长期定位施肥对土壤磷素吸持特性与淋失突变点影响的研究

The Impact on Soil Phosphorus Adsorption Characteristics and Leaching Change-point under Long-term Fertilization

通过对黄土旱塬地区长期(26a)定位施肥条件下的不同施肥处理的土壤磷素及其吸持参数的测定,以及通过室内模拟试验对土壤磷素淋失突变点的测定,研究了土壤磷素吸持参数、土壤磷素淋失突变点和部分土壤性质之间的关系。结果表明,经过26年的长期施肥,M75P60和M75N120P60处理的Olsen-P含量比CK处理的提高了10.7和9.8倍,全磷(T-P)含量比CK处理的提高了60.4%和57.7%。长期磷肥和有机肥投入可以减低土壤磷素的最大吸附量(Qm),而提高土壤磷素的吸附饱和度(DPSS),M75N120P60处理的Qm比CK的减低了49.92%,而DPSS比CK的提高了21.5倍。相关分析表明,黄土旱塬土壤的Qm与Olsen-P、T-P和CaCl2-P呈极显著的负相关关系(P<0.01),与土壤有机质呈显著负相关关系(P<0.05)。零净吸附浓度磷(EPC0)与Olsen-P和CaCl2-P呈极显著正相关关系,与T-P和SOM也达到显著正相关,而与pH值的关系不显著,但土壤磷最大缓冲能力(MBC)与pH值的关系达到极显著。DPSS与Olsen-P、T-P、CaCl2-P和SOM呈极显著正相关关系。土壤磷素淋失的Olsen-P突变点值与土壤吸持参数Qm呈极显著正相关,与MBC也达到显著正相关,与DPSS、Olsen-P、T-P和CaCl2-P呈极显著负相关关系。该地区土壤磷素淋失的Olsen-P突变点值与DPSS15%的值极为吻合,即可以用DPSS15%值作为该地土壤磷素淋失的突变点值。

Soil P and its sorption parameter of different fertilization treatments under 26-year long-term fertilizing field experiment on loess arid plateau were determined. Meanwhile, soil P leaching change-point was measured by lab cultivating experiment. Relations between part of soil properties and soil P adsorption parameter or P leaching change-point were studied, as well as the relationship between soil P adsorption parameters and P leaching ehange-point. The results showed： after 26 years of long-term fertilization, contents of Olsen-P of M75P60 and M75N120P60 respectively increased 10.7 and 9.8 times than CK treatment and content of T-P respectively increased 60.4% and 57.7% than CK treatment. Long-term application of phosphorus fertilizer and organic fertilizer reduced the maximum P adsorption capacity （Qm） of the soil, but increased the degree of P sorption saturation （DPSS） of the soil, the Qm of M75N120P60） reduced 49.92% than CK treatment, but DPSS of M75N120P60 increased 21.5 times than CK treatment. There was highly significant negative correlations between Qm and Olsen-P, T-P or CaC12-P（P〈0.01） and significant negative correlation between Qm and SOM （P〈0.05）. There was highly significant positive correlations between EPCo aml Olsen-P or CaC12-P and significant positive correlations between EPC0 and T-P or SOM, while the relationship with pH value was not significant, but MBC was highly related to pH value. DPSS was highly related to Olsen-P, T-P, CaCl2-P and SOM. The leaching change-point of soil Olsen-P had very significant positive correlation with Qm, and had significant positive correlation with MBC, while the relationships between it and DPSS ,Olsen-P ,Total-P or Ca C12-P was very significant. Results also indicated the value of soil Olsen-P leaching change-point of loess soil arid land coincided with DPSS15% value, namely, the value of DPSS15% can be taken as soil Olsen-P leaching change-point of the present study area.