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1. Nitrogen and Phosphorus Fertilization of Cool Season GrassStudies were initiated at two locations on cool season grass in central South Dakota to evaluate the effects of nitrogen and phosphorus on forage and seed yields. Nitrogen rates (0,30,60,90,120,1501b Nacre) and phosphorus rates (0,30,60,90,180 Ib P,Odacre) were applied to established crested or intermediate wheatgrass once and harvested for either two or three years depending on location. Nitrogen increased dry matter yield by 48 and 62% at the two locations and seed yield by 166 percent. Phosphorus... |
2. Predicting Subsoil Nitrate Content from Surface MeasurementsPreplant soil profile nitrate (NO,-N) tests are effective for I predicting corn (Zea mays L.) responsk to applied N. The difficulty of obtaining profile soil samples is one of the main obstacles to more extensive use of preplant tests. One approach to overcoming this barrier is to develop and use models to predict subsoil NO -N contents 3 from surface soil NO -N measurements. Data from 2295 routlne field 3 samples submitted to the University of Wisconsin Soil and Plant Analysis Laboratory from 1989... |
3. Changes in Iowa's Soil Test P and K Interpretations and RecommendationsResearch results from long-term and short-term experimentation in Iowa have been consistent in the response or lack of response of Iowa field crops to applications of fertilizer phosphorus (P) and potassium (K) at various soil test levels for P and K. Analyses of the research data have established critical soil test values for P and K and the most economic soil test range for P and K to maintain (Mallarino, Webb, and Blackmer, 1991a and 1991 b; Mallarino and Blackmer, 1992 and 1994; Webb, Mallarino,... |
4. Adjusting N Recommendations Based on a Previously Grown CropNitrogen recommendations in North Dakota are based on a yield goal multiplied from some empirically derived factor in a linear formula. There are a three adjustments to the N recommendations that result form these formulas (Franzen and Cihacek, 1996). They are the soil test nitrate-N to some depth, a sampling date adjustment ifthe sampling was conducted in the fall prior to September 15, and a previous crop credit. Two of these three adjustments are based on some knowledge regarding mineralization... |
5. Delivering Continuing Education to Ag Professionals- The Crop Adviser InstituteContinuing education is essential for agricultural professionals, whether required by a certifjmg organization or completed voluntarily as a supplemental educational opportunity. Agricultural continuing education has traditionally been delivered on-site, but temporal, geographical, and other constraints often prevent individuals from attending these courses. The Crop Adviser Institute (CAI) has been established to provide an alternative method of delivering continuing education. Implementation of... |
6. 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... |
7. Slow Release Nitrogen Fertilizer and its Impact on Sustainable Turf Grass GrowthThe methodology of this project aims at developing an efficient, yet effective, means of providing various nitrogen (N) fertilizer sources to turf grass with the ultimate goal of maintaining sufficient biomass production while minimizing the use of excess fertilizer that may eventually end up contaminating our groundwater and waterways. Nitrogen is the nutrient required in the largest quantity by plants, and also poses the greatest threat when nutrient leaching and water contamination are considered.... |
8. Phosphorus Dynamics of Land-Applied Compost Bedded Pack Dairy Barn Product in Low and High Soil Test Phosphorus EnvironmentsCharacterizing and understanding the nutrient dynamics of land applied compost bedded pack dairy barn (CBP) products is necessary because this waste management system and its fertility use are increasingly common. An aerobic mineralization study was conducted to observe the phosphorus (P) dynamics of land-applied CBP product in low and high soil test P (STP) environments. An innovative phosphorus fractionation strategy employing UV-assisted organic P decomposition helped quantify fractions corresponding... |
9. Nitrous Oxide Emissions in Claypan Soils Due to Fertilizer Source and Tillage/Fertilizer PlacementNitrogen fertilization for agricu ltural production is a major contri butor to increased soil nitrous oxide emissions. These emissi ons may contribute to global warming and ozone depletion. Nitrogen fertilizer source and placeme nt can influence soil nitrous oxide (N 2O) emissions by affecting the concentration of ammonium and nitrat e available for nitrification and denitrification throughout the growing season. The objectives of this research were to quantify the effect of tillage / fertilizer... |
10. Grid Soil Sample Interpolation Using Geographicaly Weighted Regression and Random ForestSoil sampling is useful in agriculture for setting fertilizer application rates. High density soil samples can also be used for variable rate seeding and other precision agriculture applications. Half-acre grid soil samples were collected from 6 soybean fields, and phosphorous (P), potassium (K), and organic matter (OM) were measured. Each soil parameter was interpolated for each field, with terrain attributes as covariates, using two different methods: geographically weighted regression (GWR)... E. Matcham, S. Subburayalu, J. Fulton, E. Hawkins, P. Paul, L. Lindsey |
11. Topsoil Thickness Effects on Phosphorus and Potassium Dynamics on Claypan SoilsDue to variable depth to claypan (DTC) across landscapes, nutrient supply from subsoils, and crop removal, precise P and K fertilizer management on claypan soil fields can be difficult. Therefore, a study was performed to determine if DTC derived from soil apparent electrical conductivity (ECa) could be used to improve P and K management for corn (Zea mays L.) and soybean (Glycine max [L.]). Research was conducted on a claypan soil at the University of Missouri’s... L. Conway, M. Yost, N. Kitchen, N. Kitchen, K. Sudduth |
12. Grain Yield and Nutrient Removal Relationships in High-yield Modern Corn Hybrids Under In-season Sulfur and Potassium ApplicationsAdvancements in modern corn genetics and adoption of intensive management practices, including in-season sulfur (S) and potassium (K) applications, have helped corn farmers set higher yield goals while prompting new questions about plant nutrient dynamics during the season and cumulative nutrient removal with grain at harvest. The primary goal of this study was to investigate how hybrid and fertility management decisions in situations with high yield potential (>225 bushels acre-1) impact plant... G. Verhagen, T. Vyn |
13. Seed Germination as Influenced by Fertilizer Type, Seed Coating, and Duration of StorageOverseeding forages into existing pastures and hayfields helps maintain dense stands and sustain productivity. Fertilizer applications to stimulate early spring growth provides an opportunity to blend forage seed with fertilizer. Additionally, seed treatments are often used to improve the ability to handle small seeds and to improve percent germination over raw or uncoated seed. Little is known about how seed coating, fertilizer type or duration of exposure to fertilizer will influence seed germination.... E. Ritchey, C. Teutsch |
14. The Alfalfa Yield Plateau: is Soil Fertility the Cause?Alfalfa is a perennial forage legume known for its ability to produce high quality hay, earning it the title the “Queen of Forages.” It is produced across the United States as feed for the beef, dairy, and equine industries. During the 1950s, alfalfa yields rose exponentially due to advances in technologies such as improved varieties, synthetic fertilizers, and pesticides. However, yields plateaued at approximately 3.3 tons per acre in the 1980s for reasons not fully understood and... W. Fleming, E. Ritchey, C. Teutsch, J. Grove |
15. Comparing the Effectiveness of Calcium Products in Neutralizing Soil AcidityProper pH management is the foundation of a good soil fertility program. Soil pH influences nutrient availability, root growth and function. Acid soils are neutralized by the addition of carbonates, oxides, and hydroxides present in limestone products. However, there is a common perception that calcium is responsible for the neutralization of acid soils rather than the carbonates associated with calcium in the limestone. The effectiveness of three calcium products in raising soil pH were compared... E.L. Ritchey, J.H. Grove, C. Teutsch |
16. Can CRP Serve As a Soil Health Benchmark: A Minnesota Case Study Utilizing SMAFSoil health is an important concept relating to sustainable agriculture and food security. However, the absence of a universally accepted benchmark for soil health complicates its application as a tool to measure soil functional capabilities. Here we propose the use of Conservation Reserve Program (CRP) soils as a potential benchmark for soil health in Southern Minnesota. The Soil Management Assessment Framework (SMAF) was used to evaluate soil health indicators and quantify the soil health gap... O. Hoffman, C. Chorpenning, C. Buchanan, T. Trimarco, N. Carr, J. Ippolito |