We examined soil fumigation effects on soil protozoan abundance and community structure in greenhouses and explored the capacity of protozoa to recover after disturbances. A randomized complete block design with five ...We examined soil fumigation effects on soil protozoan abundance and community structure in greenhouses and explored the capacity of protozoa to recover after disturbances. A randomized complete block design with five treatments and 4 replicates was set up in Qingzhou, Shandong Province, China. In addition to methyl bromide （MB） and untreated control （CK）, three alternative fumigation treatments were studied, including MB＋VIF （virtually impermeable films）, metham sodium （MS） and MS＋VIF. Tomato cultivars （Lyeopersicum eseulentum Mill）, cv. Maofen-802 were selected as test crops. Results of four fumigations were demonstrated through three-level ten-fold dilution methodology. Abundance of three groups of soil protozoa-flagellates, amoebae, and ciliates was measured from July 2002 to July 2003. Results indicated that two chemical fumigants and their combinations with physical material all significantly repressed soil protozoan abundance. MB was a stronger fumigant than MS, and use of VIF increased their repressive power. The most serious population reduction occurred in amoebae, thus, they also required the longest time to recover. MB and MS also changed the protozoan community structure. MB use decreased the percentage of amoebae but increased percentage of ciliates, while MS incrcased the percentagc of amoebae and decreased the percentage of flagellates in the protozoan community.展开更多
文摘We examined soil fumigation effects on soil protozoan abundance and community structure in greenhouses and explored the capacity of protozoa to recover after disturbances. A randomized complete block design with five treatments and 4 replicates was set up in Qingzhou, Shandong Province, China. In addition to methyl bromide （MB） and untreated control （CK）, three alternative fumigation treatments were studied, including MB＋VIF （virtually impermeable films）, metham sodium （MS） and MS＋VIF. Tomato cultivars （Lyeopersicum eseulentum Mill）, cv. Maofen-802 were selected as test crops. Results of four fumigations were demonstrated through three-level ten-fold dilution methodology. Abundance of three groups of soil protozoa-flagellates, amoebae, and ciliates was measured from July 2002 to July 2003. Results indicated that two chemical fumigants and their combinations with physical material all significantly repressed soil protozoan abundance. MB was a stronger fumigant than MS, and use of VIF increased their repressive power. The most serious population reduction occurred in amoebae, thus, they also required the longest time to recover. MB and MS also changed the protozoan community structure. MB use decreased the percentage of amoebae but increased percentage of ciliates, while MS incrcased the percentagc of amoebae and decreased the percentage of flagellates in the protozoan community.
