CHEN Lin1, FEI Liangjun1, LIU Lihua1, et al. Effects of Soil Initial Water Content on Transport Characteristics of Free Infiltration Water and Nitrogen Under Film Hole Irrigation with Muddy Water[J]. 2018, 32(2): 58-66.
DOI:
CHEN Lin1, FEI Liangjun1, LIU Lihua1, et al. Effects of Soil Initial Water Content on Transport Characteristics of Free Infiltration Water and Nitrogen Under Film Hole Irrigation with Muddy Water[J]. 2018, 32(2): 58-66. DOI: 10.13870/j.cnki.stbcxb.2018.02.009.
Effects of Soil Initial Water Content on Transport Characteristics of Free Infiltration Water and Nitrogen Under Film Hole Irrigation with Muddy Water
In order to explore the water and nitrogen transport characteristics under water and fertilizer integration of film hole irrigation with muddy water irrigation
through the indoor fertilizer infiltration test
the migration characteristics of infiltration
wetting front migration
soil moisture
ammonium nitrogen and nitrate nitrogen were studied under different soil initial water content (6.02%,7.40%,8.23%,10.08% and 13.20%). The relationship between cumulative infiltration volume
the wetting front migration distance and the soil initial water content of liquid fertilizer infiltration of film hole irrigation with muddy water were established. An empirical model was proposed to calculate the cumulative infiltration volume and the wetting front migration distance under different soil initial water content. Results showed that: The cumulative infiltration
the wetting front migration distance
the water transport in wetting body
the distribution and transformation of nitrogen were all affected by the soil initial water content. At the same infiltration time
the cumulative infiltration reduced
while the wetting front migration distance increased
with the increase of soil initial water content. The higher the soil initial water content was
the larger the wetting volume was
and the wider water
ammonium nitrogen and nitrate nitrogen in soil distributed. The higher the soil initial water content was
the smaller the value of infiltration parameter K was
and the larger the value of infiltration index α was. After irrigation
ammonium nitrogen was mostly distributed in the wetting body with humid radius which was less than or equal to the range of 5 cm. Meanwhile
ammonium nitrogen content decreased with the increase of soil depth in the wetting body when the wetted radius was larger than 5 cm and less than 10 cm. The ammonium nitrogen content obviously decreased when the humid radius was larger than 10 cm. Nitrate nitrogen was mainly distributed in the range from the center of the membrane pore to the wetting radius of 10 cm. The nitrate nitrogen content in the horizontal direction and the vertical direction decreased with increasing distance from the center of the film hole
the nearer was away from film hole center the higher nitrate nitrogen content was in both vertical and horizontal direction. The greater the initial soil water content was
the higher the mass fraction of ammonium nitrogen and nitrate nitrogen was at the same position. With the redistribution of soil moisture
the wetting front gradually went down
the wetting of ammonium nitrogen gradually downwardly migrated and its content decreased. Nitrate nitrogen concentration front transported with time prolongation
the soil nitrate nitrogen content decreased in the upper layer and gradually increased in the lower layer new wetting body
the content of nitrate nitrogen in wetting body tend to uniformly distribute. The research results could lay the foundation for further study on the transport and transformation of nitrogen fertilizer under the film hole irrigation with muddy water.