不同施肥条件下旱田养分淋溶规律实验研究

从当今世界范围看 ,每年转入陆地生态系统中的总Ｎ量约为 2× 10 8ｔ。其中来自工业肥料的Ｎ含量占 2 0 %。目前全世界的施肥量仍在增加 ,发展中国家的增加速率比发达国家高得多。目前 ,我国的大部分耕地都需要补充Ｎ素 ,一半以上的耕地需要补充磷肥 ,大约 1/3～ 1/4以上的耕地需要补充钾肥。然而 ,由于种种原因 ,我国农田土壤养分的利用率一直较低 ,损失率较大。旱地土壤Ｎ素 (尿素 )利用率仅为 2 0 %～ 4 0 %。Ｐ的利用率 15 %～ 30 %。这一方面提高了农产品的成本 ,另一方面 ,过多的使用肥料又造成了环境问题1,2 ] 。其中 ,一部分养分沿…

Experiment on the Law of upland Nutrient Leaching by Fertilizing at Different Doses

In order to find out the effect of nutrient leaching on the environment caused by fertilizing, nutrient leaching experiment was designed with soil column in size of 1.0m in depth and 0.3m in diameter, planted with oats glass fertilized at different doses. The leaching water was sampled once a month to analyze the content of nutrient. Results indicated that nitrogen in the form of NH 4 -N changed with the dose of fertilizer and the seasons. The amount of nutrient leaching is positively related to the amount of urea applied. The amount of NO 3-N detected was generally much higher than that of NH 4 -N, which indicated that NO 3-N was the main part of nitration and leaching of nitrogen, and organic nitrogen has no relation with fertilizing. Results also indicated that fixition of phosphorus was a dynamic process, and fertilization could also result in the loss of phosphorus. Fertilizing influenced leaching of potassium. However, the amount of leaching is under the standards of national and OECD's drinking water. The experiment showed that rational application of fertilizer could result in less pollution of underground water by NO 3-N leaching.