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1. 15Nitrogen Uptake and Use Efficiency in Corn in Response to Fertilizer Rate and TimingUrea fertilizer applications at planting are becoming increasingly common for U.S. upper Midwest corn (Zea mays L.) production but wet spring conditions may result in significant nitrogen (N) fertilizer loss. Split-applications may avoid wet conditions and improve fertilizer uptake and use efficiency. Six field studies were performed to determine the effect of urea fertilizer rate and application timing on fertilizer-derived N (FDN) and soil-derived N (SDN) plant uptake over two consecutive... F. Fernandez, J. Spackman |
2. Pecan Response to Foliar Nickel ApplicationsNew Mexico’s pecan industry is one of the state’s most important agricultural assets. In 2010, pecan growers in Dona Ana County produced 19,504 kg of pecans, on over 10,000 ha and was worth over $123 million dollars, making Dona Ana county the number one pecan producing county in the nation. Nickel (Ni) is a component of the enzyme urease which is critical for the mobilization of nitrogen within the pecan tree. Deficiency symptoms are often expressed in pecan as a “mouse-ear”... R. Flynn, R. Heerema, S. Moran duran |
3. Measured and Predicted Temporal Changes in Soil Nitrate-n Levels from Late Summer to Early Spring in MontanaMost soil sampling is conducted from August to November in Montana because of better soil sampling conditions and because it provides more time for growers to make fertilizer decisions prior to application. Fertilizer guidelines in Montana are based on spring nitrate-N levels in the upper 2 ft because they are more indicative of growing season available N than fall nitrate-N levels. It is not known how much nitrate-N levels change between late summer and spring, nor is it known what factors affect... C. Jones, A. Lenssen, C. Chen, K. Mcvay, B. Stougaard, M. Westcott, J. Eckhoff, J. Weeding, M. Greenwood |
4. Managing Alfalfa Under Low Water or Drought Conditions... L. Lauriault |
5. Phosphorus Dynamics in Organic Matter-amended SoilsGenerally, phosphorus (P) is considered immobile in calcareous soils. Yet, numerous studies have found that the addition of organic wastes (e.g. manures) can enhance P mobility in these soils. We believe that the soluble organic matter present in these wastes increases P solubility by inhibiting the sorption of inorganic P on soil colloidal surfaces and subsequently preventing the formation of insoluble calcium phosphates. This results in increased P bioavailability. Likewise, tests used to assess... P. Grossl, R. Koenig, C. Jones, S. Trolove |
6. Urea and Ammonia Volatilization in Dryland Grass Seed Systems1The purpose of this study was to evaluate the influence of grass seed production conditions and management practices on NH3 volatilization, Kentucky bluegrass seed yields and N recovery from urea. Laboratory incubations suggest the potential for NH3 volatilization is greater from stands in which post-harvest residue is baled and removed than from stands in which residue is burned. Both burned and unburned stands have a surface pH > 7.9, although pH declined with time in the burned... R. Koenig, C. Proctor, W. Johnston, C. Golob |
7. Phosphorus Dynamics and Wheat Response to Applied P in a Spatially Variable Environment1Considerable spatial and temporal variability exists in soil chemical and physical properties across farm landscapes in eastern Washington State. The purpose of this research is to investigate changes in P mineralogy across the Palouse landscape and ultimately to determine the influence of mineralogy on plant-available P and fertilizer P responses at different landscape positions. Soil samples were collected from landscape positions with varying soil pH and soil test P concentrations. Mineral... R. Koenig |
8. Removing Nitrogen, Phosphate, and Fecal Coliform from Dairy Effluent Using Multi-soil-layer (Msl) SystemsDairy effluent disposal has long been a concern in Hawaii. Dairies often establish multiple lagoons to accumulate and store effluent. Occasionally, the lagoons overflow leading to the transfer of nutrients, such as nitrogen (N) and phosphorus (P), and other contaminants such as pathogenic bacteria to surface, subsurface, and coastal waters. The objective of this study was to quantify the effectiveness of MSL systems in removing inorganic nitrogen, phosphate, and fecal indicator organisms (Fecal... R. Yost, R. Pattnaik, G. Porter |
9. Nutrient Cycling in Effluent-irrigated Soil (Mollisol) Planted to Tropical Grasses in a Tropical Island EnvironmentDairy producers accumulate large quantities of effluent in lagoons. Lagoons occasionally overflow causing the nutrients and other contaminants in effluent to pollute the land and water bodies. Alternative uses of effluent are, therefore, urgently needed for a sustainable and environment-friendly dairy production. This study determined the sustainable effluent application rate and assessed the effects of effluent irrigation on plant and soil (Cumulic Haplustoll) properties. Five tropical grasses—... R. Valencia-gica, R. Yost, G. Porter, R. Pattnaik |