Proceedings
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1. 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... |
2. Alternative Approaches to Making Fertilizer RecommendationsThe objective of this research project was to evaluate, both agronomically and economically. some common altcrnative methods of making fertilizer recornmcndations for corn, soybeans, and soft-red winter wheat used in Indiana. Over a period of six years ( 1992- 1997) the effect of seven alternative fertilizer recommendation philosophies on soil test levels, crop yields, plant tissue analysis, and fertilizer additions were measured in an attempt to determine differences in performance between thes... |
3. 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 ... |
4. 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... |
5. Basic Concepts of Soil Acidity and LimingMost midwestern soils require periodic applications of aglitne or other liming materials for optimum crop production. Liming has several beneficial effects: I ) it reduces harmhl or potentially tosic conditions which can develop in acid soils; 2) it increases the availability of some of nutrients: 3) it replaces the supply of calcium and magnesium essential for plant growth which is depleted as soils become acid; 4) it ensures favorable conditions for the activity of certain herbicides; and 5) i... |
6. 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... |
7. Chloride Fertilization on Wheat, Corn, and Grain SorghumResearch in the Pacific Northwest and the Northern Great Plains has documented positive cereal grain responses to chloride (CI) fertilization. Field research was conducted in Kansas evaluating CI fertilization on winter wheat, corn, and grain sorghum. Chloride fertilization consistently and significantly increased plant CI concentrations in all crops. Chloride fertilization increased grain yields or one or more winter wheat cultivars at 3 of 4 sites. The most dramatic yield increases were at th... |
8. 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... |
9. 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... |
10. 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... |
11. 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... |
12. Deep Banding Phosphorus and Potassium for No-till Corn and SoybeanThe information presented is part of ongoing research to identify effective fertilizer placement methods and diagnostic tools lor phosphorus (P) and potassium (K) in no-till corn and soybeans. There is uncertainty about soil test interpretations and cost-effective methods of fertilizer application for the no-till systcni. Moreover, producers are uncertain about the value of soil testing in conservation tillage because of large variability and lack of knowledge concerning techniques for collectio... |
13. 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 ... |
14. 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... |
15. 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 ... |
16. Effect of Nutrient Combinations and Nitrapyrin in Starters on CornExperiments were conducted from 1994 to 1996 at the Belleville Research Center of Southern Illinois Univerity and the Dixon Springs Agricultural Center of the University of Illinois to evaluate the effect of starter fertilizers. nitrapyrin (N-Serve) amendment of the starters, and tillage on conn. The soil at the Belleville site was an Iva silt loam, a low organic matter soil with relatively high P and K soil test levels. At Dixon Springs a Bonnie silt loam (bottomland) soil was used and the soil... |
17. 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... |
18. 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) .... |
19. 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... |
20. 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... |
21. 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 ... |
22. 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)... |
23. 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... |
24. Hypoxia in the Northern Gulf of Mexico- Causes and ConsequencesSeasonally severe and persistent hypoxia, or low dissolved oxygen concentrations, occur on the inner to mid-Louisiana continental shelf to the west of the Mississippi River and Atchafalaya River deltas. The areal extent during mid-summer surveys of 1993- 1997 ranged from 15.800 to 18,200 km2. The shelfwide distribution in mid-summer for 1985 to 1992 averaged 8,000 to 9,000 km2. Hypoxia occurs below the pycnocline from as early as late February through early October, but is most widespread, persi... |
25. 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... |
26. 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... |
27. 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... |
28. 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... |
29. Influence of Nitrapyrin on Nitrate Concentrations in SoilsIn central Ohio most of the water used for d&g comes from the Scioto River Watershed. This water shed in primarily composed of farmland in which corn and soybeans are the dominant crops. Periodically the nitrogen in the Scioto River exceeds safe drinlung water standards of 10 ppm nitrate nitrogen. Several EPA studies have concluded the high nitrate nitrogen levels are the results of nitrate flushes through the underground tile in agricultural fields. These flushes of high nitrates usually from l... |
30. Intensive Nitrogen Management of Soft Red Winter WheatThe current system of making nitrogen recommendations for wheat in the Eastern cornbelt assumes that nitrogen fertilizer required is a simple function of yield potential. The higher the yield potential, the more N fertilizer needed. The problem with this assumption is that factors such as soil type and ability of a site to release N through mineralization, climate, variety. disease pressure and managetnent practices all affect nitrogen use efficiency, and are not considered in making nitrogen re... |
31. Interaction of Soil Applied Herbicides with Soil pHManagement of soil pH is important in enhancing the availability of certain plant nutrients and in minimizing toxic levels of other elements to crops. However, the reaction of herbicides with soils under varying soil pH levels can affect both crop growth and herbicide performance. Soil pH affects herbicide performance in several ways. When crops are under stress due to nutrient imbalance from unfavorable soil pH levels, application of certain herbicides may increase risk of crop injury. When soi... |
32. 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... |
33. 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... |
34. Limestone Sources and Factors Affecting Their QualityAddition of liming materials to correction soil acidity is an age old practice. According to Barber (1984). Cato and Varro used lime to correct soil acidity about 200 B.C. In America. benefits derived from liming acid soils were docuniei~ted in the early 1800's (Ruffin, 1821). In a sunfey conducted in 1980. all but two of the North Central States (North Dakota and South Dakota) reported that research had shown a need !'or limc (Whitney, 1980). The need has not changed over the last 17 years, i.e... |
35. Liming in No-till SystemsIn 1985 a study was initiated at Penn State to look at the effects of surface application of lime on a very acid, long-term no-till soil. Since 1977 this field had been in no-till corn production with no limestone applied. The initial pH of "plow layer" was 5.1 and the surface 2 inch pH was 4.5. The limestone recommendation, based on the SMP buffer pH and a target pH of 6.5, was 6000 Ib calcium carbonate equivalent (CCE) per acre. The study included four limestone rates (0. 3000, 6000.9000 Ib CC... |
36. 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... |
37. 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... |
38. 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... |
39. 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... |
40. Methods and Limitations of Zone Sampling Using Topography as a Logical BasisTwo forty-acre fields in North Dakota were sampled in a 110 foot grid. Each field was measured for elevation in the same 110 foot grid. Topographic sampling zones were identified in each field and a correlation of the sampling based on these zones was compared to the correlation values from a 220 foot grid. Nitrate-N and the 220 foot grid were both correlated to the 110 foot sampling values for nitrate-N and P. A map of field nitrate-N levels from topography sampling compared to the 220 foot gr... |
41. 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... |
42. 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 ... |
43. Nitrogen Availability to Corn Following Small GrainsNitrogen rate recommendations for corn are generally reduced following legumes compared to following corn or small grains. A 4-yr field study was conducted on a Plano silt loam soil in southern Wisconsin to evaluate the capability of soil NO3 tests to predict N availability to corn follo~b-ing small grains. Previous crop small grains included \vinter wheat, winter qe. and oats harvested for grain and straw. Nitrogen fertilizer was applied to corn at rates of 0 to 180 Ib/a in 30 Ib increments. Gr... |
44. 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... |
45. 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 ... |
46. Nitrogen in the Mississippi River Basin- Sources and Factors Affecting Loss of Nitrate to the RiverNitrogen (N) is a naturally occurring element that is essential to plant growth and crop production. In a soil system, nitrate-N is continually supplied through mineralization of soil organic matter. Other sources of N include fertilizers, animal manures, municipal sewage wastes, agricultural and industrial wastes, atmospheric deposition. and dinitrogen fixation, all of which either occur as nitrate-N or can be converted to nitrate-N through mineralization and nitrification. ... |
47. 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... |
48. 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 ... |
49. Performance of Early vs. Late Maturing Corn Hybrids in MichiganThe planting of fill-season, or late maturing hybrids in Michigan is encouraged by their tendency to produce higher yields. Full-season hybrids can take advantage of the entire growing season available at a particular location. Shorter season hybrids reach physiological maturity sooner and generally yield less. Recent experience with cool, wet springs resulting in delayed planting, and growing seasons that provided less growing degree days (GDD) than normal has caused corn producers to question ... |
50. 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... |
51. Precision Phosphorus Management for SoybeanSoybean responds to phosphorus fertilization in the Midwest. Most correlation and calibration data suggests that soybean is less responsive than corn. Because of this. normal management in the Upper Midwest is to fertilize before the corn crop in a corn-soybean rotation for both the corn crop and following soybean crops. This saves the cost of one application and the logistical problem of fertilization with P after a corn harvest. This management works well in soils tvith a pH less than 7.4 and... |
52. Predicting N Fertilizer Rates for CornSixteen N rate experiments were carried out in farmer fields in 1995 and 1996. The objective was to measure optimum N fertilizer rates and see whether they could be reliably predicted ahead of time. Yield response to N was measured in each experiment along with soil N measurements (planting and sidedress), and tissue N and chlorophyll meter reading at sidedress time. A very wide range of economically optimum N fertilizer rates was found, fairly evenly spread from 0 to 200 Ib N/acre, with an aver... |
53. 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... |
54. 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 ... |
55. 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... |
56. Remote Sensing as a Tool for AgricultureThe tendency for nearlv everything in our society to be bigger, better, faster, easier, cheaper, and safer than in the past has resulted in many challenges. Agriculture is not immune from these trends, and in some cases agriculture even leads the way. Incorporation of remote sensing into site- specific management activities is one area where technologies are being merged to develop a new array of products that are intended to help producers and consultants make better and more timely management ... |
57. Response of Minimum-till Corn to Starter Fertilizer and ACAStarter fertilizer containing N and P often increases grain yield under no-till management. but yield responses to starter have riot been consistently observed under conventional tillage. Experiments were established in 1996 and 1997 at six sites varying in latitude, soil type. fertility, and crop rotation to evaluate the effect of starter fertilizers on corn grown under high-residue minimum-till systems. In one experiment, a factorial combination of 3 N. 2 P, and 2 K rates placed in a 2x2 band ... |
58. 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 ... |
59. 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 ... |
60. 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... |
61. 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... |
62. 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... |
63. 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... |
64. 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. ... |
65. 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... |
66. Spoke Injection of Fertilizer Phosphorus for GrassesFertilization of forge grasses with phosphorus has shown limited forage increases in South Dakota, even with low soil tests. Lack of response to added phosphorus may partially be due to fertilizer placement on established grass stands. Traditionally broadcasting fertilizer has been the only placement method available. Since P moves very iiiile in the soil, root feeding from tne added P must occur very ciose to the soil surface. A dry soil surface could limit P uptake by grasses, limiting any yie... |
67. 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... |
68. 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... |
69. 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... |
70. 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... |
71. 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... |
72. 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... |
73. Topsoil Thickness Influence on Phosphorus and Potassium Availability and Crop ResponseSoil testing to estimate nutrient availability and fertilizer needs is a widespread management practice for cropping systems in the United States. as well as in other countries. The purpose of soil testing is to simulate the ability of the plant roots lo uptake these various nutrients critical for normal growth. Crops generally uptake a s~nall amount of phosphorus (P) compared to potassium (K). The portion of soil P that is readily available for plant growth maybe limiting due to the small quant... |
74. 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... |
75. 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... |
76. Using Soil Properties to Predict Soluable Phosphorus Losses from Indiana SoilsEscessive phosphorus (P) levels in surface water can degrade water quality by causing algal blooms and accelerating the eutrophication process. Agriculture has bceri implicated as a major nonpoint source of P, so many states have considered restricting P applications from inorganic fertilizers, manures, and other Pcontaining materials once soil test P levels esceed "threshold values". Relationships between soil properties and soluble P loss potential have not been welldocumcnted. This laboratory... |
77. 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... |
78. Variable Fertilizer Nitrogen Application Based on the Delta Yield Index- A Field StudyA quick review of the both the scientific and popular literature indicates that many different approaches have been suggested for the prediction of variable fertilizer N applications in the field. In previous meetings of this conference we have presented the general outline and approach taken for our site-specific crop management project in Ontario. Briefly, historical data sets of grain corn response trials to fertilizer N (encompassing some 300 site-years worth of data) indicated that most yi... |
79. 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... |