Effect of Irrigation Regime and Phosphorus Fertilizer on Growth Characteristics and Seed Yield and Forage Yield of Two Grasspea (Lathyrus sativus L.) Ecotypes

Grasspea (Lathyrus sativus L.) is a forgotten plant and its cultivation is important in the scope of sustainable crop production. In a field experiment, using split factorial arrangements in randomized complete block design with three replications, the effects of irrigation regimes; 50, 75 and 100% of evaporation of class A evaporation pan, and different rates of phosphorous fertilizer (triple superphosphate); 0, 60 and 120 kg ha-1 on growth characteristics, seed yield and forage yield of two grasspea ecotypes; Lalehzar and Sharekord, in Lalehzar region in Kerman province, Iran, in 2018 and 2019 growing seasons was studied. The results showed that drought stress significantly reduced pod no. m-2, plant height, seed yield and biological yield. Application of phosphorous fertilizer increased grasspea growth and yield. Overall, Shahrekord ecotype showed higher seed yield (2401 kg ha-1) and biological yield (5612 kg ha-1). The highest phosphorus productivity (39.98 kg seed kg P-1) achieved in 75% of evaporation irrigation regime plus 60 kg ha-1 triple superphosphate fertilizer. Therefore, growing Shahrekord grasspea ecotype in Lalehzar region would be reasonable in terms of saving water and managing the application of phosphorous fertilizer.