Growth and yield of cassava as influenced by grain cowpea population density in Southeastern Nigeria

The use of some leguminous crops for soil fertility improvement is being promoted for root and tuber crops production in Nigeria. Cowpea has a lot of advantages and is more compatible with cassava than other legumes. Cowpea (Vigna unguiculata) was intercropped with cassava (NR 8082 at 10,000 plants per hectare) at four plant densities (20,000; 40,000; 60,000 and 80,000 plants per hectare) in 2004 and 2005 planting seasons at the National Root Crops Research Institute (NRCRI) research farm in Umudike (07° 33 ‘ E, 05° 29 ‘ N), Southeastern Nigeria. The experiment was arranged in a randomized complete block design (RCBD) with three replications. The leaf area index (LAI) of cassava was highest with the highest cowpea planting density in 2005, but not in 2004 planting year. Similarly, maximum fresh root yield (t/ha) of cassava was influenced by population density in 2005, but not in 2004 planting year. Cassava root yield was highest with the cowpea planting density of 80,000 plants/ha. Cowpea variety IT93K- 452-1 at a population density of 80, 000 plants/ha is recommended for increased soil fertility for cassava production in the Southeastern Nigeria.