Radiation, water, and nitrogen use efficiencies of Gossypium hirsutum L.

Abstract

Resource use efficiency is a baseline for productive agriculture and proper management of different resources (water, nitrogen, light, and land), and it plays a pivotal role in the accomplishment of this goal. Three field experiments were carried out at the experimental farm area of the Central Cotton Research Institute, Multan, Pakistan, in 2009 and 2010 to investigate the effects of different resources on cotton crops. Treatments for the first experiment included 4 cultivars and 6 nitrogen levels. The second experiment comprised 3 variables, irrigation methods, cultivars, and plant spacing, whereas 2 variables, including different irrigation regimes and glycinebetaine application, were used in the third experiment. Different attributes, such as physiological efficiency, irrigation water use efficiency, and agronomic and economic nitrogen use efficiency, were studied during the course of experimentation. The statistical results revealed that cumulative intercepted photosynthetically active radiation, radiation use efficiencies, water use efficiencies for total biomass, seed cotton, lint, and cottonseed yield were enhanced with the addition of each incremental dose of nitrogen fertilizer and were also recorded as higher for the application of irrigation water through the drip method at the narrow plant spacing of 10 cm. Furthermore, exogenously applied glycinebetaine also significantly increased the attributes studied. Different agronomic and economic nitrogen use efficiencies for seed cotton, lint, and cottonseed yield were notably increased with the application of different nitrogen fertilizer levels and were greater at 160 kg N ha-1.