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1. A Comparison of Point Injected and Knifed Phosphorus for Winter WheatThere are almost 2 million acres of winter wheat grown in South Dakota. Most is produced in the southwest part of the state on residual clay soils in a wheat fallow rotation with only limited, shallow sweep tillage. Very reduced tillage is necessary for wind and water erosion control, and water conservation on the long steep slopes. The continued use of shallow tillage on highly buffered, high pH soils has made broadcast phosphorus fertilizer inefficient in increasing wheat yields, even though p... |
2. A Weighted Classified Method for Nitrogen Zone DelineationEven though zone management in precision agriculture is a relatively new science. extensive research has been conducted on the best predictors for determining optimal nitrogen management zones in site-specific farming (Bausch et al., 2002; Fleming and Buchleiter, 2002; Franzen and Nanna, 2002, Hendrickson and Han, 2000; Lund et al.. 2002: Stenger et a].. 2002). Different techniques. varying from cluster analysis (Jaynes et al.. 2003; Kitchen et al., 2002: Ralston et al.. 2002) to neural networks... |
3. Aglime for Corn and Soybean ProductionLiming acid agricultural soils has been a long-time proven practice to maintain/improve crop yields, particularly forage legumes, and to favorably affect soil chemical, biological and physical properties. Summaries of soil test results from the Iowa State University Soil Testing Laboratory for the past 35 years have shown a consistent 2 to 3 percent of soil samples with a soil pH below 5.5 and 14 to 16 percent with soil pH between 5.6 and 6.0. There has been an increasing percentage (from 21 to ... |
4. Ammonium Thiosulfate Effects on Corn ProductionAmmonium thiosulfate ((NH,),S,O,, ATS) and urea-ammonium nitrate solution (UAN) were applied in different combinations to corn grown in five site-year studies to assess any effects of ATS on corn performance. Ammonium sulfate ((NH4),S04, AS) was included in three of these comparisons as an alternate sulfur (S) treatment. Adding ATS to UAN increased corn yield in one comparison, decreased it in another and had no effect on yield in others. Adding AS had no effect on corn yield. Neither S material... |
5. An Overview of On-Farm Nitrogen Rate ResearchBecause crop advisors, farmers, and some in the fertilizer industry questioned the University's N recommendations as being too low and raised concerns that the N calibration research had been done primarily in small plots on University Experiment Station land. numerous N calibration studies for corn after soybeans were conducted on farmers' fields in southern Minnesota and northeastern Iowa from 1989 through 2002 to validate present N recommendations. On-farm replicated trials were conducted by ... |
6. Assessing Crop Nitrogen Needs with Chlorophyll MetersTissue testing of corn leaves for nitrogen (N) concentration is not widely used because it is easier and perhaps more economical to apply sufficient fertilizer than to risk a yield reduction because of an N deficiency. Environmental concerns related to N fertilizer will require producers to improve N management practices to reduce the potential for nitrate leaching. Applying fertilizer N on an "As Needed" basis rather than using a "Lump Sum" approach has both environmental and economic implicati... |
7. Assessing Spatial and Temporal Nutrient Dynamics with a Proposed Nutrient Buffering IndexContinued adoption of precision agriculture will lead to the accumulation of spatially and temporally dense soil fertility and yield data. Current soil fertility recommendation strategies use regional estimates of soil buffering properties to adjust application rates. A site specific nutrient buffering index (BI) is presented that uses accumulated yield maps and soil test data to locally estimate soil buffering properties relative to fertilizer additions and crop removal. BI is a quantity-inten... |
8. Assessing the Variability of Corn Response to NitrogenBecause results of experiments designed to test the response of corn to N rate tend to vary considerably with the environment. repetitions of such studies over time are essential. It is not clear, however, what number of repetitions are needed in order to deduce sound recommendations for application of N fertilizer to succeeding crops. We used the results from 16 years of a crop rotation x N rate study conducted at Monmouth, Illinois to assess the effect of duration of such an experiment on the ... |
9. Banded Potassium for Ridge-till Planting SystemsThe ridge-till planting system is a proven tool for controlling soil erosion and providing maximum efficiency of water use by corn. The use of the ridge-till planting system in the northern Corn Belt has increased substantially in the past several years. Recently, however, potassium (K) deficiency symptoms have been reported in many fields. These observations have occurred even though soil test values for K have been in the high range. As the number of reports of K deficiencies increased, it was... |
10. Best Management Practices for Nitrogen in MinnesotaAtrention to nirrogen (N) nlanagemerzt and to rhe influence of N on ground- rvarer qzraliry was significanrly enhanced in Minnesota wirh the passage of the Conlprehensive Groundwater Protection Acr in 1989. That legislative act mandated the fonnarion of u Nirrogen Fertilizer Task Force whose duty was ro study the eflecrs and impacrs on water resources fro,n N fenilizer use so rhar besr management practice (BMPs), a fenilizer managenlenr plan, and N fem'l- izer use regulations could be developed... |
11. Challenges for making intensive soil sampling and VRT Pay. Ongoing Iowa Studies with PhosphorusSoil fertility evaluation and management can be greatly improved with the use of precision agriculture technologies. Differential global positioning systems @GPS), yield monitors, various forms of remote sensing, geographical information system (GIs) computer software, and variable rate technologies are available for use to producers. Intensive soil sampling, crop scouting, and other practices complete the new technological package. Soil testing is a diagnostic tool especially adapted for site-s... |
12. Changes in Iowa's Soil Test P and K Interpretations and RecommendationsResearch results from long-term and short-term experimentation in Iowa have been consistent in the response or lack of response of Iowa field crops to applications of fertilizer phosphorus (P) and potassium (K) at various soil test levels for P and K. Analyses of the research data have established critical soil test values for P and K and the most economic soil test range for P and K to maintain (Mallarino, Webb, and Blackmer, 1991a and 1991 b; Mallarino and Blackmer, 1992 and 1994; Webb, Mallar... |
13. Comparison of Nitrogen Management Zone Delineation MethodsAn alternative to dense grid soil sampling for delineating residual soil N levels or N availability is a zone sampling approach. The zone approach assumes that soil N patterns are logically linked to some inherent causal effect, either natural or man-made. A number of delineation methods have been examined. including apparent soil EC (Kitchen et al.. 1999). yield mapping (Taylor and Whitney. 2001: Diker et al.. 2002), topography (Franzen et al.. 1998), aerial imagery (Williams et al., 2002 Srip... |
14. Comprehensive Nutrient Management Plan from a USDA PerspectiveLivestock manure has emerged over the past few years as a major political, as well as an environmental issue. As the Congressional Research Service described the situation in a May 1998 report: "Social and political pressure to address the environmental impacts of livestock production has grown to the point that many policy-makers today are asking what to do, not whether to do something." It added: "The bulk of current policy debate on animal waste issues, both legislative and regulatory, is occ... |
15. Corn Nitrogen Response Across Environments and Crop RotationRecent research on corn has tended to show variability in N response. Brown et al. (1993) reported that economically optimal N rates among 77 sites in Illinois ranged from zero to more than 200 lb N per acre. Results from other studies show similar variability in time and space. Even with such variability, results over environments have been combined and used to develop an N fertilizer rate guideline in Illinois based on anticipated corn yield (Hoeft and Peck, 2002). This guideline suggests pro... |
16. Corn Nitrogen Tests in MissouriExperiments were carried out in farmer fields starting in 1995 with the objective of evaluating or developing field-specific tests to optimize N fertilizer rates for corn. Because some of the soil nitrate tests seem to work differently when manure or alfalfa is in the cropping system, most farms had pairs of experiments, one with an organic N source and the other with none. Descriptions of the experimental locations are given below. Location 1 2 Year 1995 1995 1995 1995 1995 PROCEDURES Countv Ca... |
17. Corn Yield Response to the Urease Inhibitor N-n-Butyl Thiophosphoric Triamide (NBPT) When Applied with UreaUrease inhibitors are applied to reduce ammonia volatilization and immobilization losses from surface-applied urea or urea-ammonium nitrate solutions (UAN). The urease inhibitor N-(n-buty1)thiophosphoric triamide (NBPT) was evaluated at rates of 0.25 to 1.0 % (w/w) in 78 U.S. trials conducted with corn (Zea mavs L.) during the period 1984 to 1989. When averaged over N rates for all locations and years, NBPT increased grain yields by 4.3 bu/acre when compared to similar rates of unamended urea. A... |
18. Correlation and Calibratin of the SMP Lime Requirement Test with Direct Titration of Soil AcidityThe SMP Buffer method (Shoemaker, et al, 1961) of routinely determining lime requirement on soil samples has been used at the University of Kentucky Soil Testing Laboratory (UKSTL) since the mid-1960's. Initial correlation and calibration for Kentucky soils was a result of incubating several soil samples over a period of time after mixing different rates of lime with them (D.E. Peaslee, 1975, personal communication). During the ensuing years, county agricultural extension agents have raised many... |
19. Cover Crop Impacts on Corn and Soybean Nitrogen Accumulation and YieldThe need to retain soil N between economic crops has renewed interest in cover crops for the eastern cornbelt but their management remains a barrier to widespread adoption. We conducted a 3 site-yr study to determine effects of cover species (wheat or rye) and biomass management (burndown 40 d, 20 d, or 2 d preplant) on corn and soybean yields. Sites included a very poorly drained (wland wlo tile drainage) and a well drained silt loam. With adequate drainage, cover biomass 40 d preplant averaged... |
20. Deep Zone Tillage in Southeast Minnesota1 Deep Zone Tillage In SE MN (Rawson) i - --4 I Continuous corn y~eld as affected by trllage system at Rochester, 1997-00 (4-yr avg) LSD (0 10) = 3 bu - 170 IW 9 3 I 163 160 No-hll Rawson Stnp-UI Chtsel + . tillage system at Rochester, 1997-2000. LSD (0 10) = NS Rawson Stnptll Onepass Corn following soybean treatments Tillage for ' Tn # Soybean Corn 1 No-till No-till 2 Chisel + 3 No-till Ripstrip 4 Chisel + 5 No-bll Fall striptill 6 Chisel + 7 No-till One-pass 8 Chisel + 9 Chisel + Ch~sel 34kMj ... |
21. Diagnosis of Nitrogen Deficiency in Maize and the influence of Hybrid and Plant DensityThe precise diagnosis of maize N status has proven to be a difficult task because of annual 1 variation in internal N-use efficiency (kg grain kg- N uptake) and temporal change in N concentration in plant tissue. Analysis of leaf N concentration (g N leaf) has not been a consistently successful N diagnostic because of temporal and hybrid differences in specific leaf weight (SLW=g leaf me2 leaf). An alternative N diagnostic; specific leaf nitrogen (g N m-2 leaf), is unrelated to leaf mass. Maximu... |
22. Early Season Stresses in CornSpatial variability in corn yield is frequently associated with lost yield potential caused by plant stresses. Early-season stresses are difficult to recognize because growing conditions (soil temperature and water status) are not ideal and seldom uniform throughout a field. The impact that climate has on plant growth is dificult to determine because it also affects nitrogen (N) availability. Nitrogen stress was imposed sequentially until the V8 growth stage and then all plots were sidedressed w... |
23. Economic Perspective on Variable Rate FertilizationSoils form a continuum across every farmer's field, constantly changing in both physical and chemical characteristics. Sometimes these changes are visible; sometimes they are completely masked to the eye. Variables such as organic matter, water-holding capacity, pH, and soil nutrient levels differ, and combined, they affect crop yield goals. In either case, these differences should result in different management practices, including fertilizer applications, being recommended for different soils ... |
24. Effect of Alfalfa Stand Density or Cutting Management on Nitrogen Supplying CapacityEconomic, energy and environmental considerations are making the efficient use of nitrogen fertilizers increasingly important for Wisconsin crop producers. Excessive nitrogen applications cannot be tolerated environmentally due to the potential for N leaching to groundwater, or economically due to the relatively high cost of N fertilizers. The potential exists for many producers, farming in legume rotation, to unknowingly over-apply N by not fully applying credits for previously grown alfalfa. A... |
25. Effect of Irrigation and Nitrogen on Corn Yield and ProfitAn understanding of the interaction of various inputs on corn yield and profit is important in decision making for corn production. This study was conducted to evaluate 1) the effect of irrigation, hybrid, seeding rate and nitrogen rate on yield of corn and 2) the effect of these inputs on marginal return and cost per bushel for corn production. This study was conducted for three years at two 1 ocations on a Conover 1 oam and a Zi lwaukee clay soi 1 . The three years represented a normal rainfal... |
26. Effect of N Fertilization on Accumulation and Release of Readily-Mineralized Organic NIncreased nitrogen (N) fertilizer use has generated concern about groundwater contamination by nitrate (NO,?. The objective of this work was to determine how previous N management and cropping system affect fertilizer N use efficiency. Research plots from a long-term N rate study on a silt loam soil were used to evaluate the impact of long term N rates on immobilization and mineralization of fertilizer N. Labeled '5~~,15~~, was applied at rates of 0, 60, 120, 180, and 240 lblacre to subplots of ... |
27. Effect of Rotation on Corn Yield and Economic Returns Under Composted Manure or Fertilizer ManagementThe benefits of growing corn in rotation with other crops as opposed to continuous corn have been mentioned in numerous research and technical publications. The benefits of adding to the crop mix include improved soil structure (Raimbault and Vyn, 1991) and soil nutrient availability (Copeland and Crookston, 1992). especially from rotations that include legumes such as soybeans or legume cover crops. Other benefits include better weed (Bhowmik and Dow, 1982). insect (Benson, 1985) and disease co... |
28. Effect of Subsoil Tillage on Crops Grown in No-Till and Reduced Till ManagementsThree different subsoil tillage experiments were conducted in southern Illinois on soils with root-limiting claypans that restrict crop growth. In the first experiment conducted at the SIU Belleville Research Center, subsoiling to 16 inches depth was compared to no subsoiling in a field that had been in long term, continuous no-till corn production. After 4 years of study, only small corn and soybean yield increases have observed with the tillage (2.0 bu/ac for corn and 1.0 bu/ac for soybeans) .... |
29. Effect of Time of N Application for CornThe economic benefit associated with the application of N fertilizers for corn has been known for over 5 decades. As a result, over 99 % of the farmers in Illinois apply N fertilizers when corn is grown. Unlike phosphorus and potassium, there is no good soil test to predict the amount of N needed, instead, farmers use a factor times yield potential with appropriate credits for legume and other N sources to set N rates. While this works well over a number of years, there are years when less N wil... |
30. Effects of Chloride From Poultry Litter and Muriate of Potash on Cured Tobacco Leaf QualityPoultry litter is growing more popular as a soil amendment in western Kentucky. due to recent poultry industry expansion. There is concern among the tobacco industry that chloride levels in poultry litter may have detrimental effects on cured leaf quality. A three year study is being conducted at the University of Kentucky to compare availability of chloride fiom poultry litter and muriate of potash and its effect on cured leaf quality. A randomized complete block design structure was chosen, wi... |
31. Effects of Phosphorus Application Method and Rate on Furrow-irrigated Ridge-tilled Grain SorghumThe objective of this research was to investigate the effects of method of phosphorus (P) placement and rate on inigated grain sorghum grown in a ridge-tillage system on a soil low in available P. This experiment was conducted from 1993-1 995 on a producer's field near the North Central Kansas Experiment Field Experiment Field at Scandia, Kansas on a Carr sandy loam soil. Treatments consisted of fertilizer application methods: surface broadcast, single band starter (2 inches to the side and 2 in... |
32. Establishing (and Differentiating) On-farm Research and Demonstration TrialsAs the 1990s begin, funding agencies are looking beyond the traditional definition of who does "research." While university, USDA and private industry have traditionally conducted research in the past, grassroot organizations, local agency personnel and individual farmers are now proposing and implementing research of various types. An overall trend seems to be for research experiments to be evaluated on farmersf fields. Some of this movement may be a political statement against traditional meth... |
33. Evaluation of Nitrogen Management Practices in No-till Corn ProductionExperiments were conducted fiom 1995 to 1998 at the Dixon Springs Agricultural Center of the University of Illinois and the Belleville Research Center of Southern Illinois University to evaluate agronomically and economically several nitrogen (N) management options, including the use of the urease inhibitor Agrotaii, in no-till corn production. Compared in these studies were N sources (urea, UAN, ammonium nitrate, and anhydrous ammonia), placement (dribble vs. broadcast for surface-applied N and... |
34. Evaluation of Soil Profile NO3-N for Prediction of N Fertilizer RequirementsCurrent N recommendation systems based on yield goal with adjustment for previous legume crop or manure applications have worked well in many situations. In the example given in Table 1, multiplying the 8 year average yield times 1.2 lb N/bushel would result in a recommendation within 20 Ibs N/acre of the optimum in 6 of the 8 years. As expected, this system resulted in significant over recommendation in the 1988 and 1989 drought years. While these results provide confidence that the system wor... |
35. Evaluation of the Amino Sugar-N Based Soil test in Iowa Corn ProductionAn important improvement in estimating economic N applications for corn production would be to predict the soil N supply capacity each year. The objective of this research is to evaluate the adaptability and potential calibration of the amino sugar-N based Illinois N Soil Test in corn production fields across diverse Iowa soils. Nitrogen rate trials were conducted at multiple sites over several years, many on producer fields. Soil samples were collected at 0-6 and 0-12 inch depths in the fall an... |
36. 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 andlor 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 rowr where the soil will dry out and warm up earlier in the ... |
37. Fertilizer Recommendations in the Eastern Corn BeltThe purpose of this paper is to discuss fertilizer recommendations for corn and soybeans made by three universities and by three private institutions in the Eastern Corn Belt. For lack of a better term, the six sources of recommendations will be referred as "labs", a commonly-used abbreviation for soil testing laboratories. This term does not accurately describe Countrymark which uses the results from other labs on which to base its recommendations. ABSTRACT Nitrogen (N), phosphorus (P) and pota... |
38. Field Scale Variability of Corn Yield response Functions to Fertilizer Nitrogen ApplicationVariable rate nitrogen (N) application assumes that corn response to N fertilizer varies within a field. However, this hypothesis has not been formally tested yet. Field variation of corn response to N fertilizer and economically optimum N fertilizer rates (EON) were assessed in on- farm experiments throughout central Illinois. Fields (16 to 32 ha.) were subdivided into 13 to 20 areas. Five nitrogen rates were randomized within these areas in 28 kg N increments (2 rates) and decrements (2 rates)... |
39. Foliar Fertilization of Soybeans in MissouriSoybeans may benefit from foliar fertilization during the reproductive phase of growth. Foliar fertilizers consisting of factorial combinations of boron, calcium, magnesium and phosphorus were applied to soybeans every other week for eight weeks beginning at flowering at three locations. The foliar fertilization treatment containing B+Mg (1.0 lb/acre B + 2.0 lb/acre Mg total) and split into four applications at Mt. Vernon and the Delta Center increased yields by 8 and 4 bulacre, respectively. Th... |
40. Grid Sampling or Topography Sampling for Soil NutrientsSite-specific application of fertilizers uses field soil sampling for its information basis. Many fields are currently sampled using a grid approach. In North Dakota, examination of grid sampling showed nitrate-N to follow topographic patterns in a field, allowing the possibility of less intensive sampling for N. Reviewing previous grid sampling work in Illinois, some soil properties may be associated with landscape features, including nitrate-N in the surface 6 inches and soil pH. However, Ill... |
41. Ground Water Quality Research and Demonstration Projects in NebraskaTwo projects were initiated in Nebraska in 1990 to address concern with increasing levels of nitrate in ground water as part of USDA's Water Quality Initiative. The Nebraska Management Systems Evaluation Area (MSEA) Water Quality Project is a joint effort of USDA Agricultural Research Service (ARS) and University of Nebraska-Lincoln scientists. One phase of the project is investigating the direct impact of four management systems on ground water quality. Another phase of the project is evaluatin... |
42. Illinois Nitrogen Soil Test for Sugar Beets and Corn in MichiganIn Michigan the presidedress nitrate test (PSNT) (Magdoff et al.. 1984) is used to adjust nitrogen (N) recommendations for corn and sometimes sugar beet. Many growers do not use the PSNT because the presidedress soil sampling time does not conveniently fit into their operation. Preplant nitrate tests do not provide a good estimate of plant available N because of the relatively wet weather conditions during Michigan springs. .Another drawback to the PSNT is that it tends to recommend N on soils w... |
43. Impacts of Management, Moisture, and Phosphorus Form on Phosphorus Loss PotentialPhosphorus (P) is considered one of the major nutrients contributing to degradation of water quality in the United States. Our objectives were to examine P loss potential associated with: 1) high moisture conditions. 2) application (surface and incorporated) of manure from animals fed different diets and 3) sorption dynamics of inorganic and organic P compounds. The study of high moisture conditions evaluated the effects of near surface moisture conditions (wet and saturated), time (up to 28 day... |
44. Improving Nitrogen Recommendations in NebraskaSoil nitrate tests offer a unique opportunity to fine tune our nitrogen management into the 90's. Nebraska has had a long history of research and extension programs using soil nitrate levels to modify fertilizer nitrogen recommendations. Because of our climatic regime nitrate tests work well across the whole state. We have a large data base on research plots that shows the tests are very effective. A large number of farmer demonstrations conducted over the last 10 years also show that the techno... |
45. In-Furrow Starter and Broadcast Phosphorus and Potassium Fertilization for CornIncreasing awareness of potential impacts of farming on the environment has renewed interest in further study of fertilizer management strategies that reduce nutrient inputs. Fertilizer recommendations for phosphorus (P) and potassium (K) usually are based on soil-test values and nutrient removal with crop harvest. Many Midwest fmers follow these recommendations. but many others apply removal-based P and K fertilizer rates even in high-testing soils. The typical farmer applies P and K fertilizer... |
46. Influence of Elemental Sulfur on Soil pH and Soil Test LevelsSoil test summaries from South Dakota State University Soil Testing Lab show that 16 percent of South Dakota soils have a pH of 7.6 or higher. These high pH soils can reduce nutrient availability to plants. A major concern is for reduced phosphorus availability and fertilizer use efficiency. High pH soils also reduce the availability of micronutrients such as iron and zinc. Due to these issues, questions are often asked on how to reduce soil pH. A number of materials such as sulfuric acid, alumi... |
47. Interpretation and Presentation of Research InformationCrop yields have increased over time as the knowledge base supporting crop production practices has increased. The educational process of transfer of information based on research bears a deep sense of responsibility. Selection of research results on which to base recommendations is a matter of judgement that can be enhanced by proper statistical analysis. Experimental objectives, experimental design, treatment selection, number and years of experiments, environments in which the experimentatio... |
48. Interrelationship of the Nitrogen Cycle and Carbon Sequestration- Greenhouse Gas Mitigation in Row CropsAgiculture's contribution to global warming is principally through its historical release of carbon in soil and vegetation to the atmosphere and through its contemporary release of nitrous oxide and methane. The sequestration of soil carbon in soils now depleted in soil organic matter is a well-known strategy for mitigating the buildup of COz in the atmosphere. Less well- recognized are other mitigation potentials such as better management of nitrogen fertility. A full-cost accounting of the eff... |
49. Is There a Role for Gypsum in Midwest AgricultureFor the past two years, there has been an increased interest in gypsum throughout the Midwest. It's reasonable to ask if this interest is a consequence of improved crop production or the follow-up of increasted sales activity. For many years, gypsum has been used to improve crop production in some parts of the United states. In most of these situations it was used to supply sulfur (S). In some cases, gypsum has been used to supply calcium, an important nutrient for profitable peanut production T... |
50. Long Term Tillage and Fertility Effects in CornA long term study to evaluate tillage methods and fertilization practices on corn under monoculture was initiated in 1970. Effects on grain yields and soil property changes were evaluated over 20 growing seasons. Four tillages evaluated were continuous conventional, alter- nate till (2 years no-till: 1 year conventional till), continuous chisel till, and continuous no-till. The five fertilizer treatments evaluated were: control, 0-0-0; 175-0-0; 160-0-0 broadcast plus 15-80-120 row banded at plan... |
51. Long-Term Measurement of Nitrate Leaching Below Corn Agreosystems and a Restored PrairieMany studies have evaluated nitrogen leachmg from tile drained agricultural soils, but less research has been performed on many well drained soils also common throughout the Midwest. This study measured nitrate leaching fiom chisel-plow (CP) and no-tillage 0 agroecosystems in order to determine the effects of common agricultural practices on the quality of water that drains past the root zone of crops. In an effort to obtain background levels of nitrate leaching from a natural ecosystem, measure... |
52. Long-Term Nitrogen Fertilization Effects on Corn Yields and Soil PropertiesA long-term experiment (1 958-2002) provides information about the sustainability of long-term nitrogen (N) fertilizer use and continuous corn production in the northern Corn Belt. The experiment includes three N rates (none, medium, and high) applied annually in a randomized complete block design with four replications. Nitrogen rates in the medium and high categories increased over time and are currently 125 and 250 lb Nlacre. Lime treatments were imposed on the long-term N rates in 1985 using... |
53. Manganese Fertilizer Antagonism of Glyphosphate EfficacyMichigan soybean producers have observed antagonism of glyphosate efficacy in tank mixtures with foliar manganese (Mn) fertilizers. The objectives of this study were to (1) evaluate four Mn fertilizer formulations for their effect on glyphosate activity. (2) evaluate the effect of Mn fertilizer application timing on glyphosate activity, (3) evaluate the efficacy of three adjuvants in overcoming the Mn fertilizer antagonism of glyphosate. (4) determine the spray solution ratio of h4n2' and glyph... |
54. Manure ManagementNutrient management should be looked at as an integrated, continuous process. It starts with an assessment of the overall nutrient balance on the farm If this simple assessment indicates a nutrient imbalance, a more detailed assessment will indicate specific field imbalances that need to be considered in the manure management process. Once an assessment has been accomplished, management options for dealing with the situation can be explored. If there is an overall nutrient imbalance on the farm,... |
55. Manure Management Policy IssuesTraditionally nutrient management has been concerned with optimizing the economic return from nutrients used to produce a crop. The main emphasis was on the expected crop response from adding nutrients. In practice however, manure is not always applied to optimize plant nutrient use. Historically, a common practice has been to apply commercial fertilizer without giving credit for nutrients already applied in manure. Applying manure in excess of plant needs, or at the wrong time, or handling it i... |
56. Missouri Grid Soil Sampling ProjectA grid soil sampling project has been conducted over the past three years in S.E. htissouri for creating a database to provide for variable fertilizer application within fields. Results have shown widely varying soil test levels in excess of 100% variation for P and K. Gross returns to variable spreading of P and K are estimated using an expected soil test and nutrient response function. As may be anticipated, returns to variable fertilization application within a field are also highly variable... |
57. N x K Interactions- CornA study was conducted at OARDC-Western Branch near Springfield, OH for 4 years starting in 1992 to investigate the effects of N and K on corn production N uptake. The soil series was a Crosby Silt Loam with approximately 2.5% organic matter. All nutrients were in the above average levels on the soil test except for exchangeable K levels. See table 2 for soil test K levels. The corn hybrid Countryrnark 735 was seeded approximately the last week of April at 35,000 seeddacre. A split plot design w... |
58. Nitrate Concentrations in Drainage Water from a Continuous Corn Production System- Impacts of Tile Spacing and Precipitation EventsCharacterization of agricultural drains as point sources for nitrates in surface waters has generated keen interest in regional grab-sample monitoring programs. Grab sample tile drain monitoring programs are being explored by numerous public and private organizations interested in encouraging BMPYs for nitrogen and/or implementation of TMDL policy. Our objective was to determine if nitrate concentrations in water collected from individual tile lines could be interpreted independent of informatio... |
59. Nitrate Test Clinics in MichiganNitrate contamination of groundwater in Michigan is becoming an increasing public concern. Fertilizer N, animal manures and rural septic systems have been implicated as possible nonpoint sources of contamination. A state wide program of monitoring nitrate N in soil and well water was initiated. In the spring of 1989 and 1990, 74 nitrate testing clinics were conducted. Over 3,600 soil samples and 1,900 water samples were analyzed for nitrate N using the nitrate ion-specific electrode. More soil n... |
60. Nitrification of Banded Liquid FertilizersField studies were conducted in 1990 at three sites to compare the relative effectiveness of ammonium thiosulfate (ATS, 12-0-0- 26s) , dicyandiamide (DCD) , and nitrapyrin (NP, ' N-Serve 24E' ) as nitrification inhibitors in combination with banded urea-ammonium nitrate (UAN). Applications were banded prior to planting spring wheat, and soil samples taken 2, 4, and 8 weeks after application. ATS, DCD, and NP inhibited nitrification at all three sites. ATS inhibited nitrification at the 4 week sa... |
61. Nitrogen and Phosphorus Fertilization of Cool Season GrassStudies were initiated at two locations on cool season grass in central South Dakota to evaluate the effects of nitrogen and phosphorus on forage and seed yields. Nitrogen rates (0,30,60,90,120,1501b Nacre) and phosphorus rates (0,30,60,90,180 Ib P,Odacre) were applied to established crested or intermediate wheatgrass once and harvested for either two or three years depending on location. Nitrogen increased dry matter yield by 48 and 62% at the two locations and seed yield by 166 percent. Phosph... |
62. Nitrogen Availability from Composted ManureComposting of manure has been proposed to play a role in manure management programs designed to protect water quality. It is known that the biological activity involved in composting changes the nutrient availability of the material and in some cases will reduce the nutrient content. The major role of composting in alleviating some of the on-farm manure nutrient excess problems is by facilitating manure movement from a farm with an excess to a farm with a deficit of nutrients. There are several ... |
63. Nitrogen Fertigation on SoybeansNutrient requirements for soybeans are greatest as seeds are developing during reproductive pod fill. This peak nutrient demand period physiologically coincides with decreased efficiencies in both symbiotic nitrogen (N) fixation and root efficiency (Brun, 1978). Large N applications during vegetative growth stages limit N fixation and fail to consistently increase grain yields (Fla~ery, 1986). However, smaller N applications during flowering and pod fill have been reported to augment plant N sta... |
64. Nitrogen Fertilizer Equivalency of Anaerobically Digested Municipal SludgeCrop yield response to municipal sludge is largely affected by the amount of nitrogen (N) made available during the growing season. The effect of sludge rate and N fertilizer rate on either grain sorghum [Sorghum bicolor (L.)] or corn [Zea mays (L.)] yield response was studied on three fms in Lancaster county, Nebraska. A combination of five rates of dewatered (80% H20) anaerobically digested sludge and five rates of N fertilizer (NH&03) were applied before planting and incorporated by discing ... |
65. No-till Corn Response to Starter Ffertilizer in MissouriEarly research on starter fertilizer showed that it usually increased early season crop growth, but in Missouri and adjacent states this only occasionally translated into a yield advantage. With widespread changes in tillage practices over the past twenty years, this conclusion may be changing. Recent starter fertilizer trials from other states are frequently showing corn yield responses in no-till systems. Dave Mengel at Purdue University found a yield response to starter in 8 of 11 no-till sit... |
66. No-till Nitrogen Management Research in MissouriNo-till nitrogen management research on corn in Missouri has focused on the field response of N sources and placement. Results suggest consistent significant response to the use of a non-volatile N source when broadcast on the soil surface compared to N sources that contain urea and potentially can lose ammonia through volatilization. Knifed application of N in no-till has . consistently provided higher yields and N uptake compared to either surface band or broadcast application of potentially v... |
67. North Central Regional Nitrate Soil Testing ProjectAlthough preplant soil nitrate (NO -N) tests have a long history of 3 successful use in semi-arid regions of the Western and Great Plains region of the United States (Hergert, 1987), soil NO -N testing in humid 3 regions is currently receiving substantial research attention. One of the most promising approaches to KO testing in the higher rainfall areas 3 of the Midwest and Eastern states is use of the pre-sidedress soil NO test (PSNT) (Magdoff et al., 1984). Research conducted in the humid 3 re... |
68. Nutrient Credits for Manure--Differences Between Theory and RealityIt has been a mainstay recommendation for many years--take credit for the nutrients in the manure you spread on your fields. While it may seem that everyone is referring to an identical procedure, there are numerous strategies to crediting nutrients contained in manure. Although it appears to be simple, the complexities involved in crediting have resulted in few livestock and crop producers properly crediting nutrients from manure. Research and educational efforts have sharply increased in the p... |
69. Nutrient Management Implications of Relay Cropping on the EnvironmentResidual nitrogen (nitrate-N) remaining in the root zone after seed corn production is frequently greater than under commercial corn production. This nitrate is subject to leaching into the shallow ground water of the Platte River Valley in South-Central Nebraska. as noted by elevated nitrate-N concentrations under seed cornfields compared to other fields. Hard-red winter wheat was planted into seed corn residue in early October of 2001 as a cover crop to scavenge residual- N from the root zone ... |
70. On-Farm Nitrogen Fertilizer DemonstrationsThe Magdoff Pre-Sidedress Nitrate Test (PSNT) has been successful 1y used in the Northeast and humid parts of Midwest to improve N fertilizer recommendations. A modified version of the Magdoff PSNT was evaluated in 1989 and 1990 in Michigan. Fifty-three large scale on-farm corn N demonstrations were carried out. Two rates of N (a reduced rate and a high rate) were rep1 icated 3 to 6 times in each field. Forty-six sites showed no significant (p=.05) yield reduction due to the reduce N rate. Forty... |
71. Optimal Phosphorus Response in Site-specific FarmingSite-specific farming has provided an opportunity to collect large amounts of field data, but traditional agronomic yield response models have not been developed to exploit this mformation. This research presents a yield model that incorporates detailed site-specific field information (e.g., soil pH. soil test P, K, and N, fertilizer rates), providing improved fertilizer decision making. A quadratic yield response function and a modified asymptotic Mitscherlich function are compared for irrigate... |
72. Overview of Soil Fertility Research in Ontario, 1991The major areas of focus in soil fertility research at the Department of Land Resource Science, University of Guelph over the past year have concerned increased nuhent use efficiency and environmental impact. These studies have examined the development of nitrogen soil test for corn, nitrate movement to groundwater, the fate of manure N, the placement of phosphorus fertilizer and the role of VA mycorrhizae in plant phosphorus numtion. The following is a summary of the projects being conducted in... |
73. Phosphate Management for the Corn Soybean RotationThe evaluation of rate, Frequency, and placement of phosphorus (P) fertilizer on production in the codsoybean rotation was evaluated for two contrasting tillage systems. A primary objective of this study was to evaluate both yield and economic response for the full crop rotation. Tillage systems compared were fall chisel plow and no-till. Application rates ranged from 0 to 92 Ibs P205 ac-' yr-l and were fall applied either annually or at double the rate on a biennial basis. The biennial applicat... |
74. Phosphorus Losses in Runoff Water as Affected by Tillage and Phosphorus FertilizationPhosphorus (P) in runoff from cropland can contribute to nutrient enrichment and eutrophication of surface water bodies. Research was continued during 1996 to determine which tillage systems and which methods of applying P fertilizer will result in the least P losses in runoff water for grain sorghum production under somewhat poorly drained soil conditions in east-central Kansas. The tillage systems evaluated were a chisel-disk-field cultivate system, a ridge-till system, and a no-till system. F... |
75. Phosphorus Placement and Tillage Effects on Corn and Soil P LevelsIncreasing crop production costs have producers scrambling to gain the greatest efficiency possible from added fertilizers. A field study was conducted at two locations in southern Illinois is assess the effect of phosphorus (P) rates and placement methods on yield and P uptake by corn under no-till (NT) and conventional (chisel and disk) tillage (CT) systems. Phosphorus rates consisted of 0, 20, and 40 pounds P205/Ac with placement methods of surface broadcast, dribble and 2x2 at planting. Afte... |
76. Potassium Placement in Conservation Tillage- cropping System ConsiderationsSoil fertility specialists have repeatedly observed that significant stratification of both P and K occurs on fields which are kept in no-till production, even if that time period is as short as three years. The actual degree of K stratification is affected by soil texture, the method of fertilizer application, crop rotation history, precipitation levels and surface residue management. Potassium stratification isn't inherently deleterious to crop production in a given environment. Crop yield los... |
77. Predicting Plant Available Potassium using a Modified Sodium Tetraphenylboron MethodCurrent potassium (K) fertilizer. recommendations in the midwest are based primarily on the ammonium acetate exchangeable K (NH,OAc) soil test. In soils where nonexchangeable K comprises a major portion of plant available K, the ammonium acetate soil test is unreliable. Soil K extraction by sodium tetraphenylboron (Na-TPB) accesses both exchangeable and nonexchangeable K and mimics the action of K uptake by plant roots. A Na-TPB method utilizing a 5-minute extraction period is described, and the... |
78. Predicting Subsoil Nitrate Content from Surface MeasurementsPreplant soil profile nitrate (NO,-N) tests are effective for I predicting corn (Zea mays L.) responsk to applied N. The difficulty of obtaining profile soil samples is one of the main obstacles to more extensive use of preplant tests. One approach to overcoming this barrier is to develop and use models to predict subsoil NO -N contents 3 from surface soil NO -N measurements. Data from 2295 routlne field 3 samples submitted to the University of Wisconsin Soil and Plant Analysis Laboratory from 1... |
79. Providing Flexibility in P and K RecommendationsHistorically, land grant Universities have generally provided a single rate recommendation for nutrients such as phosphorus (P) and potassium (K). Depending on the particular University in question, these nutrient rate recommendations are generally based on two widely recognized approaches to managing soil and fertilizer P and K - the nutrient sufficiency approach and the build-maintenance approach. The goal of a nutrient sufficiency based soil fertility program is to apply just enough P andior ... |
80. Reducing the Severity of Phyophthora Root Rot Damage in Soybeans with Selected Management OptionsPhytophthora root rot of soybeans (PRR) is a major concern for soybean growers in south-central and southeastern Minnesota, where it can be responsible for major yield reductions. In these regions, PRR is generally a serious problem when soybeans are grown on poorly drained soils and/or there is a moderate amount of rainfall within 2 to 3 days of planting. Previous research has shown that PRR causes a reduction in the number of harvestable plants per acre and this is the major contributing facto... |
81. Relationship Between Response Indices Measured In-Season and at Harvest in Winter WheatCurrent methods for making nitrogen recommendations in winter wheat (Triticum aestivurn L.) do not adjust for in-season temporal variability of plant available non-fertilizer nitrogen (N) sources. The purpose of this study was to compare the use of different nitrogen response indices determined in-season @INDVI and RIPLANTHEIGkm) to the nitrogen response index measured at harvest (RIHARvEST). In addition, this study evaluated the use of the in-season response indices for determining topdress nit... |
82. Relationship of Seed-placed Phosphatic Fertilizer Salt Index to Crop EmergenceThe role of fertilizer salt index in salt injury to germinating seeds has been recognized for over 60 years. Recent increased use of direct seed placement of fertilizer P has produced a need for a simpler method of making seed-placed fertilizer recommendations. Numerous field studies were conducted utilizing seed-placed P fertilizers. Published fertilizer salt index values were multiplied by the PtOs/ha application rate to give a salt indexha value. Relative plant stand (dependent variable) was ... |
83. Savi Determination in Carrots- Comparing Constant and Dynamic Soil Adjustment FactorsReliable interpretation of reflectance measurements of vegetation in incomplete canopies is confounded by the influence of soil background. Qi et al. (2000) developed a fi-actional coverage uc) model from the NDVI of target vegetation and soil. Spectral data from a two year (2001, 2002) carrot study was used to determine if the fractional coverage (fc) model could be used to estimate the observed fractional coverage of the developing carrot canopy. Reflectance measurements and matching digital ... |
84. Should P and K Fertilization be Matched to Plant Populations for CornFertilization practices and plant populations are major factors involved with corn production. Several researchers have investigated the effects of various fertilizer management practices. Likewise, the impact of plant population on corn production has been evaluated in a variety of production environments. The combined effects of plant popillation and fertilization. however, have not been thoroughly evaluated. Specifically. there has bcen very little study of the influence of plant populations ... |
85. Sidedress N applications for corn based on corn colorNitrogen-deficient corn reflects more light over the entire visible spectrum than nitrogen-suff icient corn. Our objective was to calibrate the relationship between remotely-sensed corn color and the nitrogen need of the corn. Corn color measurements were made two ways: Aerial photographs In-field spectral radiometer A successful calibration would allow: Variable-rate sidedress nitrogen applications that precisely meet the needs of the crop. Precise response to in-season N loss (Figure 1). Data ... |
86. Site Specific Nitrogen and Irrigation Management Across Nebraska Agro-ecological ZonesNitrogen leaching below hrrow irrigated ground has caused nitrate contamination in Nebraska's groundwater. Alternate row irrigation and alternate row nitrogen fertilization is proposed as a method to decrease water use and decrease nitrogen leaching. Nitrogen was applied at a uniform and variable rates based on spring grid sampling for nitrate and soil organic matter. The experiment was conducted at three sites in Nebraska that represent a range of growing conditions. At these sites the average ... |
87. Site-Specific Nitrogen ManagementApplying only the amount of nitrogen fertilizer needed for a crop at a particular point in the field makes intuitive sense - and is hard to argue against conceptually. However, in practice site-specific nitrogen (N) management is quite challenging. That is to be expected, since routine. uniform N management is often more challenging than is management of other nutrients. Because of nitrogen's mobility in soil. the fact that it is subject to a wide range of transformations and loss processes, and... |
88. Site-Specific Nitrogen Management for Reducing Soil Residual NitrateSite-specific N management has potential for increasing the efficiency of N fertilizer use, and thereby reducing environmental impact. Field studies were conducted in 2000 and 2001 to evaluate the potential for site-specific N management to reduce residual soil nitrate in Missouri cornfields. Field-size side-by-side fertilizer N treatment strips were applied in cooperating farmers' fields. The site-specific crop N requirement (optimal N rate) was determined for sub- blocks that contained a full... |
89. Site-Specific Prediction of Soybean Nitrogen ContributionsSoybean has long been recognized for its nitrogen (N) contributions and yield enhancing effects in crop sequences. Soybean N credits in the Midwest range fiom 20 to 40 Ib of Nlacre (Kurtz et al., 1984). Several Midwestern states recommend a legume credit of 40 Ib of Nlacre following an average crop of soybean. Current Wisconsin recommendations suggest a reduction in nitrogen fertilizer rates for corn following soybean of 1 Ib N hushel of soybean yield up to a maximum credit of 40 Ib Nacre (Kelli... |
90. Soil Carbon Sequestration in Agriculture- Research Efforts in the Central U.S.Since the late 1800's fossil fuel use, expansion of cultivated agriculture, and forest clearing have led to an increase in atmospheric C02 from 260 pprn to current levels >370 ppm (IPPC, 1995). Most of the recent increase in COz has been attributed to combustion of fossil fuels for energy and transportation. This increase in atmospheric COz potentially impacts climate, as it is a greenhouse gas. It has been estimated that 20-40% of targeted emission reductions in the U.S. can be met by carbon se... |
91. Soil Fertility for Functional FoodsIn the agri-food industry today, two trends cannot be ignored. First, the health conscious "baby boom" generation is demanding and will continue to demand foods that enhance their wellness. Crop producers must increasingly focus on the goal of producing crops that meet their needs. Second, the tools of molecular biology give agricultural scientists the opportunity to attain that goal. Biotechnology involves not only genetic engineering, but also includes tools that enhance the traditional select... |
92. Soil Fertility Trends in a Long Term Crop Rotataion-Soil Fertility TrialPenn State soil test recommendations are based on fertilizing for crop response at soil test levels below the critical level for response, maintenance fertilization based on expected crop removal in the optimum range just above the critical level, and finally no fertilizer recommended in the high range. Using a sufficiency level approach, a soil that was at the critical level would have a zero recommendation, however this zero recommendation would not be valid for 3 or 4 years until a new soil t... |
93. Soil Phosphorus Chemistry- Agronomic and Environmental ApplicationsPhosphorus (P) has been a heavily researched topic in soil science for many years. For example, a search of the AGMCOLA database from 1970 to present turned up nearly 6000 citations under the key words soil and phosphorus. The fact that P is essential to all forms of life has promoted these research activities. as one would expect. In addition, the complexity of the soil P cycle has yet to be fully understood and appreciated by the scientific community. Further, while early research focused on c... |
94. Soybean Chlorosis in North Dakota- Causes, Severity and Possible SolutionsSoybean acres continue to increase in northwestern Minnesota and North Dakota in spite of severe problems with iron chlorosis in some years. Soybeans often turn yellow within a few weeks of emergence and remain yellow for up to 8 weeks before plants green up and mature. Iron chlorosis tolerant soybeans available today are somewhat effective in reducing chlorotic acreage, but are not tolerant enough to counteract the soil conditions in this area. Several researchers have found that iron chlorosis... |
95. Spatial Analysis of Yield-Limiting FactorsThe spatial relationship between crop yields and soil and site parameters was modeled using several methods. Yield maps estimated by projection pursuit regression and neural network analysis agreed well with measured yields. These methods also allowed generation of response curves for estimated yield as a function of each of the input parameters. These response curves were useful for investigating the relationship between yields and individual soil and site parameters. ... |
96. Spatial Prediction of Crop Productivity Using Electromagnetic InductionAn inexpensive and accurate method for measuring water-related, within-field soil productivity variation would greatly enhance site-specific crop management strategies. This paper reports on investigations to use an electromagnetic induction (EM) sensor to map claypan (Udollic Ochraqualfs) and alluvial (Typic and Aquic Udipsarnnlents, and Aeric Fluvaquents) soil conductivity variations and to evaluate the relationship of EM measurements to grain crop production. Grain yield measurement was obtai... |
97. Starter Fertilizer for Row Crop Production Under No-till Conditions in Eastern NebraskaStarter fertilizer application often results in increased corn and sorghum yield under no-till conditions, probably due to lower soil temperatures as compared to tilled soil. Five dryland and 5 irrigated corn trials. and 12 dryland grain sorghum trials were established after soybean in 2002 and 2003 on rolling land in eastern Nebraska with different soil types and topographic positions. Three placement positions were compared: in the seed furrow. over the row. and 2" to the side and 2" deep (2x2... |
98. Starter N and P Effects on Early Maturing Corn Planted EarlyShort-season corn planted early is a water-use management option being investigated in the central plains states. This study was conducted in an attempt to determine optimum starter N and P fertilizer rates and to compare subsurface banded versus surface applications of P for short-season corn planted early. Each location had a 3x3 factorial arrangement of N and P (0, 20 and 40 lbs N or P205/acre) placed 2 inches below and beside the seed as well as one or both application methods of surface bro... |
99. Studies of Agricultural Effects on Groundwater Quality in KentuckySeveral small watersheds and tiled fields have been selected in Kentucky to assess the influence of agricultural practices on groundwater quality. Sites were selected to represent the dominant agricultural systems used in the most agriculturally important areas of the state. Within each study site, water samples from springs, wells, streams, or tile lines are being sampled monthly to monitor content of N03-N, atrazine. alachlor, and fecal bacteria. Although sampling will continue for at least an... |
100. Subsoiling No-tillage CornCurrently, over half of the corn in Kentucky is no-till planted. Many fields have received little tillage in the last 10 to 20 years. Many producers wonder if soil compaction increases with time on these long term no-till fields due to annual trafficking with heavy equipment. Subsoiling implements are available that allow subsurface tillage while preserving the surface mulch layer. This allows for continued no-till planting while introducing some tillage into the cropping system. Some producers ... |
101. Sulfur Fertilization of Smooth BromegrassStudies were initiated in 1987-88 on established smooth bromegrass at two sites in eastern Kansas to evaluate the effects of sulfur fertilization on bromegrass forage production and quality. Sulfur rates (0, 15, 30 lb S/ac) and sources (ammonium sulfate and ammonium thiosulfate) were evaluated. The addition of sulfur consistently and, in most cases, significantly increased bromegrass forage yields and forage S concentrations. Sulfur had little effect on forage protein levels. Ammonium thiosulfa... |
102. Summary of How Fertilizer Dealers Integrated Manure into Their Nutrient Management ProgramsTwo fertilizer dealers established manure brokerages in Ohio in the spring of 1992. One was in Holrnes County in Northeast Ohio with Progressive Crop Service, an independent fertilker dealer. This county is in an area which has a high concentration of poultry located in the eastern part of the county. Most of the row crop agriculture is in the western side of the county. The terrain is rolling and this is an Amish community which tends to have small fkms. The second site is in Darke County in we... |
103. The Analysis of Nitrogen and Plant Population InteractionsNitrogen and plant population are significant factors for corn production. Accurate nitrogen fertilizer and seeding rate recommendations are essential for optimizing profitability for the fmer and minimizing nitrogen losses. Research and development of yield response curves provide important information that can be used to understand the relationships between these inputs (nitrogen fertilizer and corn seeds) and output (grain yield). Over the varying levels of inputs. yield response functions ca... |
104. The Future of the U.S. Nitrogen Industry-SlidesThe Future of the U. S. Nitrogen lndustry David Asbridge November ZOO3 Nitrogen Situation U.S. Ammonia - Cost & Margins $ Per Ton 1 U.S. Fertilizer Consumption Index of U.S. Nitrogen Prices January 2002 = 1.0 January 2002 - October 2003 -% 1997-2003 Nitrogen Market Driving Factors Record increase in world nitrogen capacity World Ammonia Capacity vs Consumption 1997-2002 Nitrogen Market ( Driving Factors I 1997-2002 Nitrogen Market Driving Factors + Record increase in world nitrogen capacity + Ch... |
105. The Importance of Soil Microorganisms in Aggregate StabilityAggregate stability is a soil quality factor. Water stability of aggregates is related to microbial activity. This paper reviews microbial inputs to aggregate stability. Soil fungi have long hair-like projections, hyphae that can physically entangle soil particles and exude glues. Microbial glues are discussed with special emphasis on arbuscular mycorrhizal (AM) fungi and the glue-like compound, glomalin. produced on hyphae of this group of fungi. Influences of management practices on AM fungi a... |
106. The New Wisconsin Soil Test Recommendation ProgramThe modern Wisconsin soil testing program was originally developed in the early 1960's. It was revised rather thoroughly in 1970 and again in 1981. New research advances, additional correla- tion and calibration data, changes in user needs, and shifts in philosophical viewpoint make it necessary to periodically review the soil testing program and the recommendations that emanate from that program. The current revision is an attempt to incorporate additional research, eliminate certain inconsiste... |
107. The Soil Doctor- A Field TrialThe growing environmental concerns of the nation are causing some changes in production agriculture. One of the environmental areas receiving attention is NO,-N in the ground water. A number of universities and private companies have directed attention to this problem. The pre-sidedress nitrate test is the most common approach to reducing excess nitrogen application on corn in the humid eastern U.S. Several researchers have developed systems to use this test. Fields are sampled to a foot depth w... |
108. Timing of Spring N Application to Soft Red Winter WheatHistorically, in the northern Corn Belt, the majority of the N for winter wheat is applied as a single application when fields become green and initiate spring growth (Greenup). Time between initial spring greenup and early stem elongation (Feekes GS 6) is relatively short (four to six weeks). During this time, the potential for N loss is generally low because soil and air temperatures are cold enough to minimize volatilization and nitrification. Producers attempt to apply N at greenup because f... |
109. Trends in Soil Test P and K in IowaThe Iowa State University Soil Testing Laboratory has provided soil test information to Iowa farmers since 1931 when Professor Firkins began the service for no charge. The predecessor of today's lab was initiated in February, 1946 (~ik~) . The lab's records provide us with valuable information on the trends in the plant nutrient status of Iowa's soils (Figure 1). During the period from 1960 to 1981, the consumption of nitrogen (N), phosphate (P), and potash (K) fertilizer materials rose from 7.5... |
110. 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 Ibs Nla) 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 measur... |
111. Using Historical Yield Patterns in Fields as a Management Tool to Variably Apply NitrgenIn whole field studies in southem Illinois a uniform rate of N application was compared with variably applied rates of N based upon historical crop yields for each field. The fields used were partitioned in "low". "medium", and "high" zones of productivity depending upon the normalized yield of the preceding 5 to 10 years of crops grown. Two formulas were used to variably apply nitrogen. One formula (VRN-One) calculated a N rate that favored more fertilizer in "high" productivity regions and les... |
112. Utilizing Inhibitor Technology to reduce Ammonia Volatilization Losses from Urea Sources Applied to Conservation TillageA severe limitation to urea fertilizers and the ureacomponent in livestock wastes is the high potential for volatile loss of nitrogen (N) as ammonia. Losses are especially severe when the urea-containing materials are surface applied with no or only limited subsequent incorporation. Extensive losses are also observed when urea is applied to warm soils that are moist and undergoing rapid drylng. Soil pH, the presence of an active microbial population, and soil texture are also known to impact vo... |
113. Yield Monitoring- The Beginning or the EndAs site specific management or precision farming gains acceptance with the agricultural producer, the question remains: '.Where do I begin?". As technology creates and makes available new machines for the site specific environment: ''How do they fit into the picture?". As the yield monitor has become the most popular and accepted of these technological innovations for the agricultural producer, what role does it play in the sitc specific management concept? What is site specific management and w... |
114. Yield of Sugar Beet, Soybean,Corn, Field Bean and Wheat as affected by Lime Applications on High Soil pHLime from sugar beet processing plants has been stockpiled for 100 years. Environmental regulations and limited storage space provide an impetus for the removal of the material. Land application on alkaline soils is one alternative for disposal of this material. This study was undertaken to evaluate the effect of applying sugar beet processing lime on crop production on these soils. Studies were conducted at seven sites representing four alkaline soil series in Michigan. Lime was applied at rate... |