EFFECTS OF PLANTING METHOD AND WEEDING FREQUENCY ON PERFORMANCE OF SELECTED NEW RICE FOR AFRICA (NERICA) VARIETIES IN KERIO VALLEY AND MARIGAT, KENYA

Abstract

New Rice for Africa (NERICA) was developed to improve rice production in Africa and farmers in Kenya are beginning to adopt it. Attempts have been made to choose methods of planting and weed control but their effectiveness on performance of NERICA rice have not been well understood. This study was therefore to investigate the effects of planting method and weeding frequency on performance of selected NERICA varieties. The experiment was carried out for one season in two sites; Kerio Valley in Elgeyo-Marakwet County and Marigat in Baringo County, from September 2013 to January 2014. The two areas are classified as Arid and Semi-arid Lands (ASALs). Drilling and broadcasting methods of planting and two weeding regimes (weeding twice and weeding thrice) were evaluated for their effects on performance of NERICA 4 and NERICA 11 which are among the four varieties of NERICA released to farmers for production. The trial was a 2 x 2 x 2 factorial experiment laid out in randomized complete block design (RCBD). The treatments were replicated 3 times and each plot measured 4 m x 3 m. The parameters measured included plant height, number of productive tillers/hill, number of spikelets/panicle, weed dry matter, 1000-grain weight, grain yield, harvest index, mortality and identification of major weeds. The data obtained was subjected to Analysis of Variance (ANOVA) and the effects of treatments were separated using Tukey’s Honestly Significant Difference (HSD) test at p ≤ 0.05. The results showed that planting method, weeding frequency and variety significantly influenced the performance of NERICA in both Kerio Valley and Marigat (p ≤ 0.05). Drilling was significantly better than broadcasting, and weeding thrice was significantly superior to weeding twice while NERICA 11 significantly outperformed NERICA 4 in terms of plant height, number of productive tillers/hill, weed dry matter, 1000-grain weight, grain yield, harvest index and mortality of weeds. However, their effects on the number of spikelets/panicle were not significant. Drilling in combination with three weeding regime and NERICA 11 gave the best performance in the two areas and significantly outperformed all other combinations in Marigat with respect to grain yield. Major weeds identified in the study sites were: Echinochloa pyramidalis, Cyperus rotundus and Echinochloa colona. This study, therefore, recommends drilling method of planting, three weeding regime and NERICA 11 for Kerio Valley and Marigat.