保护性耕作对土壤线虫c-p类群及功能团的影响

以辽宁彰武县保护性耕作示范推广基地土壤为研究对象,通过实地调查和取样分析,对比研究了传统犁耕和6 a保护性耕作(免耕秸秆覆盖)条件下的土壤线虫c-p(colonizer-persister)类群及功能团,为评价保护性耕作的土壤生态效应提供理论依据.研究发现,与犁耕相比,保护性耕作显著增加了土壤线虫各c-p类群及绝大多数功能团的多度,但显著减少了Ba4和Om5功能团多度.此外,保护性耕作还改变了土壤线虫生活史和功能团的结构特征:在大部分研究土层,c-p1和c-p2线虫的相对多度显著提高,而c-p3、e-p4以及c-p3-5类群显著降低;Ba1、Ba2、Ba3、Fu4和H5功能团的相对多度显著提高,而Ba4、H3和Om5的相对多度显著降低,Fu2、H2和Om4相对多度的变化较复杂,在表土层表现为显著抑制,在15～30cm土层则为促进作用.土壤线虫c-p类群和功能团的多度及结构特征可能适合作为评价保护性耕作对土壤质量影响的生物学指标.

Effects of the conservation tillage on soil nematode c-p groups and functional guilds

In order to provide scientific basis for assessing soil ecological effects of the conservation tillage, Soil nematode c-p(colonizer-persister) groups and functional guilds were compared between traditional plow tillage(PT) and 6-yr conservation tillage(CT, no-tillage with straw mulch), in a case study in Zhangwu county of Liaoning Province. Results showed the conservation tillage significantly increased abundances of all the c-p groups and most of the guilds, reduced Ba4 and Om5 guild abundances. Also, the conservation tillage changed structure of soil nematode life-history and functional guilds. At most of the layers studied, relative abundances of c-p 1 and c-p2 nematodes significantly elevated, as declined for c-p3, c-p4 and c-p3-5. Relative abundances of Bal, Ba2, Ba3, Fu4 and H5 nematodes significantly increased, as decreased for Ba4, H3 and Om5. Fu2, H2 and Om4 nematode relative abundances showed relatively complex patterns of elevating at 0～5 cm depth, reducing at 15～30 cm layer. The study results showed abundances and structure of soil nematode c-p groups and functional guilds might be useful bio-indicators for evaluating the conservation tillage effects on soil quality.