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1. Do Soil Nitrogen Tests Relate to Nitrogen Mineralization in First-year Corn Following Alfalfa?Corn (Zea mays L.) is the most frequent first-year crop grown following alfalfa (Medicago sativa L.) in the Upper Midwest. In the majority of cases, first-year corn does not respond to fertilizer N, but sometimes large amounts are needed to optimize yield. The pre-sidedress and Illinois soil N tests (PSNT and ISNT, respectively) are early-season tests used to predict corn yield response to fertilizer N. These tests measure specific fractions of soil N and define a critical concentration to separate... |
2. Soil Nitrate Testing- A Guide for Adjusting Michigan Nitrogen Recommendations for CornPrevious attempts to use soil nitrate tests in Michigan for adjusting N fertilizer recommendations for corn have been less than satisfactory. Soil tests were typically performed on fall or spring samples taken weeks or months prior to planting. The use of residual nitrate to adjust N fertilizer recommendations in the semi humid regions of the U. S. has never been considered very re1 iable because of the large fluctuation in soil nitrate from the time of sampling to the time of maximum uptake. Soil... |
3. Managing Field Soil Fertility VariationsFertilizer and crop production inputs are most often applied as a single blanket application rate across an entire field. Yet variations in field conditions including soil characteristics and measured crop yield are known to exist and often in a systematic, fashion. Grid soil sampling for fertility variations, plant analyses, and color photography were found to be most useful tools for assessing manageable field variations. Increased profit and environmentally sound improvements in fertilizer use... |
4. 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,... |
5. 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... |
6. Nitrogen Fertilization of SoybeanNitrogen (N) requirement of soybean is high because of the high protein seed produced. One bushel of soybean requires over 3.5 pounds of N in the grain alone. Symbiotic Nz fixation supplies N for soybean, but Harper (1 974) reported that only 25 to 60% of the N in a marure soybean piant comes from N fixation while the other 40 to 75% comes from the soil. However. application of N fertilizer to soybean remains a very controversial issue because of mixed results of previous research.... |
7. Yield of Sugar Beet, Soybean,Corn, Field Bean and Wheat as affected by Lime Applications on High Soil pHLime from sugar beet processing plants has been stockpiled for 100 years. Environmental regulations and limited storage space provide an impetus for the removal of the material. Land application on alkaline soils is one alternative for disposal of this material. This study was undertaken to evaluate the effect of applying sugar beet processing lime on crop production on these soils. Studies were conducted at seven sites representing four alkaline soil series in Michigan. Lime was applied at rates... |
8. The Influence of Variably Applied Potassium Fertilizer on Yield Variations in Two Southern Illinois Farm FieldsThe basis of Variable Rate Technology (VRT) is to apply nutrients where they are needed and to reduce the application of nutrients where they are not needed. However, there is considerable uncertainty as to whether the variable application of nutrients to farmers fields should be on the basis of soil test levels or yield potentials. A field study was conducted at two locations in southern Illinois from 1997 to 1999 to evaluate VRT as a management tool for corn and soybean production on fields with... |
9. Effect of Changing the Rotation Sequence in a Long Term Tillage and Fertility StudyA continuous experiment was conducted fiom 1970 to 1999 to determine the long term effects of fertilizer application and tillage practices on soil acidity, organic matter and nutrient changes, and crop responses. Four tillage treatments were evaluated: continuous conventional: alternate till (two years no-till: one year conventional); continuous chisel till; and continuous no-till. Five fertilizer treatments were also evaluated (Ib ac-' N-P205-K20): check, 0-0-0; 175-0-0 broadcast; 160-0-0 broadcast... |
10. The Effect of Tillage and Lime Rate on Soil Acidity and Grain Yields of a Corn-Soybean RotationModern tillage systems, such as reduced tillage and no-tillage systems, provide shallow incorporation of surface applied materials at best. Because of concern of over-liming the surface few inches of agricultural soils, producers either reduce lime rates (and apply more often) or perform some sort of soil inversion to mix the lime deeper into the soil profile. The objectives ofthis field study were to evaluate the effects of tillage, lime rate and time of limestone application on corn and soybean... |
11. Varying Nitrogen and Seeding Rates of Corn Across Productivity Regions in FieldsA field study was conducted fiom 1999 to 2001 to determine the effects of variable seeding rates and variable nitrogen rates on corn (Zeu muys L.) in southern Ihois. In whole field experiments, variable seeding rates ranging fiom 18,000 to 38,000 seeds ac-' in 4.000 seed increments were planted in randomized strips (in a randomized complete block design) across the field that had soils with varying productivity based upon historical yield maps. From the yield data it was determined that the optimum... |
12. 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 images... |
13. 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 are... |
14. 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 less... |
15. 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 volatilization... |
16. Corn Response to Anhydrous Ammonia rate, Timing, and Inhibitor use: A RevisitationField experiments were conducted from 2001 through 2003 at three southern Illinois locations to obtain more current data on the effects of anhydrous ammonia rates. application timing, and nitrapyrin (N-Serve) use on corn. Nitrogen rates of 0. 60, 120, and 180 lbs Nlac \\ere evaluated at three times of application (fall, spring pre-plant, and sidedress) with and without nitrapqrin. Corn yield results suggest that fall anhydrous ammonia application is inferior to spring application even if nitrapyrin... |
17. 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... |
18. Sulfur and Nitrogen Starter Fertilizer for Corn in Northern ClimatesThe combination of cool and wet weather in early spring can reduce the amount of S and N released in soil by decomposition and mineralization of organic matter, particularly in reduced- tillage or no-till cropping systems. Recent changes to S emission regulations have decreased the amounts of S that is deposited to the soil through attnospheric channels. Field studies were initiated in 2005 at five corn (Zea mays L.) sites in Michigan to evaluate the effects of S and N starter fertilizer on nutrient... |
19. Use of Nitrogen Mangaement Products and Practices to Enhance Yield and Nitrogen Use Efficiency in No-till CornLong- term research has shown that nitrogen (N) fertilizer is usually needed to optimize corn production in Kansas. Research has also shown differences in the response to various N fertilizers, products, and practices , particularly in the eastern portion of the state, where soil and climatic conditions regularly can lead to N loss. A project was initiated in 2008 and continued in 2009 to quantify how a number of currently marketed products and commonly utilized management practices performed at... |
20. Relationship between Nitrogen Rate and Weed Removal Timing on Corn YieldWeeds actively compete for nitrogen in corn grain production systems. Field studies were conducted in 2009 and 2010 at the Michigan State University Crop and Soil s Research Farm in East Lansing , MI to evaluate the effect of N application rate and weed removal timing on grain yield . Treatments included four preplant incorporated rates of urea (0, 67, 134, and 202 kg N ha - 1 ) and four weed removal timings (5, 10, 15, and 20 cm) based on average weed canopy height. An additional season- long weed-free... |
21. 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... |
22. Nitrogen Application, Biological N Fixation, and N UptakePrevious collaborative research in the Midwest has shown that there is likely little to no need of N for soybean, except under certain conditions (such as when low soil moisture limits N fixation, or when low initial soil nitrate-N limits overall N availability). However, none of the site-years used in this synthesis analysis were on sandy soils. Because sandy soils supply little nitrate-N, the potential impact of N on crop yield is greater in sandy environments than on silt loam soils. However,... A.M. Walters, M.D. Ruark, J.M. Gaska, C. Zegler, S.P. Conley |