Proceedings
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1. Economic Optimum Rates of N for Corn Production in IowaProper nitronen (N) fertilizer is essential if crop producers are to maximize profits and minimize environmental contamination. A study to determine 'economic optimum N fertilizer rates was conducted in Iowa from-1987 to 1991. The results show that Iowa crop producers over-applied N during those years primarily due to not considering residual N in the soil. This was especially true following the drought year of 1988.... |
2. 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... |
3. Response of Corn Grown in Two Crop Rotations to Different N Rates and NitrapyrinNitrogen fertilization of corn is necessary to obtain adequate yields. Loss of soil-applied N1-L'-N fertilizers due to nitrification can decrease corn yield significantly. Nitrate contamination of ground or surface water supplies should also be considered. Use of nitrapyrin may help address these issues, though in fine textured soils response to its use is difficult to predict. A 10-year study was done to determine the effects of annual application of ammonia with nitrapyrin upon the yield of continuous... |
4. Spatial Response of Corn to Banded Zinc Sulfate Fertilizer in IowaThe solubility of zinc (Zn) decreases as pH increases. There are soil associations that contain high pH spots within fields where the surrounding soils' pHs are slightly acid. It is reasonable to expect that Zn availability, due to a difference in solubility, is different in the two areas. The objectives of this study were to find corn (Zea nlnys L.) grain yield responses to Zn fertilizers within fields and to define the soil characteristics in responsive areas. The study was conducted at twelve... |
5. Management Zone Delineation Techniques to Aid In-Season Sensor Based Nitrogen ApplicationThe increased efficiency of nitr ogen fertilizer (N) use has been a long-term goal in reduction of nitrate contamination in the stat e of Nebraska. Preliminary rese arch has shown sensor based in- season application of nitrogen has the ability to be economic and environmentally viable. Although benefits have been published there is an opportunity for increased accuracy of N application through the integration of preprocesse d georeferenced management zones. In-season sensor based N application relies... |
6. 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... |
7. Soybean Response to Potassium Fertility and Fertilizer in ManitobaSoybean acres have increased greatly in Manitoba in recent years, now occupying more than 25% of the province’s annual crop land. Potassium removal by soybean is greater than any other crop grown in Manitoba (1.1 – 1.4 lb K2O/bu). This large removal, accompanied by the large and rapid expansion in soybean acres, has contributed to an increase in province-wide potassium removal rates and likely explains the increase in incidence of potassium deficiency symptoms reported in recent years.... M. Bourns, D. Flaten, J. Heard, G. Bartley |