不同坡位杉木林土壤物理性质和养分的时空变化

对不同坡位杉木林土壤物理性质和养分的时空变化进行了研究。与2004年相比，2007年土壤容重在上坡减少，在中坡和下坡略增，各坡位的土壤毛管孔隙增加，土壤自然含水量显著增加；上坡和下坡的土壤非毛管孔隙、总孔隙和毛管持水量增加，而中坡相反。除了2004年的土壤非毛管孔隙和2007年的毛管持水量外，各坡位的土壤物理性质没有显著差异。与2004年相比，2007年各坡位的土壤pH几乎没有变化，各坡位的土壤有机质、全氮、全磷、全钾、碱解氮、速效磷和速效钾含量均显著增加。2004年和2007年各坡位的土壤pH相近，土壤有机质和全氮、全磷、全钾、碱解氮和2007年的速效钾含量均为下坡和中坡大于上坡。2004年各坡位的速效磷含量相近，2007年为下坡>上坡>中坡，2004年的速效钾含量为上坡>中坡>下坡。各坡位间的有机质和大多数养分存在显著差异。

Spatiotemporal variations of soil physical property and nutrient in Cunninghamia lanceolata stands with different slope positions

The study on temporal and spatial variations of soil physical property and nutrient was conducted in Cunninghamia lanceolata stands with different slope positions in 2004 and 2007. Compared with those in 2004, the soil buck density decreased in the upper-slope and slightly increased in the middle-slope and lower-slope; capillary porosity increased and natural water content significantly increased in the three slope; non-capillary porosity, total porosity and capillary moisture increased in the upper-slope and lower-slope and decreased in the middle-slope. There were no significant difference in soil physical property among the three slopes, except for non-capillary porosity in 2004 and capillary moisture in 2007. Compared with those in 2004, the pH value of the three slopes was almost not changed, whereas contents of the soil organic matter, total N, total P, total K, hydrolyzable N, available P and available K significantly increased in 2007; the pH value of the three slopes was closed to each other, whereas soil organic matter, total N, total P, total K and hydrolyzable N in the lower-slope and middle-slope were greater than those in the upper-slope in 2004 and 2007. The contents of available P of the three slopes were closed to each other in 2004 and was ordered by the lower-slope>the upper-slope > the middle-slope in 2007. Available K was ranked in order of the upper-slope > the middle-slope > the lower-slope in 2004, while it was greater in the lower-slope and middle-slope than in the upper-slope in 2007. There were significant differences in soil organic matter and most nutrients among the three slopes.