Field studies on 32P movement and P leaching from flooded paddy soils in the region of Taihu Lake, China.
Field experiments were done in two sites, Yixing and Changshu, Jiangsu province, China, to study P movement and leaching in flooded paddy soils. P movement in soil was investigated by using the KH2 32PO4 tracker method, and the amount of P leached from the soil layer in different depths was estimated by measuring P concentrations in the soil solution and saturated hydraulic conductivities in field. Determination was done about one month after P application. There was 46% and 42% of total 32P retained in the 0-5cm layer of soil in the Yixing site and in the Changshu site respectively. The 32P retained in the 25-30 cm layer was only about 1-2% of the total 32P added. Furthermore, 8.01% of 32P in the soil of Yixing site and 16.8% of 32P in the soil of Changshu site was lost from the layer 0-30 cm soil. The seasonal amounts of P leached from the top soil layer and from bottom layer are about 4.5-5.8% and 1.6-2.1% of the total P application, respectively. Changes of total P concentrations in soil solutions during rice growth showed that the fertilizer P applied before flooding of the paddy fields suffered a flash leaching loss and a slow leaching loss. We concluded that the fertilizer P could quickly move in the flooded paddy rice field and parts of it can enter into surface water and ground water. Unless the P application is well managed the risk of P loss and consequently environmental pollution exist.
Xie
X J
XJ
College of Natural Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China.
Ran
W
W
Shen
Q R
QR
Yang
C Y
CY
Yang
J J
JJ
Cao
Z H
ZH
D000383:Agriculture; D002681:China; D004784:Environmental Monitoring; D012275:Oryza; D010758:Phosphorus / Q000032:analysis*; D012307:Risk Factors; D012987:Soil; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*; D014881:Water Supply
D012987:Soil; D014873:Water Pollutants; D010758:Phosphorus