Surface crop residue effects on soil fungi, carbon and moisture

H. Manns*¹, N. R. J. Emery¹, C. D. Maxwell¹, B. D. Kay² and K. Dunfield²

Crop residue left on the surface of the soil with No-till (NT) agriculture could be a valued resource. Surface application of dried plant residue increased soil organic carbon (C), aggregation and moisture with oats (Avena sativa) planted in outdoor plots in southern Ontario, Canada.

Over all plots in two seasons, soil moisture formed a significant linear regression with the percentage of macroaggregates (>0.25 mm size). With changes in the initial level of C from 2.5 to 7% with no residue, fungal hyphal length correlated to soil aggregation as well, but C did not increase significantly. With surface residue on soil with high initial C (6-7%), C increased with seeded alfalfa, oat straw, hay, and compost in 2003, and with corn stalks (chopped) in 2004. Interaction of the oat plant and residue resulted in significantly increased fungal hyphal length, with maximum hyphal length and C with oats in corn residue which both correlated to heavy fraction organic matter.

This indicates, that slow decomposition of corn stalks was more important than the amount of C released by the residue in the light fraction. Surface application of crop residue can increase soil moisture, aggregate size and C without a change in yield.


Source
Organic Agriculture Research Symposium held at the 25th Guelph Organic Conference, University of Guelph, January 2006


Author Locations & Affiliations
(1)Trent University, Peterborough, Ont, K9J 7B8, Can.
(2)University of Guelph, Guelph, Ont., N1G 2W1, Can.
Corresponding Author: Hida Manns hmanns@istar.ca


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