Yield, water and nitrogen use efficiencies of sprinkler irrigated wheat grown under different irrigation and nitrogen levels in an arid region

A major challenge in crop production is to achieve the goal of increasing both yield and resource use efficiency. Irrigation water and nitrogen (N) are scarce and expensive resources constraining wheat production in arid regions. There is limited information on how irrigation and N supply can be simultaneously manipulated to achieve higher yield, water productivity (WP), and nitrogen use efficiency (NUE) of wheat in arid regions. A two-year field experiment was conducted to investigate the effects of irrigation and N rates on yield, WP and NUE of wheat in a hot, arid environment at Bikaner, India. The experimental treatments comprised of six irrigation [100% (ETm; full evapotranspiration), 90% (ETd1), 80% (ETd2), 70% (ETd3), 60% (ETd4), and 50% (ETd5) of ETc (crop evapotranspiration)] levels, and four N [0 (N0), 40 (N40), 80 (N80), and 120 (N120) kg ha−1] rates. Moderate deficit irrigation (ETd2) had greatest WP and caused a 17% reduction in water consumption with only a 5% reduction in yield compared to full irrigation (ETm). The N application improved yield and WP. The NUE declined with a reduction in water application and an increase in N rates. The yield and WP response to N rates modified with irrigation levels.The significant increase in grain yield was recorded with N120 at ETm and ETd1, with N80 at ETd2 and ETd3, and with N40 at ETd4 and ETd5 irrigation levels. The significant increase in WP was recorded with N80 at ETm, ETd1, ETd2 and ETd3, and with N40 at ETd4 and ETd5 irrigation levels. The results suggested that moderate deficit irrigation (ETd2) along with 120 kg N ha−1 could ensure satisfactory grain yield and WP of wheat in arid regions. The study also indicated that the adoption of an appropriate deficit irrigation and N rate combination can be an effective means to reduce non-beneficial water consumption, achieve higher yield, and improve WP and NUE for wheat in an arid environment.