长期施肥对黑土供磷能力及磷素有效性的影响

目的]研究长期施肥后黑土供磷能力、磷素形态的变化。方法]利用采自海伦农田生态系统国家野外科学观测研究站长期定位试验地的无肥(CK)、化肥(NP)、化肥配施有机肥(NPM)3个施肥处理黑土进行生物耗竭盆栽试验,并用Hedley方法对土壤磷素形态进行研究。结果]与长期不施肥处理相比,施化肥与化肥配施有机肥均能明显增加土壤各形态磷素;与无肥处理土壤相比,化肥有机肥配施处理土壤与化肥处理土壤植株的生物量增幅分别为31.72%和54.65%;植株吸磷量分别是CK和NP处理土壤的2.1和1.7倍;长期施用有机肥的黑土经过2批油菜耗竭后,Resin-P只减少了0.85%,远小于Resin-P在无肥处理土壤和单施化肥处理土壤中的减少量。结论]长期化肥配施有机肥的黑土可以在短期内维持一个活性磷含量较高的水平,进而提高土壤的供磷能力及其生产力。

Effects of Long-term Fertilization on Phosphorus Supply Capacity and Availability in Black Soil

Objective] The research aimed to study the effects of long-term fertilization on phosphorus supply capacity,phosphorus fractions transformation in black soil.Method] The soil samples of pot experiment were collected from a long-term field experiment which carried on Hailun Agricultural Ecology Station of Chinese Academy of Sciences.Experimental treatments included without fertilizer application(CK),applying chemical nitrogen and phosphorus fertilizer(NP),and applying N and P fertilizer and organic manure(NPM).Phosphorus fractions transformation during biological depletion was studied by Hedley’s P fractionation method.Result] Compared with no fertilizer application,applying chemical fertilizer and chemical fertilizer with organic manure could increase contents of different forms of phosphorus.The biological depletion pot experiment showed that plant biomass in NPM was 31.72% higher than NP and 54.65% higher than CK.The amounts of plant P uptake in NPM were 1.7 and 2.1 times higher than those of NP and CK soils,respectively.The concentrations of resin-P in NPM only decreased 0.85%,which was much lower than that of CK and NP after two successive growing seasons.Conclusion] Long-term application of chemical fertilizer with organic manure can maintain a high level of reactive P content,improve soil Phosphorus supply capacity and productivity in the agroecosystem.