Determination of Water Requirement of Paddy Rice under the System of Rice Intensification (SRI) Methodology at Kadawa Kano River Irrigation Project

Abstract

The water requirement of paddy rice under regulated deficit irrigation management through SRI methodology was
determined and compared to conventional method in this study. Moisture content at saturation, effective rainfall, crop
evapotranspiration and seepage percolation loses were calculated with the aid of aqua-Crop model by keeping track of the
differences between incoming and outgoing water fluxes over the concerned time period using daily meteorological data
collected from nearby Research Area for determination of irrigation water requirement during pre-saturation and normal
growth periods of Rice. The seasonal irrigation water requirement for each treatment was determined by summing up the
irrigation water used at different growth stages of the rice throughout the season. At the end of the study, the results showed
that, a total of 1696 mm to 2635 mm of water is needed to irrigate one hectare of paddy area in SRI, while 3733.4 mm is
needed under conventional farming system. The average mean irrigation water requirement of SRI treatments recorded a
convincing water savings of approximately 30 – 60 % over the conventional farming system as a result of SRI treatments.
The maximum flow rate was recorded at the initial growth stage and at the beginning of mid-season stages because a
shallow water during initial growth stage was kept in order maintain humidity during the first two weeks of transplanted
young seedlings. Large volume of water was soaked through the stem of the rice for subsequent use during flowering and
grain production at the beginning of the late-season stage. While the least flow rate was recorded at grain filling stage
because rice has already taken more water during the mid-season stage, 50% of grains were produced and shading of leaves
has occurred.