不同培肥措施对低肥力土壤生态系统蚯蚓种群数量的影响

Impact of soil fertility maintaining practice on earthworm population in low production agro-ecosystem in north China

通过在华北低肥力农田生态系统进行的不同土壤培肥试验 ,研究了不同秸秆还田方式和施肥措施对土壤中蚯蚓种群的影响。研究结果表明 :一年中 5次调查到的蚯蚓属于同一个目——后孔寡毛目 ,3科、6属、7种 ;在 7种蚯蚓中 ,天锡杜拉蚓Drawida gisti是该地区较低肥力土壤中的蚯蚓优势种。蚯蚓种群数量的季节变化趋势为 8月 >9月 >4月 >5月 >11月。在低肥力土壤上 ,单独施用化肥与对照相比可以增加蚯蚓的数量 ,施用化肥对蚯蚓的影响程度依赖于有机物的投入情况 ,没有有机物投入或只有麦秸还田条件下 ,施用化肥会对土壤中蚯蚓的种群数量产生负面影响 ,随着时间的延长 ,这种影响表现得比较明显。在同时用玉米秸和麦秸还田的情况下 ,施用化肥对蚯蚓的种群数量影响较小。有机肥的施入可以增加蚯蚓的种群数量 ,随着时间的延长这种趋势愈为明显。在几种秸秆还田的投入方式中 ,蚯蚓种群数量的大小次序为双倍麦还 >玉米麦秸全还 >麦还。因此在施用化肥的时候应当同时进行有机物投入 ,以保持土壤中良好的生物状况 ,这也是土壤培肥的重要环节。

The study was conducted in farmland with low productivity in Huantai County, Shandong Province of China North Plain to study the impact of organic manure and chemical fertilizer application on earthworm population. The result shows that there are 3 families, 6 genera and 7 species. Drawida gisti is the dominant species. The seasonal variation of the earthworm population density has following trend: August> September>April >May>November. The chemical fertilizer increased the earthworm population compared with the control treatment in the low soil fertility agro-ecosystem. The impact of fertilizer on the earthworm population depends on the input of organic material. With the increase of the organic input, the earthworm population density is increasing. The earthworm density of the treatments has the following ascending trend: Chemical fertilizer<Chemical fertilizer + Wheat Straw<Chemical Fertilizer + Wheat Straw + Corn Straw<Chemical Fertilizer +Wheat Straw + Corn Straw + Organic Fertilizer, this trend became more obvious with the time. The input of organic manure will increase the earthworm population. The earthworm population with double wheat straw return is more than that of wheat straw and wheat straw + corn straw under the same chemical fertilizer application. The results implied that in order to keep the good soil fertility, organic material input is critical.