长期施肥对河西绿洲灌漠土作物产量及土壤养分自然供给能力的影响

Effects of long-term fertilization on crop yield and indigenous soil nutrient supply in Hexi Oasis of Gansu Province

为提高甘肃河西绿洲粮食高产、稳产、高效生产能力及土壤养分资源管理水平,通过设置于甘肃河西绿洲长达25年（19822~006年）的长期肥料定位试验,研究长期施肥对作物产量及土壤养分供给能力的影响。结果表明：连续25年不施用任何肥料或单施氮肥,会导致农田土壤生产能力严重衰退;氮、磷或氮、磷、钾肥配合施用能使作物持续高产、稳产;随试验年限的延续,磷肥、有机肥增产效应逐渐积累,并表现出良好的渐进性和持续性;钾肥在试验开始后最初6年（19821~987年）无显著增产效应,中期具有一定的增产作用（19881~992年）,后期14年（19932~006年）显著增产。土壤磷素自然供给能力随试验年限的延续逐渐减小,而钾素的自然供给能力相对稳定。

A long-term（1982-2006）field experiment was conducted on calcareous soils at Zhangye city,Gansu Province under the wheat（Triticum aestivum L.）-wheat-corn（Zea mays L.）rotation system in order to determine the effects of long-term fertilization on crop yields and indigenous P and K supply of calcareous soils.The results show that the average grain yields of the 25 years are decreased in the order of MNPKMNPNPKMNNPMNCK.The crop yields are significantly increased under the application of N fertilizer combined with P fertilizer,especially N and P fertilizers combined with the farmyard manure.For the application of K fertilizer,there seem no obvious effects on increase of the grain yields during the initial 6 years（1982-1987）,moderate effects in the next 5 years（1988-1992）,and significant effects in the last 14 years（1993-2006）.Indigenous soil P supply is always decreased from 1982 to 2006,and at present time it is not reach to a stable level,while indigenous soil K supply is relatively steady.