甘肃兴隆山主要森林类型凋落物累积量及持水特性

Water-holding characteristics and accumulation amount of the litters under main forest types in Xinglong Mountain of Gansu, Northwest China

2010年,采用野外实地观测与室内浸水法,对甘肃兴隆山6种主要森林类型(青杄林、青杄-白桦林、山杨-白桦林、灌丛林、落叶松林、油松林)林下凋落物的累积量、持水量、持水率和吸水速率进行了研究.结果表明:不同森林类型凋落物层累积量在13.40～46.32t·hm-2,为油松林>青杄-白桦林>落叶松林>青杄林>灌丛林>山杨-白桦林,且针叶林累积量高于阔叶林;半分解层累积量所占比例均高于未分解层.凋落物最大持水率为185.5%～303.6%,落叶松林最大,油松林最小,持水率与浸水时间呈对数关系;针叶林未分解层持水率均小于半分解层,而阔叶林则相反.凋落物最大持水量在3.94～8.59mm,为油松林>落叶松林>青杄-白桦林>青杄林>灌丛林>山杨-白桦林;持水量与浸水时间存在对数关系;半分解层持水量均大于未分解层.凋落物吸水速率与浸水时间存在幂函数关系,在浸水前1h内,吸水速率均直线下降,而浸水1.0h后吸水速率较小,且不同时段间变化较小;半分解层吸水速率高于未分解层.凋落物有效拦蓄量(深)为青杄-白桦林(5.97mm)>油松林(5.59mm)>落叶松林(5.46mm)>青杄林(4.30mm)>灌丛林(3.03mm)>山杨-白桦林(2.13mm).

By the methods of field survey and laboratory soaking extraction, an investigation was conducted on the accumulation amount, water-holding capacity, water-holding rate, and water-ab- sorption rate of the litters under six main forests （ Picea wilsonii forest, P. wilsonii - Betula platyphl- la forest, Populus davidiana - B. platyphlla forest, Cotonester multiglorus - Rosa xanthina shrubs, Pinus tabulaeformis forest, and Larix principis-rupprechtii forest） in Xinglong Mountain of Gansu. The accumulation amount of the litters under the forests was 13.40-46.32 t . hm-2, and in the or- der of P. tabulaeformis forest 〉 P. wilsonii - B. platyphlla forest 〉 L. principis-rupprechtii forest 〉 P. wilsonii forest 〉 C. multiglorus-R, xanthina shrubs 〉 P. davidiana - B. platyphlla forest. The litter storage of coniferous forests was greater than that of broadleaved forests, and the storage per- centage of semi-decomposed litters was all higher than that of un-decomposed litters. The maximum water-holding rate of the litters was 185.5%-303.6%, being the highest for L. principis-rupprechtii forest and the lowest for P. tabulaeformis forest. The litters＇ water-holding capacity changed loga- rithmically with their soaking time. For coniferous forests, un-decomposed litters had a lower water- holding rate than semi-decomposed litters; whereas for broadleaved forests, it was in adverse. The maximum water-holding capacity of the litters varied from 3.94 mm to 8.59 mm, and was in the or- der of P. tabulaeformiz forest 〉 L. principis-rupprechtii forest 〉 P. wilsonii - B. platyphlla forest 〉 P. wilsonii forest 〉 C. multiglorus - R. xanthina shrubs 〉 P. davidiana - B. platyphlla forest. The litters＇ water-holding capacity also changed logarithmically with immersing time, and the half-de-composed litters had a larger water-holding capacity than un-decomposed litters. The water-absorp- tion rate of the litters presented a power function with immersing time. Within the first one hour of immersed in water, the water-absorption rate of the litters declined linearly ; after the first one hour, the litters＇ water-absorption rate became smaller, and changed slowly at different immersed stages. Semi-decomposed litters had a higher water-absorption rate than un-decomposed litters. The effec- tive retaining amount （depth） of the litters was in the order of P. wilsonii - B. platyphlla forest （5.97 mm） 〉 P. tabulaeformis forest （5.59 mm） 〉 L. principis-rupprechtii forest （5.46 mm）〉P. wilsonii forest （4.30 mm） 〉 C. multiglorus - R. xanthina shrubs （3.03 mm） 〉P. davidiana - B. platyphlla forest （2.13 mm）.