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
Soil biotic communities can strongly impact plant performance.In this paper,we ask the question:how longlasting the effect of the soil microbial community on plant growth is.We examined the plant growth rates at three...Soil biotic communities can strongly impact plant performance.In this paper,we ask the question:how longlasting the effect of the soil microbial community on plant growth is.We examined the plant growth rates at three stages:early,mid and late growth.We performed two growth experiments with Jacobaea vulgaris,which lasted 49 and 63 days in sterilized soil or live soil.In a third experiment,we examined the effect of the timing of soil inoculation prior to planting on the relative growth rate of J.vulgaris with four different timing treatments.In all experiments,differences in biomass of plants grown in sterilized soil and live soil increased throughout the experiment.Also,the relative growth rate of plants in the sterilized soil was only significantly higher than that of plants in the live soil in the first two to three weeks.In the third experiment,plant biomass decreased with increasing time between inoculation and planting.Overall,our results showed that plants of J.vulgaris grew less well in live soil than in sterilized soil.The negative effects of soil inoculation on plant mass appeared to extend over the whole growth period but arise from the negative effects on relative growth rates that occurred in the first weeks.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.
文摘Soil biotic communities can strongly impact plant performance.In this paper,we ask the question:how longlasting the effect of the soil microbial community on plant growth is.We examined the plant growth rates at three stages:early,mid and late growth.We performed two growth experiments with Jacobaea vulgaris,which lasted 49 and 63 days in sterilized soil or live soil.In a third experiment,we examined the effect of the timing of soil inoculation prior to planting on the relative growth rate of J.vulgaris with four different timing treatments.In all experiments,differences in biomass of plants grown in sterilized soil and live soil increased throughout the experiment.Also,the relative growth rate of plants in the sterilized soil was only significantly higher than that of plants in the live soil in the first two to three weeks.In the third experiment,plant biomass decreased with increasing time between inoculation and planting.Overall,our results showed that plants of J.vulgaris grew less well in live soil than in sterilized soil.The negative effects of soil inoculation on plant mass appeared to extend over the whole growth period but arise from the negative effects on relative growth rates that occurred in the first weeks.
