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Precision nitrogen (N) management sustains high grain yield with low N optimum dose and thus may help reduce the escape of reactive nitrogen from soils to the atmosphere. Two-year field studies wer...

Three-year multi-location field experiments were conducted in soils of varying inherent nitrogen (N) supply in diverse agro-climatic zones for improving productivity and mitigating N2O emissions in...

Site-specific fertilizer nitrogen management (SSNM) could be the best management option to avoid excessive and untimely nitrogen (N) applications in wheat. Field experiments were conducted in soils of varying inherent fertility in diverse agro-climatic zones to provide SSNM strategy for wide range of wheat genotypes. The intensity of leaf colour greenness of the first fully exposed top leaf was measured using leaf colour chart (LCC) and chlorophyll meter (SPAD) at different growth stages. The spectral properties of leaves at different growth stages differed among the different wheat genotypes except at Feekes 6 stage, thus the leaf greenness measured only at this stage can be used to make SSNM decisions. After applying 25 kg N ha−1 at planting and 45 kg N ha−1 at Feekes 2 stage, the leaf greenness of the first fully exposed top leaf measured with LCC at Feekes 6 stage was used to decide the amount of site-specific fertilizer N to be applied as topdressing. The LCC guided fertilizer N dose sustained grain yield to the level as obtained with soil test based N applications with the less use of 20–50 kg N ha−1. The practice of applying additional N or just increasing number of split doses in soils with low Walkley–Black organic carbon content may not improve grain yield unless plants really need it. The SSNM strategy improved agronomic efficiency of applied fertilizer N in different wheat genotypes grown under diverse range of agro-climatic conditions and in soils with variable indigenous N supply.

Selenium (Se), the sister element of sulfur, has gained importance recently as an essential trace element in the plant systems. It uses the transporters of sulfur for its uptake and similar biochemical pathways for its metabolism, which leads to its incorporation in various biomolecules. The wide range of beneficial effects of Se on plants has been established. Low concentrations of Se have been proven to enhance seed germination, growth, photosynthesis, respiratory potential, yield, etc. Its role in protecting the plants against various types of biotic and abiotic stresses has become an area of active research. Various studies have revealed its direct effect on antioxidative defense system thereby increasing the potential of the plants to combat the stressful conditions. Despite of its well documented positive effects, Se still is an intermediate between being beneficial or harmful because of its toxic effects at higher concentrations. Therefore, concentration of Se to be used, is still a matter of contemplation and research.