Temporal and spatial variation of soil phosphorus in Phyllostachys praecox stands under intensive cultivation management

Key words: 
• pedology /
• intensive management /
• Phyllostachys praecox stand /
• soil phosphorous /
• temporal and spatial variation

Abstract: In 2006, we investigated and sampled soils in the main production area of Phyllostachys praecox stands, namely Sankou town, Lin'an city, choosing 1, 5, 10, 15 years plantation of bamboo stands(the paddy soil nearby as the beginning soil of Phyllostachys praecox stands as a check) and each by 4 replications. The objective of this study is to analyse the temporal and spatial variation of soil P along with planting years and the profile depth in Phyllostachys praecox stands during last 15 years under very intensive management models (very heavy fertilizer application yearly and heavy winter organic mulch started after 5 plantation years). Results indicated that, with the prolonging plantation time, the soil P content increased significantly(P<0.05). Soil P content in sub surface layer of 10-20 cm were gradually increased from 0 to 15 years, total P(TP) were 0.39,0.58,0.58,0.85 and 1.57 g·kg^-1 respectively, soil organic P were 130.16, 179.83, 183.61, 209.46 and 262.79 mg·kg^-1 respectively, and soil available P (Olsen P) were 6.78, 17.41, 33.49, 100.64 and 326.36 mg·kg^-1 respectively. The soil Olsen P content rose more rapidly than others with the prolonging plantation time, especially the accumulation velocity and intensity after 10 years. The results indicated that the phosphorus fertilizer was much exceeded which it was needed by Phyllostachys praecox stand. The soil TP,organic P and Olsen P content decreased with the profile depth increase as a whole. However, before the 10 years, the soil TP content was higher at surface and bottom layers, and lower in the middle of sub-surface layer. The soil Olsen P and organic P content from 1 to 15 years had reduced gradually from surface to bottom layers and the reducing rate was expanded with the plantation time. The highly accumulation of TP and Olsen P in the stand soil not only is a big waste of valuable P resources, but also is a potential danger of pollution to its surrounding's water body. We should adjust the management of fertilization in order to save the prime cost, achieve a high yield and protect environment.