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1. Stacking and Intersecting Nutrient 4Rs and Using In-Season Canopy Health and Petiole Nitrate Analysis on Russet Burbank PotatoesThe 4Rs of nutrient management is a global outreach with an aim to improve the sustainability of major cropping systems and the environment. The objective for this project is to evaluate individual and stacked 4R management practices and how they intersect in Russet Burbank potato at a field near Grace, Idaho in 2020. Nitrogen (N) fertilizer treatments included all combinations of two sources [urea vs polymer coated urea (PCU)], two rates (207 vs. 247 kg ha-1), and two timing/placements... S. Stapley, B. Hopkins |
2. Phosphorus and Potassium How Low Can You Go In Alfalfa?Tissues testing whole alfalfa plants at harvest can more accurately direct nutrient decisions. Developing critical nutrient levels in-season improves recommendations and applications, saving producers time, expense and effort since many growers take samples for hay quality. These three experiments were designed as follows: 1) Phosphorus (P) Rate study with differing rates of P2O5 using monoammonium phosphate (MAP); including: 0, 30, 60, 120, 240 lb P2O5... S. Norberg, S. Fransen, J. Harrison, D. Llewellyn, L. Whitefield |
3. Cover Crop Suitability for High Altitude Specialty Crop Organic Food ProductionThere is a growing interest in certified organic, specialty crop food production. With a larger population demanding organic products and organic products offering a higher premium for the producer, farmers are exploring the transition to organic farming. Organic producers in southeatstern Wyoming face multiple challenges in environments with high elevation, low precipitation, and have a short growing season. These challenges include management of persistent weeds, maintaining biodiversity, and... E. Moore, U. Norton |
4. Comparative Analysis of Soil Tests for Soil Health and Nutrient ManagementOptions for soil tests to address soil health and nutrient management objectives have diversified. We compare different soil test methods to evaluate their similarities for providing recommendations. Traditional soil tests, ion exchange membranes and analyses using the Haney Soil Health Nutrient Tool and Soil Health Index were compared for soil sampled from long-term cropping system trials near Ritzville Washington and from the R.J. Cook Agronomy Farm near Pullman WA. Despite strong... D. Huggins, C. Rieser, J. Reganold |
5. Dryland Organic Winter Wheat Improvement by the Inclusion of Composted Cattle Manure and Cover CropsOrganic agriculture in semi-arid environments can face several challenges in order to produce a successful crop. These include nitrogen and phosphorus deficiencies, moisture limitations, and high weed competition. Organic winter wheat (Triticum aestivum, L.)-fallow systems can be amended with composted cattle manure and with green manure from cover crops grown in the fallow phase to help increase wheat yields and quality. Cattle manure can improve soil health with the... C. Helseth, U. Norton |
6. Long-term Soil Profile Acidification: Obvious and Hidden DangersSoil acidification is occurring in the dryland farming region of the Northwest. Historically, soil acidification in the surface foot has been characterized; however, potential acidification of subsoil is unknown. We examined soil acidification for soil profiles (0 to 5 ft) at the R.J. Cook Agronomy Farm (92 ac) for 17 years following conversion from conventional tillage to continuous No-tillage (NT). Surface soil depths (0-12 in) acidified under continuous NT to below 5. Surprisingly, subsoil... D. Huggins, S. Shiwakoti |
7. Phosphorus and Zinc Interactions in PotatoPotato production requires high soil phosphorus (P) application with potential negative environmental and nutrient uptake effects. Impacts of high available P on species in potato cropping rotations are not adequately understood, nor have the causes of reduced yield and quality from excess P been fully explored. Antagonistic interactions with cationic micronutrients such as zinc (Zn) are plausible explanations. Two hydroponic experiments were conducted with Burbank potato to elucidate P and Zn... B. Webb, B. Hopkins, J. Ellsworth, S. Barben, B. Nichols, V. Jolley |
8. Optical Sensing for Nitrogen ManagementAlthough nitrogen (N) nutrition is as or more important than other nutrients, it has been largely ignored by those applying variable rate fertilizer (VRF) due to its loss potential for VRF applications that occur many weeks prior to crop need. Applications of N are best applied as close to crop uptake as possible in order to avoid leaching, denitrification, and other losses. Spatial variability for crop N need is often considerable due to differences in yield potential and, to a lesser degree,... B. Hopkins, S. Stephens, A. Shiffler |
9. Boron Fertilization in PotatoThe high value of potato (Solanum tuberosum L.), its inefficient rooting system and the low organic matter content of sandy soils on which potatoes are cultivated result in widespread application of boron (B) and other micronutrients. However, in times of cost trimming, B may become an omitted input regardless of soil test values. Further, soil tests for B may need to be updated for higher yields, better management or improved soil test methods. Russet Burbank potato was grown at... B. Webb, B. Hopkins, J. Ellsworth, V. Jolley, R. Callahan |
10. Precision N Management: Field-scale Application of N Efficiency Indices in WheatPreliminary evaluation of precision agricultural technologies showed that on-combine grain yield and protein monitors show promise as useful tools to characterize site- specific variations in crop performance. Variable rate applicators were shown to be proficient at achieving targeted site-specific application goals. First year comparisons of uniform versus precision N management in hard red winter wheat showed that similar yield and protein goals were met with 20% less applied N in the field-scale... D. Huggins |
11. Polymer Coated Urea in Potato ProductionNitrogen (N) is the most important mineral nutrient in potato (Solanum tuberosum) production. Studies show a steady, but not excessive, supply of N is important for maximum tuber yield, size, and solids, as well as minimal internal and external defects. Although more costly and labor intensive dry broadcast applications, growers typically apply the majority of N through the irrigation water in-season in order to maximize yield components. A controlled release N fertilizer, in the form of polymer-coated... B. Hopkins, T. Taysom, A. Shiffler, S. Stephens |
12. Phytosiderophore Exudation from the Roots of Iron Stressed Kentucky BluegrassSome Kentucky bluegrass (Poa pratensis L., KBG) cultivars are susceptible to iron (Fe) deficiency chlorosis when grown on calcareous soils and are routinely treated with Fe fertilizers. Aesthetics could be improved and this costly practice could potentially be eliminated with the use of cultivars resistant to Fe deficiency. Grasses are known to release phytosiderophore into the rhizosphere to dissolve Fe for plant use, and this characteristic has been used to screen for resistant... B. Hopkins, E. Buxton, V. Jolley, R. Christensen |
13. Biochar Volatile Matter Content Effects on Plant Growth and Nitrogen Transformations in a Tropical SoilBiochars made from modern pyrolysis methods have attracted widespread attention as potential soil amendments with agronomic value. A series of greenhouse experiments and laboratory incubations were conducted to assess the effects of biochar volatile matter (VM) content on plant growth, nitrogen (N) transformations, and microbial activities in an acid tropical soil. High VM biochar inhibited plant growth and reduced N uptake with and without the addition of fertilizers. Low VM charcoal supplemented... J. Deenik, A. Mcclellan, G. Uehara |
14. Residual Soil Nitrate and Potato Yield with Polymer Coated UreaPotato (Solanum tuberosum L.) requires steady, but not excessive nitrogen (N) supply for maximum tuber yield, size, and solids, as well as minimal internal and external defects. Although more costly and labor intensive than dry broadcast applications, growers typically apply a majority of N via fertigation. A controlled release N fertilizer, polymer coated urea (PCU), is a possible alternative to this growers’ standard practice. A newly formulated PCU may meet plant demand... B. Webb, B. Hopkins, J. Lemonte, T. Taysom, V. Jolley |
15. Elemental Sulfur with Iron: Kentucky BluegrassIron (Fe) is known to improve greenness of Kentucky bluegrass (KBG; Poa pratensis L.), although applications are relatively costly and labor intensive. A new fertilizer material, elemental sulfur impregnated with Fe (ES-Fe), may provide an alternative source of Fe for KBG. The effects of ES-Fe on KBG was evaluated comparing 55 lb-Fe ac-1 ES-Fe to ferrous sulfate (FS) at the same rate and chelated Fe as a foliar (CF) or soil applied (CS) in a glasshouse study. A separate... B. Hopkins, B. Webb, K. Marcroft, R. Christenson, V. Jolley |
16. Comparing Nutrient Availability in Low Fertility Soils Using Ion Exchange Resin Capsules and Plant Bioavailability Under Greenhouse ConditionsCommonly used soil resin analysis procedures have generally been developed to determine nutrient levels in agriculture soils. The purpose of the resin capsule procedure is to determine the amount of nutrient that correlates to that which is plant available. Desert soils contain lower levels of nutrients than agricultural soils, thus the validity of using resin capsules for desert soils is uncertain. In a previous incubation study it was determined that ion exchange resin capsules can be used as... B. Webb, B. Hopkins, M. Pletsch, D. Cook, M. Vickery, V. Jolley |
17. Improving Phosphorus Use Efficiency with Carbond PPhosphorus (P) fertilizer is integral for maximizing crop production and is used abundantly to achieve desired yields. However, reduction of P fertilizer is warranted, as it is the primary source of nutrient pollution in surface waters (eutrophication leading to hypoxia) and is derived from non-renewable mineral resources. Two research studies were conducted in 2009 to evaluate a new fertilizer product, Carbond® P against traditional fertilizers ammonium polyphosphate (APP) and monoammonium... B. Hopkins, B. Webb, M. Hill, C. Ransom |
18. Advances in Nutrient Use EfficiencyThe improvement of fertilizer efficiency is driven by narrow profit margins, environmental concerns, and resource conservation. Fertile soil is the foundation for food production and successful civilizations; it is developed and maintained through the addition of nutrients lost through harvest. However, nutrient uptake by plants is inherently inefficient and the nutrients remaining in the soil after uptake can cause negative air and water resource impacts. In addition, poor fertilizer efficiency... B. Hopkins |
19. 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 |
20. K Fixation and Significance for Crop ProductionSome cultivated soils in California found on the east side of the San Joaquin Valley (SJV) and derived from granitic parent material have the capacity to fix added K, making it unavailable or less available to crops. The main soil mineral responsible for K fixation is vermiculite, which is a weathering product of mica, and which can occur in the clay, silt, and fine-sand size fractions. We have developed a model that predicts the location of K-fixing soils in the region and a practical soil test... S. Pettygrove, T. O'geen, R. Southard |
21. Dicarboxylic Acid Polymer (Avail®) Phosphorus Fertilizer Additive: ReviewImproving P use efficiency (PUE) is desirable but difficult due to poor P solubility in soils. A dicarboxylic acid copolymer (AVAIL®) fertilizer additive may enhance PUE due to increased P solubility as a result of sequestering of interfering cations. Field trials have been conducted on a wide variety of crops, with results to AVAIL addition to P fertilizer mixed—seemingly related primarily to soil test P concentrations and fertilizer P rate. Positive results were seen in many of these... B. Hopkins, C. Ransom |
22. Polymer Coated Urea: Impacts on Water/air Quality with Surface Applicaton to Permanent SodNitrogen (N) is the most commonly used fertilizer and is essential to sustain the world’s populations. However, inherent inefficiencies in the soil-plant system result in losses of N to air and water, which can result in environmental quality problems. Two permanent sod turfgrass sites were fertilized with coated and uncoated urea and compared to an unfertilized control at 224 lb-N/ac. The polymer coated urea (PCU) was Duration 45 CR®. Fertilization resulted in increased growth and verdure... B. Hopkins, J. Lemonte, J. Summerhays, V. Jolley |
23. Effectiveness of Soil-applied Zinc for PecansPecan trees [Carya illinoinensis (Wangenh.) K. Koch] are very sensitive to Zn deficiency when grown in alkaline soils due to the formation of insoluble Zn hydroxides and carbonates which have low availability to pecan roots. We tested the efficacy of soil applied Zn-EDTA, Zn-Avail®, and ZnSO4 plus animal manure for supplying Zn to young pecans. Zn-EDTA supplied adequate Zn to potted pecan trees for one season only. The other soil Zn treatments had no appreciable effect. A soil sorption... J. Walworth, H. Nunez Moreno, K. Stevens |
24. 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 |
25. Using Irrigation Nitrogen Credits for Grain CropsNitrogen contamination of surface and groundwater is not uncommon in many areas of the U.S. and Colorado is no exception. Nitrate-nitrogen (NO3-N) in groundwater is the most common form of plant available nitrogen (N), especially in shallow, alluvial aquifers in areas with intensive irrigated agriculture. When utilized as a primary irrigation water supply, this nitrate can contribute a significant portion of a crop’s N supply. Crediting water nitrate is part of Colorado N fertilizer recommendations... T. Bauder, R. Waskom |
26. Phosphorus and Organic Acid Bonding Enhances Uptake Efficiency in Crop PlantsPhosphorus (P) fertilizer is essential for crop production, but reductions are warranted to conserve resources and minimize environmental impacts. Several lab, glasshouse, growth chamber, and field studies have been performed over the past five years with a new P fertilizer (Carbond P; CBP; Land View Fertilizer, Rupert, ID, USA) in calcareous, low OM soil. This presentation will be a review of that data. Studies comparing CBP to ammonium polyphosphate (APP) applied to soil show season-long increases... B. Hopkins, T. Blair, M. Hill, C. Ransom |
27. Polymer Coated Urea (ESN): Impacts on Potato Crop and N LossesPotato (Solanum tuberosum L.) production is sensitive to a steady, adequate supply of nitrogen (N). Synergistically optimizing grower profits while maximizing N use efficiency (NUE) is critical to conserve nonrenewable natural resources used to manufacture N fertilizer and minimize N pollution to water and the atmosphere. Polymer coated urea (PCU, Environmentally Smart N or ESN®) is one type of N fertilizer which uses temperature-controlled diffusion to control N release to better match plant... B. Hopkins, C. Ransom, T. Taysom, J. Lemonte |
28. 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 |
29. Drought and Nitrogen Stress Effects on Maize Canopy TemperatureWater scarcity is a major threat to the sustainability of irrigated agriculture. Management practices, such as limited irrigation, that seek to maximize the productivity of a limited water supply are critical. Remote sensing of crop canopy temperature is a useful tool for assessing crop water status and for more precise irrigation management. However, there is potential that nutrient deficiencies could compound the interpretation of water status from leaf temperature by altering leaf color and... A. Carroll, C. Lindsey, J. Baker, B. Hopkins, N. Hansen |
30. Phosphorus and Organic Acid Bonding Impacts at Varying Soil pHPhosphorus (P) fertilizer is essential for crop production, but reductions are warranted to conserve resources and minimize environmental impacts. Several lab, glasshouse, growth chamber, and field studies have been performed over the past six years with a new P fertilizer (Carbond P; CBP; Land View Fertilizer, Rupert, ID, USA) mostly in calcareous, low OM soil. Studies comparing CBP to ammonium polyphosphate (APP) and monoammonium phosphate (MAP) applied to soil show season-long increases in... T. Blair, C. Ransom, P. Hosford, J. Svedin, L. Sutton, A. Winchester, K. Manning, T. Hopkins, B. Hopkins |
31. Minimizing Nitrogen Inputs While Optimizing Verdure and Growth of Kentucky Bluegrass with Polymer Coated UreaNitrogen (N) fertilizer increases turfgrass verdure but also increases maintenance costs due primary to mowing. A two-year fertilization study was initiated April 2014 at two established Kentucky bluegrass sites with sand and loamy sand constructed field soils in Provo, UT. A grower’s standard practice (GSP) of urea split applied monthly was compared to blend of uncoated and polymer coated urea (PCU). The PCU was applied in 1, 2, or 3 split applications. The dual application applied at 50,... J. Buss, J. Gish, B. Hopkins |
32. Nitrogen Cycling and Fertilization in Legume Inclusive Cropping SystemsAmong other benefits, legumes contribute nitrogen (N) to subsequent crops. However, predicting the impact on yield and the timing of the N release is difficult. Regardless, adjustments in the N recommendation need to be made to avoid yield and crop quality problems, as well as negative environmental and social issues. Ideally, a reduction of pre-plant/early season N fertilizer is made based on field research. Two possible approaches are used, namely the Fertilizer Replacement Value (FRV) or the... B. Hopkins, J. Stark |
33. Nitrogen Nutrition Impact on Incidence of Rhizoctonia Infection of Agrostis StoloniferaCreeping bentgrass (Agrostis stolonifera L.) is tolerant of short mowing and high traffic, but these conditions increase pathogen susceptibility. A prevalent disease on bentgrass golf course greens and tee boxes is Brown Patch (Rhizoctoniasolani). One potential component of integrated pathogen management is correct nitrogen (N) fertilization. Bentgrass was grown in a chamber hydroponically at deficient, optimum, and excessive levels of N (2.5, 10, and 80 mM; equivalent to 6.9, 27.5, and 220... B. Hopkins, B. Black, B. Neville, C. Ewell, B. Geary |
34. Summarization of 471 Field Comparisons of Avail®Phosphorus (P) is a commonly deficient essential nutrient required for crop production. Economic, environmental, and conservation issues have motivated significant efforts to enhance fertilizer efficiency. AVAIL® is a specialty fertilizer product with claims of enhancing P use efficiency to potentially increase crop yield and quality. There have been at least 471 field comparisons to evaluate the effectiveness of AVAIL with a wide variety of crops. The objective of this summarization... B. Hopkins, K. Fernelius, M. Pryor |
35. Effects of Post-fire Soil Hydrophobicity on Inorganic Soil Nitrogen and Sulfur CyclingFire plays an important role in many native ecosystems, and its suppression has increased woody encroachment across the globe. Restoring native herbaceous communities following fire in encroached systems is often challenging. Post-fire soil hydrophobicity is one factor that may further limit site restoration by limiting soil moisture, which may in turn affect soil nutrient dynamics. We conducted a field study in a burned pinion-juniper woodland to understand the effects of post- fire soil hydrophobicity... B. Hopkins, K. Fernelius, M. Madsen, K. Russell, B. Roundy |
36. Turf Response to Reduced Rates of Polymer-coated UreaPolymer-coated urea (PCU) is a controlled-release fertilizer which can enhance nitrogen (N) use efficiency (NUE), reduce N pollution, reduce the need for repeated fertilizer applications, and reduce turfgrass shoot growth and associated costs. A PCU fertilizer rated for 120 d was applied at 50, 75, and 100% of the recommended full rate and compared to an unfertilized control and urea, applied either all at once or split monthly at the full recommended rate. Spring applied PCU showed no initial... B. Hopkins, C. Ransom, M. Ruth, T. Blair, L. Sutton, D. Bradshaw, K. Campbell |
37. Phosphorus and Organic Acid Bonding Enhances Uptake Efficiency and Yield Response in Crop PlantsPhosphorus (P) fertilizer is essential for crop production, but reductions are warranted to conserve resources and minimize environmental impacts. Several lab, glasshouse, growth chamber, and field studies have been performed over the past seven years with a new P fertilizer (Carbond P; CBP; Land View Fertilizer, Rupert, ID, USA) in calcareous, low OM soil. This paper will be a review of a portion of that data. Studies comparing CBP to ammonium polyphosphate (APP) and monoammonium phosphate (MAP)... B. Hopkins, T. Blair, J. Selman, C. Ransom, T. Hopkins |
38. Evaluation of Nitrogen Gas Loss from Polymer Coated and Polymer Sulfur Coated UreaPrevious research showed reduced nitrogen (N) gas emissions from polymer coated (PCU) and polymer sulfur coated urea (PSCU) when surface applied to soil. To further verify and quantify (N) loss, experiments were conducted to measure N gas emissions. Fertilizer prills were surface applied in a semi enclosed system to allow atmospheric gases in but to prevent loss of N gases from the headspace. Nitrous oxide (N2O) and ammonia (NH3) emissions were continuously measured every 20 minutes using photoacoustic... B. Hopkins, J. Svedin, C. Ransom, J. Buss, T. Blair |
39. Soil Water and Plant Canopy Sensor Technologies to Optimize Water and Nutrient UseIn many respects, agricultural technology is doing things now that were only imagined 20 to 30 years ago. Yet, grower tools that provide information and actionable knowledge on water and nutrient availability still remain a challenge. Clearly, rapid development of data transfer and processing platforms to date has provided rich maps of grower fields with overlays of location-specific information but their utility is still limited by our ability to accurately measure the parameters that are the... C. Campbell, N. Hansen, B. Hopkins, S. Evans, E. Campbell, A. Campbell, L. Rivera, D. Cobos |
40. Nitrogen and Water Interactions: Crop Production Systems Case StudiesFarmers and urban land managers have to strike a tenuous balance between achieving plant growth goals while responsibly managing natural resources. Water quality and scarcity issues are prominent concerns, along with soil quality preservation and conservation of fuel and fertilizer resources. The purpose of this presentation will be to highlight case studies where water and crop management practices were considered together to improve the efficiency of resource use. Evidences of water scarcity... B. Hopkins, N. Hansen |
41. Estimating Non-Fertilizer Nitrogen ContributionsCalifornia growers are facing increasing pressure to reduce nitrogen (N) losses in crop production. However, growers also need to maintain high yield levels to remain competitive. This is only possible when N inputs from all sources can be quantified and fertilizer application rates can be adjusted accordingly. The major sources of non-fertilizer N include soil residual nitrate, nitrate in the irrigation water and N mineralized during the growing season from organic material, such as soil organic... D. Geisseler |
42. Nitrous Oxide Emissions: Assessment and Mitigation in Irrigated Cotton in the Western USANitrogen from fertilizers is a major source of the potent greenhouse gas nitrous oxide (N2O) in irrigated cropping systems. To date, N2O emission data is scarce for row crops in the Western USA, especially, the desert southwest, where seasonal irrigation quantities can exceed 40 inches. The objective of these studies was to assess the effect of N fertilizer management on N2O emissions from furrow-, overhead sprinkler-, and subsurface drip-irrigated (SDI) cotton (Gossypium hirsutum L.) in... K. Bronson, D. Hunsaker, K. Thorp, C. Williams |
43. Crop Genetic Variability for Nutrient Use Efficiency: Biological Foundation, and Case of Spring WheatRecent advances in plant molecular biology have elucidated the mechanisms by which plant species adapt to low-nitrogen and low-phosphorus environments. This has paved the way to new perspectives and strategies for breeding and genetic engineering: the design of low-nitrogen and low-phosphorus cultivars in order to optimize nutrients use efficiency and enhance economic and environmental sustainability. In this paper, we review the enzymatic activity of root hair-embedded transmembrane proteins,... R. Nkoa Ondoua, M. Etesami |
44. Creating Prescription Variable Rate Irrigation and Fertilization Zones: Water and Nutrient Management InteractionsVariable rate irrigation (VRI) and variable rate fertilization (VRF) technologies allow irrigation and fertilization rates to be spatially customized. VRF is widely adopted, but VRI is an emerging technology with minimal adoption. As water is often the driving force in nutrient cycling, our overall objectives are to evaluate VRI influences on VRF and vice versa; and to combine these technologies to significantly increase crop yield and quality, conserve water, and minimize environmental impacts... J. Svedin, N. Hansen, R. Kerry, R. Christensen, B. Hopkins |
45. Improving Phosphorus Use Efficiency: Right Rate, Timing, and Placement and Enhanced Efficiency Fertilizer Sources: Research SummaryPhosphorus (P) fertilization is essential for societal sustainability. However, plant P uptake is inefficient due to poor soil P solubility, especially for crops such as potato (Solanum tuberosum L.) plant due to relatively poor rooting efficiency and high demand. Phosphorus use efficiency (PUE) improves with the right rate, timing, placement, and with using enhanced efficiency fertilizer products (EEF). We have conducted several dozen studies over nearly two decades showing PUE is improved... E. Shipp, T. Hopkins, B. Hopkins |
46. Nitrogen and Irrigation Water Interactions in Drought Stressed Kentucky BluegrassThere is increasing pressure in arid regions to conserve water, especially during drought. Turfgrass is the irrigated crop of greatest acreage in the United States and water use for irrigating turf is coming under scrutiny in urban ecosystems. The purpose of this study was to evaluate water use and growth of Kentucky bluegrass (Poa pratensis L.) under various irrigation and nitrogen (N) regimes. A study was conducted in an environmentally controlled growth chamber with established Kentucky... K. Russell, A. Hopkins, N. Hansen, B. Hopkins |
47. Polymer Coated Urea: Meeting Plant Needs While Mitigating Environmental Impacts — Research SummaryFertile soil is the foundation of food production and is maintained by replacing nutrients lost in harvest or to the atmosphere and hydrosphere. Nitrogen (N) accounts for approximately half of global fertilizer inputs. However, N recovery by plants is inherently inefficient due to “leaks” in the system, causing air and water pollution. Additionally, poor fertilizer efficiency is a waste of natural resources and potentially reduces yields, crop quality, and grower profits. Nitrogen-use... S. Bartholomew, T. Hopkins, B. Hopkins |
48. Overview of the Efficacy of BiostimulantsSo-called “biostimulants” have been around a long time, but interest in these crop production products is growing exponentially. A survey of major fertilizer companies indicates it is one of the top three current trends in their businesses— with significant research, development, and investment. However, this major trend in agriculture is fraught with misperception, confusion, and generally lacking credentialed recommendations. Biostimulant is not listed as a word... B. Hopkins |
49. 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 |
50. Wastewater Reuse in the Arid West: Increased Water Supplies and New Paradigms for Nutrient ManagementIrrigated agriculture in the western United States is one of the most productive systems in the world. However, in recent years the security of water supplies for agriculture have come into question. Currently states that use Colorado Riverwater are in the process of formalizing drought contingency plans to prevent reservoirs along the Colorado River from going dry. Competition for water with the agricultural sector include both urban and environmental uses. Treated municipal effluent... C. Williams |
51. Polymer Coated Urea and Urea Blends on PotatoPotato (Solanum tuberosum L.) is a globally important crop with significant economic and environmental impacts. Nitrogen (N) has a large impact in both instances. Polymer coated urea (PCU) is a N source with the ability of improving production and the environment. Environmentally Smart Nitrogen (ESN) is a PCU that may reduce the need for continual N application throughout the season. The objective of this research was to evaluate the impacts on potato tuber yield and quality with uncoated... E. Carlock, A. Weigel, T. Searle, T. Hopkins, J. Williams, B. Hopkins |
52. Polymer Coated Urea Impact on Barley Yield and ProteinPolymer coated urea (PCU) is an enhanced efficiency nitrogen (N) fertilizer shown to regulate N release over a season benefiting production and reducing nutrient pollution. The purpose of this study was testing the effect of uncoated and coated urea blends on irrigated barley yield and protein. The study consisted of three N rates applied as all urea or a 50-50 blend of PCU and urea. As expected, N rates increased yields and protein. In general, urea resulted in increased yields with... S. Fahning, T. Searle, A. Weigel, R. Buck, T. Hopkins, B. Hopkins |
53. Struvite Phosphorous Fertilizer on Sugar BeetSugar beet is very sensitive to P deficiency early in the growing season. Crystal Green is a struvite phosphorus (P) fertilizer source that may uniquely enhance uptake in sugar beet. In this study, we examine the effect of struvite applied to sugar beet and compare the results against the use of traditional monoammonium (MAP) fertilizer and a control. There was a significant increase in response to MAP over the control for both total and sugar yield. The struvite based fertilizer had an additional... J. Fisher, E. Woolley, J. Svedin, B. Hopkins |
54. Water and Nitrogen Interactions in Kentucky BluegrassPressure is increasing in arid regions to conserve water, especially during drought. Turfgrass is the irrigated crop of greatest acreage in the United States and is coming under scrutiny in urban ecosystems. The purpose of this study was evaluating water use by Kentucky bluegrass (Poa pratensis L.) under various irrigation and nitrogen (N) regimes. A study was conducted in an established stand of Kentucky bluegrass in Provo, UT, USA. The turfgrass was split equally into 27 plots (11... A. Hopkins, C. Campbell, B. Hopkins, N. Hansen |
55. Source and Rate Interactions for Enhanced Efficiency Phosphorus FertilizersPhosphorus (P) is an essential plant nutrient and plays a major role in the health and wellbeing of ecosystems. Deficient P is detrimental to plants. Excessive P is also detrimental to plants and is potentially harmful environmentally. Soil testing is an effective tool to help growers determine if fertilizer P is needed and, if so, the rate that is needed to be applied. Rates higher than the recommended amount can be detrimental to plant health and decrease yield. In addition to applying the right... A. Norris, B. Hopkins |
56. Polymer Coated Urea in Kentucky BluegrassNitrogen (N) is a commonly over-applied nutrient in urban environments. This over-application has led to nutrient pollution of the atmosphere and hydrosphere. The losses of N to the environment can be mitigated with the use of enhanced efficiency fertilizers, such as polymer coated urea (PCU). Some PCU labels state that a single annual application is a best management practice. The objective of this study was to evaluate a PCU compared to monthly applications of ammonium sulfate/urea.... S. Stapley, J. Buss, B. Hopkins |
57. Phosphorus Fertilizer and Hydrogel for Rangeland SeedingThe US Air Force uses live munitions at Hill Air Force Base, a desert testing range west of Salt Lake City, Utah, USA. Resultant fire has disturbed rangeland vegetation. Revegetation of the area is impeded by low average precipitation rates of approximately 0.025 m per year, and opportunistic invasive species. Previous studies indicated hydrogel increases soil water content and the longevity of bottlebrush squirrel tail seedlings. In this glasshouse study, the effects... M. Valencia, S. Nelson, B. Hopkins |
58. Struvite Phosphorus Fertilizer on PotatoPotato (Solanum tuberosum L.) is a staple in the global economy and on the dinner table. It has an unusually high demand for phosphorus (P) due to its shallow, inefficient root system. Most P fertilizers are water soluble, but then precipitate quickly—potentially resulting in poor plant uptake. Crystal Green (a struvite based fertilizer) is acid soluble, but not water soluble. In theory, it remains undissolved until plant roots exude acids— potentially avoiding the precipitation... R. Woolley, J. Svedin, E. Woolley, B. Hopkins |
59. Boron Fertilization with Aspire® in Alfalfa and PotatoPotassium (K) and boron (B) are essential nutrients. The spatially even distribution of applying K fertilizer is typically not a problem, but for B fertilizer application, it is a problem. This is especially difficult for crops such as alfalfa (Medicago sativa L.) and potato (Solanum tuberosum L.) due to low B rate and limited soil exploration by roots. Fertilizer with K and B fused into a single granule could result in even distribution. Trials were performed to evaluate the performance... E. Woolley, T. Searle, T. Hopkins, J. Williams, B. Hopkins |
60. New Hydroponic System for Testing Mineral Nutrient Deficiencies and its Application to QuinoaCorrelating plant tissue nutrient concentrations with visual symptoms is valuable in combating mineral nutrient deficiencies and toxicities. Major crops tend to have large amounts of information regarding nutrient concentrations and visual symptoms of deficiencies, but this information is often lacking for minor crops, including quinoa (Chenopodium quinoa L.) Because nutrient concentrations can be easily controlled, hydroponics effectively demonstrate isolated specific nutrient related symptoms.... D. Cole, R. Woolley, R. Buck, B. Hopkins |
61. Developing Practical Phosphorus and Potassium Tissue Test Recommendations and Utilizing Struvite in Modern Alfalfa SystemsTissue testing whole alfalfa plants at harvest provides opportunities to direct nutrient decision making more accurately. Critical levels developed allow in- season recommendations and applications and would save producers time and effort since growers are already taking samples for hay quality. Three experiments were designed including: P Study with differing rates of P2O5 using monoammonium phosphate (MAP); including: 0, 30, 60, 120, 240 lbs./acre on an 8.1 ppm P soil (Olson P method);... S. Norberg, E. Mackey, S. Fransen, J. Harrison, D. Llewellyn, L. Whitefield |
62. Nitrogen Availability from Organic AmendmentsOrganic fertilizers and composts are valuable sources of nutrients. However, their nutrient availability is often not known and can be variable. How much nitrogen (N) becomes plant available depends on environmental factors, including temperature and so moisture, as well as the properties of the decomposing organic material. We investigated the effects of the carbon to N (C:N) ratio of different commercially available organic fertilizers and composts in a study where we mixed the materials with... D. Geisseler |
63. Polymer Coated Urea: Microplastics in the Urban LandscapePolymer Coated Urea (PCU) in urban landscapes has recently become a controversial practice as some fear the repercussions of the polymer coatings left behind in soils and the environment to potentially be detrimental to land and water ecosystem health. The use of PCU has been beneficial in effectively supplying nitrogen (N) to plants with less leaching, denitrification, and volatilization losses to the environment. However, the pollution of microplastics may outweigh these benefits. The purpose... C. Seely , B. Hopkins |
64. A Single Nutrient Source Hydroponic Solution: pH BufferingMES (2-[N-morpholino]ethanesulfonic acid) is a biological buffer that can be used to stabilize pH in a hydroponic system. It can, however, be toxic to plants, including soybeans. Hydroponic systems are efficient for studying plant nutrition. It is often desirable to adjust individual nutrients for unique species’ needs and/or to create multiple nutrient deficiencies within the same study. However, this is challenging to do with traditional solutions as nutrients are generally... J.D. Ioannou, B. Hopkins |
65. Biosolids-based Fertilizers as a Nitrogen Source in California Small Grains SystemsSituation/ conditions In response to regulatory and economic pressure, California growers are becoming more familiar with nitrogen budgets. In addition to seeking out ways to improve nitrogen management strategies, growers can possibly benefit by incorporating alternative sources of nitrogen to feed their crops. Liquid injected or pelletized biosolids-based fertilizers from local waste streams and processing facilities are one source that growers are beginning to explore. As... K. Mathesius, D. Geisseler, M. Savidge, M. Lundy, T. Nelson, N. Andersen |
66. Impact of Variable-Rate Nitrogen on Potato Yield, Quality, and ProfitNitrogen application in agriculture is a vital process for optimal plant growth and yield outcomes. Factors such as: topography, soil properties, historical yield, and crop stress variably affect nitrogen (N) needs within a field. Applying variable N within a field could improve yields and nitrogen use efficiency (NUE). Optimal N management is a system that involves applying a conservative variable base rate at or shortly after planting followed by in-season assessment and, if needed, variable... E.A. Flint, M. Yost, B. Hopkins |
67. Helpful or Not?- Biostimulant Use in Corn Silage ProductionThere has been a recent increase in both the availability and marketing of biostimulant products to local producers, particularly to dairymen, in southern Idaho. These products claim to increase yield and nutrient use efficiency while improving soil health on agricultural fields. If these claims are true, the use of these products would ultimately aid in promoting the overall sustainability of Idaho farms. However, there is a lack of objective data to support these claims, leaving producers uncertain... L.R. Schott, S. Hines, J. Packham, G. Loomis, M. De Haro Marti, C. Willmore |
68. Flushed Liquid Dairy Manure Solid Particle and Nutrient DistributionsLarge dairies often use liquid manure handling systems because of their ease of mechanization and low labor requirements. Some of Idaho Magic Valley dairies use flushing systems that result in large amounts of liquid dairy manure that are applied via irrigation systems to adjacent cropland during the growing season. Solids and nutrients found in liquid dairy manure pose challenges to manure handling processes and cause environmental concerns. Separating solids and nutrients from liquid dairy manure... L. Chen, K. Kruger |
69. Relationship Between Nitrogen Mineralization and Soil TextureSoil texture can affect soil temperature, soil moisture, the protection of organic material against microbial degradation, and other soil properties. All these factors potentially influence net nitrogen (N) mineralization. I will discuss results from a 10-week laboratory incubation of undisturbed soil cores from 47 sites in California, and a meta-regression analysis of 461 datasets from 20 studies. ... D. Geisseler |
70. A Classification System for Assessing Applied N Performance in Dryland Wheat Crops of the Inland PNWWheat crops in the inland Pacific Northwest demand nitrogen (N) fertilizers at high levels to achieve yield and grain protein objectives. Inefficiencies in N use can accelerate soil acidification, contribute to N2O emissions and result in unnecessary input costs. More precise applications, using wheat performance maps at the field-scale, could lead to increased N use efficiency but requires a multidimensional assessment of performance including grain protein, yield, and N efficiency.... D. Huggins, J. Casanova, C. Phillips |