Barley (Hordeum vulgare L.) Response to Partial Root Drying Irrigation, Planting Method and Nitrogen Application Rates

Barley (Hordeum vulgare L.) is an important crop in many areas of the world. Drought and scarce resource of irrigation water are serious concerns in agricultural production in Iran and other arid and semi-arid regions. The objective of this study is to investigate the interaction effects of partial root drying (PRD) irrigation, planting method and different nitrogen application rates on yield, water and nitrogen use efficiencies and economical nitrogen and water use for barley in 2011-2012 cropping season. The experiment was designed as split-split plot that arranged in randomized complete blocks with irrigation strategy as the main plot, planting method as the subplot and nitrogen levels as the sub-subplot in three replications. The irrigation strategies consisted of ordinary furrow irrigation (OFI) and variable alternate furrow irrigation (VAFI) as a PRD technique. The planting methods included of on-ridge planting (ORP) and in-furrow planting (IFP) methods. The nitrogen levels were 0 (N-0), 90 (N-1) and 180 (N-2) kg N ha(-1) as urea. The results indicated that using VAFI method, 25% reduction in irrigation water depth was occurred compared with OFI, with no significant yield reduction. Furthermore, in IFP method, yield increased 13% compared with ORP. The maximum profits, water economic productivity, water use efficiency and water productivity were obtained in VAFI with IFP and nitrogen application rate of 180 kg/ha. Nitrogen use efficiency in VAFI compared with OFI was increased due to higher nitrogen absorption by plant. Thus, it is indicated that in areas with water limiting, it is preferable to recommend VAFI, IFP and 180 kg N ha(-1) as best management practice for barley farm in the study region.