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1. Agricultural Impact on Groundwater QurlityThere has been an increasing awareness within Iowa of the impact of agriculture on groundwater quality. The data of Iowa Geologic Survey scientists from studies in northeast Iowa have focused attention on the Big Spring Basin area. A project to intensively study groundwater in the Big Spring Basin is underway. The project includes the active cooperation and participation of the following agencies: ISU Agricultural Experiment Station, Clayton County Soil Conservancy District ISU Cooperative Extension... |
2. Influence of Tillage Systems on Corn Yields and Soil Test ValuesA long term tillage study was initiated at the Greenley Memorial Research Center (Novelty, MO) in 1976 to look at the effects of 4 tillage systemsoncornproduction. Thestudywasinitiatedandconductedby researchers in the Agricultural Engineering Department. Agronomy has become involved in the study beginning in 1985 to assess the effects of tillage systems on soil chemical and physical properties. The upland soils at this site are poorly drained and are generally refered to as "claypan" soils. The climate... |
3. Sustainable Agriculture- A PerspectiveThere is little evidence tos uggest that agriculture as practices in a variety of ways is not sustainable. We think of sustainable agriculture as a management system that uses inputs ... both those available as natural resources on the farm and those purchases externally ... in the most eficient manner possible to obain productivity and profitabilty from a farming operations, while minizing advers effects on the environment. Several groups have published materials suggesting techniques that should... |
4. Nitrate Testing ClinicsThirty-eight nitrate testing clinics were held in 36 Michigan counties in the spring of 1989. A mobile testing van was equipped for nitrate analysis of soil and water samples. Over 2,200 soil samples and 1500 water samples were analyzed for nitrate N using the nitrate ion-specific electrode. More than 50 percent of the soil samples . contained less than 30 lb of nitrate N in the surface two feet. Only 35 percent of the 1,100 fields were given a nitrogen credit based on the residual nitrate test.... |
5. Response of No-till Corn to Urease Inhibitors and Placement of N SourcesN(n-buty1)thiophosphoric triamide (NBPT) and ammonium thiosulfate (ATS) were investigated as urease inhibitors when added to urea and urea-containing N sources and applied to no- ill corn. Significant - f yield increases, some in excess of 20 bu ac , were observed with NBPT treatment of the N fertilizers. Lack of a yield response from NBPT, when it occurred, was usually associated with a rain event of major proportions soon after fertilizer application. ATS showed considerably less promise as a urease... |
6. The Effect of Tillage and Soil Test and Applied K on Corn and Soybean ProductionThe buildup-maintenance fertility concept for P and K has a strong theoretical basis, but much of the research from which it was derived was not designed to accurately determine the true maintenance requirement. Most of that research was confounded by an annual application at set rates irrespective of yield obtained. Experience in recent years has shown that on some soils the K soil test has not consistently accounted for past additions of fertilizer. In addition, applications equivalent to crop... |
7. 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 nitrate... |
8. 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 35%)... |
9. 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 works... |
10. 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 broadcast... |
11. Evaluation of Three N Recommendation Systems for Corn Yield and Residual Soil NitrateProper N application rates are required for continued economic and environmental viability of U.S. agriculture. Application at rates below that required for economic optimum will place U.S. farmers at a competitive disadvantage in the world market. On the other hand, excessive rates of N fertilizers may result in contamination of ground water. ... |
12. Long Term Phosphorus Research on Corn and Grain SorghumPhosphorus fertilizer is needed for optimum production and economic returns from irrigated corn and grain sorghuni in western Kansas. A long term study shows that the yield benefit from P increases over time from no yield difference initially to over 100 butacre higher corn yields after 30 years. Without fertilizer P, soil P levels declined from 17 pprn Bray- 1 P to less than 10 pprn within five years, where they stabilized for both corn and sorghurn. The addition of fertilizer P at 40 Ib P205lacre... |
13. Nitrogen Management Systems for Ridge-tilled Corn ProductionThe use of conservation tillage methods, including ridge- tillage, increases crop residue cover which can lead to loss of urea-based fertilizers applied broadcast. ~ield tests were conducted during 1987-1991 at the ~rrigation ~xperiment Field, located near Scandia, Kansas, on a Crete silt loam soil (fine, montmorillionitic, mesic, Panchic, Arguistoll). Treatments included anhydrous ammonia (AA) applied preplant knife-injected; 28% urea-ammonium nitrate solution (UAN) applied preplant knife- injected,... |
14. Effect of NBPT-Amended Urea and UAN on No-till Corn in Northern IllinoisField evaluations of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) have been extensively conducted across the USA with encouraging results. Most response data collected to date has been with corn. In this report results from 7 'years of experiments at two southern Illinois locations (Belleville and Carbondale) are presented. NBPT addition to broadcast-placed urea, when evaluated across N rates and locations, gave no- till corn yield increases averaging 8.4 bulac in 13 experiments.... |
15. Impact of Excess Water on N LossThe impact of excess soil water on N use efficiency by corn was evaluated over several years at four locations in Illinois. At each location, 0, 4, or 6 inches of water was applied in late May to soils that were at field capacity. Prior to the addition of the excess water, potassium nitrate was applied at rates ranging from 0 to 200 Ib Nlacre. On medium to heavy textured soils, the number of days when soil moisture was at saturation provided a good estimate of the magnitude of N loss. Yields were... |
16. Variable-Rate Fertilizer Application- Update and EconomicsThe potential for application of computer-controlled, satellite-guided, variable-rate application systems for fertilizer has opened an interesting new area of research and development. While variable-rate application is not new--and does not require the com- puter or satellite systems to be useful--the technology is definitely helping to convince dealers and farmers that this concept has broader potential. Economic pressures and environmental concerns are leading them to take a closer look at how... |
17. Nitrogen Placement in No-till CornPlacement of nitrogen (N) fartilizers on no-till corn was evaluated in various single and multiple N rate experiments at the Belleville and Carbondale Research Centers of Southern Illinois University from 1983 to 1993. In 15 experiments in which granular urea placement was compared, ear leaf N and grain yield were essentially the same whether urea was broadcast or concentrated in surface bands near corn rows. Only a 2 bu/ac average yield advantage was observed for banding versus broadcasting urea... |
18. Nutrient Management and Starter Fertilizer for No-till CornNo-till corn acreage has steadily increased in Illinois. No-till presents unique problems of nutrient stratification, increased surface residue, and cool, wet soils which may influence nutrient availability. Two experiments were initiated in 1993 at 4 locations to evaluate the response of no-till corn to: 1) primary N applications of anhydrous ammonia preplant, UAN broadcast preplant, and ammonia sidedressed at V6; 2) starter fertilizers with factorial combinations of N, P, and K banded 2 inches... |
19. 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 the... |
20. 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 (Kelling... |
21. Effect of Time and Rate of N Application on N use Efficiency and Surface Water Contamination with NitratesNitrate levels in excess of the public health standard of 10 mg N/1 in public water supplies along - with concern about hypoxia in the Gulf of Mexico have drawn renewed interest to improving fertilizer N use efficiency. Prior research has indicated that some farmers may be unkaowingly contributing to these problems. The objectives of this research were to: determine the effect of rate and time of N application on nitrate-N concentrations in water from tile lines and to evaluate the effect of previous... |
22. Nitrogen Management in Irrigated Corn Using Remotely-Sensed Imagery and Small-Plot ExperimentsNitrogen management for irrigated corn (Zea mays L.) grown along the Arkansas River Valley in Kansas is a concern due to the hig&ly leachable soils and high water tables (ranging fiom 10-50 A). Irrigated corn usually requires a high input of N fertilizer to achieve maximum yields, and most farmers in this area have been applying a uniform rate of nitrogen across their fields every growing season based on the following KSU N recommendation. N Rec = [YG * 1.35 lbs bu-'1 STA - PCA - PYM - PNST N Rec-nitrogen... |
23. 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 will... |
24. 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 are... |
25. Effects of Soil Test, Tillage, and Manure and Fertilizer Application Method on Phosphorus RunoffLoss of phosphorus from agricultural lands into surface waters is of growing environmental concein. Phosphorus transported by surface runoff often ends up in streams and lakes and accelerates eutrophication, which affects the ability to use the water for drinking, fishing. recreation. etc (Foy and Withers, 1995). The niajor mechanisms by which agriculture contributes phosphorus to surface water is through runoff and erosion (Sharpley et al., 1994). Controlling run~ff and erosion from agricultural... |
26. Phosphorus and Potassium Effects on Yield Components, Nutrient Accumulation and Persistence of Alfalfa (Medicago Sativa L.)Our objective was to determine why phosphorus (P) and potassiun~ (K) are essential for high yield by analyzing alfalfa yield components. Plots of P treatments (0, 25. 50, and 75 kg/ha) and K treatnients (0. 100, 200, 300, and 400 kgha) arranged in a factorial design were replicated four times. Forage was harvested four times per growi~lg season (1998-2000), and yield. mass per shoot, shoots per area. and herbage nutrient concentrations determined. In May and December, plants were dug to determine... |
27. Potassium Deficiency in South DakotaSouth Dakota soils are typically very high in plant available potassium (K). However in the last several years there have been increasing reports of K deficiency on corn. A number of observations have been made concerning where K deficiency occurs and what factors are involved. A few research studies have been initiated to answer frequently asked questions by producers on K management for corn and soybean rotations in the state. Preliminary results indicate differential corn variety response to... |
28. Soil pH and Corn-Soybean Rotation Yield Responses to Limestone Applications and TillageFarmers growing corn and soybean in northwest Iowa must carefully consider liming needs and economics. This is because of high liniestone material cost and the fact that soils in northwest Iowa have high pH subsoil, which can moderate negative effects of acid surface soils. Another factor that must be considered is the variable effect from limestone mixing depth associated with different tillage systems. An experiment designed to evaluate six rates of aglime (0 to 6,000 Iblacre of effective calcium... |
29. The Illinois Nitrogen Soil TestNitrogen fertilizer recommendations for corn production are often estimated on the basis of a realistic yield goal, with adjustments to allow for N credits fiom other sources, such as legumes or manure. A yield-based recommendation may have merit on a long-term basis. but under- or over- fertilization is apt to occur in any given growing season since soil N availability is not taken into account. Insufficient application of N can have serious economic consequences for the farmer, whereas excessive... |
30. Phosphorus Runoff From Incorporated and Surface-Applied Fertilizer and ManureContinued inputs of fertiher and manure in excess of crop requirements have led to a build-up of soil phosphorus (I?) levels, creating an environmental rather than agronomic concern (Sharpley et al., 1994). The objective of this study was to evaluate the effects of soil test P level, source of P amendments, tillage, and manure application method on P runoff from agricultural soils. The treatments consisted of swine manure surface applied and injected at rates of 29 and 59 Ib acre-' of P, and triple... |
31. Strip till Nitrogen Placement, and Starter Fertilizer Effects on Corn Growth and YieldStrip tillage, a system where residue is removed and small ridges are formed in the fall in the position of next year's rows, has become an increasingly popular alternative to 0-till for corn in Illinois. Over three years and eight environments in Central and Northern Illinois, tillage had no effect on grain yield: conventional tillage, strip tillage, and 0-till produced 1 1.67, 11.67, 1 1.57 Mg/ha, respectively. There were also no differences in yield due to N timing, N placement, or starter fertilizer.... |
32. Sulfur Influence on Corn and Soybean Yields in Eastern South DakotaClean air legislation, the increasing use of conservation tillage, and the manufacture of phosphorus fertilizers without sulfur have all contributed to lowering soil sulfur (S) availability to crops. Soil S availability has been affected to some extent by all three issues in eastern South Dakota. Hilltop erosion has exposed subsoil in which the pH is higher and organic matter content is lower than at lower landscape positions. In some eroded shoulder positions of the landscape in no-till fields.... |
33. Update on the Illinois N TestEstimation of plant-available N is complicated enormously by the dynamic nature of soil N, owing largely to the effects of temperature and moisture supply on N-cycle processes. Numerous biological and chemical methods have been proposed as an index of soil N availability (Brernner, 1965; Keeney, 1982; Stanford, 1982; Bundy and Meisinger, 1994), but none has been adopted widely for soil testing. Biological methods are necessarily time-consuming because of the need for incubation, and the results represent... |
34. 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 providing... |
35. 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 WRh... |
36. 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 nitrogen... |
37. Comparison of Nitrogen Recommendation Models for Corn in Two Cropping SystemsSeveral lnodels exist to generate N recommendations, and the model selected can have both economical and environmental implications. A study was initiated in 1998 to compare the response of corn to N in two ci-opping systenls (corn following corn and corn following soybeans). All plots received a starter N rate of 45 kg N ha-' (2 x 2 placement). and five rates of sidedress N (0, 22, 90, 157, and 224 kg N hi') were applied at gro~vth stage V6 either as anhydrous arnmonia or urea-ammonium rli trate... |
38. Do Different Corn Hybrids Have Different N NeedsThere continue to be claims that N management can be tailored to better fit specific hybrids. but there has been no recent confirmation that hybrids differ consistently in their N response. We tested the response of ten hybrids to N rates over two years (2003 and 2004) in a productive. silt loam soil near Urbana, Illinois. The previous crop was corn. Main plots consisted of five N rates (0, 60. 120, 180, and 240 Ib Nlacre), and ten Burrus corn hybrids (438Bt, 330, 442, 576, 583Bt, 625. 645, 727,... |
39. Soil Electrical Conductivity Map Quality- Impact of Interpolation Search Neighborhood ParametersSpatial predictions of soil electrical conductivity (EC) measurements may be improved by adjusting the search neighborhood criteria. The objective of this study was to investigate how varying search parameters impacted the quality of soil EC maps. The three fields cl~osen for this study were from the Inner and Outer Blue Grass physiographic regions of Kentucky. Soil EC was measured by direct contact at all locations. The prediction datasets included EC measurements along transects that were separated... |
40. Slow Release Nitrogen Fertilizer and Dynamics in Soil Systems Part I Incubation StudyA lab study was conducted at Southern Illinois University soil fertility research facility to investigate the effects of soil type on the nitrogen (N) release dynamics. The objective of this study was to identify the effect of soil type on the release rate of N from slow release nitrogen (SRN) fertilizers under controlled conditions (moisture and temperature). Two contrasting soils from Iowa and Georgia (pH and mineralogy) were combined with 500 mg kg-, of SRN or urea and kept for 90 days under growth... |
41. Evaluation of the Illinois Soil Nitrogen Test in the North Central RegionData from 96 locations across the North Central Region was complied to evaluate the usefulness of the Illinois soil nitrogen test (ISNT) in identifying fields where corn will not respond to additional N fertilizer and predicting the yield optimizing N rate (YONR) for each field. The ISNT could not accurately predict non-responsive sites, nor could it predict YONR. Sub-setting the data based on soil drainage class and previous crop did not improve the predictive capability of the ISNT. The ISNT was... |
42. Should We Abandon Soil Testing and Yield Goals in Estimating Nitrogen Rates for CornIf the prices of corn and fertilizer-N and the shape of the N response function relating crop yield to the amount of fertilizer used are known, calculating an economically optimal N rate (EONR) for maximizing the net return to applied N is straightforward: the EONR is the N rate at which no firher increase in net return occurs. In most cropping systems and under common price scenarios, crop yield at the EONR is within 95 to 99% of the maximum yield obtained for the specific management package. In... |
43. Evaluating the Removal of Corn Residue on Crop Production and Soil QualityRemoval for corn residue as a possible feedstock for the biofuels industry leaves many producers with a number of unanswered questions. These include what impact will this have on the following crop and also the impact on soil quality associated with this practice. A field study was established in 2000 to addr ess these and other questions. Experimental treatments include three corn residue removal levels (low, mid and high); corn harvested for grain and all residue remains on the soil surface,... |
44. Using Reflectance Sensors to Predict Nitrogen Needs of CottonObjectives 1) Develop on-the-go N recommendations based on analysis of the reflectance sensor readings. 2) Determine the sensor model, height, and wa velength that give the best prediction for sidedress N. 3) Determine the best growth stag e for sensor-based sidedressing Relevance There is great spatial variability of N in the soil. Cotton fields that receive a blanket rate of nitrogen, ignoring the vari ability, will have areas of excessi ve growth. This unnecessary growth raises production cost... |
45. Effect of Phosphorus and Potassium Fertilization on Corn Development and Root Distribution in Conservation TillageIn conservation tillage systems, like no-till (NT) and strip-till (ST), phosphorus (P) and potassium (K) typically become vertically and/or horizontally stratified in the soil. This stratification has the potential to make P a nd K less available and to limit corn yield. The objective of this study is to determine the infl uence of tillage and P and K placement and rate on soil P and K content, soil water status, root and shoot development, and grain yield of corn. The experiment was arranged in... |
46. Enhanced Efficiency Nitrogen Fertiizers Release in an Illinois SoilThe release rates of ammonium and nitrate from applications of enhanced efficiency nitrogen fertilizers to soil is not well understood. A better knowledge of th e soil processes involved with N release could allow for greater acceptance of these fertilizers. The objective of this study was to compare traditional quick release fertilizers w ith enhanced efficiency nitrogen fertilizers to examine their release rates. Th e fertilizers chosen were urea and a polymer-coated urea, which were applied to... |
47. Weed Control Timing Effects on Corn Yield Response to NitrogenNitrogen (N) rate guidelines for corn are under c ontinued scrutiny to maximize N use efficiency in order to minimize potential N losses to th e environment while maximizing economic returns to growers, especially with significant N fertilizer price increases in recent years. In-season crop stress can potentially affect corn N needs for optimum production. Recently, postemergence weed control has become more common with th e availability of glyphosate resistant corn hybrids. Delaying weed control... |
48. Crop Sensor-Based N Rates Out-Performed Producer-Chosen N RatesOptimal N fertilizer rate for corn (Zea mays L.) and other crops can vary substantially within and among fields. Current N management practices do not address this variability. Crop reflectance sensors offer the potential to diagnose crop N need and control N application rates at a fine spatial scale. Our objective was to evaluate the performance of sensor-based variable-rate N applications to corn, relative to constant N rates chosen by the producer. Fifty-five replicated on- farm demonstrations... |
49. The Nitrogen Index as a Tool to Reduce Nitrogen Loss to the EnvironmentContinued population growth creates a need for increased productivity of agricultural systems around the world. Increased agricultural productivity will be needed to support a population that is anticipated to have an additional 2.5 billion people by the year 2050. Nitrogen was part of the 20th century�۪s green revolution. Nitrogen continues to be essential for the viability and sustainability of agricultural systems that are important for feeding the growing global population. It is well known... |
50. Nitrogen Loss from Sprinkler Applied Beef Feedlot EffluentLoss of nitrogen from sprinkler applied beef feedlot effluent can be costly for both the producer and the environment. Sprinkler application of effluent is common throughout the Great Plains, though little work has focused specifically on N losses from beef feedlot effluent. We quantified ammonia (NH 3) and nitrous oxide (N2O) losses from beef feedlot effluent applications under field conditions including variations in soil pH, soil water content, ammonium (NH 4+) concentration of the effluent, and... |
51. Soybean Production Research: A National ApproachU.S. soybean growers are looking for alternative methods to increase soybean yields and recent increases in commodity prices have given producers more freedom to invest in additional crop inputs or products. Unfortunately, quality data from studies addressing multiple contemporary inputs is scarce. The objective of this work was to evaluate the effectiveness of combined soybean inputs on seed yield. These high input systems were tested in six states to evaluate their value across a broad geography.... |
52. Overview of Manure Handling on Steroid Movement in Agricultural Fields from Beef Cattle SystemsManure generated from concentrated animal feeding operations may serve as a source of steroids in surface water and potentially in groundwater. The objectives of this research were to determine the amount of steroids and metabolites in runoff from beef cattle production pens, and from runoff and leaching from crop production fields. Cattle were fed a synthetic progestagen, MGA or melengestrol acetate and treated with zeranol, trenbolone acetate, and estradiol implants, while a second group was not... |
53. Evaluation of Wavelength from Ground-Based Active Optical Sensors for Corn Yield Prediction in North DakotaGround-based active-optical (GBAO) crop sensors have been used successfully to predict crop yield when used during early growth stages. The objective of this study was to evaluate two GBAO sensors wavelengths regarding their usefulness under North Dakota corn (Zea mays, L.) growing conditions. Thirty experimental sites were used in North Dakota to conduct N rate trials on corn during 2011 and 2012. All sites were designed as randomized complete blocks with four replications and six nitrogen (N) treatments;... |
54. Planting Date, Nitrogen Rate, and Nitrogen Timing Interactions to Optimize Winter Wheat ProductionWinter wheat (Triticum aestivum L.) planting date is a large contributing factor for high yield production systems located within the central Great Lakes Basin, and nitrogen (N) rate and timing strategies offer the opportunity to improve both the production and efficiency of winter wheat when considered in combination with planting date. A field study was initiated in East Lansing, MI to determine the effects of planting date, N application timing, and total N application rate on winter wheat yield... |
55. Minnesota Long-Term Phosphorus Management Trials: Phase I, The Build PeriodPhosphorus (P) fertilizer recommendations are usually made using one of two philosophies, Build and Maintain or Sufficiency. In recent years, the Sufficiency approach has been questioned because of concerns of reducing soil test levels and yield sustainability and whether it has the same yield potential as the Build and Maintain approach. Trials were initiated in 2010 at six locations across Minnesota to develop various soil test P Interpretation Classes in replicated experiments. The initial phase... |
56. Changes in P Uptake and Partitioning in Soybean Cultivars Released in the Last 90 YearsHistorical changes in nutrient uptake and partitioning of soybean [Glycine max (L.) Merr.] were not studied. Field studies were conducted in 2011 and 2012 to investigate phosphorus (P) uptake changes and partitioning through the growing season in 25 maturity group (MG) II, and 26 MG III cultivars. Plant samples were taken and partitioned at V4 (four trifoliates), R2 (full bloom), R4 (full pod), R6 (full seed), and R8 (physiological maturity) growth stages. In-season samples were partitioned into... |
57. Phosphorus and Water Quality Issues in Lake ErieWhat are harmful algae blooms? Harmful algal blooms (HABs) are so named because they can produce toxins (or poisons) that can cause illness or irritation sometimes even death in pets, livestock, and humans. The term algae is somewhat misleading since HABs are actually cyanobacteria, which are commonly referred to as blue-green algae, and are not true algae. These organisms act like many other plant and use photosynthesis to capture sunlight but unlike most plants and algae some can fix their own... |
58. Evaluation of Adapt-N in the Corn BeltNitrogen is the plant nutrient required in the largest quantity, the most likely to be deficient, and the most impactful on corn yield as well as grower profit. Providing N to a corn crop in the right amount while minimizing loss is difficult because of complex biological and chemical reactions that result in the loss of N from the crop root zone via deep percolation to ground water, lateral flow, runoff and erosion to surface waters, and volatile losses to the atmosphere as ammonia, nitrogen gas,... |
59. Switchgrass Rhizobacterial Community Structure as a Function of Cultivar and Nitrogen Fertility at Two Sites in MinnesotaBiofuel production using native perennial grasses such as switchgrass (Panicum virgatum) has potential to reduce U.S. dependence on foreign oil and curtail greenhouse gas emissions. Switchgrass can also provide significant ecosystem services, such as nutrient loss reduction and carbon sequestration. Best management practices (BMPs) for switchgrass fertility are being established on a regional basis, yet little work has been done to examine the intersection of soil fertility with soil biology in switchgrass-for-biofuel... |
60. Slow-Release Fertilizer Effect on Groundwater Nitrogen Concentration in Sandy Soils under Potato ProductionCurrent nitrogen (N) fertilizer management practices for potato farming have led to elevated levels of N in the local groundwater. Slow-release fertilizer, specifically Environmentally Smart Nitrogen® (ESN®) polymer coated urea (PCU ) may reduce the amount of N leaching to groundwater; however no field scale studies have been performed in Wisconsin to validate these assertions. Field experiments were conducted at the Hancock Agricultural Research Station using Russet Burbank potato, planted in... |
61. Evaluation of Algorithm Thresholds for Crop Canopy Sensor-Based In-Season Nitrogen Application in CornNitrogen fertilizer is frequently the most lim iting nutrient in corn production. Typically most nitrogen is applied before plan ting. Since nitrogen can leave th e soil system fairly easily, the result can be an inefficient use of nitrogen fe rtilizer. Previous research has shown increased efficiency with no reduction in yield by applying nitrogen later in the season when the crop is actively growing, with rates regul ated spatially through the use of active crop canopy sensors. This study evaluated... |
62. Effect of Late-Applied N on Corn Dry Matter, N Content, and YieldNitrogen management of corn (Zea mays L.) may be improved by delaying N application until just prior to the rapid growth phase (approximately V6-V8). This timing is commonly referred to as 'sidedress'.� Some farmers do not sidedress because they are concerned inclement weather may delay N application beyond V8, requiring high clearance equipment to apply N and possibly reducing grain yield. However, few studies have investigated the effects of late-applied N in rain-fed production environments... |
63. Nutrient Management Studies in Bio-Fuel Cropping SystemsResearch was conducted to determine the effect of nutrient management practices on bio-fuel crop production, and to evaluate long term effects of bio-fuel crop production on selected chemical, physical and microbiologi cal properties. Experimental plots for research on bio-fuel crops production were established in 2008 at two sites in Missouri. The experimental design was an 8x3 factorial laid out in a sp lit plot design. The main plots were eight bio-fuel cropping systems including: 1) continuous... |
64. Plant Density Consequences on Nitrogen Uptake Dynamics of Maize Plants from Vegetative to Reproductive StagesThere are few studies to date that have inte nsively examined the simultaneous effects of differences in plant crowding and fertilizer N availability for different hybrids and locations on N uptake and maize (Zea mays L.) grain yield. The main research objective was to utilize a quantitative framework to bett er understand the physiological mechanisms that govern N dynamics in maize plants at varying plant densi ties and N rates. Two field experiments involving paired near-isogenic hybrids (i.e.... |
65. Response of Corn to Residue Management and Nitrogen FertilizationInterest in the production of cellulosic fuel production for bioenergy has identified corn (Zea mays L.) as a suitable option. However, residue removal can affect the growth and yield of a following corn crop and its response to N fertilizer. Residue removal may also influence the optimal tillage system with regard to yield and N-use efficiency. In southern Minnesota, concern about yield reductions due to cool, wet soil conditions, partially attributed to high amounts of crop residue, have limited... |
66. Effect of Phosphate and Sulfate Application on Wheat (Triticum Aestivum) Grain Selenium Content and Yield ComponentsThe interest in Selenium (Se) has increased due to its potential anti-cancer attributes in human health. Wheat ( Triticum aestivum ) will assimilate Se according to soil availability. There is interest in developing a consiste nt grain supply of high Se wheat for markets in Europe and Asia since plant-available Se in soils of these continents are very low. Agricultural soils in some regions of central and western South Dakota ha ve high Se content. Yet the common plant available forms of Se, selenate... |
67. Effects of Glyphosate Application and Manganese Fertiization on Leaf Manganese Concentration and Yield of Glyphosate-Resistant SoybeanGlyphosate-resistant (GR) soybean is widely accep ted in the United States. Recent research in Indiana and elsewhere has observe d that post-emergence foliar applications of glyphosate may cause or exacerbate manganese (Mn) deficiency and then limit yield of GR soybeans on low Mn availability soils. The objectives of this study were to 1) better understand how glyphosate application(s) might reduce the up take and translocation of Mn in GR soybean plants, and 2) determine the effectiveness of starter-banded... |
68. 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.... |
69. 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 was... |
70. Nitrogen and Sulfur Application Effects on Soybean Quality and YieldSulfur deficiency is only becoming more prevalent in the Midwest across soybean fields with higher yields resulting in lower quality seed. Sulfur is a key component of methionine and cysteine, which are important amino acids in the nutrition in foodstuffs. The objective in this study is to explore the impact of N:S applications at different growth stages and rates on the soybean yield and seed composition and quality. In 2018 the trial was performed both in West Lafayette and Wanatah Indiana.... D. Miller, S. Casteel |
71. Correlation of the Weak Organic Acids Test of a Soil Health Tool with Crop Yield Response to Phosphorus FertilizationThe field correlation of a soil P test with yield response to P fertilization is the foundation for sound soil-test interpretations and fertilizer recommendation guidelines. Weak organic acid extractants have been used to measure soil P for decades in some northeastern states of the US and other countries, but not in Iowa or the Midwest. A new test based on a mixture of malic, oxalic, and citric acids (H3A) was developed as a component of a Soil Health Tool to measure soil P and K. The H3A... A. Mallarino, J. Jones |
72. A Combination of Soil Incubation and Chemical Extraction Tests Best Predicts Corn Yield Response to Fertilizer NitrogenSoil tests in general have served a critical role in the field of soil fertility for over half a century, and have helped to increase crop productivity and promote more efficient use of fertilizers on farms. However, N soil tests have limitations and chemical extraction tests have not predicted well the potentially mineralizable N supplied to corn over a growing season. Thus, these tests often do not accurately predict a corn’s yield response to fertilizer N. We explored 30 soil tests for... M. Mcdaniel, D. Walters, L. Bundy, C. Laboski, P. Scharf, R. Drijber, W. Horwath, J. Sawyer, J. Sawyer, M. Castellano |
73. Correlation Between Mehlich-3 and Haney Extractable Phosphorus and Potassium, and Their Relationship to Soybean (Glycine Max) Yield ResponseNumerous soil tests have been developed for estimating the plant-availability of soil phosphorus (P) and potassium (K). Understanding the relationship between these test’s results and crop response to fertilizer application is essential for developing and improving fertilizer recommendations. Field trials have been initiated at six sites located across the state of Kansas to investigate the response of soybean to broadcast P and K fertilizer application. Plots are... E. Rutter, D. Ruiz diaz, F. Hansel |
74. Can Nitrapyrin and Cover Crop Improve Fall Dairy Slurry N Availability to Corn?Fall applications of manure have the potential for high nitrogen (N) losses. Cereal/grass cover crops have been shown to take up fall applied N. Similarly, using nitrapyrin (Instinct®) has been shown to prevent loss of fall applied N. No studies have been conducted to evaluate combining these tools to prevent N loss. This experiment was performed in 2016 and 2017 on a well-drained and somewhat poorly drained silt loam soils. This study was conducted to determine if using Instinct® and... A. Teeter, T. Andraski, C. Laboski |
75. Active-Optical Reflectance Sensing Evaluated for Red and Red-Edge Waveband SensitivityUncertainty exists with corn (Zea mays L.) N management due to year-to-year variation in crop N need, soil N supply, and N loss from leaching, volatilization, and denitrification. Active-optical reflectance sensing (AORS) has proven effective in some fields for generating N fertilizer recommendations that improve N use efficiency. However, various sensors utilize different wavebands of light to calculate N fertilizer recommendations making it difficult to know which waveband is most sensitive... G. Bean, N. Kitchen, J. Camberato, R. Ferguson, F. Fernandez, D. Franzen, C. Laboski, E. Nafziger, J. Sawyer, P. Scharf, J. Schepers, J. Shanahan |
76. Manure and Fertilizer Management Influence on Soil Nutrient Levels and Grain Yields in Eastern South Dakota from 2003 to 2014Concentrated animal feeding operations (CAFOs) are required to hold a manure management permit in South Dakota. The permit encompasses available nutrients from manure, crop nutrient use and removal, soil test nitrate-N, and phosphorus and land availability for approved nutrient application rates. The management plan determines if nitrogen or phosphorus based manure application rates are used. Most CAFO’s start out following the nitrogen based plan as soil test phosphorus (P) levels... A. Bly, S. Berg, R. Gelderman, B. Rops, P. Sexton, C. Morris |
77. Post-Harvest Soil Nitrate Following Corn Production in Eight Midwestern StatesApplying nitrogen (N) at economically optimal rates (EONR) and at times of rapid crop uptake are practices that are thought to minimize the amount of residual soil nitrate (RSN) in the profile that may be susceptible to loss. The objective of this study was to evaluate the effects of rate (0 to 280 lb N/a in 40 lb increments) and timing (pre-plant (PP) or PP plus V9 sidedress (PP+SD)) of N application on corn grain yield and RSN in the top 3 feet of soil relative to the calculated EONR. Thirty-two... C. Bandura, C. Laboski, J. Camberato, P. Carter, R. Ferguson, F. Fernandez, D. Franzen, N. Kitchen, E. Nafziger, J. Sawyer, J. Shanahan |
78. Phosphorus Distribution After Long-Term P Fertilizer Placement Under Strip-TillageLong-term phosphorus fertilizer placement under strip-tillage tillage can affect the vertical and horizontal distribution of soil test P (STP). The objective of this study was to evaluate the effect of P fertilizer placement on STP distribution under strip-till. A study was established in Scandia, Kansas in 2006 under a corn- soybean rotation. Treatments included a (1) control (No P); and P applied at 80 lb P2O5 ac-1 as (2) broadcast, (3) deep band, (4) broadcast with starter 2x2, and... C. Edwards, D. Ruiz diaz |
79. Influence of Source and Particle Size on Agricultural Limestone Efficiency at Increasing Soil pHExcessive soil acidity is known to have potential negative impacts on crop production. The chemical and physical characteristics of a liming material determine its capacity to neutralize soil acidity. The calcium carbonate (CaCO3) equivalent (CCE) and estimates of particle size impact on the efficiency at increase soil pH are considered when assessing a material’s liming value. The reaction of limestone particles within the soil depends largely on the soil pH and the material surface area... J. Jones, A. Mallarino |
80. Prediction of Corn and Soybean Grain Yield Response to P in Minnesota Using the Haney H3A and Mehlich-III TestsMinnesota soils are highly variable in P availability due to the wide range of chemical properties. Currently, two soil tests are used to measure soil P in Minnesota, the Bray-P1 for pH<7.4 and the Olsen P for pH>7.4. The purpose of this study was to correlate crop response in corn and soybean rotations to the Bray-P1, Olsen, Mehlich-III, and Haney H3A extractions and to determine critical concentrations for each extraction method. Soil P tests were also correlated with one another to determine... D. Kaiser, L. Leverich, J. Vetsch, J. Strock |
81. Project Sense: Sensors for the Efficient Use of Nitrogen and Stewardship of the Environment. An On-Farm Research Effort to Increase Adoption of Sensor Based N ManagementLow nitrogen use efficiency (NUE) has been attributed to several factors including asynchrony between nitrogen (N) fertilizer application, crop demand, and spatial variability (Shanahan et al., 2008). Sidedress applied N synchronizes crop uptake demand for N, but does not address the spatial and temporal variability that exists in a field year to year. Active crop canopy sensors provide an ability to monitor and respond to spatial and temporal N variability for a given field. A three-year project,... B. Krienke, R. Ferguson, J. Luck, L. Thompson, J. Parrish, N. Mueller, T. Mieno, J. Crowther, T. Shaver, T. Ingram, D. Krull, K. Glewen |
82. Variation in Internal N Efficiency of Corn and Impact on Yield-Goal Based N RecommendationsInternal N efficiency (IE) is defined as bushels per acre (GY) produced per pound of N per acre (PMN) in the plant at physiological maturity (R6). Internal N efficiency defines the required amount of plant N content at R6 in a yield-goal based N rate recommendations (currently used in 30 U.S. states) and several commercial N recommendation models. Commonly IE is assumed to be constant at an approximate value of 0.8 bu lb-N-1 in yield-goal based recommendations. Our research objective was... M. Shafer, J. Camberato, P. Carter, R. Ferguson, F. Fernandez, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, R. Nielsen, J. Sawyer, J. Shanahan |
83. Relationship of in-season soil nitrogen concentration with corn yield and potential nitrogen lossesModeled or measured soil mineral N (SMN) levels during the corn growing season have been used to set sidedress N rates, but there has been little research linking SMN levels at different growth stages to yield to help guide this process. The degree to which SMN level influences the risk of N losses is also not known. Data from 32 site-years of field experiments in Illinois (2015–2018) that included 12 combinations of N fertilizer rate, timing, and source, were used to evaluate... G. Preza-fontes, E. Nafziger, L. Christianson, C. Pittelkow |
84. Corn Yield Response to Sub-Surface Banded Starter Fertilizer in the U.S.Sub-surface fertilizer application at planting (i.e., starter fertilization) is a common practice in U.S. corn (Zea Mays L.) production to improve early-season nutrient uptake, nutrient use efficiency, and plant growth, especially under cool and moist spring soil conditions. However, yield increases from starter applications can vary across production systems and environments. Here, we use a meta-analysis approach to quantify and generalize corn yield responses to sub-surface starter... D. Quinn, C. Lee, H. Poffenbarger |
85. Evaluation of Plant-Available Phosphorus of Dried Residuals from Wastewater Processed for Phosphorus Reduction with Aluminum or IronABSTRACT Wastewater effluent from industrial and municipal water treatment plants requires phosphorus (P) removal before being discharged to surface waters. The resulting residual materials, with elevated P concentration, are usually land applied. Basing P application rates on the nutrient value for crops is the most rational way to utilize this P resource because it would improve farmers economic return while... |
86. Oh, K? When is Too Much K Too Much?Potassium is required in large amounts by crop plants and is a staple fertilizer, mainly as KCl. Recent data across three midwestern states suggests that sometimes, especially at high rates and shortly before planting, KCl may have negative impacts on corn and/or soybean yields. Three researchers will briefly describe their research in this area and then field questions from the audience. - Kaiser Twenty-nine potassium (K) fertilizer trials were conducted in eastern... D. Kaiser, S. Casteel, D. Franzen |
87. Independence of Yield and N-Rate, and Use of EONR in N Fertilizer Recommendations in North DakotaEvidence for the independence of N-rate and yield comes from the improved relationship of N-rate with relative yield compared to raw yield in corn, spring wheat and sunflower N-rate experiments in North Dakota. Relationships were also improved in corn by grouping experiments by regional location and whether the soils are high clay (>40% clay) or not, and discriminating between long-term no-till (6 years or more continuous no-till) or conventional till. In spring wheat, regional differences... D. Franzen, H. Bu, L. Sharma, E.C. Schultz, A. Wick, B. Goettl, M. Berti |
88. Soil and Soybean Responses to Planting into Terminated Prairie StripsPrairie strips are a new conservation practice that are currently implemented in 14 Midwest US states. Prairie strips have been shown to reduce runoff, increase soil health, retain sediment and nutrients, increase biodiversity and have no effect on surrounding crop yield. Due to the comprehensive improvements to soil health under prairie strips, researchers and growers are interested in rotating them on 10-15 year cycles. We have little-to-no knowledge on the effects of planting crops in... C. Dutter, M. St cyr, M. Mcdaniel, C. Carley, A. Singh |
89. Managing Nitrogen to Optimize Yield and Quality of North Dakota Two-row Malting BarleyAs the demand of two-row malting barley (Hordeum vulgare L.) increases, having sound N recommendations is increasingly necessary. Not only does N play a role in grain yield, but it may also significantly impact grain malting characteristics including protein, plump, and test weight. To determine the impacts N rate and N availability have on two-row malting barley, two experimental sites were established in both Spring 2020 and 2021. The experiment was organized in a randomized complete... B. Goettl, H. Bu, A. Wick, D. Franzen |
90. Advances in North Dakota Soil Fertility 2022Following years of accumulating data from field studies using the GreenSeeker™ and Holland Scientific Crop Circle™ active optical sensors, algorithms for use in spring wheat for in-season N application for yield, and immediate post-anthesis N application for protein enhancement have been developed. Both algorithms require an N non-limiting area as a standard. The algorithm for protein enhancement considers whether a cultivar has inherent high protein or lower protein characteristics... D. Franzen, H. Bu, M. Berti, A. Wick |
91. Elucidating How N Management Practices and Excess Water Conditions Affect Corn N Uptake and Grain YieldFlooding and waterlogging events have been more frequent in the Midwest region, causing corn yield penalty nitrogen losses through leaching and denitrification processes. Improving N fertilizer recommendations for areas prone to flood conditions is necessary to minimize N losses and optimize corn yield. This research aimed to determine how N application practices before and after waterlogging events impact corn growth and grain yield. A field experiment was initiated in 2021 in Custar, Ohio using... W. Novais, C.D. Sprunger, L.E. Lindsey, S. Khanal, O. Ortez, M. Mann, A. . Lindsey |
92. Managing Trade-offs of Winter Rye As a Cover CropWinter rye (Secal cereale L.) is a commonly used cover crop in Wisconsin due to its effectiveness in reducing soil erosion, scavenging nitrogen, and improving soil health. However, the potential trade-offs of using grass cover crops are decreases in corn yield driven by nitrogen uptake and immobilization. The study aims to determine the single year effect of rye seeding rate on rye biomass and optimum nitrogen rate of the subsequent corn (Zea mays L.) crop, while also... M. Schauer, M. Ruark |
93. Ag Economy and Policy Outlook for 2024We will explore the factors currently shaping the ag economy and the various sectors that drive economic growth in the sector. We will investigate the connections among feed, fuel, and export markets and examine potential changes to federal agricultural policy (i.e., the Farm Bill). We will discuss the potential for agricultural profitability over the next few years and outline the challenges to reaching robust economic gains. ... C. Hart |
94. Influence of Biological Seed Treatment on Soybean Grain Yield in the U.S.Biological seed treatment in soybean (Glycine max (L.) Merr.) is a growing market in the U.S., with multiple microbially active ingredients and several proposed benefits. Some of the claimed benefits include improving nitrogen fixation, stimulation of root growth, increasing phosphorus, sulfur, and other nutrient absorption, and control of diseases, with the aim to increase soybean grain yield. Farmers are often bombarded with marketing claims about biological seed treatments. In many... F. Colet, R.A. Vann, S.P. Conley, S.L. Naeve, E.G. Matcham, S. Mourtzinis, L.E. Lindsey |
95. Effects of Variable Nitrogen Fertilizer Rates on Corn Grain Yield, Profitability, and Nitrogen Losses in Southwestern MinnesotaGlobal crop production heavily relies on the application of nitrogen (N) fertilizers, which unfortunately comes with environmental concerns. The primary pathways N is lost to the environment is through nitrate leaching into groundwater, ammonia volatilization, and nitrous oxide emissions to the atmosphere. This ongoing study started in 2021 at the University of Minnesota Southwest Research and Outreach Center in Lamberton, MN, to comprehensively assess the effects of varying N fertilizer rates... Z.J. Aanerud, F.G. Fernández, R.T. Venterea, P.H. Pagliari, A.M. Cates, J.L. Nieber |
96. Integration of Satellite and UAV Imagery for Assessing Corn Nitrogen Uptake at Early Vegetative Growth StagesNitrogen (N) fertilizer accounts for 20-25% of the variable cost of production for rotation maize in Indiana. Spatial variability within fields and variable, unpredictable rainfall patterns make N a challenging nutrient to manage, withup to 65% of the nitrogen applied being lost as nitrate. Post-emergence sidedress applications of N fertilizer can reduce N loss and improve plant uptake, so efficient and practical ways to identify maize N status at early maize growth stages is key to assessing... A. Morales ona, R. Nielsen , J. Camberato, D. Quinn |
97. Impact of Cover Crop Composition on Nitrogen Application Rates and the Subsequent Yields of Corn and SoybeanInterseeding cover crops presents a promising strategy for enhancing the sustainability of agricultural systems. Nevertheless, the practice of interseeding cover crops introduces a dynamic element to nitrogen (N) cycling, potentially altering both the quantity and timing of N release through decomposition (mineralization). This variability in N availability may, in turn, influence the optimal nitrogen fertilizer requirements to maximize corn grain yield. However, long-term studies are essential... J.D. Clark , P. Kovacs, P. Sexton, S. Osborne, S. Kodali |
98. Managing Phosphorus and Potassium Soil Test Levels and Effects on Corn Response to Nitrogen with Variable Crop PricesAnnual fertilizer investment for corn-soybean rotation systems represent a significant portion of annual input costs. Variable crop and fertilizer prices raise questions of which macronutrients can be prioritized or cut from fertilization programs. Corn yield response to N fertilization is affected by soil N supply, crop N demand, and interacting factors that affect crop N use, such as phosphorus (P) and potassium (K) supply. The later also influencing soybean yield in the rotation. To investigate... J. Jones |
99. Effect of Phosphorus and Potassium Application on the Growth and Yield of a 14 Year Old Miscanthus X Giganteus StandMiscanthus x gigantues (miscanthus) is a perennial C4 grass grown for renewable bioenergy and bioproducts. Despite its known low nutrient requirements, the specific fertilization needs of miscanthus remain poorly constrained, especially for older stands. This study aims to guide nutrient management practices for miscanthus by determining the demand for phosphorus (P) and potassium (K) fertilization and identifying the soil testing values at which these nutrients optimize yields. To address this... A. Larson, E. Heaton, N. Boersma, J. Studt, S. Emran, M. Mcdaniel, A. Vanloocke |
100. Corn Response to Sulfur Fertilization in Central Iowa SoilsReductions in atmospheric sulfur (S) deposition and increased S removal through continuous cropping have led to S fertilizer responses in many crops. Responses to S fertilization by corn (Zea mays L.), however, have been inconsistent across the upper Midwest. Our objectives with this field study were to: (i) compare S sources for corn vegetative growth and grain yield; (ii) evaluate soil extractable S and S tissue concentrations at different growth stages as S diagnostic tools;... J. Kovar, C. Crespo, C. Hart, R. Roth, P. O'brien, S. Ruis |
101. Short-Stature and Full-Stature Corn Hybrid Response to Nitrogen Rate and Plant PopulationThe recent introduction of short-stature corn (Zea mays L.) hybrids (5-7 ft height) suggests agronomic management recommendations need to be reassessed and updated in comparison to modern full-stature hybrids. Short-stature hybrids target to increase overall Midwest corn production and agronomic efficiency by reducing lodging potential under higher plant populations through improved wind tolerance, stalk strength, and plant standability. However, the optimal combination of nitrogen rate... E. Oliva, S. Casteel, D. Quinn |
102. Combined Effects of Nitrogen Rate, Source, and Enhanced Efficiency Fertilizer Use in Indiana Corn ProductionSynthetic nitrogen (N) fertilizer is the most significant fertilizer applied with regards to both quantity, cost, and yield impacts for Midwest corn (Zea mays L.) production. However, with continued risk of nitrate (NO3) leaching causing groundwater contamination, N volatilization, and dentification which increases nitrous oxide (N2O) emissions, continued N management practice improvement, enhanced efficiency N fertilizer use (e.g., nitrification inhibitors, urease... D. Quinn |