Plant nutrient uptake from the soil is dependent on fertilizers applied, soil chemicals, and other factors. The purpose of this study is to quantify the effects of applied N fertilizers on P uptake by winter wheat (Triticum aestivum L.) and on the change of soil pH in the root zone related to reductions of inorganic P fractions in the rhizosphere soil. An experiment was conducted using different forms of N fertilizers (i.e., NH4+-N and NO3--N) with three N concentrations (0, 100, and 300 mg kg-1) applied in a calcareous soil. Biomass and total N uptake of the plant increased with the N concentrations and NH4+-N fertilizer resulted in a greater biomass than NO3--N nutrition. Total P uptake in the plant was also higher with NH4 +-N fertilizer than with the NO3--N nutrition. Compared with the zero N treatment, the soil pH around the roots decreased by 0.30 and 0.65 units, respectively, with N treatments of 100 and 300 mg kg -1 of NH4+-N fertilizer. The amount of soil inorganic P fractions in the root zone decreased with increasing NH 4+-N applied. The NO3--N treatments reduced rhizosphere acidification and had a less impact on the soil inorganic P fractions. The results suggest that enhancing rhizosphere acidification attributable to applications of NH4+-N fertilizer can increase P availability in calcareous soils for plant uptake.
Scopus Subject Areas
- Soil Science