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1. Impact of Nitrogen Application Timing on Corn ProductionWater quality issues have renewed interest in timing of nitrogen (N) application as a means to improve use efficiency in corn and reduce losses. Improved economic return is also desired as N fertilization is one of the most costly inputs to corn production. Time of fertilizer application is a component of the site-specific 4R nutrient management stewardship programs. In Iowa, the Nutrient Reduction Strategy has a 7% (37% std. dev.) nitrate-N reduction with a 0% (3% std. dev.) corn yield change... J. Sawyer, D. Barker, J. Lundvall |
2. Roto and Shoot Biomass and Nutrient Composition in a Winter Rye Cover CropNitrogen loss from applied fertilizer can be a significant environmental quality issue if NO 3 moves to surface or ground water. The Iowa nutrient reduction strategy science assessment identified winter cereal rye (Secale cereal L.) cover crop as a practice that can significantly reduce N and P loss (41% NO 3-N and 21% P reduction) from corn (Zea mays L.) and soybean [Glycine max. (L.) Merr.] fields. Cereal rye, when used as a cover crop, through its fibrous root system is able to explore the soil... |
3. Basic Considerations of Soil Compaction, Tillage, and Crop ProblemsSoil compaction is one of the mosc challenging variables in crop production in the Midwest. It affects early crop growth and can lead to yield reductions. The most unusual aspect of soil compaction is the variety of crop symptoms that can develop. Few absolute answers are available on the topic of soil coapac- tion. Our research is lixited to the effects of different soil conditions on yields and some early synptoms that can be caused by soil compact ion. We have developed three principles that... G.C. Steinhardt |
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. Phosphorus and Potassium Effects on Yield Components, Nutrient Accumulation and Persistence of Alfalfa (Medicago Sativa L.)Our objective was to determine why phosphorus (P) and potassiun~ (K) are essential for high yield by analyzing alfalfa yield components. Plots of P treatments (0, 25. 50, and 75 kg/ha) and K treatnients (0. 100, 200, 300, and 400 kgha) arranged in a factorial design were replicated four times. Forage was harvested four times per growi~lg season (1998-2000), and yield. mass per shoot, shoots per area. and herbage nutrient concentrations determined. In May and December, plants were dug to determine... |
6. Comparison of Nitrogen Recommendation Models for Corn in Two Cropping SystemsSeveral lnodels exist to generate N recommendations, and the model selected can have both economical and environmental implications. A study was initiated in 1998 to compare the response of corn to N in two ci-opping systenls (corn following corn and corn following soybeans). All plots received a starter N rate of 45 kg N ha-' (2 x 2 placement). and five rates of sidedress N (0, 22, 90, 157, and 224 kg N hi') were applied at gro~vth stage V6 either as anhydrous arnmonia or urea-ammonium rli trate... |
7. A Novel Use of Data Translation Allows 3D Prediction of Soil Fertility LandscapesSoil fertility managers need better estimates of the subsoil contribution to the nutrient pool. Thls need could be achieved through 3-D predictions of subsoil fertility using a novel method of soil- profile data translation in relation to a controlling genetic horizon. For this translation, the depth of a controlling pedogenic feature is used as the origin and the rest of the profile is linearly scaled to it. When applied to a group of soils, from across a local or regional landscape, with varying... |
8. Corn Yield Response to Residual Forage Crop Rotation and Manure Amendment Effect in Potato RotationsAccurate prediction of multiple-year N availability froin organic sources is difficult and can complicate nitrogen management for producers using these sources. The objective of this study was to use corn yield and soil N monitoring to evaluate long-term nutrient availability from rotational systems on an irrigated Alfisol in central Michigan. Over a 5-year period, multiple crop sequences were grown with either annual liquid dairy manure at 12,260 L ha-' or conventional mineral fertilizer application... |
9. Tillage and Nitrogen Application Methodology Affects Corn Grain YieldMore efficient use of fertilizer nitrogen (N) is essential for improved yields and environmental stewardship. While university N recommendations for corn are based on observations typically made in conventional tillage systems, few universities have established research to evaluate if N recommendations should be different for alternative tillage systems. Generally spealung, no-till or minimum tillage systems have been identified as needing additional N to compensate for microbial immobilization of... |
10. Dealing with Sulfur Deficincies in Crop Production: The Iowa ExperienceResearch conducted for more than forty years (pri or to approximately 2005) in Iowa rarely noted improved crop yield with sulfur (S) fertilization. Studies during that time period with corn and soybean found yield increase from S fertilizer application only three times out of approximately 200 trials. Research in the early 1980's had also documented sufficient plant available S in the soil profile for crop production on most Iowa soil associations. Results of recent studies (2000- 2005) in corn and... |
11. Evaluation of Sulfur Fertilizers In Corn ProductionSulfur deficiencies and corn yield increases from S fertilization have been documented in Iowa since the mid-2000’s. Therefore, S fertilization management is an important component of high yield corn production. Many S fertilizers are available for use in correcting deficiencies. However, specific product evaluations have not been widely conducted in Iowa. In addition, a new S fertilizer has recently become available in the Midwest U.S., the mineral polyhalite. The research objectives were... J. Sawyer, M. Castellano, A. Sassman, J. Lundvall |
12. Winter Cereal Rye Nitrogen Response and Fertilization RequirementWinter cereal rye (Secale cereale L.) has been a common cover crop choice due to seed cost, winter hardiness, and rapid spring growth. It could also be an alternative grain crop to include in a corn-soybean rotation. Also, a rye crop would provide soil coverage during the springtime when corn and soybean do not. No known research has investigated the N fertilization requirement for winter cereal rye seed production in Iowa. The objectives of this study were to evaluate N response in cereal... C. Martins, J. Sawyer, J. Lundvall |
13. Impact of sulfur and its interaction with N rates on wheat and barley in North Dakota and Western MinnesotaEffects of S, N, and their interactions were assessed on grain yields and protein of spring wheat and barley, across eight site years in Western Minnesota (MN), and ten site years (hereafter, sites) in North Dakota (ND) from 2015 to 2019. The studies were to determine if S improves yields and protein in wheat, and if the effects were dependent on N rates. Treatments included all combinations of five N rates of N (0, 60, 120, 180, and 240 lbs/ac) and three rates of S (0, 10, 20 lbs/ac) in MN. In... J.M. Teboh, S. Yuja, B.G. Schatz, G. Pradhan |
14. Integrating Management Zones and Canopy Sensing for Improved Nitrogen Recommendation AlgorithmsActive crop canopy sensors have been studied as a tool to direct spatially variable nitrogen (N) fertilizer applications in maize, with the goal of increasing the synchrony between N supply and crop demand and thus improving N use efficiency (NUE). However, N recommendation algorithms have often proven inaccurate in certain subfield regions due to local spatial variability. Modifying these algorithms by integrating soil-based management zones (MZ) may improve their accuracy... J. Crowther, J. Parrish, R. Ferguson, J. Luck, K. Glewen, T. Shaver, D. Krull, L. Thompson, N. Mueller, B. Krienke, T. Mieno, T. Ingram |
15. Comparison of Ground-Based Active Crop Canopy Sensor and Aerial Passive Crop Canopy Sensor for In-Season Nitrogen ManagementCrop canopy sensors represent one tool available to help calculate a reactive in-season nitrogen (N) application rate in corn. When utilizing such systems, corn growers must decide between using active versus passive crop canopy sensors. The objectives of this study was to 1) determine the correlation between N management by remote sensing using a passive sensor and N management using proximal sensing with an active sensors. Treatments were arranged as field length strips in a randomized complete... J. Parrish, R. Ferguson, J. Luck, K. Glewen, L. Thompson, B. Krienke, N. Mueller, T. Ingram, D. Krull, J. Crowther, T. Shaver, T. Mieno |
16. A Combination of Soil Incubation and Chemical Extraction Tests Best Predicts Corn Yield Response to Fertilizer NitrogenSoil tests in general have served a critical role in the field of soil fertility for over half a century, and have helped to increase crop productivity and promote more efficient use of fertilizers on farms. However, N soil tests have limitations and chemical extraction tests have not predicted well the potentially mineralizable N supplied to corn over a growing season. Thus, these tests often do not accurately predict a corn’s yield response to fertilizer N. We explored 30 soil tests for... M. Mcdaniel, D. Walters, L. Bundy, C. Laboski, P. Scharf, R. Drijber, W. Horwath, J. Sawyer, J. Sawyer, M. Castellano |
17. Corn uptake of soil- and fertilizer-derived nitrogen in response to rate and timing of fertilizer application.While nitrogen (N) fertilizer is essential for high-yielding corn (Zea mays L.) production, over-application or application of fertilizer N before rapid corn N uptake may result in N loss that negatively impacts the environment and reduces fertilizer use efficiency. To better understand how fertilizer rate and application timing impact corn grain yield and fertilizer recovery in the soil-corn system, six two-year field studies were conducted at Minnesota field sites of contrasting soil... |
18. Exploratory analysis of event-based edge-of-field phosphorus lossesUnderstanding how the timing of management activities, particularly manure and fertilizer applications, impacts P losses in runoff can improve farmers’ decisions on when to apply nutrients. The University of Wisconsin Discovery Farms and Discovery Farms Minnesota have been monitoring edge-of-field nutrient losses since 2004. This data set includes over 125 site-years of runoff across 26 fields and includes 1574 individual runoff events. The objectives of this study are to: (i) determine... |
19. Corn Tissue Nutrient Concentration Related to Soil Fertility LevelsSoil health metrics, such as active carbon or soil respiration, may be important factors influencing corn nutrient uptake. The push for increasing soil health has promoted the question of how soil health and soil fertility interact. This research determined how different soil health metrics impact early-season corn tissue potassium (K), sulfur (S), or phosphorus (P) nutrient content. Research conducted in 2019 on 35 producer Missouri fields encompassed many soil types and management practices.... M.B. Henry, N.R. Kitchen, K.S. Veum, J.D. Svedin |
20. Can Soil Health Metrics Improve Standard Soil Fertility Recommendations?It is commonly speculated that integrating soil health (SH) testing with soil fertility (SF) testing would improve fertilizer recommendation decisions. However, quantified impacts of SH properties, specifically soil biological properties, on fertilizer demand have not been well established. The objective of this research was to explore corn (Zea mays L.) yield response to phosphorus (P) and potassium (K) fertilization as influenced by established SF analysis and common SH metrics.... C.J. Ransom, J. Svedin, N.R. Kitchen, K. Veum, S.H. Anderson |
21. A Minnesota-Wide Assessment of Critical Pre-Plant and in-Season Soil Nitrate for Adjusting Nitrogen Rate GuidelinesThe pre-plant (PPNT) and pre-sidedress (PSNT) soil nitrate tests are often used as indicators of soil nitrogen (N) availability in Minnesota. The assessment of available soil nitrogen (N) provides corn (Zea mays L.) growers with key information on N credits to adjust their N fertilizer rates. However, current N management recommendations in Minnesota were based on research conducted 40-yr ago and did not specify differences between environments and management. Through a comprehensive... E. Souza, F.G. Fernandez, J. Coulter, M. Wilson, J.A. Vetsch, P.H. Pagliari, R.T. Venterea, D.E. Kaiser, K.P. Fabrizzi, D. Bernau, C.J. Rosen, K. Mizuta, Y. Miao, V. Sharma |