Proceedings
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1. Predicting Fertilizer Nitrogen Requirements for Corn in OntarioThe nitrogen fertilizer requirement of a crop under field conditions is influenced by numeraus factors including soil, climate and managanent variables. Most of these factors are very difficult, if not impossible to predict in advance. The major factors influencing nitrogen fertilizer nquhment are (Gch and Haynes, 1986); 1. the requirement of the crop for N as determined by its yield (or yield patential) , 2. the availability of fertilizer N or the fertilizer use - efficiency, and 3. the amount of... |
2. Quantitative Risk AssessmentThank you for giving me the opportunity to speak to you today about carcinogens in drinking water and water quality standards. In the United States today, many if not most public water supplies contain chemicals that cause cancer in animals when, in laboratory tests, the animals are exposed to high levels of the chemical. Elost of these chemicals are man-made, but there are exceptions, such as the chlorinated methanes and, probably, related compounds. These chemicals are the byproducts of chlorinating... |
3. Fertilizer use in the Future- A University PerspectiveOver the last few years, several agrodc, economic, political, environmental and sociological trends have begun to eruerge which will significantly affect fertilizer use in the next decade and perhaps beyond. The wide-spread use of fertilizers is a relatively recent developmt. Over the past 40 years, farmers repeatedly saw the benefits of fertilizer applications and developed a faith in their need. Hwever, the 1990's are not the 1950's. As point& out by Dean L. M. Walsh in a recent paper in Dealer... |
4. Effect of Alfalfa Stand Density or Cutting Management on Nitrogen Supplying CapacityEconomic, energy and environmental considerations are making the efficient use of nitrogen fertilizers increasingly important for Wisconsin crop producers. Excessive nitrogen applications cannot be tolerated environmentally due to the potential for N leaching to groundwater, or economically due to the relatively high cost of N fertilizers. The potential exists for many producers, farming in legume rotation, to unknowingly over-apply N by not fully applying credits for previously grown alfalfa. A... |
5. The New Wisconsin Soil Test Recommendation ProgramThe modern Wisconsin soil testing program was originally developed in the early 1960's. It was revised rather thoroughly in 1970 and again in 1981. New research advances, additional correla- tion and calibration data, changes in user needs, and shifts in philosophical viewpoint make it necessary to periodically review the soil testing program and the recommendations that emanate from that program. The current revision is an attempt to incorporate additional research, eliminate certain inconsistencies... |
6. Alfalfa Responses to PotassiumThe potassium requirement of alfalfa is greater than that for any other nutrient. Potassium influences several systems within alfalfa plants including enzyme activity, carbohydrate production and transport, stornatal activity, photosynthesis through chlorophyll content and C02 exchange rate, and nitrogen fixation. Excellent reviews on the role of K in physiological processes are provided in the most recent potassium monograph (Munson, 1985). Potassium also markedly influences alfalfa agronomically... |
7. Fertilizer Recommendations- Fact or FictionFertilizers are all important and expensive part of the crop production systenl in Indiana. Indiana farmers spend nearly a half billion dollars each year on fertilizer and lime. The question is. is this expense really nccessary? Farmers obtain fertilizer reconlmendations from a number of sources. Soil testing labs. fertilizer dealers. crop consultants and extension all make fertilizer reconunendations. In many cases the reconlmendations are quite different. Is there a valid reason for these differences... |
8. Site-Specific Management of N Fertilization in OntarioSignificant within field variability of soil properties, such as soil fertility, and plant growth have been well docome~ited. Standard soil testing practices and fertilizer recommendations which enco~npass an average soil test value for a field and a constant rate of fertilization will obviously result in certain areas of a field being either over or under fertilized. As indicated by Kachanoski and Fairchild (1995), for a single (constant) rate of fertilizer application, reconimendations based on... |
9. Alfalfa Response to K Rate, Source and Time of ApplicationThe potassium (K) requirement of alfalfa is greater than that for any other nutrient. Potassium influences several systems within-alfalfa plants, including enzyme activity, carbohydrate production and transport, stomata1 activity: photosynthesis through chlorophyll content and CO, exchange rate, and nitrogen fixation (Munson, 1985). Potassium also markedly influences alfalfa agronomically through yield increases and improvements in forage quality, disease resistance, and overwinter survival. A significant... |
10. Effect of Tillage on Legume N Credit to Winter WheatAlthough there has been a significant amount of work done on the availability of legume-nitrogen for corn following alfalfa, several questions have arisen as to the sufficiency and availability of the legume N when winter wheat is raised as a following crop. This is especially true if the wheat is planted soon after the alfalfa is killed. The synchrony of nitrogen released from legumes with crop demand for N has been a concern even with crops such as corn, where N uptake can occur through- out the... |
11. Field Estimate of Dairy Manure Nitrogen Availability to PotatoesWithin Wisconsin, there is a distinct movement toward dairy herd expansion and consolidation of small farms. With the increase in manure production, these large dairies are considering various land and manure management arrangements with non-livestock farmers, such as potato producers. The purpose of this study is to evaluate several potato production issues resulting from such partnerships including the availability of dairy manure nutrients to potatoes. Nitrogen and phosphorus availability were... |
12. Estimating Second- and Third Year Nitrogen Availability from Dairy manure: It is common practice to repeatedly apply dairy manure to the same fields. To accurately assess the total plant availability of rnanure nutrients, it is necessary to account for the nutrients remaining in soil fiom previous years applications. A corn (Zea mays) field experiment has continued since 1998 on a Plano silt loam. Residual manure N availability was estimated for two and three years after a single rnanure application fiom differences in whole-plant N uptake using 1) fertilizer N equivalence... |
13. Cereal Rye Cover Crops Mitigate Soil Phosphorus Stratification from Long-term No-tillageMinimal or no-tillage is a widely adopted soil conservation practice and has been documented to reduce soil erosion, increase soil organic matter, and even reduce nutrient losses. Without tillage cultivation, however, phosphorus (P) can become stratified in surface soil layers and this may limit availability to crops or even increase bioavailable-P losses. Our primary objective was to measure the long-term (12-year) effects of long-term no-tillage (NT), cereal rye cover crops (CC), and their interaction... R.W. Barker, M.J. Helmers, M.D. Mcdaniel |