ABSTRACT

Five field experiments each in two cropping seasons were conducted at Michael Okpara University of Agriculture, research farm, Umudike between 2000 and 2003 to evaluate the growth and yield of cassava, soybean and okra in cassava soybean and cassava/okra intercropping systems in the rainforest zone of southeastern Nigeria. The experiments were: Evaluation of the productivity of cassava soybean intercropping system with particular reference to soybean plant density under additive series in 2000/2001 and 2001/2002. The experiment was laid out in a simple randomized complete block design (RCBD) with three replications. The treatments were cassava (10,000 plants/ha) intercropped with soybean (66,500; 133,000; 199,500 and 266,000 plants/ha), respectively. Sole crop cassava and soybean were established. Intercropping significantly (P<0.05) reduced growth and yield of soybean compared to the sole crop. Soybean plant density had no effect on fresh tuber yield of cassava. However, grain yield in soybean was significantly (P<0.05) increased with increase in plant density. Fresh tuber yield of cassava and weight of marketable tubers per plant were positively correlated while grain yield in soybean and seed weight per plant had the same association. Optimum yield was achieved at soybean mixture of 199,500 plants/ha, which gave the highest yield advantage. Evaluation of cassava genotypes for compatibility in intercropping involving ssava/soybean in 2000/2001 and 2001/2002. The treatments comprised cassava genotypes (NR 8212, TMS 91934 and TMS 30572) each intercropped with soybean in a simple RCBD with three replications. Sole crop plots of the cassava genotypes and soybean were established. The results showed that intercropping increased cassava yield but significantly (P<0.05) reduced growth and yield of soybean. The highest soybean yields of N533.67 kg/ha (2000/200 1) 462.00 kg/ha (200 1/2002) were realized under TMS 91934. Tuber yield of cassava was significantly (P<0.05) correlated with canopy diameter showing that the crop intercepted more incident light in favour of tuber yield. TMS 30572 and soybean mixture gave the highest productivity values in both seasons. Evaluation of the' productivity of cassava/okra intercropping system as influenced by okra plant population in 2000/2001 and 2001/2002. The treatments comprised of okra planting densities (14,000; 28,000; 42,000 and 56,000 plants/ha) intercropped with cassava (10,000 plants/ha). Sole crops of cassava and okra were planted. Okra plant density had no effect on fresh tuber yield of cassava but significantly increased fresh pod yield in okra as okra plant density increased from 14,000 to 56,000 plants/ha, which gave the highest yield advantage. Effect of relative time of introducing soybean and cassava planting method on the performance and productivity of the component crops in cassava soybean intercropping system in 200 1/2002 and 2002/2003 cropping seasons. The treatments comprised five relative time of introducing soybean (2, 4 weeks before, same day with, 2 and 4 weeks after cassava) and two cassava planting methods (slanting and horizontal) in a 5 x 2 factorial in RCBD with three replications. Intercropping significantly (P<0.05) reduced growth and yield of cassava and soybean compared to sole cropping. Soybean planted four weeks before cassava significantly (P<0.05) gave higher grain yield than those planted two weeks before, same day and two or four weeks after cassava. Planting cassava slanting gave better yield than horizontal method. Fresh tuber yield of cassava was highly correlated with number of marketable tubers per plant while soybean grain yield showed strong association with canopy diameter and number of nodules per plant. The highest productivity values were realized when soybean was introduce 4weeks before cassava that was planted slanting. Influence of spatial arrangement and cassava genotype on the growth, development and productivity of the component crops in cassavalsoybean intercropping in 2001/2002 and 2002/2003. The treatments comprised three cassava genotypes (TMS 30572, TMS 91934 and NR 8212) factorially arranged in an RCBD with three replications. Sole cassava genotypes and soybean were established. Compared with intercropping, sole cropped cassava and soybean gave higher yield values in both seasons. The best pattern of cassava/soybean mixture was triple rows soybean alternated with one row cassava while the highest gross returns of N168,3601ha (2001/2002) and N21 1,532.80 (2002/2003) were achieved under TMS 30572 mixture.