WATER USE,GROWTH AND YIELD OF AMARANTHUSCAUDATUS(Qufuo~ UNDER IRRIGATED CONDITION

Abstract

Soil water is a major hinting factor to crop production particularly under dry season condition. Field experiments were conducted in the early and late season periods of year 2000 at the experimental farm of the Department of Agricultural Engineering, Federal University of Technology, Akure (F.U.T.A.). The aim was to evaluate the growth and yield of amaranthus under irrigated condition and to determine water use pattern of the crop with a view to developing a good water management strategy. The treatments were: irrigation at full pan evaporation (T4), Irrigation at 3;4 pan evaporation (T3) and irrigation at ~ pan evaporation (T2). Soil moisture content was measured weekly at lOcm, 20cm and 30cm soil depth using gravimetric methods. Biomass yield was determined weekly throughout the growing season until maturity. Other agronomic measurements include plant height, root depth and leaf area index (LAI). Meteorological data were taken at the experimental site. It was observed that treatment T4 had the best result in terms of plant height, LAI, and total biomass yield of 1.95 tonlha during second planting season. crop water use (determined by water balance method) differed among treatments and the amount corresponded to the magnitude of total water applied. The highest amount of crop water use (ET) was 4.1 mm/day and 7.9 mmlday during the two seasons and was observed at 14 DAE at the 4th WAE, the treatment T4 gave the highest value of water use efficiency (WUE) of 0.5 kg/ha-mm of water. This was observed during the second planting season. However, on considering the overall result, it is proposed that amaranths will yield maximum result when water is applied at the rate of % pan evaporating during emergence, at full evaporation during the maximum vegetative cover and at ~ pan evaporation during the maturity stage. Irrigation at full evaporation improved crop performance by increasing agronomic attributes such as plant height, leaf area and biomass yield. Crop water use (ET) differed among treatments and it reflected an influence of irrigation water application and hence soil moisture availability for crop growth and yield. The highest water use (4.1 mmldayand 7.9 rnmIday) was observed at 14 DAE during the first and second planting seasons. The highest WUE (0.5 kg/hamm of water) was obtained form irrigation at full pan evaporation at the 4th WAE during the second planting season. It could be concluded that to obtain maximum yield, amaranths should be supplied with water at 314 of pan evaporation during the emergence, at full pan evaporation during the maximum vegetative cover and at 12 pan evaporation during the maturity stage of the crop.The results obtained in this study would be useful in water stress studies, which can be used for irrigation scheduling and yield prediction.