IMPROVING RICE GROWTH AND YIELD THROUGH INTEGRATED COMPOST AND UREA FERTILIZER APPLICATION IN LOWLAND RICE

There is a spiral increase in inorganic fertilizer prices in Ghana and as a result, most farmers cannot apply inorganic fertilizers at the recommended rate for optimum grain yield. To address this challenge, a study was conducted at the Soil and Irrigation Research Centre, University of Ghana-Kpong, during the 2014 and 2015 cropping seasons, to assess the effect of compost, urea fertilizer and their combinations on growth and yield of rice. The experiment was laid out in a randomized complete block design (RCBD) and replicated three times. The treatments included; T1: Control (no nitrogen application), T2: 100% recommended N rate (Rec N = 90 kgN/ha) from compost, T3: 50% Rec N from compost + 50% Rec N from urea, T4: 70% Rec N from compost + 30% Rec N from urea, T5: 30% Rec N from compost + 70% Rec N from urea, T6: 100% Rec N from urea. Soil incorporation of compost or urea fertilizer significantly affected chlorophyll content, above ground biomass, plant height and grain yield in both seasons. Combined application of compost and Urea N at ratios of 50:50 (T3) and 30:70 (T5) were at par with 100% urea N application in terms of above ground biomass, plant height, chlorophyll content and grain yield in both seasons while 100% N through compost alone (T2) produced the lowest rice growth and yield among the nitrogen fertilizer treatments. Therefore, to reduce heavy dependence on inorganic fertilizer and encourage use of organic waste for rice production, the combination of inorganic fertilizer and compost at the ratio of 50:50 is recommended.