Effect of Striga Trap Crops and Nitrogen Fertilizer Application on Yield and Yield Related Traits of Sorghum [Sorghum bicolor (L.) Moench] at Fedis District, Eastern Ethiopia

Abstract

Striga causes a serious threat to successful cultivation of sorghum in areas of low and erratic rainfall and poor soil fertility. Therefore, to reduce yield losses and severity of Striga, a field experiment was conducted during the cropping season of 2015 on heavily Striga-infested field in Fedis District, Boko site to determine the effect of trap crops (cowpea, soybean, desmodium, control) and N fertilizer rates (0, 46, 92 and 138 kg N ha﹣1) on management of Striga, yield related traits and yield of sorghum. The experiment was laid out in a factorial arrangement in a randomized complete block design (RCBD) with three replications. Moreover, LAI, plant height, head weight plot﹣1 and aboveground dry biomass yield of sorghum were significantly (P < 0.05) increased by 4%, 9%, 28% and 33%, respectively, by use of cowpea as a trap crop over the control. Likewise use of cowpea as a trap crop significantly (P < 0.01) increased kernel weight head﹣1 by 6% and grain yield by 23% over the control. Similarly, the main effect of nitrogen showed that increased nitrogen rate up to 46 kg ha﹣1 significantly reduced Striga number at sorghum emergence by about 49.8% over control. Days to heading, flowering and maturity on sorghum were significantly (P < 0.01) affected by nitrogen fertilizer rate and the application of 46 kg N ha﹣1resulted in earlier heading by 6% over138 kg N ha﹣1. Application of 138 kg N ha﹣1delayed days to flowering by 6 days over 46 kg N ha﹣1. Plots that received 46 kg N ha﹣1 attained 90% physiological maturity earlier (127.1 days) than other treatments. Application of 46 kg N ha﹣1significantly increased kernel weight head﹣1 by 12% and aboveground dry biomass yield by 33% over the control. LAI and grain yield were significantly (p < 0.01) affected by main effect of N where the highest (2.387) leaf area index and the highest (3116 kg ha﹣1) grain yield were obtained with 46 kg N ha﹣1.