Water requirements of some selected crops in Kampe dam irrigation project

A study was carried out to determine the crop water requirement of some selected crops for the area around Kampe (Omi) Dam Irrigation Project. These crops include rice, maize, tomato, vegetable amaranth, pepper, onion and cabbage. Crop water requirement for each of the crops was determined by using 25-year climatic data in CROPWAT. Reference crop evapotranspiration (ETo) was determined using the FAO Penman Monteith method. For all the crops considered, three decades: decades I, II, and III and seven crop growth stages: nursery, nursery/land preparation, land preparation, initial stage, development stage, mid-season and late season stage were considered. Crops were planted during the 2007 Rainy Season and the crop coefficient for each was determined. The study shows that for the area under study, reference evapotranspiration (ETo) varied from 3.4 to 4.8 mm/day. Crop evapotranspiration (ETc) and crop water requirement for paddy rice varied from 0.28 to 4.18 mm/day and 2.0 to 102.4 mm/day, for maize from 1.82 to 4.88 and 1.3 to 45.6 mm/day, for tomato from 8.7 to 52.8 and 0.0 to 45.2 mm/day, for vegetable from 3.07 to 4.74 and from 7.4 to 45.6 mm/day, for pepper 3.13 to 4.8 and from 15.1 to 40.7 mm/day, for onion from 1.80 to 38.4 mm/day, and for cabbage from 28.2 to 40.9 mm/day respectively. The peak water requirement was 0.63 l/s/ha or 5.4 mm/day with an application efficiency of 65%. Irrigation water requirement was estimated as about 61.2 MCM while the actual water diverted was 131 MCM. The reservoir capacity was 220 MCM. Thus the dam can conveniently supply the water required for irrigation in the area.