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A laboratory procedure was sought which would determine available sulfur in soils. As finally evolved, the method consists of extracting the sulfur with 0.5M NaHCO 3 at pH 8.5 and determining sulfur in the extract by the Johnson-Nishita procedure. Sulfur determined in this manner correlated very well with sulfur "A" values, an "r" value of 0.89 being obtained for 30 surface soils. Soils having < 10 ppm. S as determined by the proposed procedure generally responded to applications of sulfur.

Synopsis Organic amendments in addition to flooding were injurious to rice yields and increased plant Fe uptake but decreased Mn. The Fe levels in plants grown submerged in water and unsubmerged without organic amendments were found comparable, but the submerged yields were higher and were accompanied by a Mn uptake more than tenfold that of rice grown unsubmerged. Marked yield response to Mn was obtained in upland cultures. Levels of Mn found in plants indicate that rice has a high requirement for and an exceptionally high tolerance to Mn.

Propazine [2‐chloro‐4, 6‐bis (isopropylamino)‐s‐triazine] hydrolysis in acidic aqueous soil‐free systems was pH dependent, increasing with lower pH values. At a given pH, degradation followed first‐order kinetics. At 23.5C, the relationship was log t½ (days) = 0.59 pH −0.21. Adsorption of propazine by organic matter prepared from Michigan peat was also pH dependent, but both molecular and cationic adsorption occurred. An increased rate of degradation in the presence of organic matter was postulated as due to hydrolysis by ionized surface hydrogen. Increasing the calcium saturation resulted in decreased hydrolysis. Increasing the CaCl2 concentration of the propazine‐organic matter‐aqueous system had no effect on acid hydrolysis. In the salt‐amended systems, an increased hydrolysis, to be expected from the lower pH in the ambient solution, was apparently offset by a decreased hydrolysis due to the lowered amounts of ionized surface hydrogen.