Proceedings
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1. Effect of Residual Profile Nitrate on Corn Response to N Fertilization in WisconsinResearch in several Great Plains and Western states has shown that crop yield response to fertilizer N is closely related to the amounts of residual nitrate in soil profiles. Based on this work, nitrogen fertilizer recommendations in these low-rainfall areas are adjusted to reflect the contribution of residual nitrate to the total crop nitrogen requirement. Use of residual profile nitrate data in development of N fertilizer recommendations has received much less research attention in the higher rainfall... |
2. Compaction - K Fertility Interactions in Corn ProductionSoil compaction is recognized as a significant factor affecting yield in crop production today. The pressure to produce crops profitably has often led gruwers to farm greater acreages, with larger equipment under soil conditions which favor compaction. Effects of compaction are not limited to the surface lay- of a soil but often may be apparent cut much of the root zone. With the interest in soil compaction and its effects on crop growth, a research project was initiated to accomplish the fol lowing... |
3. Environmental Sulfur Sources as Inputs for Predicting Sulfur NeedsCrop responses to sulfur fertilization have been damstrated in mt states in the midwest, but the frequency of these responses is relatively lm. Sulfur deficiencies are usually confined to areas where one or mre of the follcrwing conditions exist: (1) Sandy or shallow soils; (2) Low soil organic matter content; (3) No recent manure applications; (4) Low atmospheric sulfur deposition; (5) High crop sulfur requirement. Although diagnostic tests to predict crop response to applied sulfur are an cbvious... |
4. 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... |
5. Soil Nitrate Test Performance on Medium and High-Yield Potential SoilsImproved N recommendation methods for corn (Zea mays L.) are essential for increased profitability and reduction of potential N losses to the environment. A 4-yr study (49 site-yr) was conducted to evaluate the performance of preplant (PPNT) and pre-sidedress soil nitrate tests (PSNT) for predicting optimum N rates for corn at sites with inorganic and organic N inputs. Soil samples were obtained before planting (PPNT) and when corn was 6 to 12 inches tall (PSNT). and analyzed for nitrate-N. Corn... |
6. Site-Specific Prediction of Soybean Nitrogen ContributionsSoybean has long been recognized for its nitrogen (N) contributions and yield enhancing effects in crop sequences. Soybean N credits in the Midwest range fiom 20 to 40 Ib of Nlacre (Kurtz et al., 1984). Several Midwestern states recommend a legume credit of 40 Ib of Nlacre following an average crop of soybean. Current Wisconsin recommendations suggest a reduction in nitrogen fertilizer rates for corn following soybean of 1 Ib N hushel of soybean yield up to a maximum credit of 40 Ib Nacre (Kelling... |
7. Manure and Tillage Effects on Phosphorus in RunoffPhosphorus (P) loss in runoff from cropland is an environmental concern because this P often promotes weed and algae growth in lakes, rivers, and streams. Water bodies with a large supply of nutrients (well nourished) are termed eutrophic. Eutrophic conditions can result in excessive algae and plant growth and when these weeds and algae die and decompose, dissolved oxygen levels in the water is depleted resulting in odors, fish kills, and a general degradation of the aesthetic and recreational value... |
8. Scale of Measurement Effects on Phosphorus Runoff Losses from CroplandAs phosphorus (P)-based nutrient management planning becomes necessary for some farms in Wisconsin, it will be critical to have reliable, research-based planning tools. The Wisconsin P- hdex provides one method for preparing P-based nutrient management plans. The P-Index was developed largely from small plot-scale data showing the relationships between various site and management variables and runoff P losses. Thls study was conducted to compare runoff composition measurements at the subwatershed... |
9. 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... |
10. Nitrogen Availability to Corn Following Small GrainsNitrogen rate recommendations for corn are generally reduced following legumes compared to following corn or small grains. A 4-yr field study was conducted on a Plano silt loam soil in southern Wisconsin to evaluate the capability of soil NO3 tests to predict N availability to corn follo~b-ing small grains. Previous crop small grains included \vinter wheat, winter qe. and oats harvested for grain and straw. Nitrogen fertilizer was applied to corn at rates of 0 to 180 Ib/a in 30 Ib increments. Grain... |