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1. Strip-Tilled Corn Responses to Deep Placement of Phosphorus and Potassium- 2005 UpdateReduced tillage systems modify some of the most important variables related with the plant-soil- weather environment and consequently affect the last expression of this relation: yield. A possibly more restrictive root growth scenario (due to lower soil temperatures and higher mechanical impedance), as well as pronounced horizontal and vertical stratification in nutrients within the soil profile (particularly for no-till systems) could lead to a reduction in root uptake of nutrients. This situation... M. Cánepa, T.J. Vyn |
2. Effects of Glyphosate Application and Manganese Fertiization on Leaf Manganese Concentration and Yield of Glyphosate-Resistant SoybeanGlyphosate-resistant (GR) soybean is widely accep ted in the United States. Recent research in Indiana and elsewhere has observe d that post-emergence foliar applications of glyphosate may cause or exacerbate manganese (Mn) deficiency and then limit yield of GR soybeans on low Mn availability soils. The objectives of this study were to 1) better understand how glyphosate application(s) might reduce the up take and translocation of Mn in GR soybean plants, and 2) determine the effectiveness of starter-banded... |
3. Plant Density Consequences on Nitrogen Uptake Dynamics of Maize Plants from Vegetative to Reproductive StagesThere are few studies to date that have inte nsively examined the simultaneous effects of differences in plant crowding and fertilizer N availability for different hybrids and locations on N uptake and maize (Zea mays L.) grain yield. The main research objective was to utilize a quantitative framework to bett er understand the physiological mechanisms that govern N dynamics in maize plants at varying plant densi ties and N rates. Two field experiments involving paired near-isogenic hybrids (i.e.... |
4. Corn Plant Uniformity Following Shallow NH3 Placement in Precision-Guided, Pre-Plant Nitrogen ApplicationsCorn (Zea mays L.) production relies extensively on different types of N fertilizers, and anhydrous ammonia (NH 3) continues to be a dominant N s ource in much of the Corn Belt. Timing and placement of NH 3 fertilizer can affect plant-to-plant uniformity and yield of corn, and especially so when high N rates are applied and there is little time between spring pre-plant NH 3 application and planting. The effects of shallow pre-plant NH3 placement on corn plant-to- plant uniformity were investig ated... |
5. Adapt-N: A Computational Tool for Precise N Management in CornCurrent approaches to estimation of optimum N fertilizer rates are based on mass balances, average expected economic return based on field experiments, soil N tests, an d crop leaf or canopy sensing. However, denitrification and leaching losses of nitrogen may occur from dynamic and complex interactions among weather, soil hydrology, crop water and N uptake, and management practices , and result in high variability in annual crop N needs in maize ( Zea mays L.) production. W eather impacts the soil... |
6. Consequences Of Shallow NH3 Placement And Timing On N Use Efficiencies In Corn ProductionA field study in west-central Indiana was conducted to investigate the effects of shallow anhydrous ammonia (NH 3) placement and timing on N use efficiencies in a conventionally tilled corn production system following soybean crop. The spring NH 3 was applied either pre-plant (6- inches offset from future corn row) or side-dress (at mid-row position) at different rates (0, 80, 130 or 180 lbs N acre -1). Aboveground biomass harvest and combine harvested yield were used to determine N recovery, N internal... |
7. Soybean Production Research: A National ApproachU.S. soybean growers are looking for alternative methods to increase soybean yields and recent increases in commodity prices have given producers more freedom to invest in additional crop inputs or products. Unfortunately, quality data from studies addressing multiple contemporary inputs is scarce. The objective of this work was to evaluate the effectiveness of combined soybean inputs on seed yield. These high input systems were tested in six states to evaluate their value across a broad geography.... |
8. Relationship of in-season soil nitrogen concentration with corn yield and potential nitrogen lossesModeled or measured soil mineral N (SMN) levels during the corn growing season have been used to set sidedress N rates, but there has been little research linking SMN levels at different growth stages to yield to help guide this process. The degree to which SMN level influences the risk of N losses is also not known. Data from 32 site-years of field experiments in Illinois (2015–2018) that included 12 combinations of N fertilizer rate, timing, and source, were used to evaluate... G. Preza-fontes, E. Nafziger, L. Christianson, C. Pittelkow |
9. Corn Yield Response to Sub-Surface Banded Starter Fertilizer in the U.S.Sub-surface fertilizer application at planting (i.e., starter fertilization) is a common practice in U.S. corn (Zea Mays L.) production to improve early-season nutrient uptake, nutrient use efficiency, and plant growth, especially under cool and moist spring soil conditions. However, yield increases from starter applications can vary across production systems and environments. Here, we use a meta-analysis approach to quantify and generalize corn yield responses to sub-surface starter... D. Quinn, C. Lee, H. Poffenbarger |
10. The MRTN Approach: Past, Present, and FutureThe method of using crop N response data assimilation, now called the “MRTN approach”, was conceived at a September, 2004 meeting in Bettendorf, Iowa of scientists from several Corn Belt states. This meeting was prompted by findings in field trials that showed substantially lower optimum N rates than those based on using corn yield goal to predict crop N needs; most also showed no correlation between EONR and yield at EONR across trials. The MRTN method is straightforward: yield data... E. Nafziger, J. Sawyer |
11. Comparison of Wheat and Barley to Rye As a Cover Crop for MaizeCover crops are used by farmers in Kentucky to prevent soil erosion and uptake residual nitrogen in between growing seasons of cash crops. Cereal rye has become a popular cover crop due to its sizeable biomass production and superior nitrate uptake ability. Wheat and barley have similar fibrous root systems and may have value as a cover crop. A field study was conducted at the University of Kentucky North Farm in Lexington, KY, in 2021 and 2022. The objectives of this study were to determine if... R. Nalley, C. Lee |
12. Comparison of Wheat and Barley to Rye as a Cover Crop for CornWinter cereal cover crops have become an essential management practice for sustainable corn production. Rye is the most popular winter cereal for cover crop, but wheat and barley may provide a comparable value due to their similar fibrous root systems. Winter cereals provide organic matter, scavenge residual nutrients, and protect the soil from erosion. Winter cereals can immobilize nutrients for the corn crop and can reduce corn stands in some situations, reducing corn yield. The primary objective... R. Nalley, C. Lee, H. Poffenbarger |
13. Effect of Barley and Winter Pea Cover Crops on Nitrogen Availability in No-Till CornCover crops are known to have positive effects on soil health and reduce erosion. However, popular cereal grains used as cover crops, such as rye (Secale cereale), wheat (Triticum aestivum), and barley (Hordeum vulgare) can negatively affect nitrogen availability for the subsequent corn crop. Legumes, such as winter peas (Pisum sativum) could reduce competition for nitrogen between the cereal cover crop and the summer corn crop. This study's objective is to determine if barley as a cover crop... E. Marsh, C. Lee |
14. Effect of Barley and Winter Pea Cover Crops on Nutrient Availability in No-Till CornCover crops are reported to have long-term soil health improvements, the first of which is reducing erosion. However, popular cereal cover crops, such as rye (Secale cereale), have the potential to cause a yield penalty in the following corn (Zea mays) crop. Legumes, such as Austrian winter pea (Pisum sativum), are thought to reduce this yield penalty in no-till systems. Additionally, sulfur deficiencies have been observed in some studies following cover crops. The main... E. Marsh, C. Lee |
15. Understanding Wheat Head Counts Effect on YieldWheat (Triticum aestivum) is grown in many parts of the world, with soft red winter wheat (SRWW) being the most popular type grown in Kentucky. Wheat is the fourth most economically important crop in Kentucky and is used in a variety of food products as well as in feed for livestock. Crop scouts reported wheat head counts above the current University of Kentucky threshold for head counts needed to maximize yield. Wheat in other states north reported higher head counts than those observed... A. Mutter, C. Lee |