长期施肥条件下黑垆土有效磷对磷盈亏的响应

Response of Olsen-P to P Balance in Black Loessial Soil Under Long-Term Fertilization

【目的】阐明不同施肥条件下土壤有效磷与土壤磷素累积的响应关系,为黄土高原旱作农区科学施用磷肥提供依据。【方法】分析了黑垆土28年(1979—2007年)肥料长期定位试验中,不同施肥处理下土壤磷素盈亏与土壤有效磷的变化特征。【结果】长期施用化肥(NP)、单施有机肥(M)及化肥与有机配施(NPM),土壤有效磷含量随试验年限的延长呈极显著(P<0.01)上升趋势,年均分别增加0.54、0.64和1.11mg·kg-1,而不施肥和单施氮肥处理土壤有效磷含量呈持平或下降趋势。土壤有效磷增加量随磷盈亏而变化,二者呈极显著(P<0.01)正相关,施用化学磷肥、单施有机肥和有机无机肥配施,土壤中的磷素均有盈余,土壤中每盈余100kg·hm-2磷所能增加的土壤有效磷分别为3.85、0.29和0.53mg·kg-1。施用化学磷肥土壤有效磷的增加速率是施有机肥的11.6倍。【结论】土壤有效磷随土壤磷素盈余而变化与加入磷素形态密切相关,长期单施化学磷肥提升土壤有效磷的速率显著大于单施有机肥。

Objective Response of Olsen-P to P balance in a black loessial soil was studied in a long-term fertilization experiment carried out in Pingliang,Gansu province for the purpose of providing a theoretical basis for the scientific application of phosphate fertilizer in the Loess Plateau dryland farming areas.Method The relationships between Olsen-P change and the budget of soil P balance in the treatments of CK,N,NP,M,NPM were studied by the method of linear regression based on a 28-year（1979-2007） experiment.Result The results showed that long-term application of M,NP,and NPM resulted in significant increase of Olsen-P by 0.54,0.64 and 1.11 mg·kg-1·a-1,respectively.While the soil Olsen-P content remained stable or showed a decreasing trend in the CK and N treatments.The increase amount of Olsen-P changed with P balance.Application of NP,M,NMP increased the amount of Olsen-P significantly.The P balance was very significantly（P0.01） correlated with the Olsen-P.With an average surplus of 100 kg phosphorus per hm2,the soil Olsen-P increased by 3.85,0.29 and 0.53 mg·kg-1,in the NP,M,and NPM treatments,respectively.Application of chemical fertilizer increased Olsen-P was 11.6 times higher than that of manure,followed by the chemical fertilizer combined with manure.Conclusion Changes of soil Olsen-P followed soil phosphorus surplus and the close correlation between the increased amount of Olsen-P and the form applied phosphorus were observed.Long-term application of chemical P fertilizer resulted in the increase of the amount of Olsen-P is higher than manure obviously in black loessial soil.