RESPONSE OF HEAD CABBAGE (Brassica oleracea L.) TO DIFFERENT RATES OF NITROGEN FERTILIZER AND FARMYARD MANURE AT BORE, SOUTHERN ETHIOPIA

Abstract

Cabbage (Brassica oleracea L.) is a member of the cole crops, and it is an important fresh and processing vegetable crop in most of the countries of the world. However, yield of the crop is often constrained by low and imbalanced nutrient supply in the country at large and in Gudji Zone in particular. Therefore, this study was conducted at the Bore Agricultural Research Center (BoARC) during the period from July 1, 2014 to December 2, 2014 main cropping season to assess the effects of different rates of Nitrogen (N) and farmyard manure (FYM) on growth and yield of cabbage. The treatments consisted of five levels of N (0, 59,119, 235 and 294 kg N ha-1) and four levels of FYM (0, 3, 6 and 10 t ha-1) in factorial combinations and were laid out in randomized complete block design (RCBD) with three replications. The results showed that interaction effects of N and FYM highly significantly (P<0.001) affected plant height, number of expanded leaves, days to head initiation, days to 90% maturity, head height, head diameter, untrimmed head weight, trimmed head weight, yield with and without wrapper of head cabbage. The highest N (294 kg ha-1) and FYM (10 t ha-1) result in maximum number of leaves (16.66), shortest days to head initiation (63.33) and early days to maturity (112). Similarly the combination of N and FYM (235 kg + 6 t ha-1) produced the highest head height (18.14 cm), highest head diameter (17.03 cm), highest untrimmed head weight (2296.67 g), highest trimmed head weight (1766.67 g), maximum yield with wrapper (107.47 t ha-1) and highest head yield without wrapper (72.36 t ha-1) of head cabbage. There was an increasing trend in the yield without wrapper or marketable head yield with the increase in nitrogen rate till 235 kg N ha-1 and FYM to 6 t FYM ha-1, but the yield declined above these combinations. Generally results of the study revealed that head cabbage responded well to the combined application of N and FYM. Based on partial budget analysis the highest net benefit was obtained from treatment combinations of 235 kg N ha-1 with 6 t FYM ha-1 with a marginal rate of return 2535.31%. Therefore, this combined nutrient application rates can be recommended since it is the most feasible rates for the producers because of its low cost of production and higher benefits. This study was conducted for one cropping season which might not allow to make final recommendation; therefore, it is necessary to conduct the experiment once more to make final recommendation