土柱模拟条件下降雨强度对滇西和豫中典型植烟土壤氮淋失的影响

Effects of Rainfall Intensity on Nitrogen Leaching from Typical Tobacco Growing Soils in Western Yunnan and Central Henan under Soil Column Simulation

通过室内土柱模拟降雨,比较不同典型植烟土壤氮淋失差异。选取豫中(襄城县)和滇西(洱源县)典型植烟土壤,设定总降雨量600 mm,模拟3种不同降雨强度P1(0.52 mm/h)、P2(1.04 mm/h)、P3(1.56 mm/h),研究淋溶液渗出量及硝态氮、铵态氮的淋失情况。结果表明,高降雨强度削减土壤持水量,滇西植烟土壤持水量高于豫中。氮素淋失集中出现在淋失初期,硝态氮的淋失浓度及淋失量随降雨量增加下降迅速,铵态氮下降较缓慢。植烟土壤硝态氮、铵态氮淋失总量及淋失速率随降雨强度增加而增加,淋失形态以硝态氮为主,两地平均占比90%,土壤硝态氮的淋失浓度受降雨强度影响不明显,受土壤残留氮含量影响较显著。滇西地区植烟土壤氮淋失量及淋失速率均高于豫中,氮淋失污染风险较高。

The difference of nitrogen leaching loss in different typical tobacco planting soils was compared by indoor soil column simulated rainfall.This experiment selected typical tobacco planting soils in central Henan(Xiangcheng County)and western Yunnan(Eryuan County),set a total rainfall of 600 mm,simulate three different rainfall intensities P1(0.52 mm/h),P2(1.04 mm/h),P3(1.56 mm/h),and study the amount of leaching solution and the leaching of nitrate nitrogen and ammonium nitrogen.The results showed that high rainfall intensity could reduce soil water capacity,and the water capacity of tobacco planting soil in western Yunnan was higher than that in central Henan.The concentration of nitrogen leaching occurred at the initial stage of leaching.The leaching concentration and amount of nitrate nitrogen decreased rapidly with the increase of rainfall,while the ammonium nitrogen decreased slowly.The total amount and rate of nitrate nitrogen and ammonium nitrogen leaching in tobacco planting soil increased with the increase of rainfall intensity.The nitrate nitrogen was the main form of leaching,accounting for 90%on average in the two places.The concentration of nitrate nitrogen leaching in soil was not significantly affected by rainfall intensity,but was significantly affected by the content of residual nitrogen in soil.The amount and rate of nitrogen leaching from tobacco planting soil in western Yunnan were higher than those in central Henan,and the risk of nitrogen leaching pollution was higher.