Effect of Irrigation Scheduling and Nitrogen Fertilizer Rates on Growth and Productivity of Cabbage (Brassica oleracea L.Var. Capitata) at Buyo Kachama Kebele Seka Woreda Jimma

Abstract

A field experiment was conducted to investigate the effect of irrigation schedules and nitrogen fertilizer application rate on growth and productivity of cabbage. The study was conducted from November 2015 to March 2016 at Buyo Kachama Kebele Seka woreda Jimma, Western Ethiopia. Three irrigation scheduling (3 days, 6 days and 9 days) and five nitrogen fertilizer levels (0, 23, 46, 69 and 92 kg/ha) were used. The experiment was laid out in Randomized Complete Block Design (RCBD) in 3x5 factorial arrangements with three replications and one farmer practice. Copenhagen market variety of cabbage was used for this experiment. Results indicated that marketable yield, unmarketable yield, total head yield, whole fresh weight, head diameter, head height, plant height and plant spread were significantly(P<0.001) affected by the interaction effect of irrigation scheduling and nitrogen fertilizer rates. The highest Dry matter(7.36%) was recorded at 92kg ha-1 nitrogen fertilizer rate and 9 days irrigation schedules, marketable yield(64.5 t/ha), lowest unmarketable yield(7t/ha), highest total head yield(71.52 t/ha), biggest whole fresh weight(5.73kg/plant), biggest head diameter(17.43cm), highest head height(19.67cm), highest plant height (24.65cm),wider plant spread(38.77cm), highest water use efficiency(152.47kgha-1 mm-1 ) and nitrogen recovery(89.9 %) was recorded at 9 days irrigation schedules and 23 kgha-1 nitrogen fertilizer rate which is statically similar with 9 days irrigation scheduling and 46 kg/ha nitrogen fertilizer rate. On the other hand harvest index significantly affected by nitrogen fertilizer rate and irrigation scheduling but not by its interaction effect. Highest harvest index (60%) recorded at 6 days irrigation scheduling and 60.7% at 92kg ha-1 nitrogen fertilizer rate. As well as outer leaf number was not affected by interaction effect of irrigation scheduling and nitrogen but it was affected by nitrogen fertilizer rate. Higher outer leaf number was obtained at control nitrogen fertilizer rate (18.66) which is statically similar with 23 kgha-1 nitrogen fertilizer rate (18.66). Yield and yield components were better recorded at treatment combinations of 3, 6 and 9 days irrigation scheduling combined with 92 kg N ha-1 compared to the traditional farmers irrigation and fertilizer management. However, further investigations may be suggested to be carried out at different seasons of the year, location, soil type, cabbage varieties and different farmer practice so as to come up with precise and comprehensive recommendation.