杉木林改造后的土壤pH和养分动态

Seasonal dynamics of pH and soil nutrients of Cunninghamia lanceolata forest after reconstruction with broadleaved trees

利用红锥(Castanopsis hystrix)、火力楠(Michelia macclurel)、黎蒴(Castanopsis fissa)、山杜英(Elaeocarpussylvestris)和樟树(Cinnamomum camphora)对杉木林进行改造,从2008年4月到2009年4月,对5种改造林分的土壤养分动态进行研究。结果表明,各林分的土壤pH值变化范围为4.3～5.1,属强酸性土壤,一般呈现下降后上升的趋势。红锥林0～20 cm和20～40 cm土层、火力楠林、黎蒴林和山杜英林0～20 cm土层的碱解氮含量下降后上升,其他均为下降、上升后下降。土壤速效磷含量夏季(7月)较高,秋季(10月)较低。土壤有效钾呈现下降后上升的趋势。5个林分的土壤速效养分含量均为0～20 cm土层高于20～40 cm土层。

Cunninghamia lanceolata forest reconstruction was conducted using seedlings of Castanopsis hystrix, Michelia macclurel, Castanopsis fissa, Elaeocarpus sylvestris, Cinnamomum camphora, and soil nutrient dynamics was studied in five young Cunninghamia lanceolata stands after reconstruction with broadleaved trees from April 2008 tO April 2009. The results showed that the soils of the five young stands were rather strong in acidity with the pH value ranged from 4.3 to 5.1, which firstly decreased, and then increz^sed. Alkali-hydrolyzable N content decreased followed by a increase in 0-20 cm and 20-40 cm soil layers of C. hystrix stand, and in 0-20 cm soil layer of the stands ofM. macclurel, C. fissa and E. sylvestris, whereas it decreased followed by an increase and then decreased again in 0-20 cm soil layer of C. camphora stand and 20-40 cm soil layer of the five stands. Available P content was relatively high in July and low in October in all stands, whereas available K content tended to decrease and then increased. Available nutrients in the 0-20 cm layer were higher than those in 20-40 cm laver.