Effect of ratooning and Nitrogen application on lint yield and quality of cotton varieties in Central Kenya
About 14 percent of cotton farmers in Central, Eastern and Coastal regions of Kenya grow ratoon cotton. They cut the stalk of the main cotton crop at various heights above the ground surface after the first harvest leaving the stumps to regenerate into new shoots at the onset of the next rainy season to give the ratoon cotton crop. Performance of the ratoon cotton depends on the management of the previous season's cotton crop including the height of cutting and availability of soil moisture and plant nutrients. Information on the effects of cut heights and nitrogen application on growth, pest incidences, seed cotton yield and quality of ratooned cotton varieties in Kenya is limited hence need for this study. The study was conducted during the 2007/08 and 2008/09 growing seasons at Kirogo farm situated at Kenya Agricultural Research Institute (KARl) Mwea in Kirinyaga County. The objective was to evaluate the effect of cut height and nitrogen application on growth, pest incidences, yield and quality in ratoon crop of three cotton varieties (HART 89M, A540 and F962). The experimental design was a randomized complete block design using a split-split plot arrangement with four replications. The varieties were assigned to the main plots, cut heights (control,S ern, 10 ern and 15 cm above ground surface) to the sub plots and nitrogen (N) fertilizer application levels (0 and 110 kg N ha") to the sub-subplots. Data on plant height, plant count; number of sprout stems, pest counts,seed cotton yield, lint percentage, and percent of grade 'AR' seed cotton was recorded and subjected to analysis of variance using Genstat statistical software, and means compared using Fisher's least significant difference (LSD) test at a probability level of 0.05.