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1. Long Term Phosphorus Research on Corn and Grain SorghumPhosphorus fertilizer is needed for optimum production and economic returns from irrigated corn and grain sorghuni in western Kansas. A long term study shows that the yield benefit from P increases over time from no yield difference initially to over 100 butacre higher corn yields after 30 years. Without fertilizer P, soil P levels declined from 17 pprn Bray- 1 P to less than 10 pprn within five years, where they stabilized for both corn and sorghurn. The addition of fertilizer P at 40 Ib P205lacre... |
2. Influence of Seed Placed Fertilizer on Corn, Soybean and Sunflower EmergenceSix phosphorous fertilizer materials were placed with corn, soybean and sunflower seed to determine their influence on seed injury and emergence. Fertilizer rates used were 0, 12.5, 25, 50 and 100 Ib/A P,O, as dry TSP (0-46-O), MAP (1 1-55- 0), DAP (18-46-0) or liquid 10-34-0, 7-21-7 and 9-18-9. Seed emergence ranged from 0 to 100% depending on crop, fertilizer rate and materials used. Corn was most tolerant of fertilizer injury while soybean was extremely sensitive with stand reduction with even... |
3. Corn Nitrogen Tests in MissouriExperiments were carried out in farmer fields starting in 1995 with the objective of evaluating or developing field-specific tests to optimize N fertilizer rates for corn. Because some of the soil nitrate tests seem to work differently when manure or alfalfa is in the cropping system, most farms had pairs of experiments, one with an organic N source and the other with none. Descriptions of the experimental locations are given below. Location 1 2 Year 1995 1995 1995 1995 1995 PROCEDURES Countv Callaway... |
4. Sidedress N applications for corn based on corn colorNitrogen-deficient corn reflects more light over the entire visible spectrum than nitrogen-suff icient corn. Our objective was to calibrate the relationship between remotely-sensed corn color and the nitrogen need of the corn. Corn color measurements were made two ways: Aerial photographs In-field spectral radiometer A successful calibration would allow: Variable-rate sidedress nitrogen applications that precisely meet the needs of the crop. Precise response to in-season N loss (Figure 1). Data reported... |
5. No-till Corn Response to Starter Ffertilizer in MissouriEarly research on starter fertilizer showed that it usually increased early season crop growth, but in Missouri and adjacent states this only occasionally translated into a yield advantage. With widespread changes in tillage practices over the past twenty years, this conclusion may be changing. Recent starter fertilizer trials from other states are frequently showing corn yield responses in no-till systems. Dave Mengel at Purdue University found a yield response to starter in 8 of 11 no-till site-years,... |
6. Field Scale Evaluation of Innovative N Management Systems for CornPrevious research has shown that N fertilizer need for corn can vary widely, both between fields and within fields. Producers, however, almost always apply the same N fertilizer rate to whole fields, and vary N fertilizer rates minimally if at all over whole farms. Matching N fertilizer rates more closely to N needs could produce both economic and environmental benefits. Our objective is to test a range of innovative N management systems for their ability to match N rate recommendations to N needs... |
7. Detecting Spatially Variable Corn Nitrogen Needs Using Green Reflectance from 35MM PhotographsRising fertilizer costs and environmental concerns are reasons producers are looking to decrease nitrogen (N) fertilizer rates. This study investigated the use of relative green reflectance fiom 35 rnrn aerial photographs to detect spatially variable corn [Zea mays L.] N needs for developing variable rate fertilizer maps. Photographs were taken at three different growth stages (V7, V11, R3) at altitudes from 3,000 to 5,500 fi for two Missouri fields representing alluvial and deep loess soil types.... |
8. A Crop-Based Approach for In-Season N Management of CornOver-application of nitrogen (N) fertilizer on corn has resulted in elevated levels of N in ground and surface waters. A major factor contributing to decreased N use efficiency and environmental contamination for traditional corn N management schemes is routine pre-season application of large doses of N before the crop can effectively utilize this N. Our long-term research goal is to reduce these over-applications by using remote sensing to direct fertilizer only to areas needing N at times when... |
9. Zinc Deficiency Response of Sorghum, Wheat, and CornZinc (Zn) deficiency in corn (Zea mays L.) is more common than in sorghum (Sorghum bicolor (L.) Moench) or wheat (Triticum sp.). The ability of wheat to withstand low soil Zn conditions is related to increased release of phytosiderophore, a natural chelate, fiom its roots. The reasons for sorghum's ability to utilize low levels of soil Zn have not been adequately explored. The objective of this research was to: 1) ascertain if Zn deficiency can be induced with sorghum, wheat, and corn grown in a... |
10. Making Urea Work in No TillNo-till and reduced tillage production systen~s are widely used today in the United States as well as around the world due to their capacity for reducing soil erosion and topsoil loss, reducing phosphorus movement to surface water, and reducing labor, fuel, and equipment requirements. In no-till systems, an average of 25% of the N applied as broadcast urea can be lost via ammonia volatilization. Therefore, N losses due to ammonia volatilization will decrease corn and wheat yields. independently of... |
11. Aerial Photographs to Guide Corn Fertigation DecisionsCorn producers with pivot irrigatio n have the potential to apply in-season nitrogen (N) fertilizer much more easily than their non-irrigated counterpa rts. A demonstration project was initiated in 2006 to take advantage of this potential. One advantage for in-season N application is that the risk of N loss prior to crop uptake is minimal. Another advantage is the opportunity to diagnose N n eed. A range of studies have shown that N need can vary widely from one field to another, as well as within... |
12. Using Reflectance Sensors to Predict Nitrogen Needs of CottonObjectives 1) Develop on-the-go N recommendations based on analysis of the reflectance sensor readings. 2) Determine the sensor model, height, and wa velength that give the best prediction for sidedress N. 3) Determine the best growth stag e for sensor-based sidedressing Relevance There is great spatial variability of N in the soil. Cotton fields that receive a blanket rate of nitrogen, ignoring the vari ability, will have areas of excessi ve growth. This unnecessary growth raises production cost... |
13. Crop Sensor-Based N Rates Out-Performed Producer-Chosen N RatesOptimal N fertilizer rate for corn (Zea mays L.) and other crops can vary substantially within and among fields. Current N management practices do not address this variability. Crop reflectance sensors offer the potential to diagnose crop N need and control N application rates at a fine spatial scale. Our objective was to evaluate the performance of sensor-based variable-rate N applications to corn, relative to constant N rates chosen by the producer. Fifty-five replicated on- farm demonstrations... |
14. Corn Nitrogen Evaluation in South DakotaCurrent Nitrogen (N) recommendations for corn in South Dakota use an N rate calculator approach (yield goal x 1.2 ⤓ soil test Nitrate-N (0-2 ft) ⤓ legume credits ⤓ other credits such as manure application or N in starter fertilizers + 30 lbs N/a for no-till). The N coefficient has been modified in the past from 1.45 in 1975, to 1.3 in 1982 and currently 1.2 determined 1991. The N coefficient is in dire need of re-evaluation because... A. Bly, S. Berg, P. Sexton, R. Gelderman |
15. In-season N for Corn Reduced Nitrous Oxide Emissions and Drainage Water Nitrate ConcentrationFarmers want to get the N fertilizer they apply into their crop, not lose it to air and water. This can be difficult to accomplish during wet years when N loss processes are going strong. Applying N in-season can be difficult to accomplish during wet years, but reduces the odds that N will be lost before the crop has a chance to take it up. We compared 2 N management strategies (140 lb N/acre applied pre-plant and variable-rate N applied sidedress based on canopy sensor measurements) and 3 drainage... |
16. Minnesota Long-Term Phosphorus Management Trials: Phase I, The Build PeriodPhosphorus (P) fertilizer recommendations are usually made using one of two philosophies, Build and Maintain or Sufficiency. In recent years, the Sufficiency approach has been questioned because of concerns of reducing soil test levels and yield sustainability and whether it has the same yield potential as the Build and Maintain approach. Trials were initiated in 2010 at six locations across Minnesota to develop various soil test P Interpretation Classes in replicated experiments. The initial phase... |
17. Nitrogen Timing, Loss, and Replacement... |
18. Predicting N Fertilizer Rates for CornSixteen N rate experiments were carried out in farmer fields in 1995 and 1996. The objective was to measure optimum N fertilizer rates and see whether they could be reliably predicted ahead of time. Yield response to N was measured in each experiment along with soil N measurements (planting and sidedress), and tissue N and chlorophyll meter reading at sidedress time. A very wide range of economically optimum N fertilizer rates was found, fairly evenly spread from 0 to 200 Ib N/acre, with an average... |
19. Re-Evaluating Rate, Time, and Placement of Urea and Other Nitrogen Sources in MinnesotaUrea is increasingly an important nitrogen (N) source in Minnesota. Approximately 43% of our farmers use urea as their major N source. In the southwestern, south-central and west-central areas approximately 45% of the N is applied in the fall, 50% is applied in the spring, and 5% is applied at sidedress. While most of those that use urea as the major N source apply it in the spring, approximately 4% do the major application with urea in the fall and there are others that apply some of their N... F. Fernandez, K. Fabrizzi, J. Vetsch, D. Kaiser |
20. 4R Nutrient Management for Corn Production on Upper Midwest SoilsCorn (Zea mays L.) demand for nitrogen (N) is often met using inorganic fertilizer on Upper Midwest soils. While applying the right rate of fertilizer N normally has the greatest impact on yield and N use efficiency (NUE), selection of the right fertilizer source, placement, and application timing can fine-tune rate recommendations, improve NUE by matching soil N availability to corn demand, and minimize loss to the environment. Given the diversity of corn production environments, the... J. Spackman, F. Fernandez, K. Fabrizzi |
21. Cover Crops Influence Soil Health and Nutrient Cycling in a Multi-Location Study in South DakotaSoil without living roots potentially loses mobile nutrients and retains excess water. Unprotected soil degradation and erosion enable the loss of carbon and nutrient rich top soil. Cover crops provide armor for the soil protecting from carbon and nutrient loss. Cover crop blends may influence soil health parameters and nutrient cycling. This multi-locational study depicts the influence of cover crop species blends with varying grass and broadleaf concentrations on established soil-health indicators... D. Sanyal, J. Wolthuizen, D. Karki, J. Clark, A. Bly |
22. Do cover crops improve soil health and enhance nutrient availability to cash crops?Bare soils are prone to erosion and lose soluble nutrients. Cover crops provide protection to the soil against erosion and nutrient loss. We hypothesized that the cover crops should uptake available nutrients from the soils in the fall when there is no cash crop, assimilate the nutrients in their tissues, and in the following spring, should release the nutrients back to the soil during the next cash crop growing season. In our study, we are quantifying the nutrients taken up by the cover crops... D. Sanyal, A. Rahhal, H. Bielenberg, J. Wolthuizen, J. Clark, A. Bly |
23. No-till and Cover Crops Influence Soil Health and Nitrogen Rate and Timing Recommendations: Early ResultsThe idea of improving soil health has become increasingly more talked about by researchers, agronomists, and farmers in the past five years. Management practices such as no- or reduced-tillage and planting cover crops are recommended to improve soil health because of their potential to improve organic matter and soil structure leading to a greater capacity to hold water and nutrients needed for plant growth. Research in South Dakota has been occurring these past two years to determine the influence... J.D. Clark, A. Bly, D. Karki, D. Sanyal, J. Wolthuizen, P. Kovacs |
24. Nitrogen Source and Timing Effects on CornThe 4R’s of nutrient management call for the right source, applied at right time, at the right rate at the right placement. Producers in South Dakota ask when the correct time to apply nitrogen fertilizers. Mean annual precipitation in the major South Dakota corn growing areas ranges from 16 to 26 inches. This is a relatively dry climate compared to other major corn growing regions and the effect of nitrogen timing might not be as important. Therefore, a research question that challenges... A. Bly, S. Berg, D. Karki |
25. Performance of Grain Oats at Different Nitrogen Regimes when Grown with and without Plant Growth Regulator (PGR)Among small grains grown in the South Dakota (SD), oat is considered the most susceptible to lodging which can result to significant yield loss due to harvest difficulty. Although current South Dakota State University (updated 2005) recommends 1.3 pounds nitrate N per bushel of oats (minus soil test N and legume credit), producers have been using lesser than the SD recommended rate to avoid lodging. This study was initiated in 2016- i) to evaluate the response of oat grain yield at various nitrogen... D. Karki, A. Bly |
26. Corn, Rye, and NitrogenThe U.S. still has an erosion problem. Half of the topsoil is gone over much of the Midwestern U.S., and erosion continues at an unacceptable rate. Protecting soil after soybean is grown is the weakest link in the chain because soybean leaves so little residue that even with no tillage the soil is vulnerable. Cover crops offer great promise to solve this problem. Rye is cheap, hardy, grows well in cool fall weather, and is easy to kill, but evidence continues to mount that rye causes yield loss... P. Scharf |
27. Active-Optical Reflectance Sensing Evaluated for Red and Red-Edge Waveband SensitivityUncertainty exists with corn (Zea mays L.) N management due to year-to-year variation in crop N need, soil N supply, and N loss from leaching, volatilization, and denitrification. Active-optical reflectance sensing (AORS) has proven effective in some fields for generating N fertilizer recommendations that improve N use efficiency. However, various sensors utilize different wavebands of light to calculate N fertilizer recommendations making it difficult to know which waveband is most sensitive... G. Bean, N. Kitchen, J. Camberato, R. Ferguson, F. Fernandez, D. Franzen, C. Laboski, E. Nafziger, J. Sawyer, P. Scharf, J. Schepers, J. Shanahan |
28. Tillage, Crop Rotation, and Cover Crop Impact on Corn Nitrogen Requirements in Southeastern South DakotaNitrogen is the lifeline of corn production. There is uncertainty whether nitrogen (N) requirements are the same for corn raised under long term no-till versus conventional till production systems. The objective of this study was to evaluate N fertilizer requirements for long term no-till soils in southeastern South Dakota, while considering effects from cover crops and crop rotation. This was a two year study at the SDSU Southeast Research Farm near Beresford, SD on long term no-till plots established... S. Berg, P. Sexton, R. Gelderman, A. Bly, C. Derdall |
29. Corn Nitrogen Calibration in South DakotaSouth Dakota (SD) corn nitrogen (N) rate recommendations were last established in 1991 and based on the coefficient of 1.2 lbs N/bu of the yield goal. The South Dakota corn N rate calculator subtracts the pre-plant soil test NO3-N (0-2ft) and legume credits and adds 30 lbs N/a for recently established no-till. Much improved corn genetics, shifting farming practices, and climate changes warrant re-calibration of corn N rate recommendations. During 2013-2105, N rate studies were conducted at 20... A. Bly, S. Berg |
30. Phosphorus Distribution After Long-Term P Fertilizer Placement Under Strip-TillageLong-term phosphorus fertilizer placement under strip-tillage tillage can affect the vertical and horizontal distribution of soil test P (STP). The objective of this study was to evaluate the effect of P fertilizer placement on STP distribution under strip-till. A study was established in Scandia, Kansas in 2006 under a corn- soybean rotation. Treatments included a (1) control (No P); and P applied at 80 lb P2O5 ac-1 as (2) broadcast, (3) deep band, (4) broadcast with starter 2x2, and... C. Edwards, D. Ruiz diaz |
31. Effects of Applied Soil Micronutrients on Corn and Soybean Yields in Eastern South Dakota EnvironmentsMicronutrients although taken up by plants in small quantities, their deficiencies can have significant detrimental effects on grain yield. As growers aim for maximum corn and soybean yields, availability of micronutrients in agricultural market both as individual source or combined with other secondary nutrients have also increased. However, effects of micronutrients on corn and soybean grain yields are not well documented for South Dakota (SD) soils, and growers seem to be concerned if application... D. Karki, A. Bly, S. Berg |
32. South Dakota Producers Use of Soil Testing to Make Soil Fertility DecisionsSoil fertility guidelines in South Dakota are primarily based on soil testing results. There are several possible soil sampling procedures regarding timing, frequency, and type of soil sampling that can be followed by producers. Survey information collected from South Dakota producers can inform us what soil sampling procedures they are commonly using. We distributed a survey to 3,000 South Dakota producers based on crop reporting district, crops grown, and farm size. We reminded producers three... |
33. Cover crops nutrients uptake did not cause yield loss in cornBare soils are susceptible to erosion and nutrient loss. Cover crops and residues provide physical protection against erosion and nutrient loss, and improve nutrient cycling as well as biodiversity. We hypothesized that cover crops store available nutrients from the soil in the fall and release them the next spring for the next cash crop, minimizing potential nutrients loss with no adverse effect on cash crop yield. A four site-year study throughout South Dakota was conducted to compare... |
34. Can Cover Crops Help to Improve Soil Health While Having a Positive Effect on Corn Grain Yield?Cover crops have recently gained attention in the U.S. Mid-west because of their potential to increase soil organic matter and improve overall soil health. There is some concern however, that cover crops may negatively impact corn grain yield. This study was conducted to determine the effects that different cover crop mixtures have on soil health measurements and corn grain yield at increasing nitrogen rates. Cover crops were planted in the fall as a dominantly grass mixture, dominantly... |
35. 35 years of nitrogen researchThis presentation will hit the high points of 35 years of nitrogen research in corn, wheat, and cotton, focusing mostly on timing and rate. With all three crops, applying no N early did not hurt yield—thus no benefit to splitting N. Exception is wheat with low tiller density at greenup, which needs early N Later N applications often gave higher yield than earlier applications for corn and wheat. When... P. Scharf |
36. Corn Nitrogen Fertilizer Management Practices in Eastern South DakotaThe adoption factors of N best management practices (BMPs) that can lessen N loss needs to be understood to help increase adoption rates. Understanding the local, small-scale factors (geographic location, tillage type, and farm size) that influence the use of N BMPs will help nutrient management professionals provide the research and information needed to increase the use of N BMPs. South Dakota (SD) survey data from 465 producers was used to examine the above local, small-scale factors that influence... J.D. Clark, A. Bly, P. Kovacs, J. Ulrich-schad |
37. What Soil Measurements Relate Best to Corn Economic Optimal N Rate?The use of nitrogen (N) fertilizer is critical for optimizing corn (Zea mays L.) yield. However, improper applications can reduce fertilizer efficiency, create environmental issues, and reduce grower profits. The N cycle is largely affected by biological processes. Therefore, the inclusion of biological soil tests alone or in combination with other soil chemical and physical properties may enable us to improve the accuracy of corn N fertilizer needs to optimize yield. From 2018-2021,... J. Clark, P. Kovacs, A. Bly, A. Ahlersmeyer |
38. Comparing Yield Goal and Maximum Return to N Based Methods in Predicting Corn Economic Optimal Nitrogen RatesThere are two main N rate recommendation systems used in the U.S.–Yield goal and maximum return to N (MRTN). The current yield-goal based system for calculating corn N rate recommendations in SD has not been evaluated for accuracy since 2013. Therefore, the objective of this project was to 1) evaluate the accuracy of the current yield goal-based equation and 2) create a database of N response trials and evaluate the accuracy of using the MRTN approach for predicting N rate requirements.... J. Clark, P. Kovacs, A. Bly, C. Graham |