Effects of akidi (Vigna unguiculata sub spp. Sesquipedalis) planting density on growth, yields and land use efficiency of akidi/cassava intercrop

Abstract

Field experiment was conducted at the Teaching and Research Farm, College of Education, Afaha Nsit, Akwa Ibom State, Nigeria to determine the effects of akidi (vegetable cowpea) planting density on growth, yields and productivity of akidi/cassava intercropping system in 2008 and 2009 planting seasons. The experiment was laid out in randomized complete block design with three replicates. Treatments were seven akidi populations of 20,000, 30,000, 40,000, 50,000, 60,000, 70,000 plants/ha and a sole cassava. Akidi was also planted sole and in intercropped with cassava. Results indicated that the average plant height of 180.66 and 180.74 cm obtained from the akidi plots at 60,000 and 70,000 plants/ha was significantly (P<0.05) higher than the average of 170.12 cm obtained from sole cassava. Similar trend was also observed in cassava leaf area index. A significantly (P<0.05) lowest number of pods/plant (7.37) was obtained from the intercropped plots of akidi (70,000 plants/ha). Dry seed yield of 313.00 kg/ha obtained from the sole plots of akidi (60,000 plants/ha) was significantly higher than 284.97 kg/ha obtained from intercropping akidi at the same planting density. Akidi plots at 60,000 and 70,000 plants/ha produced significantly higher cassava tuberous root yields than the yields obtained from sole cassava and from the plots of other akidi densities in the intercrop. Although akidi at 70,000 plants/ha produced the highest cassava tuberous root yield advantage by 30.1% over sole cassava; the highest land equivalent ratio (2.34) was however obtained from akidi plots at 60,000 plants/ha. From this study, it appears that integration of optimum akidi density (60,000 plants/ha) in cassava intercrop can enhance cassava growth, tuberous root yield and increased land use efficiency.