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1. An Overview of the Thompson/Baker Farming Systems StudyThere is a general lack of quantitative information, collected from field-scale studies, that can be used to assess long-term effects of alternative farming systems. The objective of an on-going study in central Iowa is to quantitatively evaluate several chemical, physical, biological, and economic parameters on the Richard Thompson (alternative) and Eugene Baker (conventional) farms. This project was initiated in 1989 on adjacent 32-ha tracts of land, that have Clarion loam, Nicollet loam, Canisteo... |
2. Assessing the Source of Groundwater Nitrates- And You Thought Good Wine Took TimeControversy continues with elevated groundwater nitrate concentrations being attributed to N fertilizer use. Current research defining best management practices in farming system K management seldom addresses the influence these practices have on groundwater. Why? The results of this Missouri research show that the influence of management on groundwater nitrates may last for decades. The study provides support for time requirements when assessing farming system impact on groundwater quality. ... |
3. Real-Time Soil Nitrate SensingIon-selective field effect transistors (ISFETs) have inherent features such as small dimensions. low output impedance. high signal-to-noise ratio, low sample volumes and the potential for mass production, which are required for a real time soil sensor. However, ISFETs have the disadvantage of long-term drift, which is diminished by the use of a Flow Injection Analysis (FIA) system. In fact, FIA and ISFETs are complementary since the small sample volumes and rapid response of ISFETs allow the miniaturization... |
4. Spatial Analysis of Yield-Limiting FactorsThe spatial relationship between crop yields and soil and site parameters was modeled using several methods. Yield maps estimated by projection pursuit regression and neural network analysis agreed well with measured yields. These methods also allowed generation of response curves for estimated yield as a function of each of the input parameters. These response curves were useful for investigating the relationship between yields and individual soil and site parameters. ... |
5. Spatial Prediction of Crop Productivity Using Electromagnetic InductionAn inexpensive and accurate method for measuring water-related, within-field soil productivity variation would greatly enhance site-specific crop management strategies. This paper reports on investigations to use an electromagnetic induction (EM) sensor to map claypan (Udollic Ochraqualfs) and alluvial (Typic and Aquic Udipsarnnlents, and Aeric Fluvaquents) soil conductivity variations and to evaluate the relationship of EM measurements to grain crop production. Grain yield measurement was obtained... |
6. An Evaluation of Methods for Determining Site-Specific Management ZonesNumerous procedures have been examined for identifymg management areas within fields. Traditional soil surveys give a general understanding of the effects soil mapping units have on crop productivity. In the USA. county soil surveys report the average grain yield of major crops by soil series. Slope position and landform are topographic features thal also have been used to explain water and crop productivity relationships (Mulla et al., 1992; Sudduth et al., 1997). Generally, footslope positions... |
7. Deep Tillage in a Corn-Soybean Production SystemMany crop producers in the Midwestern United States are currently using deep tillage, accomplished with equipment designed to run at depths of 30 to 40 cm, even though the effects of this practice are not well characterized. We assessed the effects of deep tillage, no tillage, and chisel plowing in the fall, with and without secondary tillage in the spring, on penetrometer resistance, plant stand, and yield of corn and soybean grown in rotation. In the spring, averaged across two years and six locations... |
8. 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.... |
9. Soil Phosphorus Spatial Distribution in Pastures Receiving Poultry Litter ApplicationsEnvironmentally-based P management strategies could be improved by debeating management zones incorporating the effects of landscape position on soil morphology, hydrology, and soil P distribution. Three farm pasture sites in SW Missouri receiving long-term poultry litter applications were sampled by landscape position (summit, shoulder, upper backslope. middle backslope, lower backslope, footslope, drain) for soil P (Bray 1 P, CaCl2 P, total P) at two depths (0-5 cm, 5- 15 cm). Low landscape positions... |
10. Assessing Spatial and Temporal Nutrient Dynamics with a Proposed Nutrient Buffering IndexContinued adoption of precision agriculture will lead to the accumulation of spatially and temporally dense soil fertility and yield data. Current soil fertility recommendation strategies use regional estimates of soil buffering properties to adjust application rates. A site specific nutrient buffering index (BI) is presented that uses accumulated yield maps and soil test data to locally estimate soil buffering properties relative to fertilizer additions and crop removal. BI is a quantity-intensity... |
11. Do Different Corn Hybrids Have Different N NeedsThere continue to be claims that N management can be tailored to better fit specific hybrids. but there has been no recent confirmation that hybrids differ consistently in their N response. We tested the response of ten hybrids to N rates over two years (2003 and 2004) in a productive. silt loam soil near Urbana, Illinois. The previous crop was corn. Main plots consisted of five N rates (0, 60. 120, 180, and 240 Ib Nlacre), and ten Burrus corn hybrids (438Bt, 330, 442, 576, 583Bt, 625. 645, 727,... |
12. Determining Economic Optimum Nitrogen Rates with the Illinois Soil Nitrogen Test and Soil Organic Nitrogen FractionsDevelopment of a diagnostic test to estimate soil N supplying capability is a continuing research need. The Illinois soil nitrogen test (ISNT) has been proposed as a method for adjusting corn (Zea Mays L.) N recommendations for to account for soil organic N contributions. We evaluated the ISNT as a tool for predicting corn N response in Wisconsin by comparing ISNT values and corn N response data from-81 experiments conducted between 1984 and 2004 with a range of crop rotations, management histories,... |
13. An Environmental Assessment of Sensor-Based Variable-Rate Nitrogen Management in CornIn order to address the problem of nitrate contamination of surface and ground waters, various methods have been used to try to account for spatial variability of N within agricultural fields. One approach to account for this variability and thereby reduce nitrate pollution is in-season site- specific N application according to economic optimal N rate (EONR). Recently, active crop canopy sensors have been tested for mid-season, on-the-go N fertilizer application in corn. This 2004 and 2005 study... |
14. Corn Hybrid Responses to Nitrogen Fertilizer RatesEfficient use of nitrogen (N) fertilizer is becoming increasingly important in modem corn (Zea mays L.) production due to rising nitrogen fertilizer prices and growing concerns about NO3- contamination of ground and surface waters. Interest has arisen in whether nitrogen management can be improved by choosing hybrids that respond better to nitrogen. In order to see if hybrids respond differently to varying rates of N fertilizer, we grew nine hybrids at five N rates for three years at Urbana: Illinois.... |
15. Response Surface Models Of Subsoil K Concentration For Loess Over Till Soils In MissouriCrop uptake of potassium (K) has demonstrated sensitivity to subsoil variation in K content. This fact has not been sufficiently considered in K management strategies in part due to logistical difficulties in sampling spatially variable subsoil K. We propose a simplified soil factorial model, a response surface, to enable site-specific accounting of whole root zone K supply for loess over till soils. We compared the performance of two peak functions and a non-parametric local regression procedure... |
16. Can Soil Information Better Inform Canopy Sensor Algorithms for Corn?Corn production is often limited by the loss of nitrogen (N) due to leaching, volatilization and denitrification. The use of canopy sensors for making in-season N fertilizer applications has been proven effective in matching plant N requirements with periods of rapid N uptake (V7-V11), reducing the amount of N lost to these processes. However, N recommendation algorithms used in conjunction with canopy sensor measurements have not proven accurate in many fields of the U.S. Cornbelt, resulting in... , N.R. Kitchen, J. Camberato, P.R. Carter, R.B. Ferguson, F.G. Fernandez, D.W. Franzen, F.G. Fernandez, E.D. Nafziger, C.J. Ransom, , J. Shanahan, G.M. Bean |
17. What Do You Do When Your N-Rich Reference Fails?In recent years, canopy reflectance sensing has b een investigated for in-season assessment of crop N health and fertilization. Typically, the procedure followed co mpares the crop in an area known to be non-limiting in N (the N-rich area) to the crop in a target area, which may be inadequately fertilized. Measurements from the two areas are used to calculate a relative reflectance to represent the potential need for add itional N fertilizer. Establishing N rich areas or strips is often inconvenient... |
18. What are the Benefits of Canopy Sensing for Variable-Rate Nitrogen Corn Fertilization?Canopy reflectance sensing for assessing crop N health has been proposed as a technology on which to base top-dress variable-rate N applicat ion. The objective of this research in Missouri was to evaluate the economic a nd environmental benefit of activ e-light crop-canopy reflectance sensors for corn N rate decisions. A total of 16 field-scale experiments were conducted over four seasons (2004-2007) in three major soil areas. Mu ltiple blocks of randomized N rate response plots traversed the length... |
19. Chloride Fertilization on Wheat, Corn, and Grain SorghumResearch in the Pacific Northwest and the Northern Great Plains has documented positive cereal grain responses to chloride (CI) fertilization. Field research was conducted in Kansas evaluating CI fertilization on winter wheat, corn, and grain sorghum. Chloride fertilization consistently and significantly increased plant CI concentrations in all crops. Chloride fertilization increased grain yields or one or more winter wheat cultivars at 3 of 4 sites. The most dramatic yield increases were at the... |
20. Topsoil Thickness Influence on Phosphorus and Potassium Availability and Crop ResponseSoil testing to estimate nutrient availability and fertilizer needs is a widespread management practice for cropping systems in the United States. as well as in other countries. The purpose of soil testing is to simulate the ability of the plant roots lo uptake these various nutrients critical for normal growth. Crops generally uptake a s~nall amount of phosphorus (P) compared to potassium (K). The portion of soil P that is readily available for plant growth maybe limiting due to the small quantities... |
21. Soil and Soybean Responses to Planting into Terminated Prairie StripsPrairie strips are a new conservation practice that are currently implemented in 14 Midwest US states. Prairie strips have been shown to reduce runoff, increase soil health, retain sediment and nutrients, increase biodiversity and have no effect on surrounding crop yield. Due to the comprehensive improvements to soil health under prairie strips, researchers and growers are interested in rotating them on 10-15 year cycles. We have little-to-no knowledge on the effects of planting crops in... C. Dutter, M. St cyr, M. Mcdaniel, C. Carley, A. Singh |
22. Effects of Silicon Supplementation on Growth and Silicon Accumulation in Tall Fescue (Festuca arundinacea) and Bentgrass (Agrostis stolonifera)This study assessed the effect of silicon (Si) supplementation on biomass production and Si accumulation of tall fescue (Festuca arundinacea) and bentgrass (Agrostis stolonifera). Plants were grown in buffered Hoagland’s media (pH 6) with four Na2SiO4 treatments (0, 0.5, 1, 2, 4 mM). The two species responded differently to Si supplementation in terms of biomass. For bentgrass, biomass was enhanced by Si supplementation, but only significantly (p... S. Qian, J. Unrine, H. Poffenbarger |
23. Manure Total Nitrogen Variability Due to Analytical Method and Total Solids ContentKnowing the nutrient analysis of a fertilizer source is essential to ensure adequate nutrients for crop growth, while not causing potential environmental impacts by overapplying nutrients. Using manure as a nutrient source can complicate matters as the nutrient content can be variable and the manure can come in a range of liquid to solid consistencies. There are multiple laboratory methods to determine different nutrient parameters and for manure total nitrogen levels the most common methods... N.L. Bohl bormann, M.L. Wilson, E.L. Cortus, J. Floren, R.O. Miller, L. Gunderson |
24. Updating Phosphorus Recommendations for IllinoisIllinois soil phosphorus (P) recommendations are outdated and make use of concepts such as soil P supply power are outdated. This 2022 Illinois State Report provides a summary and outlook on key considerations for P recommendations that may be instructive to other North Central states. ... A. Margenot |
25. County-Level Phosphorus Balances for 2017 in IllinoisCropland phosphorus (P) balances (manure and fertilizer P minus crop P removal) are great sustainability tools to assess long-term managements at farm, county, and state levels. Our objectives were to estimate county, regional, and state-level cropland P balances for Illinois in 2017. Based on the census data in 2017, Illinois county P balance ranged from -14.38 to 36 lb/acre/yr. Overall, Illinois had a negative P balance at about -3 lb/acre/yr. About 71% of counties, had a negative P balance,... X. Liu, S. Xu, A. Margenot, A. Sadeghpour, O. Zandvakili, M. Guzel |
26. Phosphorus Management in the North Central Region: A Brief History, Current Unknowns and Next StepsThe history of phosphorus (P) reflects the history of agriculture in the North Central region. The yield-limiting importance of P, secondary to nitrogen, was recognized as at the turn of the 19th century. An overview of key developments and unfinished business following the picking of these low hanging fruit in the 20th century that face researchers, agronomists, and producers will be discussed. These include assessing P mobility, P sources from fertilizer versus soil, the concept of... A. Margenot |