Effect of irrigation methods and potassium fertilizer on grain yield and water use efficiency on Corn

The experiment was conducted in Islamic Azad University - Ramhormoz Branch in 2011، based on a complete randomized block design as split-plot with three replications on S 500 corn cultivar. The main plots consisted of three irrigation methods including full، variable، and fixed irrigation methods. Each subplot received three rates of potassium fertilizer as 0، 150 or 300 kg ha-1. The results showed that the plots received full irrigation resulted in significantly higher grain yield than other irrigation methods. The highest water use efficiency (1. 29 kg m-3) was obtained in variable irrigation and the lowest one (1. 08 kg m-3) was in full irrigation. Potassium application increased relative water content and grain protein percentage in variable irrigation and fixed irrigation than full irrigation treatment. Full and fixed irrigation treatments produced the lowest and the highest abscisic acid concentration at any potassium levels. Considering that the alternative irrigation method، whether variable or fixed، decreased used water and also increased water use efficiency، therefore using mentioned irrigation method can be a suitable method in deficit water condition and high water cost، could be better than full irrigation method in corn in this region.