Effects of Irrigation Water Salinity and Water Depth on Growth and Yield Parameters of Nerica Rice (Oryza sativa L. X Oryza glaberrima L.)

Abstract

NERICA rice was developed through the hybridization of Oryza Glaberrima and Oryza sativa in an attempt to produce a higher yield in areas with a limited water supply. This study investigated the interactive effects of irrigation water salinities (0.38, 1.5, 3.0, 5.0, 7.0, 10.0 and 15 dSm(-1)) for various water depths (5, 10 and 15 cm) on crop yield and related components of NERICA rice variety. This study showed that increased levels of irrigation water salinity resulted in reduced rice yield, biomass weight, plant height, harvest index, 1000 grain weight, evapotranspiration, water use efficiency, stomatal conductance, and chlorophyll content, and increased plant sterility for all irrigation water depths. The threshold values of soil salinity for the NERICA rice for the 5, 10, and 15 cm depths were 2.14, 81 2.80, and 1.98 dSm(-1), respectively. The study showed that the optimum salinity/water depth condition for the production of transplanted NERICA rice is irrigation water salinity < 1.50 dSm(-1), and a 10 cm water depth. This irrigation water salinity level maintains the soil ECe at or below the salinity threshold value of 2.80 dSm(-1). This study showed that NERICA rice has a salinity threshold value of 2.80 dSm(-1). Since rice is generally considered to be more salt-sensitive during germination, it is recommended that farmers apply the least saline water available during the rice germination stage of growth. Information from this study will assist policymakers and farmers to better manage NERICA production in Sub-Saharan Africa.