A number of greenhouse and field experiments were carried out to determine the relative availability of phosphorus in superphosphate, waste pond, and rock phosphates. Sumter, Eutaw, and Cecil clays; Hartsells very fine sandy loam; Norfolk fine sandy loam; and Decatur clay loam were used in the greenhouse studies. The field experiments were conducted on decatur clay and clay loam, Cecil clay, Hartsells very fine sandy loam, and Norfolk fine sandy loam. The following general conclusions were drawn from these experiments: 1. The results from greenhouse pot tests and field experiments indicate that superphosphate is far superior to waste pond or rock phosphate as a source of phosphorus for the growth of cotton, sorghum, hairy vetch, and Austrian peas. 2. Neither rock nor waste pond phosphate increased the growth of vetch or sorghum significantly on Sumter clay (a calcareous soil), while superphosphate greatly increased the growth of these plants on this soil. 3. Waste pond and rock phosphate appear to be equal in their ability to supply phosphorus for plant growth. 4. As the rate of application of waste pond or rock phosphate was increased from 48 to 384 pounds of P2O5 per acre, there was very little, if any, increase in the crop yields.

Of 464 lines of sudan grass selfed for 2 years or more and grown in the nursery in 1941, 400 carried red coloring, 59 tan, and the remaining 5 lines were apparently segregating for red and tan. All but five of the tan or segregating lines originated from plant material known to contain Leoti sorghum genes. Data are presented that corroborate those of previous workers in showing that the inheritance of red and tan color is contolled by a single difference with red dominant. No possible causal organisms were isolated in connection with the leaf spots under observation. In the red lines the spots were red or bordered with red and similarly in the tan lines the discolorations were tan. The F2 and F3 data from crosses involving three types of leaf spotting as well as observations made among seed lines of sudan grass indicate that the particular leaf spots under observation here are conditioned by inheritance but that the inheritance--disregarding color--is not simple. Leaf spots vary in size, shape, and number and in the time and place appearance on the host plant.

Studies dealing with the addition of leguminous plant materials to soil as green manures, hay mulches, and accumulated residues were made to determine the effects of these various methods of application on the organic matter content of soils, the available soil nutrient supply, and yields of succeeding crops. The results obtained warrant the following conclusions: The average organic matter content of the cultivated soils in the Piedmont section of South Carolina is approximately 1%, while plant materials supplied by growing lespedeza, vetch, and crimson clover have raised the percentage of organic matter to 1.5. Only where lespedeza is grown continuously on the same soil for a number of years from 2.5 to 2.7% have been attained, indicating that amounts as high as 2.7% would be difficult to maintain under ordinary farming practices. Analyses for nitrate nitrogen show that under field conditions check soils produced a maximum of 41 p.p.m., while 4 tons of crimson clover applied either as a mulch on the surface, or incorporated with the soil accumulated 80 p.p.m. The lespedeza accumulated residues treatment maintained approximately 10 p.p.m. and remained at this level until these residues were incorporated, when 61 p.p.m. of nitrate nitrogen developed after 120 days of incubation. The acid-soluble phosphorus tests showed that soils from nonlegume areas contained 16 p.p.m. of available phosphorus, whereas 25 to 30 p.p.m. were found in the soil receiving the leguminous plant material. The replaceable potassium content varied with treatment, giving 48 to 64 p.p.m. for nonlegume plats, while the legume-treated soils contained from 136 to 188 p.p.m. Significant yield differences were secured for sorghum and rye from the addition of plant materials to the soil over that produced on the adjacent soil receiving only commercial fertilizer. These results suggest that leguminous plant additions are beneficial for soil improvement not only for the nitrogen supplied, but also because they render phosphorus and potassium more available.

A 47,000-acre demonstration project for the control of wind erosion was established by the Soil Conservation Service, U.S. Dept. of Agriculture, in 1934 in the vicinity of Dalhart, Texas. In 1936, a research station, consisting of 912 acres, was established near Dalhart to study the causes of wind erosion and to develop methods for its control. At both of these locations studies were made of the change in elevation of ground surface of certain types of land from year to year. This change in elevation was caused largely by wind action and was found to vary considerably with different types of vegetative cover. About 16,000 10-foot readings were taken on the demonstration project and several thousand other similar readings were taken at the Sand Dune Research Station. These were made during the years 1937 to 1940, inclusive, all of which were years of below normal rainfall. It was found that: 1. The amount of soil blowing from idle or abandoned lands showed a closer correlation to the precipitation that occurred during the previous years than did crop lands. 2. Milo which was harvested with a combine or header type machine suffered much less from erosion by blowing than did milo which was hand headed. 3. Certain crops, such as broomcorn, cane, and sudan, did not lose soil because of the fact that they are usually planted thickly. Crops such as hegari, milo, kafir, and corn lost a considerable amount of soil, apparently because these crops are usually planted rather far apart in order to produce a grain crop. When the spacing of sorghum crops was controlled, differences such as this were not so apparent. 4. Wheat was variable in its ability to control wind erosion, depending entirely upon the kind of stand obtained. 5. The removal of soil from rows which ran parallel to the direction of the prevailing wind was somewhat greater than from rows which were at right angles to the prevailing wind. This difference, however, was slight in comparison to the differences caused by other factors. 6. It is indicated that terraces without vegetation on their surface do not have much effect in preventing wind erosion. When the vegetation on the terrace was heavier than it was in the intervals between terraces, however, there was a definite tendency for terraces to collect most of the soil lost from the intervals between. 7. Weeds were variable in their ability to collect soil and resist erosion. The effect of Russian thistles depended on their growth, small thick stands accumulating soil during most of the blowing season, while large thistles broke away from their roots and left the ground bare. Silver leaf nightshade which is becoming a serious pest in the Dalhart vicinity was generally an exceedingly poor cover crop, often being no better than bare ground. Other weeds had a consistent tendency to accumulate soil during the blowing season. 8. Since winds of high velocity may occur in any month of the year, either removal or accumulation of soil may occur continually throughout the year. Whether a given field loses or accumulates soil, depends upon its vegetative cover at the time of each high wind.