Browse on keywords: fertility microbes
Search results on 05/21/13
4067. Marsh, J.A.P., H.A. Davies and E. Grossbard. 1977. The effect of herbicides on respiration and transformation of nitrogen in two soils. I. Metribuzin and glyphosate.. Weed Research, 17:77-82.
The effects of metribuzin and glyphosate at 100 ppm on carbon dioxide evolution and nitrogen transformation in two soils have been investigated in the laboratory. Both herbicides reduced carbon dioxide evolution from Boddington Barn soil (organic carbon content 1.5%, pH 6.6) at some dates, but neither gave any consistent effects on Triangle soil (organic carbon content 4.0%, pH 5.1). Both metribuzin and glyphosate stimulated mineralization of nitrogen for at least 9 weeks. Only metribuzin on Triangle soil gave any indication of inhibition of nitrofication. Metribuzin degraded more rapidly in Triangle soil than in Boddington Barn.
4766. Murray, T.J.. 1921. The effects of straw on the biological soil processes.. Soil Sci. 12(3):233-259.
Experiments are conducted to describe microbial processes. The addition of straw to soil has a harmful effect on nitrate accumulation. Nitrate being lost is transformed to organic N. The process of ammonification is inhibited above 0.9% straw content of soil. Straw is a source of energy for N fixing bacteria. Straw does not effect the biodiversity of microbe populations. Straw stimulates bacteria reproduction. Nitrates from straw are transformed to organic N and are not available to plants. The intensity of the reaction depends on the amount of the straw. T: many, eg.: Effects of straw on nitrogen fixation. Number of bacteria in soils variously treated. Bacteria in various straw treatments.
6638. Steel, S.. 1990. Your tiniest livestock.. Farm Journal (mid-January).
Discusses the importance of the microbial population for a number of factors. Available P levels have increased in low input systems years after the last commercial P was added, probably due to microbial action. The microbial biomass from a LISA system had a higher proportion of N than that from a conventional system. Microbes improve soil structure. A marked increase in infiltration was observed after only one application of manure. John Doran found 10-26% more microbes on manured plots than unmanured. Also, there were more microbes in the top few inches of land planted to oats and clover than to corn or soybeans. This is mostly due to carbon levels and C:N ratios.
7066. Vandecaveye, S.C. ad S. Anderson. 1934. Longevity of Azotobacter in soils treated with lime and superphosphate.. J. Am. Soc. Agron., 26:353-364.
Few Azotobacter in soils below pH 6.0, according to early studies; need several thousand colonies per gram of dry soil to get appreciable N fixation: liming increased Azotobacter in acid soils; phosphorus addition had no effect; large seasonal fluctuation in Azotobacter; highest numbers in spring and fall. T: Seasonal Azotobacter changes; effect of pH, lime, P.