Sugarcane response to liming, manuring and inorganic fertilizers on acid acrisols in Western Kenya

Abstract

Effects of agricultural lime, organic manure and selected inorganic fertilizers on sugarcane growth, yield and quality were determined in four trials conducted from 2009-2011 on acid acrisols in western Kenya. Predominantly grown sugarcane variety CO 945 was used in all experiments that were laid out in a randomized complete block design with three replications. The treatments comprised absolute control (no manure, no fertilizer), compost (18 t/ha), compost (18 t/ha+100 kg/ha diammonium phosphate (DAP) + 100 kg/ha Urea), standard practice (200 kg DAP + 200 kg Urea), agricultural lime (3 t/ha + 200 kg/ha DAP + 200 kg/ha Urea), agricultural lime (3 t/ha + 100 kg/ha DAP + 100 kg/ha Urea), Mavuno NPK (350 kg/ha + 200 kg/ha Urea) and Single Super Phosphate (SSP 450 kg/ha + 200 kg/ha Urea). Soil analysis results generally indicated low levels of pH, total nitrogen, phosphorus, potassium, calcium, magnesium, organic carbon and C.E.C in all sites. The soils were classified as acrisols with sandy clay, clay loam and sandy clay loam texture and high bulk density in all sites. Emergence, tillering, stalk number, height, inter-node length, cane and sugar yields differed significantly (p < 0.05) among the treatments in all locations. Higher cane and sugar yields were consistently recorded in treatments where agricultural lime and compost were included. There was no difference in yield between treatments that received full or half dose of the recommended Nor P along with the lime and compost amendments. Juice quality was highest in the SSP+Urea treatment ranging from 13.58 - 14.43 % Pol and lowest in the compost treatment ranging from 11.43- 13.37 % Pol. Smut incidence was notable in the compost and control treatments. Agronomic efficiency was highest in treatments where compost and agricultural lime were included, ranging from 90.3 to 481.5 kg sugarcane/kg nutrient. Highest net returns and value cost ratios were also recorded in treatments with compost and agricultural lime. Results of this study clearly demonstrated that utilization of agricultural lime and organic compost along with inorganic fertilizers improved sugarcane yield with potential benefits of reduced dosage of N and P to 50% of the local recommendation.