Aluminium Dynamics In Soils Of Intensively Cultivated Stands Of Phyllostachys Violascens

The diversifications on soil chemical properties and aluminium speciation in different soil profiles of intensively cultivated stands of Phyllostachys violascens planted in different years were investigated for better understanding the influence of soil acidification on soil chemical properties especially on distribution of aluminium speciation which would be a theoretical support to evaluate the contribution of aluminium toxicity to the recession land capability.This study was focused on the interaction amang soil chemical properties, soil acidity and contents of different aluminium species associated with conversions of rice paddy field, juvenile Taxus wallichiana forest field to Phyllostachys violascens plantation, using a set of eight stands (rice paddy field and juvenile Taxus wallichiana foresty field as controls of the trial, stands of Phyllostachys violascens that has been planted (in 2a, 6a, 8a, 11a, 16a and >20a)) in the town of Taihu headstream , Lin'an, China. Soil samples were collected from all sufficient deep horizons as 0-10cm, 10-20cm, 20-40cm, each trial has three subplots. The results indicated that over time due to Phyllostachys violascens cultivation, the value of soil pH was declined in the layers of surface (0-10cm) and subsurface (10-20cm), soil organic matters and cation exchang capability rose up afer organic material cover activities. The concentration of acetic acid extractable aluminium(Al-AA), 8-hydroxyquinoline extractable aluminium(Al-HQN), copper chloride extractable aluminium (AlCu), sodium pyrophosphate extactable aluminium(AlP) and substracting aluminium extracted by copper chloride from aluminium extracted by sodium pyrophosphate(AlP-AlCu) in the layers of surface(0-10cm) and subsurface (10-20cm) soils of Phyllostachys violascens were increased significantly over time due to Phyllostachys violascens cultivation and declined soil acidty. The changes of soil total noncristalline aluminium and inorganic noncrystalline aluminium were not observably.These results suggested that the risk of phytotoxic Al species and organic Al complexes in soils was going up in the layers of surface and subsurface as a result of sustained acidification over time due to intensively cultivated stands of Phyllostachys violascens, which was significantly increased in stands cultivated more than 16 years.