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

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 experimentalfarm area of the Central Cotton Research Institute, Multan, Pakistan, in 2009 and 2010 to investigate the effects of different resourceson cotton crops. Treatments for the first experiment included 4 cultivars and 6 nitrogen levels. The second experiment comprised 3variables, irrigation methods, cultivars, and plant spacing, whereas 2 variables, including different irrigation regimes and glycinebetaineapplication, were used in the third experiment. Different attributes, such as physiological efficiency, irrigation water use efficiency, andagronomic and economic nitrogen use efficiency, were studied during the course of experimentation. The statistical results revealedthat 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 alsorecorded 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 useefficiencies for seed cotton, lint, and cottonseed yield were notably increased with the application of different nitrogen fertilizer levelsand were greater at 160 kg N ha–1.