直播稻田渗漏水磷素动态变化及渗漏流失潜力研究

通过田间实验,对太湖流域丹阳地区直播水稻田不同施磷水平下渗漏水磷素动态变化特征及流失潜力进行了研究。结果表明,施磷能明显提高地下60cm以上深度土层渗漏水磷的含量。各土层渗漏液总磷浓度随土层深度的增加呈下降趋势。随着施磷量的增加,稻田渗漏水磷素含量也会随之增加。土壤磷素发生渗漏流失的土壤表层Olsen-P含量的突变点change-Point为25.17 mg/kg。当土壤中的Olsen-P浓度小于25.17mg/kg时,20～40cm土层渗漏水中TP浓度基本上不随土壤Olsen-P浓度的变化而变化,但当土壤中Olsen-P大于25.17mg/kg时,20～40cm土层渗漏水中TP浓度会大量增加,且土壤中的Olsen-P每增加10 mg/kg,渗漏水TP将增加0.21 mg/L。稻田当季累计土壤磷素渗漏流失负荷为1.02 kg/ha,占当季施磷量的2.80%。

Study on the Dynamic Change of Phosphorus in the Seepage Water and Its Potential Loss in Direct Seeding Paddy Field

The dynamic change of phosphorus in the seepage water and its potential loss were studied in the direct seeding paddy fields with different level of phosphorus applied in Danyang region of Taihu Lake area. The results showed that by application the phosphorus content would increase significantly in seepage water of soil layer deeper than 60 cm. The total phosphorus concentration in seepage water decreased with soil depth and increased with the increasing of phosphorus applied. The change point of Olsen-P content in soil surface with phosphorus leaching was 25. 17mg/kg. When the content of the soil Olsen-P was less than 25. 17 mg/kg, the total phosphorus eontent in seepage water for 20 - 40cm soil layer had little change. While when the content of the soil Olsen-P was more than 25. 17mg/kg, it would increase very much. For every 10 mg/kg of Olsen-P increased in soil, the TP concentration would increase by 0. 21 mg/L. The accumulative P loss by leaching was about 1.02 kg/ha, aeeotmting for 2. 80% of the amount of seasonal phosphorus application.