| dc.description.abstract | Rice (Oryza sativa L) constitutes one of the most important staple foods of over half of the world's population. Globally, it's ranked third after wheat and maize in terms of production. In Kenya, rice is the 3rd most important cereal crop after maize and wheat. Upland rainfed rice-cultivation is being promoted in Kenya against a background of increased rice demand in the country. About 90% of the rice grown in Kenya is from irrigation schemes established by Government while the remaining 10% is produced under rainfed conditions. The rainfed rice varieties promoted are the New Rice for Africa (NERICAs) produced through interspecific hybridization of Oryza sativa Land Oryzaglabberima S which are cultivated under rainfed conditions where crop production is limited by soil moisture availability in Kenya. Research on NERICA has been on agronomy, pests, diseases and
weeds but little is known about field management practices for NERICA rice production. The objectives of the study were to evaluate the seasonal evaporation of rainfall, quantify the plant available water capacity and evaluate the rainfall use efficiency of NERICA 4 rice variety grown on four management conditions. A field experiment was conducted during April2012-August 2012 and October 2012 to February 2013 to evaluate the efficiency offield management practices-on the yield and yield components ofNERICA 4 in upland ecologies of western Kenya. Three replicates of each of four different methods of field management to create different water retention characteristics in the soil were established in a Randomized Complete Block Design (RCBD).The four field management practices included; (a) 10% sloping field, no bunds, no straw mulch (SF); (b) Flat field, no bunds, no straw mulch (FU); (c) Flat field with bunds, no straw mulch (FB); (d) Flat field, no bunds, with straw mulch (FUM). Seasonal evaporation was measured by use of microlysimeters, soil moisture was monitored using the soil moisture probe while the seasonal rainfall use efficiency was calculated from above ground biomass and grain yield. Data were analyzed using the SAS computer package and differences between means were separated by the Duncan's critical range test and Fisher's least SIgnificance difference (LSD) test at 5%
significance level. The FUM treatment reduced seasonal soil surface evaporation by 52.94% -54.55% during-the vegetative and reproductive phases of growth comparec.Mo other treatments and significantly increased soil moisture retention at 10 em depth with a significant increase in the PAWC by 12%-16% which resulted to a significantly higher RUEb by 14.29% and subsequently increased RlJEg by 20.89% .The FB treatment significantly increased AWC by 20-25% with asignificant increase in RUEg by 10.99%. Adoption of the FUM practice will enhance NERICA rice grain production, conserve the environment for sustainable agricultural productivity and reduce on rice imports by the country. | en_US |
