[Influence of simulated acid rain on nitrogen and phosphorus contents and their stoichiome-tric ratios of tea organs in a red soil region, China].

A 25-year-old tea plantation in a typical red soil region was selected for an in situ simulated acid rain experiment treated by pH 4.5, 3.5, 2.

Soil phosphorus functional fractions and tree tissue nutrient concentrations influenced by stand density in subtropical Chinese fir plantation forests.

Stand density regulation is an important measure of plantation forest management, and phosphorus (P) is often the limiting factor of tree productivity, especially in the subtropics and tropics. However, the stand density influence on ecosystem P cycling is unclear in Chinese fir (Cunninghamia lanceolata) plantations of subtropical China. We collected rhizosphere and bulk soils, leaves and twigs with different ages and roots with different orders to measure P and nitrogen (N) variables in Chinese fir plantations with low density (LDCF) and high density (HDCF) at Fujian and Hunan provinces of subtropical China.