关键词: 高寒沙地, 乌柳人工防护林, 养分含量, 改良土壤

Abstract:

This study was conducted in restored Salix cheilophila plantations on high-cold sandy land, with the dune slacks served as the control, to study effects of different ages (6, 11, 16 and 21 years) of plantations on the soil water content, soil nutrients (soil organic matter, total nitrogen, nitrate nitrogen, ammonium nitrogen, available phosphorus and available potassium) content and soil pH value. The result showed that the soil water content in the plantation was influenced by the forest age and the soil depth (P<0.05). The water content in the top soil layers increased gradually with the extension of restoration time. The soil organic matters showed accumulation on the top soil layers compared with the lowland between dunes, and increased significantly with the extension of revegetation time. The content of the soil nutrients (soil organic matter, total nitrogen, nitrate nitrogen, ammonium nitrogen, available phosphorus and available potassium) varied significantly in different stand ages. In the same stand age, total nitrogen, nitrate nitrogen, ammonium nitrogen, available phosphorus, and available potassium contents in the upper soil layers (depth<100 cm) were higher than the lower soil layers. Soil pH values decreased gradually with the extension of restoration time. Correlation analysis showed the soil nutrient contents were positively and linearly correlated with soil organic matters but negatively linearly correlated with soil pH values. The research demonstrated that the soil chemical properties and soil fertility levels were improved gradually after the establishment of Salix cheilophila plantations in the vegetation restoration area.

Key words: high-cold sand land, Salix cheilophila plantation, nutrient content, soil improvement