模拟酸雨对施肥条件下赤红壤氮磷淋失特征的影响

通过土柱模拟淋洗试验,研究了施用等量有机复合肥条件下,不同酸度模拟酸雨对赤红壤氮磷淋失特征的影响。结果表明,铵态氮、硝态氮、无机氮和总氮淋失量均随酸雨pH值增大而下降;pH 2.0模拟酸雨和对照(pH 6.5)的无机氮和总氮淋失量差异不显著,但均显著高于pH 3.0、pH 4.0和pH 5.0酸雨;pH 5.0模拟酸雨无机氮和总氮淋失量均最低,表明强酸性酸雨和中性淋洗液均促进氮淋失,而酸度与土壤接近的酸雨减少氮淋失。与对照相比,模拟酸雨对DP淋失无显著影响,但显著降低PP和TP淋失;不同模拟酸雨各形态磷淋失量均无显著差异,表明酸雨对赤红壤磷淋失影响有限。酸雨对淋滤液氮磷浓度动态变化和氮磷累计淋失量动态变化等均无显著影响。

Effects of Simulated Acid Rain on Nitrogen and Phosphorus Leaching Characteristics in Latosolic Red Soils with Application of Organic Compound Fertilizer

A soil column method was applied to study influences of simulated acid rain on leaching characteristics of nitrogen and phosphorus from organic compound fertilizer in latosolic red soil in south China.Results revealed that leaching loss amounts of ammonia nitrogen,nitrate nitrogen,inorganic nitrogen and total nitrogen all decreased with increase of pH values of the simulated acid rain.Inorganic nitrogen and total nitrogen leaching amounts of the pH2.0 acid rain and the control(pH6.5) were not significantly different at p<0.05,but were significantly higher than those of pH3.0,pH4.0 and pH5.0 acid rain.Among all the treatments,pH5.0 acid rain had the lowest nitrogen leaching losses.Therefore,both strong acid rain(pH2.0) and neutral leaching water(pH6.5) enhanced nitrogen leaching,while acid rain with acidity close to the soil(pH5.0) caused slightest nitrogen leaching loss.Compared to the control,acid rain had no significant effects on DP leaching,but significantly reduced PP and TP leaching losses.Moreover,no significant differences existed in phosphorus leaching amounts among acid rain of different pH values.So,acid rain had marginal effects on phosphorus leaching in latosolic red soils.Also,no significant effects of acid rain were observed on the dynamics of concentrations and accumulative leaching loss amounts of nitrogen and phosphorus.