Modeling water balance components in relation to field layout in lowland paddy fields. II: Model application

Abstract

In a companion paper, the development of a water balance model to predict the changes in water balance components in relation to field layout in lowland paddy fields was outlined. In this study, the model was applied to a large irrigated area to assess and compare the water balance of intensive and extensive field layouts. The results show significant differences in water balance which are attributed to the layouts and water management practices. The field layouts influenced the equity of water allocation, effective rainfall, water use efficiencies and relative proportion of various water balance components. Eight indices are computed to evaluate the effects of layout under different land and hydrological conditions. Appropriate measurement scales for ranking the indices are proposed.