Effect of pea cultivar and replacement and additive intercropping ratios of pea and spinach on yield and competition indices

In order to investigate the effect of pea (Pisum sativum L.) cultivar as well as replacement and additive intercropping ratios of pea and spinach (Spinacia oleracea L.) on yield and competition indices, a factorial experiment has been conducted based on randomized complete block design with three replications at Gonbad Kavous University research field during 2016-2017. Intercropping ratios at nine levels consisted of pure pea, pure spinach, 33%, 50%, and 67% spinach instead of pea, addition series of 33%, 50%, 67%, and 100% spinach to pea. Also, pea cultivars have been Shamshiri and Pofaki. Land equivalent ratio and relative crowding coefficient in additive treatments have been more than replacement treatments, above one in all treatments. The highest land equivalent ratio with 1.333 has been observed in 100% pea + 100% spinach. In replacement series, pea has been the dominant plant, while in additive series spinach has dominated. No actual yield loss is observed in all treatments. The highest system productivity index has been related to 100% pea + 100% spinach with 3045. Overall, the land equivalent ratio of more than one and positive system productivity index of especial treatment, equal to 100% pea + 100% spinach indicate the benefit of pea and spinach intercropping.