Experiment Research On Moisture And N Transport Under Surge Flow Irrigation

The paper, based on review national and international research result on the surge flow irrigation , combined with the National Nature Science Fund Project "the study on the characteristic of the field N transport and the effective usage with the surge flow irrigation under the fertilization" and the practice of irrigation fertilization in Guanzhong, Shannxi province, research the characteristic of surge flow irrigation intermit -tent infiltration and influence factors .It leads the way of the research on surge flow irrigation intermittent infiltration N transport.By indoor experiment this paper analysis the characteristic of the intermittent infiltration from infiltration amount, infiltration rate, wetting front and moisture content in soil. The experiment shows the intermittent infiltration can reduce the capacity of infiltration, make moisture distribution even and wetting front transport slowly.This paper studies the effect of the texture, unit weight and intermittent time on intermittent infiltration. The result indicates that, to some extent, the reducing infiltration rate of intermittent infiltration will increase with the soil clay content increasing and reduce with the soil unit weight increasing, and the ratio of reducing infiltration increases with the intermittent time increasing. The boundary slit has notable effect on intermittent infiltrationand the preferential stream caused the boundary slit which make the effect of reducing infiltration worse.According to the fertile water infiltration experiment, the paper studies NO3- transport and distribution characteristic. The results show the wetting front transport speed of fertilizer water infiltration is lower than that of continuous infiltration, the NO3- concentration front is higher, and the NO3-content is better distributed. During the redistribution, the NO3- content reduces more greatly and concentration front runs faster.This paper analyzes the effect of different intermittent time on the NO3-transport and distribution of intermittent infiltration. The result indicates that with the intermittent time increasing, the distribution of moisture and NO3-become more even and the redistribution process reduces more slowly.The continuous and intermittent infiltration experiments with the same infiltration amount show that under the condition of intermittent infiltration, the infiltration rate is lower, the wetting front transport more slowly, the moisture and NO3- content distribute more evenly, and the moisture and NO3-content reduces slowly in the course of redistributionThe paper studies the moisture and NO3- distribution law under the condition of surface fertilization through interior experiment. Under the condition of surface fertilization, soil NO3- content increases as the soil depth increases during continuous infiltration, and the soil NO3- mainly distributes near the wetting front during intermittent infiltration and the content is low in the above soil layer.The paper contrasts surface fertilization with fertile water infiltration, the difference is not obvious in wetting front and moisture content. The NO3-content mainly distributed near the wetting front under the surface fertilization.