Proceedings
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1. Nitrogen Management for no-till Grain SorghumField experiments evaluating the effects of nitrogen management for no-till dryland grain sorghum were coacted in 1985 and 1986. Nitrogen rates (0, 50, 100 lbs N/A and placement methods for urea ammonium nitrate solution (UAN) have been evaluated in eastern Kansas. Placement methods have included surface broadcast, surface banded, pressure injected, and knifed. Results to date shm that nitrogen consistently increases yields and tissue and grain N contents, and that method of UAN placement produces... |
2. Effects of Chloride Rates and Sources on Winter Wheat in KansasOn wheat, and some other cereal grains, chloride has been reported to have an effect on plant diseases, either suppressing the disease organism or causing the plant to be able to withstand infection. It is hypothesized that yield increases are due to these effects. Researchers from several states have been able to show yield increases from chloride containing fertilizers. The most common source is potassium chloride, KC1. In many cases, soil test potassium levels are high, and most soil test recommendations... |
3. Nitrogen Management for Cool Season Grass ProductionStudies were initiated in 1985 on established smooth bromegrass and tall fescue to evaluate urea granule size effects on forage production and quality. Other work, evaluating N source by previous source effects and UAN placement methods and the addition of ATS, was conducted on established smooth bromegrass. Nitroger1 rates were also evaluated in all these studies, and the addition of N significantly increased forage yields and N concentrations in each study. Use of large (1.0g) urea granules produced... |
4. Sulfur Fertilization of Smooth BromegrassStudies were initiated in 1987-88 on established smooth bromegrass at two sites in eastern Kansas to evaluate the effects of sulfur fertilization on bromegrass forage production and quality. Sulfur rates (0, 15, 30 lb S/ac) and sources (ammonium sulfate and ammonium thiosulfate) were evaluated. The addition of sulfur consistently and, in most cases, significantly increased bromegrass forage yields and forage S concentrations. Sulfur had little effect on forage protein levels. Ammonium thiosulfate... |
5. Nitrogen Management for No-Till Production SystemsNitrogen management practices including rates and sources were evaluated in high residue no-till production systems involving corn and grain sorghum. A urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT) was evaluated. This research also assessed the impact of type of previous residue on performance of surface applied N. A chlorophyll meter was evaluated as an in-field N assessment tool. Results to date indicate that NBPT is effective in improving the performance of surface broadcast urea.... |
6. Nitrogen Fertilization of SoybeanNitrogen (N) requirement of soybean is high because of the high protein seed produced. One bushel of soybean requires over 3.5 pounds of N in the grain alone. Symbiotic Nz fixation supplies N for soybean, but Harper (1 974) reported that only 25 to 60% of the N in a marure soybean piant comes from N fixation while the other 40 to 75% comes from the soil. However. application of N fertilizer to soybean remains a very controversial issue because of mixed results of previous research.... |
7. Evaluation of Starter Fertilizer Formulations and Placements for Conservation Tillage Production SystemsWith the interest in and importance of the use of starter fertilizers in conservation tillage production systems, research was continued to evaluate higher rates of N in starter fertilizers and different starter fertilizer placements. The use of starter fertilizer containing N, P and K significantly increased corn yields compared to a N only program, even though soil P and K levels were high. Increasing N rates in direct seed placed starter did not increase yields and significantly reduced plant... |
8. Providing Flexibility in P and K RecommendationsHistorically, land grant Universities have generally provided a single rate recommendation for nutrients such as phosphorus (P) and potassium (K). Depending on the particular University in question, these nutrient rate recommendations are generally based on two widely recognized approaches to managing soil and fertilizer P and K - the nutrient sufficiency approach and the build-maintenance approach. The goal of a nutrient sufficiency based soil fertility program is to apply just enough P andior K... |
9. Evaluation of Fertilizer Management in Strip-till and No-till Corn ProductionStrip-tillage for corn production may have advantages over no-till. particularly in areas with heavy soils andlor high rainfall during spring months. With these conditions in no-till systems. planting delays and/or slow, uneven emergence are common. Strip-tillage creates a narrow tilled area for the seedbed ivhile maintaining the intcr-row residue cover, allowing for the erosion protection associated with no-till, yet providing an area in the row where the soil will dry out and warm up earlier in... |
10. Strip Tillage and No Tillage Fertilization Systems Evaluated for Eastern Kansas Rain Fed CornRow-crop agriculture in East-Central and Southeast Kansas is facing increasing pressure to reduce sediment and nutrient losses via runoff. Edge-of-field measurements show that no-tillage with fertilizers placed below the surface of the soil has significantly less sediment and total P losses in runoff compared to conventional tillage (Janssen et al., 2000). However, for rain-fed corn, no-tillage in these regions can provide serious challenges some years because of frequent spring rains and an abundance... |
11. Corn Residue Harvesting Effects on Yield Response to N FertilizationProducers have many choices of diverse tillage practices for their corn (Zea mays L.) production systems. However, no-till has become an important soil management practice to help reduce water and wind erosion, as well as nutrient runoff, while conserving soil moisture for crop use. No-till systems also help farmers by saving labor and time, as well as reducing farm costs due to less equipment and fuel consumption. Nevertheless, no-till production is typically more successful and has higher crop... |
12. Corn and Soybean Response to Starters After Broadcast Fertilizer ApplicationCorn response to fertilization and placement methods has always been a subject of interest and extensive research; however studies on soybean response to placement have been limited in Kansas. The objective of this study was to evaluate the effect of starter and broadcast fertilizer application on corn and soybean in a typical corn-soybean rotation in Kansas. Grain and seed yield, early growth, nutrient concentration and uptake were evaluated over eight site-years trials in Kansas for both corn and... |
13. Iowa Soybean Nitrogen Fixation Consider in Nitrogen BudgetsSoybean (Glycine max) is one of the most important agricultural commodities grown in Midwestern states of the US and some other parts of the world. Like many other legumes, soybean can associate symbiotically with nitrogen (N) fixing bacteria, which can transform the N2 from the atmosphere into NH3 a more available N form, through a process known as biological N fixation (BNF). However, BNF is an energy expensive process for soybean that requires carbohydrates from... S. Cordova, R. Dietzel, M. Licht, S. Archontoulis, M. Castellano |
14. Precision planting impacts on winter cereal rye growth, nutrient uptake, spring soil temperature, and adoption costGrowing winter cereal rye (Secale cereale) (WCR) has been identified as an effective in-field practice to reduce nitrate-N and phosphorus (P) losses to Upper Mississippi River Basin (UMRB), USA. In the Midwestern USA, growers are reluctant to plant WCR especially prior to corn (Zea mays L.) due to N immobilization and establishment issues. Precision planting of WCR or “Skipping the corn row” (STCR) can minimize some issues associated with WCR ahead of corn while reducing... |
15. Evaluation of Soil Test Potassium Guidelines in MinnesotaChanges in corn and soybean potassium guidelines in states in the Upper Midwest have resulted in questions from consultants and farmers as to how best to manage the nutrient. In Iowa, soil samples analyzed on a field moist basis have been suggested as a method to predict the amount of potassium required for corn and soybean production while in North Dakota the ratio of illite to smecite in soil samples is utilized to determine the appropriate critical level to determine where potassium fertilizer... D. Kaiser, L. Leverich-nigon |
16. Effect of Long-Term Tillage and Crop Rotation on Mineral Associated Organic Matter Distribution Along the Soil ProfileSoil carbon (C) stability in soil organic matter (SOM) is critical for mitigating climate change as well as for providing food security. SOM associated with mineral Mineral-associated organic matter (MAOM) has a longer residence time than the light, sand-sized particulate organic matter (POM). Therefore, it is important to study the effect of conservation practices like no tillage and crop rotation on MAOM distribution to better understand carbon stability and persistence. The objective of this... A. Gautam, T. Vyn, S. Armstrong |
17. The Iowa Nitrogen InitiativeThe Iowa Nitrogen Initiative is a private-public partnership with a vision to provide Iowans with the best nitrogen science for the benefit of productivity, profitability, and environmental performance. We are working alongside agricultural service providers, farmers, and their advisors to design, execute, and interpret hundreds of coordinated on-farm, scientifically robust nitrogen rate trials every year. In 2024, we conducted more than 400 scientifically robust, fully replicated trials. Data... S. Archontoulis, M. Castellano, M. Miller, M. Baum, R. Osman |
18. Nitrogen Fertilizer Application Consultation Tool (N-FACT)The N-FACT is a decision support web tool that leverages data from the Iowa Nitrogen Initiative on-farm nitrogen rate trials with cropping systems modeling. The web tool was released in February 2025 (https://n-fact.ag/start). The web tool summarizes results on optimum nitrogen fertilizer rate for corn from hundreds of on-farm trials across Iowa. Additionally, the web tool allows users to select a county, crop rotation, planting date, fall... S. Archontoulis |