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1. Compost Application in California Tomato Cropping SystemsWith the implementation of California Assembly Bill (AB) 341 the availability of composts such as green waste (GW) and co-composted green waste and food waste (FW) as a soil amendment is increasing. The use of those organic amendments in agricultural production systems has been recommended as an effective strategy to make full use of organic waste and improve soil health. However, little information is available to tomato growers to reassess N inputs from using GW and FW. This study was conducted... Q. Yi, W. Horwath, S. Haas, X. Zhu-barker |
2. Ammonia Volatilization from Urea Vs. Alternative Nitrogen FertilizersSubstantial ammonia (NH3) volatilization can occur from surface application of urea on sandy soils with low pH buffering capacity such as those in the semi-arid Columbia Basin. Previous studies have reported loss of up to 60% of urea-N as ammonia on these soils. The objective of this study was to quantify ammonia loss per acre for urea and for alternative N fertilizer products, including: sulfur-coated urea (SCU), urea coated with NBPT urease inhibitor (urea + Agrotain), ammonium sulfate... S. Del moro, D. Sullivan, D. Horneck |
3. Chloride Effects on Nitrogen Uptake in Potato ProductionPotassium (K) can be supplied by potassium chloride (KCl) or sulfate (K2SO4) salts. Past research has shown that potatoes can take up and accumulate large amounts of chloride (Cl). Plant uptake of Cl can sometimes reduce petiole nitrate-N (NO3-N) concentration and it may have other effects on potato tuber yield and quality. In contrast, sulfate-S (SO4-S) typically does not compete strongly with NO3-N for plant uptake. This research was designed to evaluate the effect of Cl application on petiole... D. Sullivan, S. Light, D. Horneck |
4. Choosing Your Nitrogen Fertilizers Based on Ammonia VolatilizationUntil recently we have not been able to measure ammonia volatilization without impacting the surrounding environment. In the past we have used closed chambers with acid traps. These closed chambers did not reflect surrounding weather conditions, at the minimum both temperature and wind were influenced. The use of the vertical flux method allows ammonia in the air to be monitored and modeled to reflect ammonia loss without any interference of the surrounding environment. ... D. Sullivan, D. Horneck, J. Holcomb, G. Clough |
5. Ammonia VolatilizationLittle work has been reported on the loss of ammonia from soils where fertilizers have been applied in an undisturbed environment. There are a multitude of studies that have used a chamber of some sort to estimate ammonia loss. The use of a chamber of some sort means that the environment has to be altered making the data derived suspect when translated into a loss number such as kg/ha. The advent of passive vertical flux method by Wood et al., 2000 at Aubrn University in Alabama, allows for the... J. Holcomb, D. Horneck, G. Clough, D. Sullivan |
6. Influence of Dairy Manure Applications on Corn Nutrient UptakeCorn silage is the predominant crop in Idaho used for recovering phosphorus (P) that has accumulated in soils from dairy manure applications. However, little is known about how much phosphorus and other nutrients are being recovered under Idaho conditions. The objective of the study is to estimate phosphorus removal by irrigated corn silage crops cultivated throughout Southern Idaho with variable soil test P concentrations, and to identify effects of increasing soil test P on potassium (K), calcium... A. Moore, B. Brown, J. Ippolito, S. Hines, M. De haro marti, C. Falen, M. Chahine, T. Fife, R. Norell |
7. Evaluation of Irrigation Application Management Practices to Protect Groundwater QualityAgricultural management practices relative to irrigation application and type and frequency of nitrogen fertilizer application can impact levels of nitrates in groundwater. In recent history, high levels of nitrates were reported in public water supply wells in Goshen County, WY. Subsequent research efforts concluded that likely sources of nitrate were organic soil nitrogen and ammonium or nitrate fertilizer. Some focus was then turned to agricultural production higher up in the watershed. Best... K. Reddy, A. Wann, C. Wenzel |
8. Ammonia in the Columbia River GorgeAir in the Columbia River Gorge (CRG), a national monument, is impacting vegetation, haze and even rock hieroglyphs. Air quality in the CRG is derived from three geographical locations, the Gorge itself, West of the Cascades and East of the Cascade Mountains. Paper mills, power plants, wood burning stoves, forest fires, combustion engines, agriculture... all contribute to CRG haze. Ammonia is an important player in CRG haze. Ammonia combines with NOx and SOx to form ammonium sulfate and ammonium... D. Horneck |
9. Soil Testing to Improve Phosphorus Management on Intensive Vegetable Farms in HawaiiAccording to a recent survey of soil samples sent to the Agricultural Diagnostic Service Center (ADSC) at the University of Hawaii between October 2002 and September 2003, a majority of the samples showed soil test P (STP) levels in the high or excessive categories. Despite high soil test P, many farmers in Hawaii continue to apply P fertilizers. We began a project to evaluate soil P status on a range of vegetable farms throughout the state, to determine crop response to P fertilizers on soils... J. Deenik, S. Fukuda, R. Hamasaki, R. Shimabuku, R. Uchida |
10. The Effects of Calcium Source and Placement on Soil Factors and Wheat Performace FactorsWheat production is a critical component of U.S. Pacific Northwest agriculture, with approximately 80% of the global soft white wheat grain supply originating from this region. Ammonium-based nitrogen fertilizers are widely used on typically alkaline soils in Eastern Oregon dryland production areas by wheat growers. However the nitrification process that biologically converts ammonium to nitrate increases the soil concentration of H+. This process ultimately creates acidic soil conditions, which... S. Ellickson, A. Moore, R. Zemetra, C. Hagerty |
11. Floral Hemp Responses to Nitrogen Fertilization in the High DesertThe performance of floral hemp under N fertilization is influenced by environmental conditions, management and cultivar selection. This field study evaluated the effect of no supplemental N and N fertilization at 90 kg ha-1 on three hemp cultivars (Berry Blossom, Red Bordeaux, and Tahoe Cinco) in Northern Nevada. Nitrogen increased plant height, canopy cover, stem diameter and shoot biomass, but other physiological parameters were dependent on cultivar. We evaluated the use... F. Barrios masias, M. Farnisa, J. Solomon, G. Miller |