Building soil structure in agroecosystems is important because it governs soil functions such as air and water movement, soil C stabilization, nutrient availability, and root system development. This study examined, under laboratory conditions, effects of organic amendments comprised of differing proportions of labile and semi-labile C on microbial community structure and macroaggregate formation in three variously textured soils where native structure was destroyed. Three amendment treatments were imposed (in order of increasing C lability): vegetable compost, dairy manure, hairy vetch ( Vicia villosa Roth). Formation of water stable macroaggregates and changes in microbial community structure were evaluated over 82 days. Regardless of soil type, formation of large macroaggregates (LMA, >2000. μm diameter) was highest in soils amended with vetch, followed by manure, non-amended control, and compost. Vetch and manure had greater microbially available C and caused an increase in fungal biomarkers in all soils. Regression analysis indicated that LMA formation was most strongly related to the relative abundance of the fungal fatty acid methyl ester (FAME) 18:2ω6c ( r= 0.55, p<. 0.001), fungal ergosterol ( r= 0.58, p<. 0.001), and microbial biomass ( r= 0.57, p<. 0.001). Non-metric multidimensional scaling (NMS) ordination of FAME profiles revealed that vetch and manure drove shifts toward fungal-dominated soil microbial communities and greater LMA formation in these soils. This study demonstrated that, due to their greater amounts of microbially available C, vetch or manure inputs can be used to promote fungal proliferation in order to maintain or improve soil structure.
|Number of pages||11|
|Journal||Applied Soil Ecology|
|State||Published - Mar 2014|
Bibliographical noteFunding Information:
We thank the editor, Dr. Heribert Insam, and the two anonymous reviewers for their thoughtful consideration of our manuscript, Georgia Zeigler for technical assistance, The University of Kentucky Division of Regulatory Services for soil testing, Julie Beale for help with microscopy of fungi, and Richard Dick and Nicola Lorenz for training in the fatty acid methyl ester method. This research was partially supported by a grant from the USDA Sustainable Agriculture Research and Education program (Southern SARE grant number GS08-065 ).
- Fatty acid methyl esters
- Microbial community
- Soil amendments
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)
- Soil Science