Abstract: Based on the simulating cultivation experiments with three and two seperated compartments, the uptake effect of low grade rock phosphate by radish (Raphanus sativus) and wheat (Triticum aestivum) was analyzed. The Puptake by radish was restricted by the range of its root action. Radish could efficiently utilize rock phosphate in root compartment, and its dry weight was increased by 23.3%. Whether the rock phosphate was applied in root compartment or not, radish could only slightly utilize the rock phosphate applied in outer compartment, suggesting that it was activated by the small amount of organic acids infiltrating into outer compartment. This small part of phosphate utilized by radish could not obviously increase its dry weight. Wheat could not efficiently utilize low grade rock phosphate, whether it was applied to root compartment or outer compartment.

Key words: Acid soil, Radish, Wheat, Low-grade rock phosphate, crop growth, ammonia volatilization, straw-derived biochar, biochar-C loss, successive incorporation