ITH ONE FIGURE) Ever since the ten essential elements for plant nutrition were established by the work of SACHS, BOUSSINGAULT, NOBBE, and other investigators, sulphur has been recognized as one of them. The ash analysis method of determining sulphur in plants, however, which was in use during this early period, showed such a small amount present that the needs of the plant were thought to be amply taken care of by the supply in the soil. Contributions during the last twenty years by BERTHELOT,

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... ARLOW, FRAPS, Goss, BESTLE, SHERMAN, and others have shown that in ashing plant material much of the sulphur may be lost. The amount of sulphur in plants as determined by analyzing the ash may be only a fraction of the real amount. Thus the whole question of the relation of sulphur to plant nutrition has been reopened, for if plants use several times as much sulphur as had been supposed, then perhaps the supply in the soil is not sufficient for the needs of the plant. Recently there have been a number of contributions to the subject. The first questions to be considered have naturally been how much sulphur do crops use and what are the supplies to meet these needs. Thus the first problems to be investigated have been the sulphur content of crops, the sulphur content of soils, the amount of sulphur brought down by the rain, and the amount lost by drainage, etc. Next, sulphur was added to soils found to be low in it to see whether the yield of crops would be increased. In the present paper no attempt is made even to approximate a resume of the sulphur literature, rather complete digests of which may be found in papers by CROCKER (4) and OLSON (Iv). Botanical Gazette, vol. 74] [32 This content downloaded from 080.082.077.083 on March 07, 2018 05:05:48 AM All use subject to University of Chicago Press Terms and Conditions (http://www.journals.uchicago.edu/t-and-1922] EATON-SULPHUR CONTEXT OF SOILS 33 ROBINSON and co-workers (22, 23) have analyzed a number of soils from different parts of the United States. The sulphur content is not high, the average for thirty-five important agricultural soils being 0.052 per cent, with a range of O.OI2-O.I56 per cent. SHEDD (24) finds the soils of Kentucky much poorer in sulphur than in phosphorus, and is inclined to place sulphur in the same class with phosphorus, potassium, and nitrogen as one of the chief limiting factors in crop production. In pot experiments with some of these soils, tobacco, soy beans, turnips, radishes, mustard, and alfalfa were benefited by sulphur fertilization. AMES and BOLTZ (i) report analyses for certain Ohio soils. The unfertilized soils range in sulphur content from 0.020 to as high as 0.055 per cent. BROWN and KELLOGG (2) find nearly twice as much sulphur as phosphorus in some of the larger soil areas of Iowa. The Mississippi less proves to be lowest, the soil samples in this area ranging in sulphur content from 44I to 847 pounds per two million pounds of soil. SWANSON and MILLER (27) have analyzed a number of the soils of Kansas and find that the cultivated soils analyzed have an average sulphur content of 0.027 per cent. Certain cultivated soils of Wisconsin, analyzed by HART and PETERSON (8), prove to be low in sulphur, the average being 0.020 per cent. They summarize the results of their analyses of a number of crops by stating that cereal crops remove from the soil about two-thirds as much sulphur trioxide as phosphorus pentoxide, the grasses of mixed hay as much sulphur as phosphorus, while the legume hays may take from the soil about as much sulphur as phosphorus, or, as in the case of alfalfa, more sulphur than phosphorus. Such crops as the cabbage and the turnip may remove two to three times as much sulphur trioxide as phosphorus pentoxide. REIMER and TARTAR (2I) give analyses for a number of Oregon soils. The range in the sulphur content of the surface soils is O.OI5-0.038 per cent. The phosphorus content is much greater. The sulphur fertilization of alfalfa grown on these soils produces greatly increased yields. Increased tonnage yields of 50-I000 per cent are secured, and the protein content is increased in some cases almost 2 per cent. In experiments in Washington by This content downloaded from 080.082.077.083 on March 07, 2018 05:05:48 AM All use subject to University of Chicago Press Terms and Conditions (http://www.journals.uchicago.edu/t-and-BOTANICAL GAZETTE [SEPTEMBER OLSON (ig), sulphur fertilization of alfalfa caused increased yields of 200-300 per cent. The purpose of the present investigation was (i) to increase our knowledge of the sulphur content of soils, and (2) to study the relation of sulphur to chlorophyll development in certain plants and its effect on the yield of these plants. The phosphorus content of all the soils was also determined. Phosphorus, together with nitrogen, is considered the most generally limiting element of crop production in the soils of the United States. It was thought that it would be interesting to compare the sulphur content of the soils with their content of such an element as phosphorus. Investigation SOIL ANALYSIS It is important for American agriculture to discover how many soils in the United States are suffering from lack of sulphur, as are the Oregon soils to which reference has already been made. The Oregon results might be duplicated, perhaps, in the case of many other soils; on the other hand, many soils are probably not lacking in sulphur. The samples were chosen with a view of giving some idea of what range in sulphur content might be expected in the soils of the eastern and central United States. Thus, samples from the Atlantic and Gulf coast regions, from one of the southern states, from certain of the north central states, and from Chicago were analyzed. Investigations on the Atlantic coast during the early history of the United States showed great benefits from the use of gypsum as a fertilizer. It was thought that the analysis of certain of the coast soils might give some interesting results. On the other hand, soil analyses and sulphur fertilization tests in the central states may be said to indicate, in general, a higher sulphur content in the soils of this section than in the coast soils. It was desired to analyze a number of soils of the central states to compare with the coast soils. It is well known that rain carries down much more sulphur from a smoky atmosphere than from one less contaminated with smoke. It was thought that the Chicago soils might prove to have a very high sulphur content, owing to this fact.