JOURNAL OF NATURAL RESOURCES ›› 2021, Vol. 36 ›› Issue (2): 490-500.doi: 10.31497/zrzyxb.20210217

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Effect of land use types on soil moisture in typical small watershed of humid region of Eastern China

ZHOU Cai-yu(), XU You-peng(), LIU Peng-fei, WANG Qiang, WANG Jie   

  1. School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China
  • Received:2019-06-05 Revised:2019-11-20 Online:2021-02-28 Published:2021-04-28
  • Contact: XU You-peng E-mail:caiyu615@163.com;xuyp305@163.com

Abstract:

The urbanization process in Eastern China has been accelerating in recent years, leading to underlying surface changes affecting soil moisture in the region. Knowledge of soil moisture is critical to understanding many of the hydrological processes that are of interest in soil hydrology, meteorology, and ecology research. Long-term time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land cover change. In this study, we used rainfall and soil moisture data collected at waxberry forests, bamboo forests, farmland, and slope cropland sites in the Hualong River region of Eastern China in 2015 to 2018 to analyse the response of soil moisture to rainfall event size at different soil depths. The results showed the following: (1) In general, the soil moisture content of waxberry forests was slightly higher than that of farmland, slope cropland, and bamboo forests. In the vertical section, the soil moisture in the surface layer (10-20 cm) changed greatly while the soil moisture in the deep layer (60-80 cm) changed little. Meanwhile, the temporal variation of surface soil moisture was larger than that of deep soil moisture. (2) Under different rainfall intensities, the soil moisture of bamboo forests responded more substantially to rainfall than did waxberry forests, farmland, and slope cropland. The greater the rainfall intensity, the greater the response degree of soil moisture. The soil moisture was in a fluctuant downward trend after the rainfall stopped. (3) Quantification of soil moisture by increasing coefficient and reducing coefficient demonstrated that the bamboo forest had the most obvious regression. The other three types of land use varied equally. The soil moisture of waxberry forests, farmland, and bamboo forests changed more dramatically at the surface layer than at the deeper depths. In addition, the soil moisture in the deep layer of slope cropland was affected by the infiltration of surface soil water in the process of regression; this change was complicated, which needs further studies. These research results provide a theoretical basis for the quantitative description of the soil hydrological conversion process, the mechanism of runoff and stream flow, agricultural production, and water resources allocation in the monsoonal Eastern China.

Key words: soil moisture, rainfall, land use types, humid watershed