Photomicrographic Study of Soil Aggregates and Microorganisms As Influenced by Stubble Mulching and Plowing
1961
Turelle, J. W. | McCalla, T. M.
A photomicrographic study was made of the soil at the surface of stubble-mulched and plowed soil plots on July 7, August 28, and October 22, 1959. These soils had been subjected to stubble mulching or plowing for a 20-year period. The plots were in corn in 1959 following wheat in 1958. The surface of the stubble-mulched soil had larger soil aggregates and voids than plowed soil. Contact slides placed in the plots showed more microorganisms on stubble-mulched than on plowed soil. Water-stable aggregates from each type of tillage were also embedded in plastic compounds. These aggregates were sliced in sections 30 and 0.2µ thick and photomicrographed with light and electron microscopes, respectively. A major problem was the impregnation of soil aggregates for sectioning. The cross-sections of aggregates from stubble-mulched plots seem to be less compact and more porous than from plowed plots in both the 30 and 0.2µ sections of soil aggregrates.
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