ON-FARM IRRIGATION MANAGEMENT FOR SHALLOW WATER TABLE SOILS AT NORTH NILE DELTA EGYPT BASED ON TILLAGE PRACTICES AND ECONOMICS

摘要

Proper management of water irrigation by la-bouration reduces irrigation water saving,increases crop yields,reduces irrigation costs and maximizes water productivity.The integrative effects of irrigation control on farm,through controlled irrigation run length and stream size,under different tillage depths on the crop yield and its water relation are not well documented in the shallow water table soils.Over a two-year field analysis,therefore,the impact of irrigation run length and stream size on wheat yield and water productivity under different tillage depths and the contribution from the water table to the requirement of wheat water was assessed.A split-split plot design with three replicates was used.Two tillage depths occupied the main plots,at 10-20 cm (Tl) and 20-30cm (T2) depth.The stream size treatments; 2 (SI),3 (S2) and 4(S3) LS"1m"1 were arranged in the sub plots,where the sub-sub plots were devoted to irrigation run length treatments ; 100 of run length without cut-off (Cl),cut-off at 90 (C2) and at 80 (C3) of strip length.Results showed that,the combination of (T2),(S3) and (C2) had the highest during the two growing seasons and the average values of water productivity were (2.29kg.m3 ),water application efficiency was 73.42,water saving was 42.84,wheat grain and straw yield were 10.297 and 10.708ton.ha"1,and the highest contribution of ground water (CGW) was 21.4 compared with control treatment (T1S1C1) that had no CGW.Also,results revealed that the T2S3C2 treatment achieved the highest net return (NR) that was 1173.99$US ha_1and benefit cost ration (BCR) was 0.9 compared with the control treatment T1S1C1 thatwas 522.77$US.ha_1 and 0.36,respectively.Therefore,cut off irrigation at 90 of strip length with stream size 4LS'1m"1 under tillage depth 20-30cm resulted in a promising strategy to maximize wheat yield and to improve the water productivity under the conditions of shallow water table areas.