The effects of tillage and rotation on soil nematode community in different depth

• Main Authors: Jia-SiangJhao, 趙嘉詳
• Other Authors: Song-Bin Chang
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/96847165081499568734

碩士 === 國立成功大學 === 生命科學系碩博士班 === 101 === Tillage and rotation are routine management practices applied in agriculture to improve the quality and productivity of crop. It has long been known that agricultural managements have significant impact on the soil nematode community. To investigate the effects of tillage and rotation on nematode community at different depths, a field experiment with a complete random block design was performed. The treatments were the combination of two tillage systems: no-till (NT) and conventional tillage (CT); and two crop rotations: maize-maize continuous cropping (MM) and maize-soybean rotation (MS). We used soil nematodes as bioindicator to assess the healthiness of soil. Nematodes were categorized into appropriate functional guilds, including bacterivores, fungivores, omnivore-predator, and plant-parasite. Nematode ecological indices were used to analyze the trend of soil nematode community. The results showed that the nematode channel ratio (NCR), NCR (Fil), structure index (SI) and SI (Fil) was higher in NT, which indicated that NT was dominated by bacterial decomposition pathway, and the soil food web suffered less disturbance in NT than in CT. MS was suitable for bacterivore of colonizer-persister class 1 (BV1): Mesorhabditis and Rhabditis, and BV2: Acrobeloides, Cephalobus and Heterocephalobus, leading to higher basal index (BI) and BI (Fil) in soil depth of 0-5 and 15-30 cm, and higher enrichment index (EI) and EI (Fil) in 5-15 cm deep. Furthermore, data showed a significant difference between depths, and bulk density played a key role in this study. Both of NCR and channel index (CI) indicated that the abundance of fungivores was lower in NT. There was a significant seasonal variation in soil nematodes community. The fatal winter in Northeast China brought about the significant vertical distribution of soil nematodes. Nematodes aggregated at 15-30 cm under NT, and at 5-15 cm under CT to find adequate temperature, soil moisture and food resources. Therefore, most of the soil nematode characteristics were impacted by depth and bulk density. Tylenchinae performed as fungivores in this study, especially the genus, Filenchus, and we suggested that Tylenchinae was better to be identified as fungivorous nematode.