Integrated nutrient and moisture management for improved upland rice production in Uganda

Abstract

Whereas integrating nutrient and moisture recommendations is viewed as a lasting intervention to increased upland rice production, studies about this subject are evidently scarce both in Uganda and elsewhere. As such, a study was conducted to contribute to increased upland rice production through integrated N, P and moisture management. A screen house study with three phosphorus rates (0, 15 and 30 kg N ha-1), three nitrogen rates (0, 60 and 120 kg N ha-1) and three moisture rates (20, 40 and 60 mm 5 days-1) was conducted at the JICA centre of excellence for rice research, Namulonge. The experiments were planted in a Ferrallitic soil from Bulindi, Hoima district which was found to be acidic (pH=5.2), highly deficient in P (Bray 1 P=0.52) and low in percentage N (% N=0.15). Treatments were arranged in a CRD-Split with three replicates and the experiments were planted twice. Two promising upland rice varieties NERICA 10 and NARIC 2 were used. Data on plant height and number of tillers were collected at 55 DAE. At maturity, data on total biomass, grain yield, NAE, PAE, WUE, number of panicles, number of grains per panicle, weight of 100 grains and percentage grain filling were collected. Treatment effects were analysed using Split plot ANOVA technique at 95% and means separated by LSD. At 20 mm, nutrient application either suppressed or had no effect on grain yield, NAE, PAE and WUE. At higher moisture levels, combined application of N and P increased grain yield, NAE and PAE by between 5-15-fold. Sole nutrient applications especially N had no effect on yield, nutrient and moisture use. The two varieties were found not to be suitable for areas that receive not more than 20 mm 5 days-1 of moisture. Integrated nutrient and moisture management generally increases yield, nutrient and moisture use. Whereas there is a need to verify results from this study under field conditions, NERICA 10 when planted with 15 kg P ha-1 and top-dressed with 60 kg N ha-1 is likely to yield optimally in areas that receive at least 60 mm 5 days-1. Upland rice variety NARIC 2 is recommended for low resource farmers who may not afford the cost of P fertilizers.