3种人工林凋落物的持水特性

Water Holding Characteristics of Litter in Three Plantations

用浸水法对2个常绿阔叶混交林和1个杉木林凋落物的贮量、持水量、持水率和吸水速率进行了研究.结果表明,每公顷常绿阔叶混交林1、常绿阔叶混交林2和杉木林的凋落物干质量分别为2 220、898和1 255 kg.3种林分中常绿阔叶混交林1的凋落物最大持水量较大,达6.8×103kg.hm-2,杉木林居中,为4.1×103kg.hm-2,常绿阔叶混交林2较小,为3.3×103kg.hm-2.在浸泡不同时间后,林分的凋落物持水率均呈现常绿阔叶混交林2>杉木林>常绿阔叶混交林1.常绿阔叶混交林1、常绿阔叶混交林2和杉木林的凋落物最大持水率分别为403%、462%和423%.常绿阔叶混交林2的凋落物吸水速率居首位,常绿阔叶混交林1中等,杉木林最小.凋落物持水量和凋落物持水率随着浸泡时间的增长按照对数关系增加,吸水速率则随着浸泡时间的增长按照乘幂关系下降.

The characteristics, including litter amounts, water holding capacity, and proportional water holding capacity and absorption rates, were studied in two evergreen broadleaf mixed plantations and a Cunninghamia lanceolata plantation using water immersing method to understand water-conserving functions of the three plantations. The dry mass of litter in evergreen broadleaf mixed plantation 1, evergreen broadleaf mixed plantation 2 and C. lanceolata plantation were 2 220,898 and 1 255 kg · hm^-2, respectively. The biggest water holding capacity of floor mass of evergreen broadleaf mixed plantation 1 was the largest （6. 8 × 10^3 kg · hm^-2） among the three plantations, followed by the C. lanceolata plantation （4.1 × 10^3 kg · hm^-2） and the evergreen broadleaf mixed plantation 2 （3.3 × 10^3 kg · hm^-2）. The order of proportional water holding capacity as a percentage of the dry mass of litter was evergreen broadleaf mixed plantation 2 〉 C. lanceolata plantation 〉 evergreen broadleaf mixed plantation 1 after every time immersed in water. The biggest proportional water holding capacity as a percentage of the dry mass of litter in evergreen broadleaf mixed plantation 1, evergreen broadleaf mixed plantation 2 and C. lanceolata plantation were 403% ,462% and 423% , respectively. The water absorption rate of litter of evergreen broadleaf mixed plantation 2 was the largest, followed by the evergreen broadleaf mixed plantation 1 and the C. lanceolata plantation. The total water holding capacity and proportional water holding capacity of litter increased logarithmically with increasing time immersed in water. Water absorption rates of litter in all plantations decreased according to power correlation with increasing time immersed in water.