Soil microbial biomass and selected soil enzyme activities: effect of fertilization and cropping practices
1985
Bolton, H. Jr | Elliott, L.F. | Papendick, R.I. | Bezdicek, D.F.
Selected microbiological properties of soils receiving different fertilizer management regimes were studied from adjoining wheat farms in the highly productive Palouse region of eastern Washington. Since 1909, the only N input to the soil of Farm Management System 1 has been through leguminous green manure crops consisting most recently of Austrian winter peas (Pisum sativum ssp. arvense L., Poir), plus native soil fertility for N and all other plant nutrients. The soil of Farm Management System 2 received regular applications of anhydrous ammonia, P and S at recommended rates for the last 30 yr. There were no differences in numbers of soil microorganisms as determined by plate counts; however, soil from management system 1 had significantly higher levels of urease, phosphatase and dehydrogenase at all three samplings and significantly higher soil microbial biomass at the first two samplings. The data indicate that management system 1 soil had a larger and more active soil microflora.
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