Effects of nitrogen applied to cassava on growth and yield of Cowpea in the long term intercropping experiment site

Abstract

The main objective of this study was to evaluate the growth and yield of cowpea in the cassava-cowpeaintercropping under the long term experiment. The experiment design was Randomized Completely Block Design(RCBD) with four replications and four treatments: T1 = No nitrogen T2 = 8 kg.N/rai, T3 = 16 kg.N/rai and T4 = 16kg.N/rai + lime. Fertilizer application for cowpea was a basal application with 0-4-4 kg./rai of N-P2O5-K2O. Forcassava, it was conducted in two stages i.e. 1) 0, 4 and 8 kg.N/rai with 8 and 8 kg/rai P2O5-K2O, respectively at onemonth after cassava planting 2) 0, 4 and 8 kg.N/rai + 8 kg./rai K2O three months after planting. Lime application wasdone before planting. The results showed that nitrogen application rates of 0, 8 and 16 kg./rai and 16 kg./rai with lime gave average yield of cowpea equal 28.91, 39.75, 34.60 and 56.09 kg./rai, respectively. Treatment of N fertilizer + limegave significantly higher yield than the others treatments. Cassava had no effect on grain yield of cowpea. However,it showed increasing trend when nitrogen application was increased. However, application of fertilizer rates had noeffect on dry matter of cowpea. The two methods of leaf area estimation can be concluded that measurement withAAC-400 was higher than that from PCI 7.0 estimation.