Assessment on Contents of Heavy Metals and Properties of Apple Orchard Soil with Different Planting Ages in Luochuan County

Soil properties and the contents of its heavy metals in the 20 and 60 age apple orchards of Luochuan County were studied and its environment quality was evaluated.Results show that all the soil samples collected from the orchards were loamy soil with the maximum content of CaCO3 being 141.71 g/kg,the average content of organic matter being more than 1.26%,and pH value being 7.95~8.62.The soil basically meets the requirements of green apple production.The contents of soil heavy metals in the orchards were higher than its background values.The maximum average content of As was 14.4 mg/kg;Cr,84.4 mg/kg;Cu,31.7 mg/kg;Pb,24.8 mg/kg;Ni,33.1 mg/kg,and Zn,144.5 mg/kg.However,single-factor indices of all the soil samples were below 1 and synthetic pollution indices of soil heavy metals were below 0.7.Soil environment quality in the orchards of Luochuan County is evaluated to be good,reaching the clean level.