Nitrogen-use-efficiency (NUE) in plants under NaCl stress

Abstract

Increasing population growth rate, shortage of good arable land, use of low quality water coupled with intensive cropping system are forcing crop production into more marginal environments and thus, limiting the adaptation and productivity of food crops. In Pakistan, considerable information is available regarding nitrogen (N) requirement of plants grown in normal healthy soils. But scanty information is accessible regarding nitrogen requirement of plants grown in salt-affected soils, which cover an area of about 11.5 × 10 6 ha. The unfavorable conditions as well as inadequate and imbalance use of N in such soils is affecting considerable decline in crop yield. No doubt, soil salinity alters the N metabolism in plants but, use of N fertilizers affects growth dilution to alleviate detrimental effects of moderate salinity and helps to improve economic yield of crops. The concentration of soluble cations and anions in the soil solution is high enough to induce water stress, specific ion effects and nutrient imbalance which generally decrease crop growth and ultimately the harvestable yield. Generally, N fertilization increases productivity and yield of the plants at low NaCl concentration as compared to the situation where salinity is a major growth limiting factor. Various experiments have been conducted to determine appropriate N fertilizer rates for different textured soils for the protection of environment while achieving high production of crops. Since, due to different physical and chemical properties of soils, requirements of N and other mineral nutrients of crops on salt-affected soils are different than those on normal soils. Therefore, farmers will be economically benefited by the judicious use of N fertilizer for optimum crop production from their marginal land resources without disturbing the biosphere equilibrium. Increased farm income will help to decrease rural poverty and migration from rural to urban areas which is another benefit of optimum use of N during amelioration of salt-affected soils by using amendments and low quality waters. This chapter presents an account of NUE in crop plants under the influenced by salt stress.