西天目集约经营雷竹林土壤硅存在形态与植物有效性研究

在雷竹主产地临安西天目选取了集约经营下不同种植年限(1、5、10、15 a)的雷竹林地,采集不同深度(0～10 cm、10～20 cm和20～40 cm)土样,运用逐级化学提取等技术,研究集约经营雷竹林土壤硅素含量与形态随种植年限和土壤剖面深度的变化规律,为雷竹林地土壤有效态硅调控提供理论依据。研究结果表明:(1)雷竹林土壤不同土层有效态硅的含量(0.084～0.318 g kg-1)和所占的比例(1.60%～12.3%)随种植年限和有机物覆盖年限的增加呈先下降后上升趋势;(2)雷竹林表层土壤无定形硅含量(2.58～5.15g kg-1)和所占比例(75.1%～87.7%)随种植年限的增加呈上升趋势;(3)覆盖有机物可同时促进无定形硅向有效态硅、有机结合态硅、铁锰(氢)氧化物结合态硅转变。

Fractions of silicon in soils of intensively managed Phyllostachys pracecox stands and their plant-availability

Phyllostachys pracecox stands under intensive management different in history (1, 5, 10 and 15 years) in West Tianmu, Linan City, a major Phyllostachys pracecox production area, were selected for sampling of soil profiles, 0~10 cm, 10~20 cm and 20~40 cm, separately, in depth. These samples were subjected to sequential extraction for analysis of variation of contents and fractions of silicon with plantation age and soil depth. Results show that the content (0.084~0.318 g kg^-1) of available Si and its proportion (1.60%~12.3%) to soil Si in the profiles varied with the age of plantation and organic mulching, showing a curve downwards first and then turning rise . The content (2.58~5.15 g kg^-1) of amorphous Si and its proportion (75.1%~87.7%) in the topsoil increased with the age of plantation. Organic mulching promoted transformation of amorphous Si into available Si, organic Si and Fe/Mn-oxide Si. The findings of the study may be offered as reference for regulation of soil bioavailable Si in the soil of Phyllostachys pracecox stands.