河套永济灌域土壤酸碱性与养分元素的关系

为了探讨干旱区灌区不同土地利用方式下盐碱化土壤剖面pH值与土壤水分和养分之间的关系，测定河套永济灌域荒地、林地、农田3种土地利用方式下0~20、20~40、40~60、60~80、80~100 cm剖面土壤pH值、含水率（SMC）、有机质（OM）、总氮（TN）、Zn、Cu的含量。结果表明：土壤pH值平均值为9.13；土壤含水率2.96%~31.35%；土壤OM、TN含量平均值分别为11.30、0.49 g·kg^-1；微量营养元素Zn、Cu平均值分别为107.20、32.78 mg·kg^-1，是相应背景值的1.9、1.7倍；3种土地利用方式下，土壤pH值差异性极显著（P<0.001），高低顺序为荒地 > 农田 > 林地，在垂直剖面含量差异并不显著（P>0.05）；3种土地利用方式下，土壤pH值主要受TN含量的影响，回归方程为Y_pH=9.336-0.409X_TN（P=0.001）；表层（0~40 cm）土壤pH值在一定程度上受Cu含量的影响，回归方程为Y_pH=0.018 X_Cu+8.523（P=0.003）。在河套永济灌域，一方面土壤碱化会导致土壤养分含量的贫瘠，另一方面施肥等农业活动在一定程度上降低了土壤表层碱性，同时造成微量元素的累积，加重土壤碱性的作用也非常显著，因此在增加农业投入的同时应合理科学地施用农药化肥。

Correlation between Soil pH and Nutrients in Yongji Irrigation Sub-district of Hetao Irrigation District,Inner Mongolia

Yongji Irrigation District was selected to investigate the correlation between pH,water contents and nutrients of saline-alkali soils as the investigative area in arid irrigation districts.The concentrations of pH,soil moisture content (SMC),organic matter (OM),total nitrogen (TN),Zn and Cu in soil profiles under 3 land-use patterns were measured to analyze the distribution of soil pH and the fitting equations.The results showed that the mean pH was 9.13;the soil moisture contents ranged from 2.96% to 31.35%;the average mean of OM and TN was 11.30 and 0.49 g·kg^-1,respectively;the mean value of Zn and Cu was 107.20 and 32.78 mg·kg^-1,1.9 and 1.7 times higher than the background value respectively.There were very significant differences in soil pH under 3 land-use patterns (P<0.001),decreasing in the order of wasteland > cropland > forestland,but there was similar among soil profiles (P>0.05).The variation in soil pH was primarily affected the variation in TN for 3 land-use patterns and the regression equation was Y_pH=9.336-0.409 X_TN(P=0.001);for topsoil (0-40 cm),the content of Cu suggested influences of soil pH,and the regression equation was Y_pH=0.018 X_Cu+8.523(P=0.003).So in our study,on the one hand soil basification resulted in the short of soil nutrients.On the other hand,agricultural activity such as fertilization may lower the pH in topsoil,but the accumulation of microelement caused by the activity significantly increased soil pH.Therefore,increasing the agriculture inputs should pay more attention to apply the pesticides and fertilizers scientifically and reasonably,at the same time.