A new method for indirectly estimating infiltration of paddy fields in situ

摘要

Infiltration is one of the major procedures in water balanceresearch and pollution load estimation in paddy fields. In this study, a newmethod for indirectly estimating infiltration of paddy fields in situ wasproposed and implemented in Taihu Lake basin. Since when there were norainfall, irrigation and artificial drainage, the water depth variationprocess of a paddy field is only influenced by evapotranspiration andinfiltration (E + F). Firstly, (E + F) was estimated by deciding the steady decreasing rate of water depth; then the evapotranspiration (ET) of the paddy field was calculated by using the crop coefficient method with the recommended FAO-56 Penman-Monteith equation; finally, the infiltration of the paddy field was obtained by subtracting ET from (E + F). Results show that the mean infiltration of the studied paddy field during rice jointing-booting period was 7.41 mm day−1, and the mean vertical infiltration and lateral seepage of the paddy field were 5.46 and 1.95 mm day−1 respectively.