EFFECT OF LIME AND VERMICOMPOST AMENDMENTS ON SELECTED SOIL PROPERTIES AND WHEAT (Triticum aestivum L.) PRODUCTIVITY ON NITISOLS OF NEGASA AREA, EAST WOLLEGA ZONE, ETHIOPIA

Abstract

Soil acidity is one of the major soil chemical constraints which limit crop productivity in the high rainfall regions of Ethiopia in general and in the study area in particular. In view of this, a field experiment was conducted at Negasa area in Guto Gida district on farmer’s field to study the effect of lime and vermicompost amendment on selected soil properties and yield and yield components of wheat (Triticum aestivum L.), grown during 2016 main cropping season. The factors studied were four levels of agricultural lime (0, 50, 100 and 150% of recommended rate based on exchangeable acidity method) applied one month before planting and three levels of vermicompost (0, 2.5 and 5 t ha-1) applied two weeks before planting. The treatments were laid out as a randomized complete blocked design (RCBD) in a factorial arrangement, with three replications. Net 95 and 23 kg ha-1 of N and P respectively were applied to all plots. Representative soil samples were taken before and after planting and analyzed following standard procedures. Phenology, growth, yield and yield components of the crop were recorded properly and statistically analyzed. The soil pH, PBS and exchangeable basic cations (Ca and K) were significantly increased by 7.62, 6.54, 31.16 and 26.08% respectively while percent acid saturation, exchangeable acidity and exchangeable Mg were significantly decreased by 45.03, 47.73 and 26.53% respectively due to lime application at a level of 150% RR compared to control. While only exchangeable Mg, K and Na and soil bulk density were significantly increased due to vermicompost application. The interaction effect of lime and vermicompost significantly influenced bulk density and total nitrogen of the soil. Simple correlation analysis among soil properties indicated that soil exchangeable acidity is significantly and negatively correlated with soil pH, exchangeable Ca and Na whereas it was significantly and positively correlated with acid saturation. The results from the experimental crop revealed that the main effect of applied lime rates significantly influenced all studied phenological, growth, yield and yield related traits of wheat. The main effect of vermicompost significantly influenced days to 50% flowering, physiological maturity, plant height, spike length, thousand kernel weight, dry biomass and grain yield. Only harvest index was significantly influenced by the interaction effect of the two factors. The highest grain yield (2.51 t ha-1), dry biomass (5.83 t ha-1) and other growth and yield components of the crop were recorded at the highest rate (150% RR) of lime application. It can be concluded that application of lime at the rate of 150% RR improve most chemical properties of such acidic soil and led to the maximum yield and yield components of wheat. Similar effort should be done over years to determine the long-term effect of lime and vermicompost on the soil and the crop