Preparation of a P-rich Soil Amendment and Its Effect on the Pot Growth of White Mustard

A pot growing test was conducted to evaluate the amelioration effect of the P-rich soil amendment on acid soil and pot growth effect of the white mustard. The P-rich soil amendment was prepared by calcinating a mixture of low-grade rock phosphate and dolomite with a fusing agent of CaSO₄. The amendment was rich in P, Si, Ca, Mg and S nutrient elements and displayed an alkalescent. The contents of nutrient elements in the soil amendment dissolved in 0.1 mol·L^-1 citric acid solution were 8.94% P₂O₅, 19.82% CaO, 3.97% MgO, 13.37% SiO₂ and 0.86% SO₄^2-. Its pH value was 9.16. In the pot growing, the soil amendment was applied to the pot at four application rates, 1 g/Kg(L₁), 2 g/Kg(L₂), 3 g/Kg(L₃), 4 g/Kg(L₄) with 7 treatments and control (CK). The results of white mustard growth for 2 months indicated that applying the P-rich soil amendment could effectively increase the seeding emergence, the whole plant height, the stem thickness, the root length, the dry and wet biomass. The optimized application rate of the P-rich soil amendment was 3g·kg^-1. The growth rate of biomass (wet weight) reached 13.52%~115.80%. The experimental results also suggested that the P-rich soil amendment could increase the biomass of white mustard and ameliorate the acid soil, and improve the content of the available phosphorus in the soil.