Water supply and water movement in a small rainfed watershed as related to intensive multiple cropping potential in Iloilo [Philippines]
1983
Cablayan, D.M.
In 1978, the total inflow to the upland landscape unit was 1.56 m and was solely from rainfall. The side slope had 21% higher inflow than the upland and the lowland had 32% higher inflow. The increase in inflow to the lower section of the toposequence was due to contribution of surface runoff. In 1979, the total inflows were 2.24 m, 3.02 m and 3.34 m for the upland, sideslope and lowland respectively. S and P was highest in the sideslope of 4.8 mm/day and lowest in the lowland having negative average value of -1.0 mm/day in 1979. The soils of the lower sections of the toposequence remained under saturation longer due to this negative seepage and percolation manifested as artesian flow conditions. The upland landscape unit had higher cropping intensity averaging 245% for the two years of the study as compared to the sideslope having an average cropping intensity of 170% and the lowland having 132%. Rice yields in the lowland and sideslope were much higher, almost twice those of the upland thus the higher cropping intensity of the upland was offset by this yield difference
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