Sp lit-p lot field experiment with 2-year-old trip loid Populus tom en tosa clone S1, S6, S8 and S11 asexperimental materials and dip loid clone S10 as control was carried out in Wei County, Xintai City, HeibeiProvince. Annual change of soil nutrients in different p lantation and tree growth indices of height, DBH and volumewere determined. The results showed that soil pH increased and the content of organic matter decreased obviously ina year. Total N, available N, total P, available P, and total K decreased to some extents, while no regulation wasfound for available K. Different clones had no significant effect on the decline of the soil nutrients. Compared withthe control S10, the trip loid Populus tom entosa grew much better and took up more soil nutrients, with S8 as thebest and followed by S1 and S6.

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。