Application of biological and integrated fertilizers mitigates the adverse effects of drought stress on barley

Abstract:Reaching high yield using new soil management operations in areas with scarce water resources and low soil organic matter is a promising necessity in sustainable intensive agriculture. The objective of this research was to study the effect of various combinations of organic and chemical fertilizers and water deficit systems on barley production. The field experiment was set up in two successive growing seasons of 2007 and 2008. Experimental design was a split plot arrangement based on a randomized complete block design with four replications. The treatments consisted of three irrigation regimes (main plots) and six soil fertilizing systems (sub-plots). The irrigation treatments were applied at different phenological stages of barley according to Zadoks scale (1974), and consisted of: non-stressed (NS, normal irrigation to the end of physiological maturity), moderate stress (MS, ceased irrigation from the beginning of flowering (Zadoks, 65) to the beginning of the grain filling stage (Zadoks, 70), and severe stress (SS, ceased irrigation from the beginning of flowering stage to the end of physiological maturity). Fertilizing systems consisted of 1. no fertilizer (Control) (NF), 2. phosphorous and nitrogen bio-fertilizers (Bio-fertilizer is a complex of different free living nitrogen fixing and phosphorus solubilizing bacteria) (BF), 3. 100% chemical fertilizer (NPK) (based on soil chemical analysis) (CF), 4. vermicompost (VC) (applied 5 t/ha), 5. 50% chemical fertilizer (NPK)+50% vermicompost (2.5 t/ha) (CV), and finally 6. 50% chemical fertilizer (NPK)+bio-fertilizer (CB), assigned to the sub plots. Seed yield, 1000-grain weight and biomass production were significantly affected by water deficit. Sole application of chemical fertilizer reduced chemical nitrogen fertilizer efficiency, though HI was less than the other fertilizing systems. Organic fertilizers could reduce water stress effects through more water maintenance in the soil. Our results clearly proved the advantage of integrated application of organic and bio-fertilizer along with chemical fertilizer on growth and yield of barley under water deficit and arid conditions.