-chemical, biological properties, beneficial, and harmful nematode populations in the IGP, which will aid researchers and policymakers in farming research priorities and policy for ensuring sustainability in RWCS.

Efficient use of available resources in agricultural production is important to minimize carbon footprint considering the state of climate change. In this context, the current research was conducted to identify carbon and energy-efficient fodder cropping systems for sustainable livestock production. Annual monocropping, perennial monocropping, annual cereal + legume intercropping and perennial cereal + legume intercropping systems were evaluated by employing a randomized complete block design with three replications under field conditions. The lucerne (Medicago sativa L.) monocropping system recorded significantly lower carbon input (274 kg-CE ha−1 year−1) and showed higher carbon indices viz., carbon sustainability index (165.8), the carbon efficiency ratio (166.8) and carbon efficiency (347.5 kg kg-CE−1) over other systems. However, higher green fodder biomass led to statistically higher carbon output (78,542 kg-CE ha−1 year−1) in the Bajra–Napier hybrid (Pennisetum glaucum × Pennisetum purpureum) + lucerne perennial system. Similar to carbon input, lower input energy requirement (16,106 MJ ha−1 year−1) and nutrient energy ratio (25.7) were estimated with the lucerne perennial system. However, significantly higher energy output (376,345 and 357,011 MJ ha−1 year−1) and energy indices viz., energy use efficiency (13.3 and 12.2), energy productivity (5.8 and 5.3 kg MJ−1), net energy (327,811 and 347,961 MJ ha−1 year−1) and energy use efficiency (12.3 and 11.2) were recorded with Bajra–Napier hybrid + legume [lucerne and cowpea (Vigna unguiculata (L.) Walp.)] cropping systems, respectively. However, these systems were on par with the lucerne monocropping system. Additionally, Bajra–Napier hybrid + legume [cowpea, sesbania (Sesbania grandiflora (L.) Pers.) and lucerne] cropping systems also showed higher human energy profitability. Concerning various inputs’ contribution to total carbon and energy input, chemical fertilizers were identified as the major contributors (73 and 47%), followed by farmyard manure (20 and 22%) used to cultivate crops, respectively, across the cropping systems. Extensive use of indirect (82%) and non-renewable energy sources (69%) was noticed compared to direct (18%) and renewable energy sources (31%). Overall, perennial monocropping and cereal + legume cropping systems performed well in terms of carbon and energy efficiency. However, in green biomass production and carbon and energy efficiency, Bajra–Napier hybrid + legume (lucerne and cowpea) cropping systems were identified as the best systems for climate-smart livestock feed production.

Heat stress (HS) is one of the major abiotic stresses affecting the production and quality of wheat. Rising temperatures are particularly threatening to wheat production. A detailed overview of morpho-physio-biochemical responses of wheat to HS is critical to identify various tolerance mechanisms and their use in identifying strategies to safeguard wheat production under changing climates. The development of thermotolerant wheat cultivars using conventional or molecular breeding and transgenic approaches is promising. Over the last decade, different omics approaches have revolutionized the way plant breeders and biotechnologists investigate underlying stress tolerance mechanisms and cellular homeostasis. Therefore, developing genomics, transcriptomics, proteomics, and metabolomics data sets and a deeper understanding of HS tolerance mechanisms of different wheat cultivars are needed. The most reliable method to improve plant resilience to HS must include agronomic management strategies, such as the adoption of climate-smart cultivation practices and use of osmoprotectants and cultured soil microbes. However, looking at the complex nature of HS, the adoption of a holistic approach integrating outcomes of breeding, physiological, agronomical, and biotechnological options is required. Our review aims to provide insights concerning morpho-physiological and molecular impacts, tolerance mechanisms, and adaptation strategies of HS in wheat. This review will help scientific communities in the identification, development, and promotion of thermotolerant wheat cultivars and management strategies to minimize negative impacts of HS.