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| Effects of soil bulk density on vertical migration of soil water and nitrogen |
| LIU Le, FEI Liangjun*, ZENG Jian, CHEN Lin,FU Yuliang, ZHONG Yun |
| Institute of Water Resources, Xi′an University of Technology, Xi′an, Shaanxi 710048, China |
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Abstract To study the difference of vertical one-dimensional infiltration migration characteristics of soil water and nitrate-nitrogen in red soil and loess under various soil bulk densities, and to improve the water and fertilizer utilization efficiency in red soil and loess area, the Jiangxi loam clay and the Xi′an silty loam were taken as the study objects. The vertical one-dimensional infiltration mode was used to simulate the effect of soil bulk density on the vertical movement of water and nitrate-nitrogen in the two soils. The results showed that the wetting front migration distance and infiltration rate of the Jiangxi loam clay and the Xi′an silty loam were both negatively correlated with soil bulk density. Whether at the end of irrigation or after the redistribution of 1 day, the moisture content of the two soils was negatively correlated with soil bulk density, and the moisture content of the Xi′an silty loam was slightly larger than that of the Jiangxi loam clay. The greater the soil bulk density was, the more the nitrate-nitrogen was concentrated in the deep soil and the higher its peak value. In the redistribution process, the peak value decreased, and that of the bulk density of 1.25, 1.35 and 1.40 g/cm3 decreased greatly. At the end of irrigation, soil bulk density had a significant effect on the nitrate-nitrogen concentration in the 40-50 cm soil layer(P<0.05). After the redistribution of 1 day, there was little difference between the concentration of nitrate nitrogen in 0-30 cm soil layer of the two soils, the concentration of nitrate nitrogen in 30-60 cm soil layer was higher, but the concentration of nitrate nitrogen in Xi′an silty loam soil was higher. Therefore, the nitrate-nitrogen of the Jiangxi loam clay more ea-sily leaches, while soil moisture and fertility retention properties of the Xi′an silty loam are better.
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Received: 05 January 2018
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