Assessing Ground Cover Rice Production System on Water Saving and Nitrogen Use Efficiency in Uganda

Rice is an important food staple and source of cash income to the majority of the populace in many parts of the world including Sub-Saharan Africa where it provides up to 21% calorie intake and accounts for 29% of the total global output of the grain crops. However, water scarcity and the continued effects of fertilisers use in rice fields makes rice both a contributor and vulnerable to climate change. A number of innovations including Ground cover rice production system (GCRPS) has demonstrated water saving and increased nitrogen use efficiencies in nitrogen fertilised rice fields, respectively although, there is a paucity of information on GCRPS in Uganda. This study was therefore conducted to assess the feasibility/viability of GCRPS for water saving and nitrogen use efficiency in Uganda. The experimental design was a randomised complete block design (RCBD) with three replications. Treatments assessed included rice planted on polyethylene mulched ground, rice planted on straw mulched ground, rice planted on bare ground and traditional flooded rice system as a control. Grain yield, straw yield, plant tissue N concentration and water use efficiency were used to assess the performance of the treatments, respectively.The mulched treatments significantly (p<0.05) increased grain dry matter and water use efficiency, respectively. Similarly, the straw dry-matter, % N concentration, and N uptake were increased by the mulched treatment. In fact, the poly system consistently improved nitrogen use efficiencies, which were generally comparable to the high yielding lowland rice cultivation systems reported in literature implying the GCRPS can effectively replace lowland rice ecosystems in terms of nitrogen use efficiency. Overall, the mulched GCRPS systems resulted in water saving ranging from 76% to 84% of applied water on flooded rice. Therefore, the mulched GCRPS systems can be an effective counter against N nutrient deficient soils and the declining water resource that cannot support efficient rice production in Uganda. Keywords: Ground cover rice production systems, nitrogen use efficiency, water saving