Abstract: The transformation relationship between precipitation, soil water and groundwater is of great significance for water resources assessment, supply and demand forecasting, rational development and utilization of water resources and water-saving irrigation. In this paper, real-time monitoring of soil moisture, precipitation and groundwater in crop growth period was carried out at Wudaogou experimental station in Huaibei plain. Through the monitoring of precipitation, soil water and groundwater, the characteristic parameters algorithm and related analysis methods were used to study the response of soil moisture to precipitation and groundwater in the black soil area of the Huaibei plain. The results showed that precipitation with less rain intensity only disturbed the water content of surface soil; The trend of soil moisture change during crop growth period was opposite to the change of groundwater depth. The soil moisture content of 50 cm soil was the lowest in the growth period of summer maize, and the soil moisture content was the highest in 70 cm soil. When the precipitation in the growing season was small, the soil water and groundwater alternated more frequently. The correlation coefficient between precipitation and soil water in the study area was very low, and the relationship between precipitation and soil water cannot be expressed by a simple linear correlation. The soil moisture content of 10 cm, 50 cm and 70 cm was the best correlation with the soil moisture content of 30 cm. The groundwater depth and the soil moisture content of each layer were negatively correlated, and the correlation coefficient with the soil moisture content of 30 cm was the largest.

Key words: precipitation, soil moisture, groundwater, Huaibei plain