竹炭包膜尿素和常用氮肥的氮素淋失特征研究

通过土壤淋溶试验,探讨了竹炭包膜尿素和常用氮肥的氮素淋失特点以及施用不同氮肥对土壤性质的影响。结果表明,不同氮肥施入土壤后其氮素淋失率有很大的差异,其中硝酸钾的淋失率最高,其次为尿素,碳铵的淋失率最低。竹炭包膜尿素因具有养分缓慢释放的特点,其氮素淋失率较尿素低9.93%~16.27%。施用竹炭包膜尿素所引起土壤盐基离子的淋失量远低于施用速溶性氮肥;不同氮肥淋洗后对土壤pH值变化的影响差异较大,竹炭包膜尿素对土壤pH值变化的影响较小。施肥淋洗后,除了硝酸钾处理外,其余处理土壤的速效氮含量均比淋洗前高,两种竹炭包膜尿素处理土壤的速效氮含量均高于尿素处理;土壤介质对氮素的淋失率有较大的影响,供试氮肥在砂土中的氮素淋失率远高于其在石灰岩风化土中的淋失率。

Leaching Characteristics of Bamboo-Charcoal Coated Urea and Common Nitrogen Fertilizers

The nitrogen loss and environmental pollution from nitrogen fertilizers are increasing.The leaching characteristics of bamboo-charcoal coated ureas(BCCU) and common nitrogen fertilizers and their effects on soil are investigated in soil column leaching experiment.The results show that nitrogen leaching rates are significantly different among tested nitrogen fertilizers:potassium nitrate the highest,urea the second and ammonium bicarbonate the lowest.Urea coated with bamboo-charcoal presents slow-release property to a certain extent.Nitrogen leaching rates of BCCU are 9.93%~16.27%,lower than that of common urea.When fertilizing equal nutrition,the leaching loss of Ca2 ,Mg2 ,K ,Na caused by bamboo-charcoal coated urea is remarkably less than those caused by common nitrogen fertilizers.The soil pH and available nitrogen content are obviously different after soil column leaching with different nitrogen fertilizers.The effect of BCCU on soil pH changes is comparatively small.The soil available nitrogen content in most treatments is higher after leaching than before leaching except for potassium nitrate.The available nitrogen content of BCCU is higher than that of common urea.Soil media has a significant effect on nitrogen leaching amount.