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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. Static Range Nitrogen Management in Northwest U.S. Sugarbeet ProductionNitrogen (N) management is important in sugarbeet production. This paper presents data to support a shift from a yield-based N management approach to a static range N management approach in the Northwest U.S. Production data and research show that yield-based N management can result in over application of N. Past research has been critical to improving and understanding sugarbeet N nutrition. However continued research is needed so cumulative data can be evaluated to improve management practices.... D. Bjorneberg, D. Tarkalson, D. Olsen |
3. Developing a Soil Health Assessment Framework for Specialty Crop Systems and Soils of Washington StateTo ensure productive soils, agricultural sustainability, and food security, it is vital to maintain and improve soil health. However, over the decades, intensive agricultural practices have led to a decline in soil health. While most of these intensive agricultural practices negatively affect soil health, research has shown that it is possible to resuscitate soils with practices such as over cropping, and crop rotation. Much of the research on soil health in the US has been done in agronomic systems... K.A. Sarpong, M. Mcilquham, L. Michel, D. Griffin |
4. Vineyard Soil Health: What Soil Properties are Most Important?Washington is the second leading producer of wine grapes (Vitis vinifera) in the US, with over 60,000 acres in vineyards. With such a substantial acreage, it is crucial to know how management practices may affect soil and vine health in wine grape systems. Soil health indicators and threshold values have been extensively studied in commodity crops in the Midwest and the northeastern US, but there is much less information available for specialty crops in the Pacific Northwest. Soil... M. Mcilquham, D. Griffin-lahue, K. Sarpong, L. Michel |
5. Evaluating Cover Crops for Nitrogen Management in a Walnut OrchardCover crops provide numerous benefits in agricultural systems. From increasing soil water storage to reducing fertilizer inputs, quantifying cover crops benefits is crucial in nutrient management, crop productivity, environmental sustainability, and growers' adoption. The goal of this study was to quantify nitrogen (N) and carbon (C) inputs in a walnut (Juglans regia L. 'Chandler') orchard that implemented three cover crop mixtures. The study site was a 5-year-old walnut... D. Zapata, X. Zhu-barker, K. Steenwerth, W. Horwath |
6. Soil Acidification: Identification, Prevention, Adaptation and RestorationLow soil pH is becoming far more common in Montana soils, with at least 23 counties having at least one field with pH less than 5.5. Soil pH levels in the top 6 inches as low as 3.8 have been measured, resulting in complete crop failure insome locations, yet the problem is highly variable across fields and within soil profiles. Nitrogen fertilizer rates applied above crop nitrogen needs are the largest cause of the acidification. Low soil pH should be verified before managementpractices... C. Jones, R. Engel, S. Ewing, P. Miller, K. Olson-rutz |
7. Soil SodicitySoil sodicity refers to the amount of sodium held on soil cation exchange sites. It is typically expressed either as the percentage of the soil cation exchange capacity filled with sodium ions (exchangeable sodium percentage or ESP), or as a ratio comparing exchangeable sodium to exchangeable calcium plus magnesium (sodium adsorption ratio or SAR). Our primary interest in soil sodium is its impact on soil structure. Sodium, like all soil cations, can flocculate clay particles if present in adequate... J. Walworth |
8. Use of Biological Soil Tests to Assess Soil Health and ProductivityCrops require sufficient nitrogen (N) to attain maximum yield potential. The intrinsic N supplying potential of soils is both directly and indirectly related to soil health. Soil health can reliably be predicted with existing soil tests, however, the ability to predict soil N availability, an important proxy for soil health, remains problematic due to a lack of a robust soil tests. As a result, fertilizer recommendations are often made without an accurate assessment of the amount of N that... W. Horwath |
9. Soil Respiration Tests As Predictors of Nitrogen Mineralization PotentialEstimation of seasonal N availability via a soil test has proved difficult. This information gap has lead to fertilizer recommendations based upon soil inorganic N levels found before planting and or preside dress. Complicating matters, as famers adopt new irrigation technologies, the results from older fertilizer rate trails may also be less applicable. In general, most when not all recommendations do not account for the contribution of soil N mineralization during the growing season, which has... W. Horwath |
10. Effect of Nitrogen Rate and Cropping System on Soil Nutrient Levels in a Long-term StudyDiversified continuous cropping systems in semi-arid regions of the northern Great Plains may enhance sustainability. A study initiated in 2000 in southwest Montana was designed to evaluate crop productivity and economic returns for no- till and organic rotations that included small grains, pulses, and oilseeds. Our specific objective presented here was to compare soil nutrient differences from 2004 to 2012, to learn if economically superior rotations were building or depleting soil nutrients.... C. Jones, P. Miller, T. Rick, A. Mccauley |
11. Sidedress Nitrogen Management in Lima BeansDifferent rates of sidedress nitrogen were applied to bush baby lima beans, with and without starter fertilizer and rhizobia inoculant in Yolo County, CA in 2012. Results documented that the use of starter fertilizer (nitrogen, phosphorus, and zinc) significantly enhanced yields compared to control plots without starter fertilizer. Use of rhizobia inoculant at planting did not result in enhanced yields compared with no inoculant. Sidedressing with ammonium sulfate at 20, 40, 60 and 80 lbs/acre... R. Long, R. Meyer |
12. Polymer Coated Urea (Duration) in Turfgrass: Impacts on Mowing, Visual, and Loss to EnvironmentFall and spring applied N fertilizer trials were conducted over two years in an effort to determine if various slow and controlled release N fertilizers were equivalent to traditional urea and to determine if a reduced rate of controlled release N could be used for improved N use efficiency. An unfertilized control was compared to sulfur coated urea (SCU), polymer and sulfur coated urea (XCU), polymer coated urea (Duration 75 or 125; DR) at 50, 75, and 100% (full) rate, and urea either applied... B. Hopkins, L. Sutton, C. Ransom, T. Blair, J. Moody, K. Manning, S. Bergsten |
13. Evaluation of Soil Salinity Conditions in California Central Coast Winegrape VineyardsSoil salinity conditions in the winegrape vineyard areas of the California Central Coast were assessed by regional surveys of surface soils over multiple years, and by comprehensive evaluations of deeper salinity profiles at select locations. The multiple-year survey indicated that salinity conditions were increasing significantly, during a period characterized by below-average rainfall for the region. The survey also indicated that salinity conditions were at levels which would be expected to... M. Battany |
14. 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 |