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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. 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... |
3. 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. ... |
4. 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... |
5. 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... |
6. 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... |
7. 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... |
8. Deep Tillage in a Corn-Soybean Production SystemMany crop producers in the Midwestern United States are currently using deep tillage, accomplished with equipment designed to run at depths of 30 to 40 cm, even though the effects of this practice are not well characterized. We assessed the effects of deep tillage, no tillage, and chisel plowing in the fall, with and without secondary tillage in the spring, on penetrometer resistance, plant stand, and yield of corn and soybean grown in rotation. In the spring, averaged across two years and six locations... |
9. 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... |
10. 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.... |