氮肥投入水平对蔬菜地硝态氮淋洗特征的影响

通过3年的田间定位试验研究了不同施N条件下蔬菜地NO3--N淋洗浓度及淋洗量的变化。结果表明:在农民习惯的传统施N处理(花椰菜为450kg/hm2,苋菜为100kg/hm2,菠菜为309kg/hm2)下蔬菜地NO3--N的淋洗浓度明显高于2个优化施N处理下蔬菜地的NO3--N淋洗浓度。在花椰菜、苋菜和菠菜生长期内,2个优化施N处理下蔬菜地NO3--N平均淋洗量分别是传统施N处理下蔬菜地NO3--N平均淋洗量的19%、18%、9%和13%、34%、21%。试验期间传统施N处理下蔬菜地NO3--N年季平均累积淋洗量约占年季平均施N量的一半,其中休闲期NO3--N平均累积淋洗量占年季平均累积施N量的20%;而其他2个优化施N处理NO3--N年季平均累积淋洗量是年季平均累积施N量的27%,休闲期NO3--N平均淋洗量占年季平均累积施N量的6%,而处理间蔬菜产量并未受到明显影响。

ffect of N-Fertilizer Input Level on Characteristic of Nitrate Leaching in Vegetable Soil

A 3-year field experiment was conducted at China Agricultural University Field Station in Beijing suburb to study characteristics of nitrate leaching in vegetable fields under different applied N-fertilizer amount treatments. Results showed that nitrate concentrate under traditional N-fertilizer applied treatment was significantly higher than those of two improved N-fertilizer applied treatments; Average nitrate leaching amount during Cauliflower, Amaranth and Spinach growth under two improved applied N-fertilizer amount treatments were of 19%, 18%, 9% and 13%, 34%, 21% of those of traditional treatment; In the whole experiment period and in the fallow period, annual average cumulative nitrate leaching amount under traditional N-fertilizer treatment constituted of 1/2 and 20% of total N-fertilizer applied amount, respectively, contrasting to less than 1/4, 6% under two improved N-fertilizer treatments, respectively. No significant influence on vegetable yields was found between different treatments.