Continuous recording of precipitation and soil water content（SWC）, especially during long periods of torrential rainfall, has proven challenging. Over a 16 h period spanning 21-22 July, 2012, Beijing experienced his...Continuous recording of precipitation and soil water content（SWC）, especially during long periods of torrential rainfall, has proven challenging. Over a 16 h period spanning 21-22 July, 2012, Beijing experienced historic rainfall that totaled 164.4 mm. We used large lysimeter technology in four forested plots to record precipitation and variation in SWC at 10-min intervals to quantify the response of forestland SWC to heavy rainfall in a semi-arid area. Mean,maximum and minimum rainfall intensities were 23.4, 46.8and 12.0 mm/h, respectively. Rainfall was concentrated in 2-6 mm bursts that accounted for 67.32 % of the total rainfall event. Soil moisture conditions in this region are strongly dependent on patterns of precipitation. Water infiltration into 20, 40, 60, 80, 100, 120 and 160 cm soil layers required 1, 5,20, 37, 46, 52 and 61 mm of precipitation, respectively, and to fully saturate these soil layers required 80, 120, 140, 150, 180,200 and 220 mm of precipitation, respectively.展开更多
Soil hydro-physical characteristics influence soil nutrients availability and consequently affect crop performance. However, field determination of these properties for effective management of water for irrigation is ...Soil hydro-physical characteristics influence soil nutrients availability and consequently affect crop performance. However, field determination of these properties for effective management of water for irrigation is laborious, time consuming and expensive. Hence, this study was initiated to assess the performance of the SOILWAT model for the estimation of soil hydro-physical properties. A total of 180 disturbed and 120 undisturbed soil samples were collected from three agro-ecological zones (Savannah, Derived savannah and rainforest) in Nigeria. The samples were analyze for hydro-physical and chemical properties. Soil texture and salinity data were varied in the SOILWAT model (Version 6.1.52) to predict soil physical properties for the three agro-ecological zones of Nigeria, respectively. Measured and pre-dicted values of field capacity, permanent wilting point and soil available water were compared using T-test at α.05. The prediction of soil textural class using the SOILWAT model was sufficiently accurate for the three agro-ecological zones. However, bulk density, maximum water holding capacity, permanent wilting point and soil available water showed significant (p < .05) differences between measured and predicted values, and there were positive relationships between SOILWAT values and the observed va-lues. Thus, the SOILWAT model could be adopted for predicting soil texture and permanent wilting point for savannah, derived savannah and rainforest zones of Nigeria. Also, the inclusion of organic matter input, silt adjustment and addition of salinity in the various moisture characteristics relationships and equations could enhance its performance.展开更多
基金The National Natural Science Foundation of China(No.4143074741401013)
文摘Continuous recording of precipitation and soil water content（SWC）, especially during long periods of torrential rainfall, has proven challenging. Over a 16 h period spanning 21-22 July, 2012, Beijing experienced historic rainfall that totaled 164.4 mm. We used large lysimeter technology in four forested plots to record precipitation and variation in SWC at 10-min intervals to quantify the response of forestland SWC to heavy rainfall in a semi-arid area. Mean,maximum and minimum rainfall intensities were 23.4, 46.8and 12.0 mm/h, respectively. Rainfall was concentrated in 2-6 mm bursts that accounted for 67.32 % of the total rainfall event. Soil moisture conditions in this region are strongly dependent on patterns of precipitation. Water infiltration into 20, 40, 60, 80, 100, 120 and 160 cm soil layers required 1, 5,20, 37, 46, 52 and 61 mm of precipitation, respectively, and to fully saturate these soil layers required 80, 120, 140, 150, 180,200 and 220 mm of precipitation, respectively.
文摘Soil hydro-physical characteristics influence soil nutrients availability and consequently affect crop performance. However, field determination of these properties for effective management of water for irrigation is laborious, time consuming and expensive. Hence, this study was initiated to assess the performance of the SOILWAT model for the estimation of soil hydro-physical properties. A total of 180 disturbed and 120 undisturbed soil samples were collected from three agro-ecological zones (Savannah, Derived savannah and rainforest) in Nigeria. The samples were analyze for hydro-physical and chemical properties. Soil texture and salinity data were varied in the SOILWAT model (Version 6.1.52) to predict soil physical properties for the three agro-ecological zones of Nigeria, respectively. Measured and pre-dicted values of field capacity, permanent wilting point and soil available water were compared using T-test at α.05. The prediction of soil textural class using the SOILWAT model was sufficiently accurate for the three agro-ecological zones. However, bulk density, maximum water holding capacity, permanent wilting point and soil available water showed significant (p < .05) differences between measured and predicted values, and there were positive relationships between SOILWAT values and the observed va-lues. Thus, the SOILWAT model could be adopted for predicting soil texture and permanent wilting point for savannah, derived savannah and rainforest zones of Nigeria. Also, the inclusion of organic matter input, silt adjustment and addition of salinity in the various moisture characteristics relationships and equations could enhance its performance.
