Impacts of fertilizer application rates on phosphorus dynamics in salt-affected soil.

As a new rebuilding agricultural soil on the North China plains, the salt-affected soil had a short soil-forming process of about 30 years. This paper describes the effect of different fertilization systems on phosphorus (P) dynamics in saline-alkali uncultivated land, in the reserved natural salt-vegetation back zone, and in different phases of fertilization for 24 years on the North China plains. The treatments included control (or check, CK), N₁, N₂, P₁, P₂, N₁P₁, N₁P₂, N₂P₁, N₂P₂. The contents of total phosphorus (TP) showed a significantly decreasing trend from 1.32-1.38 g P/kg to 0.40-0.96 g P/kg. The contents of rapidly available P (RP) were low in the no-P fertilizer treatments and the RP concentrations increased with P fertilizer applications. Corn was the crop that used the most P, especially in the no-P and P fertilizer-only treatments. The treatment with 270 kg N/ha/year and 59 kg P/ha/year represents the most economical fertilizer rates for these salt-affected soils on the North China plains. [ABSTRACT FROM AUTHOR]