Some chemical and biological effects of cyanamid and certain other nitrogenous fertilizers on various Iowa soils
1934
Brown, M.H.
1. Applications of cyanamid and sodium nitrate increased the pH of the soil, while ammonium sulfate and Ammo Phos caused a decrease when these materials were applied in amounts equivalent to 21 and 63 pounds of nitrogen per acre, respectively. 2. Applications of cyanamid caused a marked increase in the amount of soluble phosphorus present in soil, while sodium nitrate and ammonium sulfate applied in equivalent amounts of nitrogen had no effect. 3. Applications of cyanamid, sodium nitrate, ammonium sulfate, and Ammo Phos exerted no marked effect on the nitrate accumulation in the soil, on the number of molds and bacteria present, on the ammonifying power of the soil, or on the nitrifying power of the soil. Applications of superphosphate, however, brought about some increase in biological activity. 4. The number of molds in soil had no marked effect on the amount of ammonia produced from dried blood in ammonification tests. The amounts produced were not affected by marked changes in numbers of bacteria.
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