. Bacteria in relation to soil fertility. Soil microbiology; Bacteriology, Agricultural. NITRIFICATION 121. Fig. 27.—Nltrlfy- i n g bacteria (nitrosococcus) (after Bonaz- zi). ceased and the ammonia in the sewage passed through unchanged. A water extract of fresh garden soil added to the tuhe soon re- started the process. This was confirmed by Warington, who further found that the oxidation of ammonia occurs in two dis- tinct stages. The first 'stage involves the changing of ammonia to nitrates, the second of changing the nitrites to nitrates. Only after many years of study was he even able to
. Bacteria in relation to soil fertility. Soil microbiology; Bacteriology, Agricultural. NITRIFICATION 121. Fig. 27.—Nltrlfy- i n g bacteria (nitrosococcus) (after Bonaz- zi). ceased and the ammonia in the sewage passed through unchanged. A water extract of fresh garden soil added to the tuhe soon re- started the process. This was confirmed by Warington, who further found that the oxidation of ammonia occurs in two dis- tinct stages. The first 'stage involves the changing of ammonia to nitrates, the second of changing the nitrites to nitrates. Only after many years of study was he even able to obtain very active impure cultures of the organism which changes nitrites to nitrates, and although he observed other organisms which change nitrites to nitrates he was un- able to obtain them in pure culture. In 1890 a Russian investigator, Wino- gradski, by a series of very ingenious experi- <; ments isolated the organisms which transform ammonia into ni- trites and the ones which transform nitrites into nitrates. He showed that the nitrifying organ- isms are sensitive to organic matter and hence do not develop on the gelatin plates used in the study of the ordinary soil or- ganisms. He grew them for some time on cultural media containing only mineral salts. He then trans- ferred them to gelatin plates on Fig. 28. — Nitrifying bacteria (nitrobacter) (after which Very feW GIbbs). colonies d e v e I -. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Greaves, Joseph Eames, 1880-; Greaves, Ethelyn O. , joint author. New York, D. Van Nostrand Co.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbacteriologyagricult
