银川市黄河滩地土壤性状空间分布特征与肥力质量评价

Spatial Distribution of Soil Properties and Evaluation of Fertility Quality of Yellow River Floodplains in Yinchuan City

为阐明银川市黄河滩地土壤性质的空间分布特征,分析不同用地类型(荒地、林地、耕地、退耕地)之间土壤性质的差异,通过均匀取样法实地采集银川市黄河滩地耕层土壤样品92份,采用地统计学和模糊数学法对土壤容重、孔隙度、田间持水量等物理性质和pH、电导率、可溶性盐、有机质、全氮、全磷、全钾、碱解氮、有效磷、速效钾、硝态氮、铵态氮等化学性质的空间分布特征进行了分析和综合评价。结果表明:银川市黄河滩地表层土壤容重在1.07~1.52 g/cm^(3),田间持水量为18.18%~31.16%,总孔隙度介于33.60%~49.83%,毛管孔隙度在26.67%~36.43%,非毛管孔隙度为5.6%~17.00%;土壤均为盐碱土,氮、磷元素含量偏低,其余养分含量处于中等水平;不同用地类型之间,林地的物理特征表现最优,退耕地土壤pH显著高于耕地(P<0.05),电导率、可溶性盐和铵态氮含量均表现为退耕地显著高于其他3种用地类型(P<0.05),全磷含量表现为林地显著低于其他3种用地类型(P<0.05),有效磷含量表现为耕地和退耕地显著高于林地和荒地(P<0.05),其余理化性状差异不显著;田间持水量、总孔隙度和非毛管孔隙度在空间上的分布总体表现为上游偏大、下游偏小,容重、pH、电导率、可溶性盐含量、有效磷含量在空间上的分布特征与之相反,其余理化性状空间分布特征规律性不明显。研究区土壤综合肥力指数(IFI)平均值处于中下水平,土壤pH和无机态氮是土壤质量的制约因子,要改善土壤酸碱度、提高氮素含量才能提高整体土壤质量水平。

To elucidate the spatial distribution characteristics of soil properties in the Yellow River floodplains in Yinchuan and to analyze the differences in soil properties among different land use types,92 soil samples were collected from the cultivated layers by homogeneous sampling,soil properties included bulk density,porosity,field water capacity,pH,electrical conductivity,salinity,organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus,available potassium,nitrate nitrogen and ammonium nitrogen were determined and their spatial distribution characteristics were discussed,meanwhile soil fertility quality were also comprehensively evaluated by geostatistics and fuzzy mathematical methods.The results showed that soil bulk weight was of 1.07–1.52 g/cm^(3),field water capacity of 18.18%–31.16%,total porosity of 33.60%–49.83%,capillary porosity of 26.67%–36.43%,and non-capillary porosity of 5.6%–17.00%;soils were alkaline and with low nitrogen and phosphorus contents.Forest land had the best soil physical characteristics,the pH of the abandoned land was significantly higher than that of the cropland(P<0.05),electrical conductivity,salinity and ammonium nitrogen were significantly higher in the fallow land than in the other three land types(P<0.05),total phosphorus significantly lower in forest land than in the other three land types(P<0.05),and available phosphorus significantly higher in cropland and abandoned land than in forest and wasteland(P<0.05),while the other physicochemical properties were not significantly different among different land use types.The overall spatial distribution of field water capacity,total porosity and non-capillary porosity were larger upstream and smaller downstream,but opposite for bulk density,pH,electrical conductivity,salinity and available phosphorus,meanwhile the spatial distribution of the other physicochemical properties were irregular.The average value of soil integrated fertility index(IFI)was from the middle to the lower levels.Soil pH and inorganic nitrogen were the factors dominating soil quality indicating soil fertility can be improved mainly by improving pH and nitrogen content.