| The effects of applying citric acid on the available phosphorus in calcareous soils, the absorption of phosphorus by wheat and biologic output were studied, using no phosphorus fertilizer and no citirc acid as control. The pot experiment showed that applying citric acid could remarkably reduce soil pH, and increased the contents of available phosphorus in calcareous soils; Under the condition of applying phosphorus rertilizer, when the application rate of citric acid was increased, soil pH was lowered, the contents of available phosphorus in calcareous soil was increased, the absorption of phosphorus by shoots and especially by roots were increased, and the biologic output of wheat was increased as well. |