Proceedings
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1. 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... |
2. 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... |
3. 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... |
4. 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. ... |
5. 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... |
6. 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... |
7. 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... |
8. 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... |
9. 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... |
10. 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... |
11. 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... |
12. 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... |
13. 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.... |
14. 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... |
15. Corn Nitrogen Response Across Environments and Crop RotationRecent research on corn has tended to show variability in N response. Brown et al. (1993) reported that economically optimal N rates among 77 sites in Illinois ranged from zero to more than 200 lb N per acre. Results from other studies show similar variability in time and space. Even with such variability, results over environments have been combined and used to develop an N fertilizer rate guideline in Illinois based on anticipated corn yield (Hoeft and Peck, 2002). This guideline suggests providing... |
16. 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,... |
17. 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... |
18. 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.... |
19. 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... |