Estimation of Different Water Stress Indices of Forage Maize for Deficit Irrigation Management

One of the effective ways to increase water productivity in arid and semi-arid regions is Irrigation management. Due to the fact that the plant is exposed to water stress in low irrigation, so it is necessary to study the water stress status of the plant. The purpose of this study is to investigate the water stress status of forage maize in different irrigation levels using different soil and plant indices. Hence a study in the form of a randomized complete block design with four levels of irrigation; (I50, I75, I100 and I125) were performed in the Faculty of Agriculture of Lorestan University. The results indicated that different levels of irrigation on CWSI, RWC, KS and residual soil moisture, crop yield and water productivity affect significantly at confidence level of one percent. The CWSI index increased from 0.18 in I125 treatment to 0.47 in I50 treatment. Decrease in soil moisture content from 68% in I125 treatment to 42% in I50 treatment, decreased the value of relative leaf water content index (RWC). The highest and lowest mean values ​​of water stress coefficient (KS) during the growth period related to I50 and I125 treatments were 0.32 and 0.94 respectively. Also, with a 50% reduction in plant water requirement, the yield compared to full irrigation conditions decreased by about 42% and treatments I100 and I50 with values ​​of 2.75 and 2.53 kg / m3, respectively, had the highest and lowest water productivity. In this study, the relationship between crop yield and indices of CWSI, RWC, KS and residual soil moisture () was obtained with a high correlation.Finally, it can be said that in water stress in forage maize can be investigated through water stress indices.