Effects of Cassava/Legumes Inter-cropping before Rice Season and Weeding Methods on Growth and Yields of Rice: Split-Plot Design Approach

摘要

Lowland cereal cropping systems face shortages of nitrogen fertilizers, which are the most important nutrient limiting yields of cereals. Some studies have been carried out on the impact of preceding lowland rice cropping with cassava/legumes intercrop in the dry season on rice yields, in which the experimental treatments were arranged in a randomized complete block design fashion. However, given the variety of problems posed by uncontrolled weed growth on crop yields, none of such studies have takeninto proper consideration, the impact of weed-control method(s) used during experimentation on rice yield. A field study was undertaken to ascertain the effects of preceding lowland rice with cassava/legumes intercrop during dry season and that of weeding methods, on growth and yields of rice using a split-plot design approach. The experiment was conducted on lowland experimental field of National Cereals Research Institute, Badeggi, in the Southern Guinea savanna zone of Nigeria during the 2013 cropping season. Seven intercropping systems (used as whole-plot treatments), four weeding methods (used as subplot treatments), and ten different rice parameters were used in the experiment, which was replicated three times. The results revealed that, for each parameter, the highest recorded rice yield was from the rice grown after intercropping Cassava with Aeschynomene legume followed by that grown after intercropping Cassava with Cowpea for every adopted weed-control method. For every intercropping system, the highest recorded rice yield was from the plot subjected to the Two-hand weeding at 3 & 6 weeks after transplanting (WAT) followed by Herbicide at 3 WAT plus hand-weeding at 6 WAT for each parameter.