Test Study On The Vertical One-dimensional Infiltration Of Soil Under Irrigating Fertilizer

This paper mainly uses the method of laboratory experiments, numerical simulation and theoretical analysis combining to study the vertical one-dimensional infiltration characteristics of soil under irrigating fertilizer. The main content and results of the study as follows:(1)The impact of fertilizer concentration on the vertical one-dimensional infiltration characteristics under irrigating fertilizer. Cumulative infiltration and wetting front under different concentration urea increases with the extension of the infiltration time going on. At the same infiltration time, the soil solution concentration is greater, the cumulative infiltration and wetting front migration distance is shorter. And with the extension of the infiltration time, the impact of cumulative infiltration and wetting front under the same concentration is more obviously, the differences are more obvious between cumulative infiltration and wetting front under different concentrations. Soil moisture content tended to increase with the soil depth increasing. On the same soil depth, the concentration of the different regions has different effects on soil water content. Compared to water infiltration, the vertical one-dimensional infiltration of soil moisture is hindered under different urea concentration of the solution.(2) The impact of infiltration head on the vertical one-dimensional infiltration characteristics under irrigating fertilizer. The changes of cumulative infiltration, wetting front and soil moisture are similar under different Infiltration head with the time going on. With the extension of the infiltration time, cumulative infiltration, wetting front and soil water at different depths increases. At the same time, the higher the infiltration head, the greater the cumulative infiltration and wetting front is. In the end of the infiltration, water content decreased gradually with the soil depth increasing. At the same depth, the higher the infiltration head, the greater the water content is.(3) The impact of soil bulk density on the vertical one-dimensional infiltration characteristics under irrigating fertilizer. The changes of cumulative infiltration, wetting front and soil moisture are similar under different Soil bulk density with the time going on. With the extension of the infiltration time, cumulative infiltration, wetting front and soil water at different depths increases. At the same time, the higher the Soil bulk density, the less the cumulative infiltration and wetting front is. In the end of the infiltration, water content decreased gradually with the soil depth increasing. At the same depth, the higher the Soil bulk density, the less the water content is.(4) The impact of Initial soil water content on the vertical one-dimensional infiltration characteristics under irrigating fertilizer. The changes of cumulative infiltration, wetting front and soil moisture are similar under different Initial soil water content. With the extension of the infiltration time, cumulative infiltration, wetting front and soil water at different depths increases. At the same time, the higher the Initial soil water content, the less the cumulative infiltration and wetting front is. In the end of the infiltration, water content decreased gradually with the soil depth increasing. At the same depth, the higher the Initial soil water content, the less the water content is.Finally, the experimental process simulated by the Hydrus-1d model, the result is consistent with the experimental, also illustrates the Hydrus-ld software has better applicability in soil water movement, it can provides technical support to determine irrigation parameters easily.