长期定位连施化肥的增产培肥效应研究

河西走廊灌区质地中壤的灌漠土上，21年的长期定位试验表明：无有机肥条件下连年施用化肥比无肥处理增产粮食19．6％-300．5％，比有机肥增产16．2％～101．6％，对粮食增产贡献率平均达50％。连续平衡施用化肥，土壤有机质含量连续19年下降了24．9％～27．4％；土壤全N比初始年提高13．7％～46．1％，速效N含量呈稳中下降的动态：土壤全P含量比初始年提高4．4％～5．1％，速效P含量提高16．3％-19．1％；土壤K素库处于长期亏缺状态。速效K含量呈稳步降低的动态。化肥养分具有明显的间接培肥效应，在生物循环中以有机肥为载体下年输入土壤的N、P、K化肥养分分别占当年投入量的27．1％～31_3％、23．8％～27．0％和33．2％；化肥增产的秸秆有机c输入下年土壤的达567．3～626．7kg／hm。，证明有机肥中相当一部分养分来自化肥及其化肥的生产物。

Effect of long-term located continuous fertilizer application on yield increasing and soil fertility developing

Based on the 21-year located tests of irrigated desert soil in Gansu corridor, the results show that： compared to no fertilizer and single organic fertilizer application, the crop yield is increased more than 19.6%- 300.5% and 16.2%- 101.6% under continuous chemical fertilizer application; The contribution quotient of chemical fertilizer to crop yield is average 50%. Under the balanced chemical fertilizer application on soil, the content of organic matter in soil is declined by 24.9% - 27.4% during 19 years;compared to the first year, the content of total nitrogen （TN） is increased by 13.7%- 46.1%, the content of available N is declined; the content of total phosphate （TP） is increased gradually by 4.4%- 5.1%;the content of soil available phosphate is increased steadily by 16.3% - 19.1%; the condition of K sink in soil is deficient for a long time with the content of available K decreased gradually. The effect of chemical fertilizer on indirect developing soil fertility is very significant. The proportion of N, P and K nutrition in soil which come from organic manure is 27.1%- 31.3%, 23.8%- 27.0% and 33.2% of total inputs in biocycle. Increased organic carbon straw in soil caused by chemical fertilizer is about of 567.3- 626.7 kg/ hm^2 in the next year. This proved that there are much organic manure nutrition come from chemical fertilizer and its products.