Effects of Nano-Potassium Fertilizer on Yield and Water Use Efficiency of Soybean Under Water Deficit Conditions (Case Study: Moghan Plain, Iran)

In order to investigate the effects of potassium nano-fertilizer on soybean and water use efficiency (WUE) under different irrigation conditions, an experiment was carried out in split plots based on completely randomized block design with four replications in Moghan plain, Iran, during 2014-2016. The main factor included four levels of irrigation (IR), that is, normal irrigation, cutting irrigation during vegetative growth, cutting irrigation during flowering stage and cutting irrigation during grain filling and a subfactor included four levels of potassium nano-fertilizer (NK): control, 1, 2 and 3 kg/ha. The results showed that using potassium nano-fertilizer at all stages of cutting irrigation decreased the effects of drought stress. Also, the highest yield (3.17 ton/ha) and yield components, morphological characteristics and WUE (for yield 0.112 kg.mm(-1)) were observed in normal irrigation with application of 3 kg/ha of potassium nano-fertilizer. In addition, oil percent and seed protein were strongly affected by deficit irrigation, especially at grain filling stage. According to the results, using 3 kg/ha of potassium nano-fertilizer, resulted in a 25% decreased in the effects of water deficit on morphological characteristics, yield and yield components, especially in seed filling stage decreased about 25%.