No abstract

Highly significant inverse yield‐protein relationships in wheat grain were found at each level of applied N in an irrigation‐N rate experiment on hard red winter wheat over a 3‐year period at North Platte, Nebraska. The chief effect of applied N with adequate water was to increase yields, while the chief or entire effect with severe water deficits was to increase protein content. In intermediate situations, N increased both yield and protein content. In dryland experiments in 1966 and 1967 showing significant grain yield response to applied N, protein content also increased. Where little or no yield response occurred, N mainly increased protein content. Content of NO3−N in the soil to a depth of 180 cm was also important in yield‐protein relationships. Average protein contents of about 20 hard red winter wheat varieties at different locations in Nebraska in 1966 and 1967 were also negatively related to grain yields. Protein contents varied more widely among locations than among varieties at each location.

Grain protein is important in human and animal nutrition and in relation to various culinary uses of flour. Various wheat (Triticum aestivum L.) cultivars are reported to vary widely in grain yield and protein concentrations. To study yield‐protein relationships, three soft red winter (Atlas 66, Knox 62, and Blue Boy) and three hard red winter (Norin 16, Tascosa, and Omaha) wheat cultivars were grown in a pot experiment at Muscle Shoals, Alabama. Response to 0, 100, 200, 400, 800, and 1,200 mg of N/pot (3 kg of Mountview silt loam) together with adequate, uniform rates of other nutrients was determined. All cultivars increased similarly in grain and straw yields, crude protein concentrations, and crude protein / pot with amount of applied N. The ranking for grain yields was: Tascosa > Blue Boy = Knox 62 > Omaha > Norin 16 > Atlas. The ranking for crude protein concentrations was in the reverse order. These trends indicate pronounced genetic differences among cultivars. At each rate of applied N, protein concentrations were also inversely related to grain and straw yields. Early uptake of N at forage and boot stages of growth was usually highly correlated with uptake in grain + straw at maturity. Nitrogen and moisture supply, light, temperature, and other growth factors greatly affect yield‐protein relationships among cultivars. Differences among cultivars tended to be greatest under optimum growth conditions.

Asbtract Distributions of NO3‐N were studied in deep loess‐derived profiles of Sharpsburg silty clay loam and Hastings‐Crete silt loams cropped to irrigated corn (Zea mays L.) in eastern Nebraska. Only with soils very high in N and high applications of fertilizer N was there any indication of appreciable leaching of NO3‐N below 180 cm in the profiles. Most of of the water‐ or KCI‐extractable N was usually found in the surface 0‐90 cm of soil. High correlations were found (r > 0.9) for a given soil site between amounts of NO3‐N in the surface 30 cm and totals to 180 cm. However, the proportion found in the surface soil varied widely among years and sites. At a given site there was a high correlation between NO3‐N in the profiles in the fall after harvest and corn yields without applied N the following year. Simple correlations of profile NO3‐N with percentage yields for different years, soils and management levels, however, were usually too low to have predictive value.

These field experiments were conducted in connection with the recent upsurge of interest in composting as a disposal method for municipal refuse. Heavy applications of compost made from municipal refuse and sewage sludge were evaluated for production of forage sorghum (Sorghum bicolor L. Moench × Sorghum sudanense P. Stapf.) and common bermudagrass (Cynodon dactylon L.) at Muscle Shoals, Ala., and for corn (Zea mays L.) at Johnson City, Tenn.Positive yield responses were observed t o annual compost application at rates up to 80 metric tons/ha on bermudagrass, 143 metric tons/ha on sorghum, and 112 metric tons/ha on corn. However, the highest yields of bermudagrass or sorghum attained from compost application were equaled or surpassed by application of fertilizer nitrogen (N) at the rate of 180 kg/ha together with adequate phosphorus (P) and potassium (K). Compost‐induced K deficiency was not observed in any crop.Incorporation of compost over a 2‐year period significantly increased moisture‐holding capacity and decreased bulk density and compression strength of the soil. The pH, organic matter, K, calcium (Ca), magnesium (Mg), and zinc (Zn) levels were also increased. Soil and plant tissue analyses indicated that potentially toxic amounts of Zn could accumulate in the soil if compost were applied at rates totaling several hundred tons/ha over a few years.