Decomposition rate and silicon dynamic of mulching residue underPhyllostachys praecoxstands

Abstract

Phytolith鄄occluded organic carbon (PhytOC) in the soils is an important long鄄term carbon pool in terrestrial and plays an important role in regulation of global carbon cycle and mitigation of global climate warming. Intensive management technique including winter mulching has been widely used in the cultivation area of Phyllostachys praecox in the subtropical regions of China. The decomposition of mulching materials with high silicon content (bamboo leaves and rice straw) provides large amounts of silicon for Phyllostachys praecox ecosystem, thus affecting the formation of PhytOC in the ecosystem. To ascertain decomposition rate of mulching materials and silicon dynamic change of mulching residue on the land of Phyllostachys praecox stand, a decomposition experiment of mulching materials was conducted in the main typical production area of Phyllostachys praecox of Lin忆 an city, Zhejiang province by using decomposition tube method. The experiment results showed that the decomposition of rice straw and bamboo leaves mainly occurred between March and October. The decomposition peak of rice straw and bamboo leaves happened in July and August and the decomposition rates were 16.3% and 19. 1%, respectively. The decomposition half鄄life of rice straw and bamboo leaves was 228 d and 166 d, respectively. Rice straw and bamboo leaves were decomposed by 67.5% and 79.3% during one year decay, respectively. During one鄄year decomposition process, C contents in rice straw and bamboo leaves decreased with time,whereas N contents