Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2001
Publication Date: November 1, 2001
Citation: COLLINS, H.P., COCHRAN, R.L., ALVA, A.K., BOYDSTON, R.A. SOIL MICROBIAL RESPONSES TO SOIL FUMIGATION AND COVER CROPS IN POTATO PRODUCTION SYSTEMS. AGRONOMY ABSTRACTS (ON CD) 2001. Technical Abstract: Commercial broad spectrum soil fumigants such as metam-sodium, used in potato production of the Columbia Basin of WA, are very effective for the control of soil borne pathogens, weeds, and nematodes that reduce crop yield and quality. Soil fumigation has been assumed to have minor impacts on the general soil microbial community, however, few data are available that adequately describe changes in microbial populations or their activities. The use of cover crops may serve as an alternative to fumigation as well as mitigating degradation to soil and environmental quality. We determined the effect of cover crops and metam sodium on the seasonal abundance, diversity, and biochemical activities of soil microbial communities. We measured soil microbial biomass, microbial populations, soil respiration, C and N mineralization and populations of several soil borne pathogens. Fumigation and cover crops had only minor effects on soil microbial populations and basic microbial functions in this initial year o plot establishment. Soil microbial biomass averaged 3 percent of the total soil C and showed only a slight increase when cover crops were present. Fumigation did not significantly effect the size of the microbial biomass or C and N mineralization potentials. However, fumigation significantly reduced total soil fungi and several soil pathogens, but stimulated the general bacterial population following fumigation. Significant differences in microbial processes, as a result of current management practices, will probably not be observed until soil C resources that stimulate the soil microflora increase. The efficacy of fumigation in Columbia Basin, WA soils and changes in microbial diversity and function require further study.