Development of China digital soil map at 1:50,000 scale

摘要

In order to meet the increasing demands for soil information of high resolution by different disciplines such as agriculture, environment, economy, and so on, a China Digital Soil Map at 1:50,000 scale (CDSM-50,000) has been developed since 1999. Soiland soil nutrient paper maps at 1:50,000 scale and soil profile records were collected from 2,300 counties of China. These maps and records were achieved during the period of the 2nd Chinese National Soil Survey from 1979 to 1985. A data model of CDSM-50,000 was developed, which contains 9 map layers. Data of about 150,000 soil profiles were, for the first time, integrated into CDSM-50,000. Every profile contains dozens of soil physical and chemical properties, such as soil depth, texture, organic matter, pH value, contents of N, P, K, S, etc. Soil nutrient information of plough layer samplings during the period from 1999 to 2008 was also collected and integrated into CDSM-50,000. To merge different county soil maps with different mapping standards into one map according to the data model of CDSM-50,000, a complicated soil data processing procedure was developed. Map data of 1,100 counties had been already merged to CDSM-50,000. The data model was approved to be successful to organize all soil surveyinformation of China in the last 30 years. Hundreds of examined soil profiles were collected from 5 provinces to test the reliability of developed CDSM-50,000. A quite nice coherence was found between CDSM-50,000 and the reality of soil type distribution. The finished digital soil maps were applied to cropland nutrient management, arable land fertility evaluation, strategy for controlling eutrophication and for study for climate change. This shows that CDSM-50,000 has played a great role for agriculture and environment.