6. Effect of nitrogen and phosphorus fertilization on yield of wheat at nine locations in western Oklahoma (1951-1952). Nitrogen applied as spring topdressing; all N plots received 40 pounds of P₂O₅ Per acre in bands at seeding time. Phosphorus plots received 40 pounds of nitrogen per acre broadcast at planting time. Data reproduced from Oklahoma Agricultural Experiment Station Bulletin No. 432.

7. Effect of irrigation on cotton Production from Amarillo fine sandy loam soil at Lubbock, Tex. (1951-1954). Treatment No. 1 no irrigation; No. 2 preplanting irrigation of 8.2 inches; No. 3 preplanting application of 8.2 inches Plus 4.3 inches in August; No. 4 preplanting application of 8.2 inches plus 3 inches in July and 4.3 inches in August. Average rainfall for the growing season during the 4 years-13.2 inches. Reproduced from Texas Agricultural Experiment Station Bulletin.

Some soils in the Rolling Red Plains lack nitrogen, phosphorus, and potassium. Cotton and sorghum respond to nitrogen and phosphorus fertilization under dryland conditions, particularly on sandy soils. Wheat growing in western Oklahoma also responds to nitrogen fertilization and to a lesser extent to applications of phosphorus.

The use of legumes and fertilizers in dryland farming in the High Plains has not been successful. Under irrigation, when both precipitation and irrigation water are precious items to be used with utmost care, fertilizers are useful for making better use of water.

8. Effect of nitrogen and phosphorus fertilizer on yield of grain sorghum and cotton on Miles fine sandy loam soil under dryland conditions at the Texas Agricultural Experiment Station, Chillicothe (1949-1953).

A preplanting irrigation to fill the soil reservoir is an excellent practice to insure a good cotton crop each year. One or two irrigations in addition to the pre-planting application can be profitable.

Nitrogen and phosphorus fertilizer is essential for continuous cotton under irrigation if maximum yields are to be obtained. Studies of the use of fertilizer at Lubbock showed that yield differences between fertilized and unfertilized continuous cotton become increasingly greater each year. Grain sorghum grown under irrigation in the High Plains requires more nitrogen fertilizer than does cotton.

Soil blowing and drifting can be serious on both cropland and rangeland. Ordinarily it is more serious on cropland, but overgrazed sandy rangelands can be damaged severely. Wind erosion on rangelands can be controlled by grazing management to maintain adequate cover, but that is difficult when you have limited feed reserves.

Prevention of wind erosion on cropland depends on effective surface roughness and vegetative cover. Surface roughness and stability of soil clods help combat wind erosion. Effective surface roughness can be developed on heavy soils by emergency tillage, such as chiseling and listing.

Some sandy soils with heavy clay subsurface layers within 24 inches of the surface can be altered by bringing the clay to the surface by deep plowing. This practice has been carried on with varying success in the High Plains of Texas and the Rolling Red Plains.

An effective way to reduce wind erosion on cropland is the production and management of crop residues.

Cotton and peanuts, leading cash crops on sandy soils that are subject to wind erosion, produce little effective residues for protection against soil blowing. Sorghum, with fair growing conditions, produces residues that, properly managed, can be effective against soil blowing. Narrow spacing of rows of sorghum on soils subject to severe blowing and drifting is more effective than conventional 40-inch plantings. Tillage operations to keep the sorghum residues on the soil surface help greatly in reducing blowing and drifting of soil.

Most cash-crop farmers have to rely on cotton and peanuts for a livelihood. They use various row combinations of high-residue producing crops (sorghum) and low-residue crops in order to insure some degree of protection against blowing. Growers of peanuts on sandy soils in the Crosstimbers plant two rows of grain sorghum and four to eight rows of peanuts in alternating strips.

Cotton growers in the High Plains use various row systems of cotton and sorghum and so achieve some protection against blowing. These various row systems are used for both wind erosion protection and more effective use of soil moisture. An approach to this two-sided problem is being made at the Department's field station at Big Spring, Tex., where a 2-year rotation of cotton and grain sorghum, in which 2 rows are cropped and 2 rows are fallow, is being studied.