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Title: FUNGAL PRESENCE IN PAIRED CULTIVATED AND UNCULTIVATED SOILS IN CENTRAL IOWA

Author
item STAHL, PETER
item Parkin, Timothy
item CHRISTENSEN, MARTHA

Submitted to: Biology and Fertility of Soils
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soil is a dynamic living medium. Plant residues are degraded while soil humus is created, aggregates are formed and destroyed and formed again, nutrients are cycled and recycled. All of these processes are catalyzed by the microscopic organisms living among the sand grains and clay particles. Along with the bacteria, protozoans and nematodes, the fungi play a key role in preserving and enhancing soil quality. Agricultural activity, especially cultivation, can have a dramatic effect on fungal populations in soil. This study was done to compare the fungal populations in paired cultivated and uncultivated sites in order to better understand the impact of agriculture on soil microbiological properties. We found that uncultivated prairie soils had twice the fungal biomass than adjacent cultivated agricultural soils. The decrease in fungal biomass may be a result of altered soil environmental conditions resulting from tillage, or lower plant residue inputs. Agroecosystems with low levels of fungal biomass and activity in soil may be less sustainable due to the important roles fungi play in nutrient cycling and soil stabilization. Land managers interested in preserving and enhancing soil quality may wish to consider the impact of tillage on soil fungi.

Technical Abstract: Amount of fungal biomass in adjacent cultivated and uncultivated soils in central Iowa were estimated and compared by quantifying soil ergosterol concentrations and lengths of fungal hyphae present. Both indices of fungal biomass, with one exception, indicated that there was at least twice as much fungal biomass in uncultivated soil as in cultivated soil. Levels of microbial biomass carbon in uncultivated soils were also determined to be at least twice that in cultivated soils. Data collected in this study indicate that fungi may be more significantly impacted by agricultural soil management practices than other components of the soil microbial community. For two of the soils examined, calculated estimates denote that fungal biomass carbon represented approximately 20% of the total microbial biomass carbon in cultivated soil and about 33% of the microbial biomass carbon in uncultivated soil. Results of this study indicate that conventional agricultural practices result in a significant reduction of fungal biomass production in soil. Implications of differences in fungal biomass between the soils are discussed.