自然降雨对黑土地表氮素养分流失的影响

Effect of Nature Rainfall on N Nutrient and Fertility in Phaeozem Surface

针对黑土利用现状,在吉林农业大学黑土区选择不同利用方式的玉米地、休闲地、果园、草地,并在玉米区进行了不同数量的施肥. 通过野外试验,采集2002年度5～10月历次自然降雨(共7次)产流及泥沙样品,同时采集降雨前后的耕层土壤样品,研究了黑土区地表径流对氮素养分特征及肥力退化的影响.结果表明:侵蚀泥沙的粒级分布特征表现为(1～0.05 mm与0.05～0.01 mm)2个粒级接近80%.土壤TN流失随植被覆盖度增加而减少;径流矿质氮流失随植被覆盖度增大并无减少,即植被覆盖度并不能减少土壤矿质氮流失;不同的植被类型,NH+4-N流失相差较大,NO-3-N相差较小.在土壤养分含量差异不明显时,施肥量对黑土径流氮素养分流失的影响表现为泥沙TN、径流TN浓度均随氮用量增加而增加;当氮肥施用量为N2(98 kg/hm2),磷肥(44 kg/hm2)施用量为P2时,泥沙和径流氮素流失相对较小.

In view of current using situation and drawing on the experience of many scholars researched methods and viewpoints, This thesis made corn land, fallow land, orchard, grass land as experimental field in JLAU black soil region, which carried out experiment by applying different amounts of N and P fertilization in corn field. By means of collecting the samples of rainfall runoff, erosion silt and surface layer soil before and after rainfall for one year nature precipitation in field, we study the effect of surface runoff on N nutrient and fertility degeneration. The results indicated that Characters of eroded of silt Size（1～0.05 mm and 0. 05～0. 01 mm） amount to 80%. With cover level increasing, TN in soil and silt decreased, but NH4^＋ —N^＋ NO3^- — N in runoff didn＇t changed; With the cover level increasing and different utilization manners, Losses of NH4^＋ —N showed notable divergence, while NO3^- —N did not changed; With increasing amounts of N and P fertilization, there were some effect on losses of N and P fertilization. With increasing amounts of N, TN in soil and runoff both increased. But applying amounts of N（98 kg/hm^2） and P（44 kg/hm^2） fertilization against other amounts in corn field, N in silt and runoff would cut down.