|
|
|
| Distribution of water and nitrogen in soil infiltration by fertilizer film hole irrigation under formation of dense soil layer |
| ZHAO Penghui1, FEI Liangjun1*, LIU Dayou2 |
| 1. State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China, Xi′an University of Technology, Xi′an, Shannxi 710048, China; 2. PowerChina Huadong Engineering Corporation Limited, Hangzhou, Zhejiang 311122, China |
|
|
|
|
Abstract To study the distribution characteristics of water and nitrogen in soil infiltrated by fertilizer liquid film hole irrigation under the conditions of dense layer formation on the surface, a two-stage indoor film hole irrigation infiltration test was carried out. In the first stage of the test, when muddy water infiltration formed a dense layer, four fertilizer liquid(calcium ammonium nitrate)mass concentration levels(0, 200, 500, and 800 mg/L)were set up for the second stage infiltration. The cumulative infiltration per unit film hole area, soil moisture content, nitrate nitrogen, ammonium nitrogen mass ratio distribution, and distribution characteristics were studied. Fertilizer solution can promote soil water infiltration. The improved Kostiakov model and the improved Philip model can well represent the relationship between cumulative infiltration per unit film hole area and infiltration time(R2>0.95), and obtain the empirical model of cumulative infiltration per unit film hole area and infiltration time with fertilizer solution concentration parameters. The high water content area volume(θ>25%)of the wetting body increases with the increase of the concentration of the fertilizer solution, and the water content is the highest near the center of the film hole. However, the fertilizer solution has little effect on the water content distribution along the radial direction of the surface soil of the film hole. The higher the concentration of the fertilizer solution, the greater the content of nitrate nitrogen and ammonium nitrogen in the soil-wetting body. The distribution of nitrate nitrogen in the wetting body is similar to the distribution of water content in the wetting body, both of which are relatively higher quality in the upper layer of the soil. The mass ratio of ammonium nitrogen in the wetting body decreases gradually with the increase of infiltration distance.
|
|
Received: 04 January 2023
|
|
|
|
|
|
|
