【摘 要】
：
NO-3-N的淋失是旱地农田氮素损失的重要途径之一,也是引起地下水污染的一个主要原因.在黄土高原地区,夏玉米生长正逢雨季,是NO-3-N淋失的主要时期.该研究基于阻水层理论和黄
论文部分内容阅读
NO-3-N的淋失是旱地农田氮素损失的重要途径之一,也是引起地下水污染的一个主要原因.在黄土高原地区,夏玉米生长正逢雨季,是NO-3-N淋失的主要时期.该研究基于阻水层理论和黄土高原地区传统的垄作习惯,在手工模拟机具成垄压实施肥的基础上研究了该施肥法与传统的平地施肥、垄沟施肥(成垄不压实)条件下土壤NO-3-N的迁移动态,结果表明,在供水量相同条件下,由于平地和垄沟条件下水分分布的差异,导致平地土壤中的NO-3-N较垄沟耕作易于迁移.在生育前期,由于作物根系对NO-3-N的吸收和拦截,成垄压实与成垄不压实
其他文献
In 2008 there are many events taking place in China: tightened currency policy, new labor law and new enterprise income tax law, as well as the Recycling Econom
Yin Guoxin is one of the heads of China’s apparel manufacturing field,his Chenfeng Group Co. Ltd became one of the largest in the world. No one can doubt his w
According to the Statistical Communiqué of the People’s Republic of China on the 2008 National Economic and Social Development,released by the National Bu
Founded in July,1994, Jiangsu LAD Group Co., Ltd is engaged in a wide range of business in its 13 subsidiary companies for apparel manufacturing & marketing,inv
Instead of on July 1st as many forecast experts had anticipated, the new policy for export VAT’s rebate rate for textile and apparel to change from 11% to 13%
试验研究了不同水平干酪乳杆菌对断奶仔猪生长性能和抗氧化能力的影响。从母猪胎次一致、产期相同的20番仔猪中选取体重相似、健康状况良好的14日龄杜×长×大三元杂
教师对学生的评价对新课程的实施起着监督作用，当然，对学生的评价也是为了实施新课程提出的培养目标。笔者认为，评价只是为了创造一种适合儿童的教育方法，我们现在更为关注的不应