Institute of Agricultural Resources and Regional Planning Academy of Agricultural Sciences/National Engineering Laboratory for Improving Quality of Arable Land 100081.R.China;
TERRA Agro-Bio Tech of Liege;
Institute of Plant Nutrition and Environment Academy of Agriculture and Forestry Sciences 100097.R.China;
Agricultural Environment and Resources Center Academy of Agricultural Sciences 130033.R.China;
long-term experiment; phosphorus fractions; soil profile; phosphorus availability; black soil;