紫色土稻田磷素流失潜能及其水分管理研究

Potential of Phosphorus Losses from Purple Paddy Field and Its Water Management

通过对紫色土稻田田面水和土壤样品磷素的分析,研究了水稻不同生育期田面水磷素含量和土壤磷素的含量特征。结果表明:田面水磷浓度随着施磷水平的提高而提高,水稻移栽后的2周内应禁止排水,这期间水稻的水分管理应采取浅水灌溉栽秧、浅水返青。田面水TP和DP浓度随时间(x)的变化呈极显著的对数(y=a.ln(x)+b)下降规律,可通过对数方程推算对环境影响小的排水时间。在水稻移栽后第36天和第86天总磷流失负荷分别为124～501g/hm2和40～211g/hm2。稻季施磷肥会造成对地下水体的污染,且田面水中磷浓度较高一直持续40天左右,稻田磷肥大量径流流失也主要发生在这一时期,要加强这期间的田间管理,并收集稻田的排水用于后期灌溉稻田。

This paper studied on the characteristics of phosphorus content in surface water and soil in paddy season which sampled from surface water and soil of purple paddy field.The results showed that surface water phosphorus concentrations increased with P application while improving the level of phosphorus.Drainage water should be prohibited in two weeks after transplanting rice;water management during this period should be taken of shallow water irrigation with cultivating rice,shallow water with turning green.TP and DP concentration with time （x） showed significant changes in logarithm （y=a·ln（x）＋b） decline,could be calculated through the logarithmic equation of the drainage time.Load of TP loss were 124～501 g/hm^2 and 40～211 g/hm^2 in rice transplanting 36 days and 86 days.P fertilizer would cause the pollution of groundwater and phosphorus concentrations were higher lasted 40 days or so in surface water,field management should be strengthened for a large number of P fertilizers losses occurred mainly during this period,and collected paddy drainage for the late rice irrigation.