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1. Predicting Crop Yield Losses Due to Soil-water Salinity: Comparison of Traditional and Alternative ApproachesIt is estimated that 2,000 ha of cropland are taken out of production daily worldwide due to salinization and sodification. Salinity is estimated to result in economic losses of $27.3 billion U.S. dollars annually. Our project aims to jointly develop techniques for quantifying the severity of soil-water salinity and impacts on crop production on surface-irrigated fields in Pakistan’s Indus River Valley and the Lower Arkansas River Valley (LARV) in Colorado. The Fairmont Drainage Distric... A. Brown, A. Andales, T. Gates |
2. A Brief History of the Great Plains Soil Fertility ConferenceThe Great Plains Soil Fertility Conference began in 1980 as the Great Plains Soil Fertility Workshop at the Denver Sheraton Hotel on Quebec in Denver, CO. This Workshop was patterned off the successful North Central Extension Industry Soil Fertility Workshop which had been in existence since 1971. Several companies provided some initial funding to get the project off and running. The objectives of the Workshop/Conference were to bring together researchers and i... L. Murphy |
3. Assessment of Long-term Effects of Tillage and Nitrogen Management Practices on Irrigated Corn Yields and Nitrogen Use EfficienciesCorn grain yields and crop nitrogen uptake are affected by management factors such as tillage intensity and nitrogen rates. Additional data about the long-term effects of tillage and nitrogen rates on yields and nitrogen use efficiencies of irrigated corn are needed. We are presenting preliminary results from a 17-year study about the effects of these management practices on irrigated corn yields and nitrogen uptake in a Fort Collins clay loam soil at Colorado State University’s Ag... J.A. Delgado, A. Halvorson, A. Villacis-aveiga, S. Del grosso, C. Stewart, D. Manter, J. Alwang, B. Floyd, R. D'adamo, G. Miner |
4. Assessment of Soil Testing As It Relates to Corn Ear Leaf Nutrition in the MidwestSoil testing for P, K and Zn for corn production the Midwest is based on the probability of crop yield response to an applied fertilizer and not on crop nutritional status. Results of three years of observational data from 98 field sites show soil test M3-K only predicted 26% of the variability in ear leaf K at growth stage R1-R2, whereas K base fraction (KBF) predicted 44% of the ear leaf variability and 56% of the variability in the ear leaf K:Mg ratio. Soil M3-P was inconsistent in predict... R. Miller |
5. Banded P Placement for Sugarbeets in Calcareous SoilPhosphorus (P) is an essential element for sugarbeet (Beta vulgaris) nutrition. Soils in the Western US tend to be calcareous and alkaline, resulting in low P solubility. Sugarbeets have difficulty exploiting soluble P in surface soil due to its tap root system. Research in the North- Central US supports P applied in a band in contact with the seed or below the seed for best results. However, grower concerns about germination problems and seedling vigor have prevented adaptation of these tech... B. Hopkins, J. Ellsworth |
6. Banding 10-34-0 on Sugar BeetsField experiments were conducted over 10 site-years in the Red River Valley of Minnesota on various soil types that tested low in available P. The objectives were to evaluate sugar beet yield response to liquid 10-34-0 and dry 11-52-0 fertilizer banded in-furrow with the seed at planting and to compare those responses to that of phosphorus (P) fertilizer rates broadcast and incorporated prior to planting. Treatments had no effect on net sucrose concentration in the root ... A. Sims, L. Smith |
7. Carbon Budget in Dryland Agroecosystems After 12 Years in No-till As Affected by Climate Gradient, Slope Position, and Cropping IntensityBecause available soil water is the most limiting factor in dryland cropping systems in the central Great Plains, summer fallow was implemented to stabilize production by storing two years of soil water for one year’s crop. The traditional dryland cropping system consists of conventional tillage management of a crop-fallow rotation which produced one crop every two years. In order for the fallow period to successfully store soil water, weeds and volunteer plants ne... L. Sherrod, G. Peterson, D. Westfall, L. Ahuja |
8. Changes in Soil Quality During the Transition from Irrigated to Dryland Cropping SystemsThe availability of irrigation water enhances crop productivity and, in turn, increases crop residue inputs and soil quality. With increased pressure on declining groundwater resources, some formerly irrigated lands are being transitioned to dryland management. However, little is known about the shifts in soil quality after conversion from irrigated to dryland cropping systems. The objective of this work was to quantify the effect of irrigation retirement on the early changes in soil quality.... A. Nunez, R. Ball, M. Schipanski |
9. Chloride Fertility: Small Grain Variety and Disease ResponsesFor spring wheat (Triticum aestivum L.), chloride fertilizer added to low chloride-testing soil results in a positive yield gain 70 % of the time. Some, but not all, of these yield responses have been attributed to chloride interaction with disease susceptibility. Because soil fertility and disease suppression are among the most important management tools used by farmers, additional research on the interaction between chloride fertility and disease suppression is ne... W. Riedell, L. Osborne, S. Osborne |
10. Chloride Response of Corn and Grain SorghumResearch in several states in the United States and in Canada has documented positive small grain responses to chloride (Cl) fertilization, yet little research has been done on corn or grain sorghum. Field research was conducted in Kansas evaluating Cl fertilization on corn and grain sorghum. Chloride rates and sources were evaluated at several farmer-cooperator sites. Corn and grain sorghum yields were consistently increased with Cl fertilization when soil Cl... R. Lamond, K. Rector, C. Godsey, L. Ferdinand |
11. Comparison of Annual and Multi-year N-based and P-based Manure ApplicationsThis 4-yr study (2000-2003) compares beef manure application strategies in their impact on soil and plant nutrient concentrations and nutrient runoff and leaching. The treatments were a fertilizer control, annual N-based manure application, N-based applied every other year, annual P-based, P-based applied every other year, and P-based applied once every four years. By the third year of the study, soil test P levels in the soil surface reflected the amount of P2O5applied ... J. Davis, C. Truman, K. Iversen, K. Doesken |
12. Comparison of Multi-spectral Analog and Imaging Systems for Assessing Plant Nitrogen Status in Irrigated CornUniform applications of nitrogen (N) across a field may result in over fertilization in some areas as well as under fertilization in others. Farmers, consultants, and other end users need rapid, robust techniques to spatially and temporally assess a crop’s N status in order to apply N “as needed” and “where needed”. The objective of this research was to compare the differences in response of a radiometer system and an imaging system for asse... W. Bausch |
13. Conservation Management and Nitrogen Fertilization to Enhance Soil Chemical and Biological PropertiesCover crops and no-tillage are increasing in use across Texas. On the Southern High Plains (SHP) these practices are important mitigators of wind erosion and are suggested to increase soil health and other positive soil attributes. This study aimed to monitor and evaluate the soil chemical and biological changes that occur shortly after implementing conservation practices and nitrogen management strategies on the SHP. It was determined that in the short term some soil chemical and ... M. Mcdonald, P. Delaune, T. Gentry, K. Lewis |
14. Developing, Delineating, and Managing Production Level Nutrient Management ZonesGrid soil sampling has been used to develop nutrient maps to guide precision fertilizer applications since the inception of precision agriculture. However, the cost and labor associated with collection and analysis of soil samples to accurately describe spatial properties of fields can be prohibitive for most agronomic crops. As a result of these limitations, much interest is now being directed to the use of production level “management zones” (MZ) to allow i... W. Gangloff, D. Westfall, R. Khosla, T. Shaver, H. Farahani |
15. Development and Use of the Soil Management Assessment FrameworkSoils perform a number of critical functions essential to productivity and environmental quality. Management practices affect these soil functions. However, spatial and temporal variation and the slow rate of change in many soil properties make it difficult to assess the effects of management on soil functions. Tools are needed to assist managers in making assessments of the effect their management practices are having on the soil resource. The Soil... B. Wienhold, S. Andrews |
16. Dissolution of Granular Fertilizers and Diffusion/lability of P from Fluid and Granular Fertilizers in Alkaline and Calcareous Soils of Southern AustraliaUnlike many soils in Europe and North America, many Australian soils are still responsive to additions of P fertilizer, especially alkaline and/or calcareous soils that dominate the low rainfall zone of southern Australia. Poor responses to granular fertilizers in these areas have recently stimulated a swing by grain growers towards the use of fluid formulations, often resulting in significant yield responses. Laboratory experiments examining P diffusion were undertaken ... E. Lombi, M. Mclaughlin, C. Johnston, T. Mcbeath, S. Stacey, R. Armstrong, R. Holloway |
17. Do Legume Cover Crops Help Mineralize Soil Nitrogen?Nitrogen (N) dynamic is dependent on multiple factor all of which influence in-season plant N availability. Inclusion of a cover crop can have additional impacts on N dynamic by utilizing fall residue soil N, reducing the potential of N leaching. Legume cover crops also have the potential to add additional N to the soil through N fixation. The objective of this study was to evaluate N dynamic of different cover crops (legume and nonlegume) compared to no cover... B. Chim, S. Osborne, R. Lehman |
18. Does Coal Char Reduce Ammonia Volatilization by Slowing Urea Hydrolysis in Soil?Ammonia volatilization due to urea hydrolysis begins immediately after N fertilizer applied in soil and continues up to two weeks. This process might adversely affect N availability in soil/ plant systems and reduce soil fertility and crop yields, as well as bring the negative impact in environment. Char, incomplete burning of coal combustion residue which contains up to 30% total C by weight, is hypothesized to reduce N losses from ammonia volatilization. A 21-day laboratory study was c... D. Panday, B. Maharjan |
19. Economics of Variable-rate N Management on CornOver the past several years’ growers have begun to adopt and implement the use of precision farming technologies. Growers and practicing consultants continue to question the profitability of this technology. No data currently exists in the Western Great Plains region demonstrating the economic feasibility of precision farming technology. The objective of this study was to assess the economics of uniform versus variable-rate nitrogen (N) fertilizer applic... R. Khosla, B. Koch, D. Westfall, M. Frasier |
20. Effect of Foliar Zinc Application on Durum and Spring Wheat Grain Yield and QualityZinc (Zn) deficiency represents a common micronutrient deficiency in human populations, especially in regions of the world where staple food crops are the main source of daily calorie intake. Micronutrients like Zn also plays an important role in growth and development of plant thereby affecting crop yield and quality. A two-year field trial was conducted at Sidney, Montana, to investigate the effect of foliar application of Zn on yield and grain quality of spring wheat. Zinc treatment i... F. Etemadi, R. Keshavarz afshar, H. He, S. Zhou, Z. Li, C. Chen |
21. Effect of Nitrogen Rate and Timing of Application on Stockpiled BermudagrassFeeding hay through the winter contributes a large portion of the costs associated with cow-calf production. Forage management strategies to lengthen the grazing season and reduce hay consumption would be beneficial in increasing profitability. Stockpiling bermudagrass for livestock consumption in late fall and winter has not been thoroughly evaluated in southern Oklahoma. This study was initiated at Burneyville, Oklahoma in 2000 to determine the effect of N rate and timing of appl... J. Ball, W. Thomason, F. Motal, S. Norton |
22. Effect of Phosphorus Rates on Bermudagrass Yields in Three Southern Oklahoma Locations in 2002-2003Small plot research tests were established on cooperating farmers’ fields in three south central Oklahoma locations in 2002 and continued in 2003. These included a Weatherford soil testing low in extractable P (Mehlich 3), a Port soil testing low in P and a Lela soil testing high in P. Rates of applied P fertilizer were 0, 25, 50, 75, 100 and 200 lbs of P2O5per acre. There were 4 replications of each rate. All plots received 200 lbs N and 120 ... E. Funderburg, D. Annis |
23. Effect of Starter Nitrogen Fertilizer on Nitrogen Fixation of Soybeans in the Northern Great PlainsEnvironmental conditions at the time soybeans (Glycine max (L.) Merrill) are planted in the northern Great Plains are such that nitrogen (N) fixation may not occur immediately, therefore additions of N as starter fertilizer may increase initial growth of soybeans and possibly increase yield and quality. The objective of this study was to evaluate the response of soybeans to low rates of N applied at planting. A field experiment was established within a two-year corn... S. Osborne, W. Riedell |
24. Effects of Residue Placement on Co2 Loss in an Irrigated, No-till Corn SystemIt is well known that residue management practices that leave crop residue on the surface, such as no-till agriculture, promote soil fertility. However, the effects of such practices on carbon sequestration can be highly variable. To better understand how residue management impacts the loss of carbon through mineralization, we investigated the effects of residue location and addition on CO2 produced from residue decomposition under no-till irrigated continuous corn in Northern Colorado. ... H. Oleszak, F. Cotrufo, S. Leichty, C. Stewart |
25. Enhanced Efficiency Nitrogen Fertilizer: Coated UreaNitrogen (N) is the most common fertilizer. However, a large percentage is lost to the environment—resulting in pollution and depletion of natural resources—representing economic losses. Enhanced Efficiency Fertilizers (EEF) help mitigate these problems by reducing the time N is in forms most susceptible to loss, increasing uptake efficiency and, often, yield and/or crop quality. One example of N EEF are coated urea fertilizers, such as polymer coated urea (PCU). Research studies ... S. Fahning, B.G. Hopkins |
26. Enhanced Efficiency Phosphorus FertilizersPhosphorus (P) is essential for plants. However, first-year phosphorus fertilizer uptake by plants is low, resulting in economic and environmental impacts. Developments with P Enhanced Efficiency Fertilizer (EEF) sources show improved uptake efficiency and increased yield and/or crop quality, while reducing environmental risk. Research with EEFs (including organic acids, maleic itaconic copolymer, and struvite) all show these improvements, especially when: 1) soil test P concentrations are lo... S. Kobza, B.G. Hopkins |
27. Evaluating the Trade-offs of Cover Crops in Dryland Wheat Systems of the Colorado PlateauOn the semi-arid Colorado Plateau, dryland farmers are challenged by severely degraded soils and low and increasingly unreliable precipitation. Cover crops have been shown to improve soil fertility and mitigate soil erosion in many regions, but are also associated with use of limited soil moisture, a cost that could mean decreased cash crop productivity for farmers. Most literature on cover crops comes from relatively humid climates, where crop yield penalties due to cover crops may be less p... L. Eash, A. Berrada, K. Russell, S. Fonte |
28. Evaluation of Cation Exchange Resin As Indicator of In-season Potassium Supply to SoybeanThe use of ion-exchange resins to measure soil nutrient availability has potential applications for fertilizer recommendations. The objective of this study was to evaluate the relationship between potassium (K) adsorption by cation exchange resins (CER) and K uptake by soybean (Glycine max) in field conditions. The study was conducted at two locations in Kansas during 2019. Two treatments were selected to evaluate the CER. Treatments included a check (0 lbs K2O acre-1) and a high K r... D. Charbonnier, D. Ruiz diaz |
29. Experiences in the Canadian Prairies with Enhanced Efficiency N Fertilizers for Winter and Spring Wheat Production SystemsThis presentation summarizes several studies all designed to address knowledge gaps around enhanced efficiency urea fertilizer (EEF) efficacy for nitrogen (N) management in western Canadian winter and spring wheat production systems. Polymer-coated urea was first studied to determine how handling effects can alter the coating integrity of environmentally smart nitrogen (ESN®). While N release rates increased from retail or farm-handling such as trans... B. Beres |
30. Fall and Spring Soil Residual Nitrate-n As Affected by Irrigation and Nitrogen ManagementNitrogen credit from residual nitrate-N from soil samples collected in spring is widely considered and accounted for in managing N in crop production. That is important from both economic and environmental perspectives. However, there is no incentives for farmers to determine post-harvest soil residual nitrate-N in fall. It is important to note that any difference in fall and spring soil residual nitrate-N would suggest environmental N losses via denitrification or leaching in that fallow per... B. Maharjan, X. Qiao |
31. Fertility Management for the Pulse-based Cropping Systems in the Semiarid Northern Great PlainsAnnual crop production of the semiarid Northern Great Plains has historically been dominated by cereals, chiefly spring wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum var durum). Low prices for cereal grains, coupled with increasing production problems in wheat- based monoculture systems, are encouraging producers to seek alternative to cereals. In the past two decades, the area devoted to production of annual pulse crops has increased significantly in the semi... Y. Gan, B. Mcconkey, G. Clayton, G. Lafond, F. Walley |
32. Fertilizer Management for Strip-till and No-till Corn ProductionStrip-tillage for corn production can be advantageous over no-till, particularly in areas with heavy soils and high rainfall during spring months. Under these conditions in no-till systems, planting delays and/or slow, uneven emergence are common. Strip-tillage creates a narrow tilled area for the seedbed while maintaining the inter-row residue cover, allowing for erosion protection associated with no-till, yet providing an area in the row where the soil will dry out and... L. Ferdinand, R. Lamond, B. Gordon, K. Janssen, C. Godsey |
33. Forgiven Not Forgotten: a Short History of Wind Erosion on the Canadian PrairiesSince agriculture arrived on the Canadian prairies in the late 1800s, wind erosion has always been a constant threat. The 1930s saw some of the worst wind erosion but spurred the invention and adoption of soil management techniques to provide better crop residue management, the number one line of defense against wind erosion. The conservation tillage movement of the 1990s saw increased no-till and summer-fallow almost disappeared. However, recent trends of more intensive tillage on the Canadi... F. Larney |
34. Functional Significance of Glomalin to Soil FertilityIn the U.S., soil is lost to wind and water erosion at a rate of nearly 2 billion tons yr-1. The formation of aggregates helps stabilize soil and increase soil fertility and water relationships. Organic matter concentration is correlated with the percentage of water-stable aggregates (WSA). The hypothesis of this study was that glomalin, a glycoproteinaceous substance produced by arbuscular mycorrhizal fungi, would be a major fraction of organic C in WSA. Four... K. Nichols, S. Wright, M. Liebig, J. Pikul jr. |
35. Harvest Grain and Crop Residue Yield Differences in Crop Rotation and Residue Management Systems in Tillage Transition in Eastern South DakotaA long-term field study was established in Brookings, SD to investigate the impact of crop rotation, tillage, and residue management on grain yield and crop residue production. These results were compiled when this field was undergoing a transition in the influence of two contrasting tillage systems in the first four years of the study. Initial soil test results indicated that the organic matter levels and pH as well as extractable K and orthophosphate-P (0-6") were high. ... H. Woodard, A. Bly |
36. Impact of Diversified Rotation on Corn N Uptake, Yield, and Soil QualityIncreased length of rotation and increased crop diversity may improve efficiency of water and nitrogen (N) use by corn (Zea mays L.) and soil quality. Objectives were to determine the effect of diversified crop rotation on: 1) N-fertilizer use efficiency (NUE) of corn, 2) water use efficiency (WUE) of corn, and 3) temporal change in soil quality attributes. An experiment was started in 1997 on a Barnes clay loam (fine-loamy, mixed, superactive, frigid Calcic Hapludo... J. Pikul jr. |
37. Impact of Fertilizer Management on the Stratification of Soil Characteristics in No-tillThe increasing cost of fuel and machinery makes no-till management (NT) a good alternative for producers. With the demanding increase of production, fertilizer utilization efficiency and cycling must be evaluated to address such demand. However, the superficial input of soil amendments under NT may lead to the soil stratification of pH and nutrients and in the first six inches. Three dry-land NT long-term trials located in Perkins, OK (NT since 2005), Stillwater, OK (NT since 2010) and Lahoma... J. bigatao souza, V. Reed, B. Finch, B. Arnall |
38. Impact of Post-feekes 6 Nitrogen Application in Winter Wheat Forage ProductionProducers have options when choosing how to utilize their wheat acreage in Oklahoma. These include, grain harvest only, dual-purpose grazing and grain, and graze-out where the wheat crop is used solely for grazing cattle. Many producers take advantage of graze out wheat as a forage for cattle during the winter season. With acreages of approximately 400,000 acres of winter wheat grown for graze out production in the state of Oklahoma in 2018, many questions regarding management of wheat for gr... B. Finch, V. Reed, J. Rogers, J. bigatao souza, B. Arnall |
39. In-furrow Placement of Dry Urea Prodcuts with Winter WheatPrevious research has shown that the application of some nitrogen fertilizer prior to or at the time of wheat seeding can positively affect the initiation of fall tillers and thus yield potential. However, there are logistical challenges in placing that nitrogen in no-till production systems. Traditionally, the placement of urea-based fertilizers in-furrow with wheat seed has not been recommended. The objectives of this project were to evaluate stand reduction and associ... L. Haag, A. Schlegel, D. Ruiz diaz |
40. Innovative Corn and Soybean Production Systems for the Great PlainsIn an eight-year study of twin row planting, our intentions were to see if additional spacing per plant would allow more ear flex and more cubic foot of soil mass per plant. In the first five years of study, over 5000 acres were planted, in five states. In each of those five years, we continually added new and upgraded agronomic facts that we held to be true, i.e. PPI work on deeper P placement, Dr. Barnie Gordons work on high N starters, split applications and precisional placemen... |
41. Inter-seeding Cover Crops Influence on Optimal Corn Nitrogen Rate in No-tillMoving from conventional to no-till with the inclusion of cover crops may change the amount and timing of nitrogen (N) provided to corn (Zea mays L.) from mineralization, which may increase or decrease needed N fertilizer to optimize corn grain yield. This study evaluated the effect of cover crop composition on corn N fertilizer requirement and corn grain yield. The effect of three cover crop treatments (no cover crop, single grass species, and grass/broadleaf mixture) on c... J. Clark, S. Osborne, P. Kovacs, R. Slaght |
42. Investigating Relationships Between Haney H3a-4 and Conventional Soil Tests for Plant Nutrients in Kansas SoilsUse of a soil test to determine fertilizer application rates requires correlation and calibration to crop yield response and/or total nutrient uptake. The Haney H3A soil test procedure has gained popularity in recent years for soil health evaluation and has been used in some circles to adjust fertilizer management practices. However, data relating this test to current soil fertility tests, relative crop yield, or total nutrient uptake are nonexistent in Kansas soils. The objective of this stu... B. Rutter, D. Ruiz diaz |
43. Irrigated Corn Response to Nitrogen Fertilization in the Colorado Arkansas ValleyHigh levels of residual NO3-N are present in the soils in the Arkansas River Valley where alfalfa, grains, and vegetable crops are produced. Nitrogen requirements to optimize yield potential of crops, such as corn, following vegetables needs to be evaluated to reduce NO3-N leaching potential in the Valley where high NO3-N levels have been reported in the ground water. The effects of N source (urea and Polyon®3) and fertilizer N rate on corn yields were evaluated for 4 years.&nb... A. Halvorson, F. Schweeissing, M. Bartolo, C. Reule |
44. Is There a Need to Provide N and S to Canola in Any Given Ratio?The importance of N and S nutrition of canola is well recognized (Janzen and Bettany 1984; Bailey 1986; Grant and Bailey 1993; Jackson 2000; Malhi and Leach 2002). Agronomists today are recommending that a N:S ratio of between 5:1 and 7:1 is adhered to when fertilizer N and S are applied. This is also reflected in the provincial recommendations. Thus, Alberta Agriculture, Food and Rural Development (2001) point out that optimum canola requires an N:S ratio of ... R. Karamanos, T. Boon goh, D. Poisson |
45. Kansas State University Fertilizer Recommendation RevisionsSoil testing has long been recognized as the cornerstone for developing cost effective, efficient and environmentally sound nutrient management programs. However, there are still many acres that do not have a sound soil test history. This indicates that there is still much education needed to increase farmer acceptance of soil testing in developing agronomically sound and profitable nutrient management programs. At the same time, USDA is placing increased emph... D. Leikam, R. Lamond, D. Mengel |
46. Long-term Cover Crop Effects on Soil Organic Carbon, Nitrogen Stocks, and Water Stable Aggregates in the Semiarid Central Great PlainsGrowing cover crops (CC) in semiarid dryland cropping systems in the central Great Plains (CGP) may provide several benefits to soil health. This study examined long-term CC management effects on soil health in a no-till winter wheat (Triticum aestivum L.)–grain sorghum (Sorghum bicolor L.)–fallow (WSF) cropping system in southwestern Kansas. The experimental design was a split-split-plot randomized complete block with four replications. Main plots were... L. Simon, A. Obour, J. Holman, K. Roozeboom |
47. Long-term Crop Rotation Diversity Effects on Soil C and NThe objective of this study was to evaluate the effects of nitrogen (N) fertilizer level and crop rotation diversity on soil organic carbon (SOC) and N stocks from a 34-yr study located in eastern Nebraska. Seven crop rotations (three continuous cropping systems; two 2-yr crop rotations, and two 4-yr crop rotations) and three N levels were compared. Soil samples were taken to a depth of 60-inches. Differences in SOC stocks were largely confined to the 0 to 3-inch depth with greater SOC (P... M. Schmer, V. Jin, B. Wienhold, G. Varvel |
48. Long-term Crop Rotation Impact on Soil Properties and Crop ResponseCrop rotations can be part of sustainable agriculture production by their effectiveness depends on understanding how crop rotations affect above- and below-ground crop characteristics. Objectives were to investigate crop rotation effects on shoot dry weight and root characteristics of cereal and grain legume crops at anthesis as well as on grain yield. Rotations were corn (Zea mays L.)-soybean [Glycine max (L.) Merr.], (CS); corn-soybean-spring wheat (Triticum ... S. Osborne, R. Lehman, W. Riedell, B. Chim |
49. Long-term Forage Rotation Yields, Soil Water Use, and ProfitabilityForages are important for the region’s livestock industry and are becoming increasingly important as irrigation capacity and grain prices decrease. Forages require less water than grain crops and may allow for increasing cropping system intensification and opportunistic cropping. A study was initiated in 2012 at the Southwest Research-Extension Center near Garden City, KS, comparing several 1-, 3-, and 4-year forage rotations with no-tillage and minimum-tillage. Data presented are from ... J. Holman, A. Obour, A. Schlegel, L. Simon |
50. Management Effects on Maturity, Seed Yield, and N2-fixation in Dry BeanThe association between dry beans (Phaseolus vulgaris L) and its associated Rhizobium symbiont (R. phaseoli) has been shown to be inefficient and as such, unable to provide adequate N for maximum bean production. Fertilization with inorganic N is sometimes recommended, but disadvantages of adding fertilizer N include delayed maturity and possible inhibition of N2 fixation. It is unknown whether N fertilizer applications are most beneficial during early growth s... K. Maxwell, B. Stevens |
51. Management of High Yielding Canola CultivarsYield potential of new canola varieties is much higher than older ones, raising questions about whether current management recommendations are adequate to ensure optimum yield. One question that arises is whether such varieties require greater inputs of fertilizer nutrients, particularly nitrogen (N), to realize optimum economic returns. We initiated a three level factorial experiment to investigate the impact of 3 seeding rates, 3 target fertility levels and a fungicide... S. Brandt, D. Ulrich, G. Lafond, R. Kutcher, S. Malhi, A. Johnston |
52. Managing Drought Risk with Post-emergent N Appliactions in Spring Wheat and CanolaFertilizer nitrogen accounts for the largest portion of total fertilizer costs. Unlike other nutrients like P and K, nitrogen is more prone to losses from leaching, nitrous oxide emission and denitrification. Producers are interested in more effective ways of managing the risks associated with N management, especially in the drier areas of the Canadian Prairies. Two separate studies were conducted. The first one examined the feasibility of post-emer... G. Lafond, S. Brandt, A. Johnston, W. May |
53. Managing Nutrients in Beef Feedlot Manure - Lessons from a 45-year Field StudyThe original objective of a long-term field experiment established in 1973 was to determine the safe loading capacity of soil with beef cattle feedlot manure. Manure was applied annually at 0, 30, 60, and 90 Mg ha-1 (wet weight) under rainfed and 0, 60, 120, and 180 Mg ha-1 under irrigated conditions. The long-term manure applications increased organic matter, nitrogen (N), phosphorus (P) and potassium (K) content and salinity in the soil, and barley forage yie... X. Hao |
54. Managing Soil Acidity in Continous No-tillRecently, management of acidic soils in no-till cropping systems has become an important issue with increasing acreages of no-till and continued surface application of nitrogen fertilizer. Our objectives were to identify vertical movement of surface applied lime, determine the most effective type of lime in changing soil pH, and determine the correct application rate of lime for no-till soils. Two sites were selected for small-plot studies in south-central Kansas in 2000... C. Godsey, R. Lamond, L. Ferdinand |
55. Mixing Wheat Seed with Fertilizer in the Drill: Seedling Injury and Wheat ResponseMixing dry phosphorus fertilizer with winter wheat seed is common in Kansas to provide a starter fertilizer benefit to the crop. This study was designed to evaluate the effects of dry phosphorus (P) sources, rates and times fertilizer mixed with wheat seed, effects on early growth and overall productivity and yield of the crop. Two winter wheat studies were conducted in the 2018-2019 wheat growing season at Manhattan (Site 1) and Topeka (site 2) in Northeast Kansas. The previous crop for site... C. Weber, D. Ruiz diaz |
56. N Mineralization Dynamics in No-till Crop Residues in the Northern PlainsAlthough many studies have been conducted on no-till cropping systems, little is yet known about the dynamics of N mineralization from accumulated crop residues as it relates to providing N to subsequent crops. We conducted incubation studies using individual crop residues placed on the surface of soil columns in leaching tubes and incubating the tubes for approximately 12 weeks (simulated growing season) with periodic leaching. This was repeated 5 times with a freezing period (win... L. Cihacek, R. Alghamdi |
57. Next Generation Application TechnologyNew technologies and new applications of new and existing technologies continue to be integrated into equipment for the application of crop production inputs including fertilizer, pesticides and seed. GPS assisted steering now allows “hands off” steering of self-propelled applicators and tractors. Results include better application accuracy, improved machine efficiency and less operator fatigue. Variable rate liquid systems are available to compete... N. Wollenhaupt |
58. Nitrogen and Crop Management Influence Irrigated Corn Yields and Greenhouse Gas EmissionsThe influence of tillage system and N fertility on corn grain yields, residue C inputs to the soil, soil organic carbon (SOC) sequestration, NO3-N leaching potential, and greenhouse gas emissions under irrigated continuous corn production was evaluated. Corn was produced on a Fort Collins clay loam using no-till (NT) and conventional-till (CT) systems at several N fertility levels. Soil and plant data have been collected since the spring of 1999. Corn grain yi... A. Halvorson, A. Mosier, C. Reule |
59. Nitrogen Availability Following Cover Crops in TX Cropping SystemsCover crops have been heavily promoted to improve soil health and function in US agricultural productions systems. Within semi-arid environments, interest in cover crops continues to grow although several concerns hinder adoption. As soil water use by cover crops is often a chief concern, nutrient availability to subsequent crops is also a concern. The objective of this study was to measure soil chemical and biological properties following various cover crops in a continuous cotton system und... P. Delaune, K. Lewis, P. Mubvumba |
60. Nitrogen Fertilization and Long-term No-tillage Impacts on Soil Properties and Deep Soil C Storage Under IrrigationThe net soil greenhouse gas mitigation potential of conservation agricultural management practices is strongly influenced by the direction and magnitude of soil organic C (SOC) change in deep soil layers (>6”). Deep SOC is typically old, highly processed, and consists of microbial products and root exudates associated with clay and other minerals. However, it can be susceptible to decomposition and priming from the addition of new, labile organic C. We examined long-term soil C dynam... C. Stewart, D. Manter, J. Delgado, S. Del grosso, F. Calderon, K. Heckman, K. Snell |
61. Nitrogen Fertilizer Source and Tillage Impacts on Surface and Subsoil C Under Rainfed CornSoil organic carbon (SOC) increases with organic fertilizer and the adoption of no-till. Soil organic C improves the ability of agricultural systems to mitigate and adapt to climate change. This study was conducted to determine the long-term effects of fertilizer type and tillage on profile SOC. The experimental site was a rainfed continuous corn (Zea mays L.) system with fertilizer treatments (150 lbs N a-1) of composted organic waste (OrgF), urea (MinF) and no ferti... S. Watts |
62. Nitrogen Managememt in Dryland Winter Wheat to Improve Grain Yield and ProteinMaximizing the yield along with adequate protein content in winter wheat is an emerging challenge for dryland wheat producers. Proper nitrogen (N) management with optimization of fertilizer application rate and timing might be a potential strategy to improve grain yield and protein. The objective of the study was to evaluate the effects of different N rates and application timing on grain yield and protein content of hard red winter wheat in Nebraska. Field study was carried out at four locat... D. Ghimire, B. Maharjan |
63. Nitrogen Management in Conservation Systems to Increase Use Efficiency and Cotton ProductionConservation management practices like no-tillage and cover crops have the potential to reduce wind erosion and stimulate ecosystem service, but lingering doubts regarding nutrient immobilization and water usage may limit their adoption on the Texas High Plains. A study was initiated at the Agricultural Complex for Advanced Research and Extension Systems (AG-CARES) in Lamesa, TX to examine the impact of supplemental nitrogen (N) fertilization on cotton yields and nitrogen use efficiency (NUE)... J. Burke, D. Kelley, K. Lewis |
64. Nodulation and Yield Responses to “Starter” N and P in Field Pea, Lentil, and Chickpea in the Semiarid Northern Great PlainsGrain legumes require a high level of N fertility to achieve maximum yield and protein (Sosulski et al., 1974; Sosulski and Buchan, 1978). In these 1970’s and 1980’s studies, nodulation and nitrogenase activity were generally poor even when the legumes were inoculated with rhizobia (Sosulski and Buchan, 1978). Although indigenous populations of rhizobia are often present in the soils, they might be ineffective for inducing N2 fixation under semiarid environments (Kucey and Hy... Y. Gan, G. Clayton, G. Lafond, F. Walley, B. Mcconkey |
65. Nutrient Management in Cotton-sorghum Vs. Continuous Cotton RotationsThis study seeks to provide information to High Plains producers on soil fertility requirements for cotton grown in rotation with sorghum. The benefits of rotation on yields and soil properties are also being studied. It is known that the practice of crop rotation benefits the soil and crops from the standpoint of soil fertility, pests, and diseases. In this project we tested cotton-cotton and cotton-sorghum rotations. Within these cropping systems ... K. Bronson, J. Booker, W. Keeling, C. Trostle |
66. Nutrient Partitioning Changes in the Past 30 Years of Cotton ProductionModern cotton (Gossypium hirsutum L.) cultivars are more compact and efficient due to optimization of genetics and changed management practices in the past 30 years. The most recent work evaluating nutrient uptake by cotton was done in early 1990s, hence a need to re-evaluate the nutrient accumulation and requirements in modern high productivity cultivars. The objective of this study was to compare the resource allocation of modern cotton cultivars (PM HS26, FM 958, and DP 1646)... I.B. Pabuayon, G. Ritchie, K. Lewis |
67. Observational and Modeling Methods to Inform Ecosystem Service MarketsInterest in quantifying the impacts of land management on ecosystem services has grown as governments, environmental organizations, and corporations have pledged to reduce greenhouse gas emissions, nutrient leaching, and other environmental impacts of human activities. Ecosystem service markets were formalized in the 1990s and originally deployed to mitigate point sources of air and water pollution. Associated protocols were fairly simple and easy to implement because quantification of point ... S.J. Del grosso, J. Delgado, D. Manter, C. Stewart, M. Vigil |
68. Optimizing Irrigation and Fertilizer Management in Cotton to Increase Nitrogen Use EfficiencyNitrogen (N) fertilizer is an important nutrient in cotton production, and if the optimal amount is not applied yield penalty may occur (Hutmacher et al. 2004). A more efficient application of N fertilizer based on plant N requirements, soil texture, and N availability can increase cotton yield and N-use efficiency (NUE). The main objective of this research was to determine the relationship between cotton lint yield and normalized difference vegetation index (NDVI) across multiple irrigation ... A. Bumguardner, T. Wheeler, K. Lewis |
69. Phosphorus Fertilizer Effects on Forage, Beef and Grain Production from Winter WheatPhosphorus fertilizer was surface applied or injected in a NPS solution and compared to a surface-applied NS solution to determine if fall forage production could be increased by P applications and to determine if the additional forage could be captured through beef production to make the P applications profitable. The experimental units were nine 25-acre pastures in which the three treatments were replicated three times and grazed with yearling stocker calves in two management sys... D. Robinson, J. Sij, W. Pinchak, R. Gill, S. Bevers, D. Mallinowski, T. Baughman |
70. Phosphorus Fertilizer Management and Cover Crop Effects on Phosphorus Loss from No-till Corn and Soybean.Loss of phosphorus from non-point source agricultural sources is a known contributor to the degradation and contamination of surface waters. Therefore, it is imperative to adapt agricultural best management practices which promote and preserve surface water quality. The goal of this study was to quantify the impacts of phosphorus fertilizer management practice (placement and timing) and winter cover crop on concentrations of total suspended solids, total phosphorus, and dissolved reactive pho... E. Carver, N. Nelson, K. Roozeboom, G. Kluitenberg, P. Tomlinson, J. Williams |
71. Plant Availability of Phosphorus in Swine Slurry and Cattle Feedlot ManureTo utilize manure phosphorus (P) for crop production, the amount of P that is mineralized and subsequently becomes plant available needs to be determined. A laboratory incubation study was conducted to determine P release and availability from applied swine and cattle feedlot manure in three soils. Treatments included incubation temperature (11, 18, 25, and 32 oC), P source (swine and beef cattle feedlot manure, synthetic fertilizer, and no manure or fertilizer), wa... B. Eghball, B. Wienhold, B. Woodbury, R. Eigenberg |
72. Point Vs. Area Grid Soil Sampling in the Great PlainsTraditionally, soil sampling has relied on the approach of collecting multiple cores (or sub-samples) from the entire area of interest (e.g., a field), and then combining them into a single soil sample for analyses. Samples were collected from throughout the area with recognition that soil fertility varied spatially. Where greater spatial variability was anticipated, size of sampling area usually was reduced to provide a better estimate of soil fertility. Unfo... T. Kastens, K. Dhuyvetter, J. Schmidt |
73. Positional Availability of Phosphorus from Surface Fertilizer BandsOur objective in this field study was to determine the relative distribution of P applied as a liquid starter fertilizer in a surface band during the early part of the corn growing season. Research was conducted during three years (2001-2003) at three locations in central Iowa. Exchange-resin membranes were used to characterize P movement. Treatments consisted of a control and 15-30-10 or 60-30-10 starter dribbled (30 gal./A) on the soil surface two inche... J. Kovar, P. Schroeder, K. Washburn |
74. Potassium Fertilization of Corn in Reduced Tillage Production SystemsPotassium (K) deficiency can be a problem on soils that have been managed with reduced tillage practices. The large amount of residue left on the soil surface can depress soil temperature and interfere with plant growth, nutrient uptake, and ultimately grain yield. Soil temperature influences both K up-take by root and K diffusion through the soil. The appearance of K deficiency in fields managed with conservation tillage systems has been reported with greater frequency in resent y... B. Gordon |
75. Quantifying Nitrate Leaching in Sandy Soils As Affected by N and Water ManagementEfficient use of nitrogen (N) fertilizer for corn production is important for maximizing economic return and minimizing NO3 leaching to groundwater, especially on irrigated, sandy soils. The objectives of this study were to quantify the NO3leaching for a sandy soil typical of Kansas’ tributaries, under current and alternative N and water management strategies for irrigated corn. Six fields were selected in 2001 and 2002 along the Republican (1), Kansas (2), and... R. Gehl, J. Schmidt, L. Stone, L. Maddux |
76. Rapid Removal of Subsoil N by Conventional and Non-N-fixing AlfalfaNitrate contamination of groundwater is an increasingly serious health issue in the Central High Plains. Although better water and fertilizer management techniques have reduced the rate of leaching from many irrigated fields, high concentrations of residual nitrate accumulating are still observed just below the root zone of irrigated row crops, particularly in fields with a history of animal waste application. Alfalfa (Medicago sativa L.) may be the ideal crop for r... T. Willson |
77. Rate and Depth of Liquid P Fertilizer Placement Affects Root Architecture and Arbuscular Mycorrhizal Fungal Associations in Grain CornA two-site, two-year study was conducted on corn root response to liquid phosphorus (P) fertilizer applications as a function of rate and depth of placement. Corn planted into no-till at two locations (Thrall & Snook, TX) was fertilized with banded liquid P applied 15 cm off seed row at different rates and depths. The upper portion of the root systems were excavated along with all top plant matter at the V10 - V12 growth stage. Digital images of washed roots were analyzed for spatial dens... J. Mowrer |
78. Real-time, In-season Nitrogen Application Using Optical SensorsVariable rate application of fertilizer materials for cereal crop production has been an intense area of research for the last several years. Non-destructive methods of plant analysis, namely crop reflectance based vegetative indices, have been evaluated and researched to determine which provides the best in-season information to make fertilizer recommendations. Because nitrogen (N) fertilizer is typically the largest seasonal crop input (with the exception of water, if ... R. Mullen, W. Raun, G. Johnson, M. Stone, J. Solie, K. Freeman |
79. Results from the First Year of On-farm N Rate and Timing StudiesStudies have shown over the past couple of years that utilizing sensor based nitrogen rate calculator (SBNRC) for in-season fertilizer has proven beneficial to yields and protein in the southern Great Plains. However, current SBNRC recommendations and algorithm are based upon trials conducted in central Oklahoma, rather than regionally based. The objective of the larger study is to determine if it is possible to develop a regional dependency component of SBNRC in Oklahoma. ... V. Reed, J. bigatao souza, B. Finch, B. Arnall |
80. Safening Seed Placed Urea with Agrotain®The introduction of no-till and direct seeding in the western Canadian prairies has necessitated placing urea N fertilizer with the seed in the majority of cases. Plant stand reduction due to seed-placement of high rates of urea N fertilizers is attributed to the toxic effects of ammonia/ammonium. Current guidelines for seed-row placement of nitrogen in general and urea in particular to avert seedling damage are based on seedbed utilization, soil texture (Saskatchewan Ag... R. Karamanos, J. Harapiak |
81. Satellite Imagery for Small Plot Research and Precision Farming - Nitrogen Relationships in Irrigated CornHigh quality satellite imagery that recently became available may be useful for predicting the N status of crops, need for additional N fertilization, and crop yield potential. Our objective was to determine if the high-resolution digital images from the QuickBird™ satellite launched in late 2001 had potential in predicting irrigated corn biomass and grain yields and available N at planting as indicated by leaf color on 27 July 2002 from conventional till and no-till research... J. Cipra, A. Halvorson |
82. Soil Acidification of Cultivated Fields in Semiarid Montana: Adaptation and Challenges to RemediationHistorically, soil acidification was not a problem in Montana because the parent material of most cultivated soils exhibited a neutral to an alkaline reaction. However, fertilizer ammonium‐N use (including urea) by farmers has grown tremendously in recent decades contributing to leading to a downward trend in soil pH and with incidences of soil acidity/Al toxicity now beginning to appear. Here we summarize the results from on-farm sugar beet lime trials to remediate soil acidity; seed-... R. Engel, C. Jones |
83. Soil Nitrogen Dynamics from Various Legume Crops Used for Fertiliy in Organic Fruit ProductionThe increasing cost of importing animal manures for organic fruit orchard fertility has forced growers to seek alternative sources of organic nutrient inputs. The objective of this study was to evaluate the nitrogen (N) dynamics of several on-farm N sources as a viable supply of organic N fertilizer. The timing of N mineralization is also critical to achieving good fruit production. Four year old organic Suncrest peach trees were used for this study. &nbs... R. Godin, S. Ela, K. Schultz |
84. Soil Phosphorus Fractions After Long-term Fertilizer Placement in Different Kansas SoilsPhosphorus fertilizer placement can affect the long-term dynamics and forms of P, and the overall soil P pools. These changes can vary by soil type, and affect P uptake and use efficiency by crops. The objective of this study was to evaluate the changes in the labile P fractions in three Kansas soil under P fertilizer placements (broadcast versus deep band) after 10 years of crop rotation. Three field studies were conducted for 10 years from 2006 to 2015 in three different soil... M. Arruda, D. Ruiz diaz |
85. Soil Quality and Nitrogen Availability After Eight Years of a Mixed Cover Crop - Wheat RotationDespite a large interest in cover crops in the northern Great Plains, little is known about their effect on both the following wheat crop and soil quality. In 2012, a cover crop study was started in Montana to compare wheat production and soil quality after growing cover crop mixes containing 2-, 6-, or 8-species, with both summer fallow and a sole pea cover crop control, in a 2-yr rotation with wheat. The 2-species mixes represented functional groups (legumes, brassicas, tap rooted, or fibro... C. Jones, P. Miller, C. Zabinski, K. D'agati |
86. Soil Test P and P Source Impacts on P Runoff from Calcareous SoilsLong-term application of phosphorus (P) to soils at rates in excess of crop uptake can result in elevated soil P levels (Snyder et al., 1993), which previous research has shown directly influences the amount of P in runoff (Sharpley et al., 1977, 1978, 1995; Daniel et al., 1994; Pote et al., 1996). Because soil test and runoff P concentrations are related, excessive soil P levels may result in significantly high runoff P levels, which accelerate surface-water eutrophication. ... A. Elliott, R. Schierer, J. Davis, R. Waskom, A. Schlegel |
87. Strategic Tillage Effects on Crop Yield and Soil Properties and Dryland Crop RotationsThis study evaluated strategic tillage (ST) to control HR weeds and improve crop yields in an otherwise long-term no-till (NT) soil. Treatments were five crop rotations: 1) continuous winter wheat (Triticum aestivum L.) (WW); 2) wheat-fallow (WF); 3) wheat-sorghum (Sorghum bicolor L.)-fallow (WSF); 4) continuous sorghum (SS); and 5) sorghum-fallow (SF) as main plots. The sub-plot were reduced tillage (RT), continuous NT, and ST of NT. Results showed tillage (ST or ... A. Obour, J. Holman, L. Simon, A. Schlegel |
88. Strategies for Maximizing Crop Recovery of Nutrients Applied As Liquid Swine ManureSince the demise in 1996 of the freight rate subsidy for transport of grains by rail from Western Canada to port, there have been increased efforts to develop a local livestock industry to utilize feed grains produced in Saskatchewan and other prairie provinces. This has led to an expansion in the number of intensive livestock operations, particularly swine production systems, on the Canadian prairies. The desire to develop responsible manure management strategies in con... J. Schoenau, S. Mooleki, S. Malhi, G. Hultgreen |
89. Sulfur Uptake and Yield Response in Corn As Affected by Fertilizer Source and RateWith sulfur deficiencies being found throughout Kansas, the evaluation of sulfur fertilization and plant uptake are vital to optimize corn production. The objective of this study was to evaluate the effect of application rates of sulfur on yield and uptake in corn. Nutrient concentrations in corn, biomass, and grain were evaluated at the Kansas River Valley Experiment Field at Rossville, Kansas in 2019. Five treatments were evaluated, including a con... T. Husa, D. Ruiz diaz |
90. The Effect of Low Rates of Commercial Humic Acid on P Availability and Spring Wheat YieldHumic acid (HA), a soluble fraction of humus, has been found to increase crop yields under certain conditions, possibly due to increased nutrient availability. A study was conducted to determine the effects of low rates of commercial HA on P availability and spring wheat yields in both a calcareous soil and non-calcareous soil. In Phase I, soluble P concentrations were monitored at 0.75, 1.5, and 2.25 in. from a MAP band that had either been coated with 1.5 lb HA/ac or l... C. Jones, J. Jacobsen, A. Mungaas |
91. The Future Role of USDA NRCS in Nutrient ManagementSince 1999 USDA Natural Resources Conservation Service has integrated nutrient management planning into the producer’s over-all conservation plan. A nutrient management plan contains the guidance for nutrient rate, form, timing, and method of application. Each action is based on specific local climate, soil, crop, and management conditions. The intent is to improve water quality, as well as soil, plant, air, and animal quality conditions, both on and off... J. Lemunyon |
92. The Role of P Fertility and Mycorrhizae in Flax ProductionEnsuring adequate P nutrition in flax is difficult, because flax is sensitive to seed-placed P and may be less efficient than many crops at using fertilizer P. Studies conducted for three years at two locations in western Manitoba indicated that flax seed yield, mycorrhizal association and Cd concentration were primarily influenced by preceding crop. Early-season P nutrition was enhanced by residual P and by side-banded P fertilizer, but effects on final seed yield ... C. Grant, M. Monreal, B. Irvine, D. Mclaren, R. Mohr |
93. Tillage and Nitrogen Management for Irrigated Sugarbeet Production in Eastern MontanaSugar beet (Beta vulgaris L.) is an important cash crop in the Lower Yellowstone River region. Nitrogen management is very critical while farmers are transitioning sugar beet production from conventional tillage to no-till system. The objectives of this study were to: (i) evaluate the effects of fertilizer-N rate and application timing on sugar beet root yield, sugar content, and quality under conventional and no-till managements, (ii) determine N uptake and N use efficiency (NU... A. Sutradhar, W. Franck, R. Garza, C. Chen |
94. Tillage and Nitrogen Rates Influenced Wheat and Sorghum ProductivityReduced tillage (RT) or no-tillage (NT) practices and reducing fallow frequency can both decrease soil losses from wind erosion and conserve soil water in the semiarid regions of the US Great Plains. This study evaluated sorghum grain yield in 2013 and wheat grain yield in 2014 and 2015 as influenced by long-term nitrogen (N) fertilizer application rates (0, 20, 40, and 60 lb N ac- 1) and tillage intensity [clean tillage (CT), RT, and NT] in dryland winter wheat–sorghum-fallow (W-S-F) c... M. Mikha |
95. Urea Application Timing Influence on No-till CornFertilizer N for no-till corn in South Dakota is often limited to surface applications of urea. Surface applied urea can volatilize. A study was conducted in 1998, 1999, 2000 and 2002 (four site years) on no-till corn comparing surface broadcast urea timing. Nitrogen rates (50 and 100 lbs N/a) were applied in the fall, winter, early spring, planting, and V-6 stage. Ear leaf samples were analyzed for N concentration in 1999 and 2000 and grain yield was measured each year. Precipitation was mea... R. Gelderman, J. Gerwing, A. Bly |
96. Use of a Crop Canopy Reflectance Sensor for In-season N Management of CornOver-application of nitrogen (N) fertilizer on corn has resulted in elevated levels of N in ground and surface waters. A major factor contributing to decreased N use efficiency and environmental contamination for traditional corn N management schemes is routine pre-season application of large doses of N before the crop can effectively utilize this N. Our long-term research goal is to reduce these over-applications by using remote sensing to direct fertilizer only to areas need... J. Shanahan, J. Schepers, D. Francis, R. Caldwell |
97. Utilizing Long-term Organic Amendments to Improve Soil Health in Semi-arid, Grazed GrasslandsDetermining soil health changes associated with long-term land application of organic amendments, such as biosolids, is important for understanding and improving overall environmental health. In 1991, a single application of biosolids were surface applied (treatment rate: 0, 2.5, 5, 10, 21, or 30 Mg ha−1) to a semi-arid grazed grassland. In 2002, a repeated application of biosolids were surface applied at the same rate to ½ of all plots. In 2018, soil samples were obtained from 0... C. Buchanan, J. Ippolito |