Assessment of water use efficiency using surface and subsurface drip irrigation system on yield of tomato in southern province of Rwanda

Surface and subsurface drip irrigation methods can play a significant role in overcoming the scarcity of water mostly in water shortage areas. The average annual rainfall of 1200mm per year is suitable for the growth of crops grown in in the country. However, it is erratic and unevenly distributed throughout the year within the agriculture seasons. In addition, it may be too little or not available at the time needed resulting into drought. These problems have adverse effect on crops grown in rainfed agriculture. Therefore, study was conducted to assess water use efficiency using Surface and Subsurface drip irrigation system on yield of tomatoes at IPRC Huye farm located in Ngoma Sector, Huye district in southern province of Rwanda as the main objective. An area of 308.76m2 (16.6 m × 18.6m) was allocated for the experiment. The soil in experimental field was found as sandy clay loam with the Bulk density between (1.0 -1.32) g/cm3. The infiltration rate of the soil was found to be 20mm/hour. Using CROPWAT 8.0 software, the peak water requirement of the tomato crop was estimated and found to be 4.24mm/day. The experiment contained five irrigation treatments viz., 90%, 80%, 70%, 60%, and 50% Crop water use (ETc) and the control (100% ETc) was laid out in RCBD design with three replications. Seedlings of tomato (Solanum lycopersicum) were raised in nursery bed (30days). Vigorous, strong and healthy ones were selected for transplanting at a spacing of 0.80 m x 0.80 m. Irrigation schedule was prepared in accordance with crop water requirement and was applied at allowable soil moisture depletion (p = 0.40) of the total available soil moisture throughout the crop growth stages. The discharge of one emitter was 0.5 l/h. Statistical analysis has been performed using Microsoft excel and GenStat software. The result showed that there is a significant difference in plant height among treatments at 20DAT while at 50 and 85 DAT a highly significant difference was found among them at 5% level of probability. The highest fruit head volume was observed from treatment received 80% ETc of subsurface drip irrigation system followed by 90% ETc of the same system while the highest yield (25.90t/ha) was found to be in control (100%ETc). Base on this study, I suggest that in an area with no water shortage, full irrigation water supply of subsurface drip irrigation system could be used for the production of tomato.