不同密度三倍体毛白杨试验林土壤养分的动态变化

Changes of Soil Nutrients Contents in the Triploid Populus tomentosa Plantations with Five Stand Spacings

以三倍体毛白杨不同密度试验林为研究对象,采用随机区组试验设计研究了4 a生长期内5个不同密度(2 m×2 m、2 m×3 m、2 m×4 m、2 m×5 m和3 m×4 m)试验林的0 20、20 40、40 60 cm土壤层次的理化指标(pH值、有机质、全N、碱解N、全P、有效P、全K和速效K含量),结果表明:(1)4 a生长期内,三倍体毛白杨各密度试验林3个土层的pH值均增加,尤其是低密度(3 m×4 m)试验林增幅最大,且随土层加深碱性增强。(2)各密度试验林3个土层有机质含量呈先降后升的变化,高密度(2 m×2 m、2 m×3 m)试验林有机质消耗量显著比其它密度的大。(3)土壤全P和有效P含量呈先升后降的变化特点,高密度(2 m×2 m)试验林有效P消耗量显著比其它密度的大。(4)高密度(2 m×2 m)试验林土壤碱解N含量增幅显著;中、低密度(2 m×4 m、3 m×4 m)试验林土壤速效K含量降幅显著;其它养分指标无明显变化规律。

Abstract：A randomized block field experiment was carried out from 2005 -2008 （a rotation period） to study the changes of soil nutrient contents in three soil layers （0 - 20 cm, 20- 40 cm and 40 - 60 cm） of the triploid Pop- ulus tornentosa （cv. B304） plantations with five stand spacings （2 m ×2 m, 2 m ×3 m, 2 m ×4 m, 2 m ×5 m and 3 m ×4m）. The results showed that ： （ 1 ） Soil pH value increased under different stand spacing after the 4-year growing, especially in low-density plantations （3 m×4 m） and deeper soil layers. （2） The contents of soil organic matter decreased at first and then increased. In the high-density plantations （2 m ×2 m and 2 m ×3 m）, the con- tents of soil organic matter were significantly lower than that of the others. （3） The contents of soil total P and avail- able P increased at first and then decreased. The available P in the plantation with stand density of 2 m×2 m was significantly lower than that of the others. （4） Significantly higher soil available N content was found in the planta- tion with stand density of 2 m × 2 m while significantly lower available K in the middle-（2 m × 4 m） and low-density （3 m x4 m） plantations. No regular variation was found in the contents of the other soil nutrients.