The dosage effects of phosphorous applications on yield of maize and chickpea under mono-cropping and intercropping systems were investigated using Jiang-Gu inorganic phosphorus fractionation method in irrigated sierozems in the Gansu Yellow River Irrigation District.

The results showed that the contents of inorganic phosphorus were in the following order: OP > Ca10-P > Ca8-P > Al-P > Fe-P > Ca2-P. With the increased uses of phosphate fertilizer, the contents of Ca2-P, Ca8-P, Al-P and Fe-P increased significantly, whereas the contents of O-P and Ca10-P did not show apparent changes. The inorganic P contents looked similar between mono-cropped and intercropped chickpeas, but lower in intercropped maize than mono-cropped one. Particularly, it was found that the Al-P at P40 level (P application rate of 40 kg·ha^-2), Fe-P at P0 (no P application) level, and Ca10-P at P80 level (80 kg P·ha^-2) of intercropped maize were significantly lower than those of mono-cropped one.