Effect of plant spacing and intercropping with two vigna species on growth and yield of forage maize
An experiment was conducted at the Teaching and Research Farm of Abia State University, Umuahia Campus, Nigeria, from the month of May to October, 2012 to determine the effect of plant spacing on the growth and yield of forage plant, maize (Zea mays), intercropped with cowpea (Vigna unguiculata sub spp. Dekintiana) and Bambara nut (Vigna subterenea). The treatments included two plant spacings (50x50 cm and 100x100 cm) either in sole or intercropped system viz: maize-cowpea 50x50 (MC50), maize-cowpea 100x100 cm (MC100), maize-Bambara nut 50x50 (MB50), maize-Bambara nut 100x100 (MB100), sole maize 50x50 (SM50) and sole maize 100x100 (SM100). The cowpea and Bambara were planted at two seeds per hole while the maize was planted three seeds per hole. NPK 15:15:15 fertilizer was applied 4 weeks after planting (WAP) at 200 kg/ha. The results obtained showed that maize growth and yield were significantly (P<0.05) affected by plant spacing and intercropping. Data at week 5 showed that MC100 and MB100 both had the highest values of 382.06 cm and 368.58 cm , respectively for leaf area, while SM100 recorded the lowest value of 190.66 cm . The same treatments recorded the highest (P<0.05) values for stem girth at weeks 5 and 7. Lowest leaf/stem ratio was 0.28 for SM100 while the highest value of 0.68 was recorded for MC50. The intercrops at closer spacing (SM50 and MC50) had similar values (P>0.05) for herbage yield and their values were significantly higher (P<0.05) than those recorded for the other treatments. Based on the findings, MC100 and MB100 had higher growth indices than the other treatments whereas the intercrops at closer spacing had higher herbage yield.