东北黑土农田跳虫对植物叶片还田的响应

The response of Collembola to plant leaf returning into phaeozem cropland of Northeast China

杂草管理是农田生产活动的重要内容,影响农田生物多样性的维持。土壤动物为农田生物多样性重要组成部分,其对不同类型叶片还田的响应值得关注。本研究在中国科学院东北地理与农业生态研究所内的实验田中开展,利用放置凋落物袋的方式,研究2种杂草(旱稗、苋菜)叶片和2种玉米叶片(新鲜叶片及老熟叶片)的分解对土壤跳虫群落的影响,旨在为农田杂草管理提供科学依据。共获得6269只跳虫,隶属于5科9属11种,优势种为Thalassaphorura encarpata、Heteroisotoma sp.1和Folsomia sp.1。叶片添加增加了跳虫优势种的绝对数量,改变了跳虫群落结构,其中玉米新鲜叶片对跳虫群落结构影响最为显著(P<0.01),但对类群丰富度无影响,对多样性指数影响较小。与玉米老熟叶片相比,新鲜叶片对跳虫有更高的吸引作用,并持续时间更长。苋菜叶片分解速率最快,其次是玉米新鲜叶片,旱稗叶片和玉米老熟叶片分解较慢。表明叶片的基质质量对分解速率有重要影响。叶片添加增加了跳虫数量,但不同的叶片种类和分解时期对跳虫影响不同。叶片分解速率与跳虫数量没有显著的相关性,这可能与跳虫食性有关。

Weed management is an important practice in agricultural activities and is known to influence aboveground biodiversity in cropland. To understand the influence of weeds on soil biodiversity,we conducted a litter-bag experiment to investigate the effects of weed leaves（ Amaranthus retroflexus and Echinochloa hispidula） and maize leaves（ fresh and mature） on soil Collembola in Jilin Province,China. A total of 6269 collembolans were collected and classified into11 species representing 9 genera from 5 families. The dominant taxa were Thalassaphorura encarpata,Heteroisotoma sp. 1,and Folsomia sp. 1. Leaf addition,especially fresh corn leaves,significantly increased soil collembolan abundance and changed the community composition. Moreover,the decomposition rate of A. retroflexus leaves was significantly higher than the decomposition rates of the other leaves. The results indicated that the substrate quality of leaves plays an important role in collembolan community composition and thus in the process of decomposition in cropland. The decomposition rate of leaf had no significant correlation with the number of collembolans,which may be related in the diets of collembolans.