In order to understand fully characteristics of soil acility and alkalinity,metal element contents of citrus orchards in Chongqing,soil pH and available nutrition content of agrochemical soil(around trees crown) and background soil(between tree lines) from 104 citrus orchards were detected in 2008.The results showed that soil pH decreased by 9.6% in 84.6% citrus orchards and soil pH value was below 6.5 in 56.8% citrus orchards.Soil pH were below 5.5 in 32.7% citrus orchards.Around 7.8% citrus orchards did n...