淹水条件下水稻田中磷的淋溶研究

P LOSS THROUGH VERTICAL LEACHING FROM PADDY FIELD UNDER SUBMERGED CONDITIONS

采用地下垂直埋入钢管收集土壤淋溶液的方法,在江苏宜兴对水稻生长季节内稻田土壤中P向下迁移作了研究,重点主要集中在淋溶液中P的浓度、渗漏速度以及P的淋溶量测定几个方面.结果表明,在整个水稻生长季中淋溶液的溶解P与全P浓度均不高,溶解P的浓度维持在0.02mg/L以下,全P的浓度则在0.03～0.08mg/L之间;土壤直渗速度为0.53cm/天;本实验方法测得的淋溶量中,整个水稻生长季在施P量为30kg/hm2的条件下,P的淋溶量为3.77 kg/hm2,其各土壤层次中土壤表层淋溶量所占比例最大,占各层总淋溶量的36%.

A new method was used in the experiment that was focused on vertical leaching of phosphorus in paddy soils during the rice-growing season. Some steel cylinders were inserted into the soil to different depths to collect water samples in Yixing, Jiangsu province. Results showed that neither the concentrations of soluble P nor the total P in the leachate was high, being below 0.02mg/L or between 0.03~0.08mg/L, respectively. The vertical leaching rate was about 0.53cm/day. The total amount of P lost through leaching was 3.77kg/hm2, 36% of which was from the depth of 0~20cm, when the P application rate was 30kg/hm2 during the rice growing season.