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  • 1
    Online Resource
    Online Resource
    Spatial Variability of the Illinois Soil Nitrogen Test: Implications for Soil Sampling
    Wiley ; 2005
    In:  Agronomy Journal Vol. 97, No. 6 ( 2005-11), p. 1485-1492
    Details
    In: Agronomy Journal, Wiley, Vol. 97, No. 6 ( 2005-11), p. 1485-1492
    Abstract: The Illinois Soil Nitrogen Test (ISNT) is a recently developed test that has shown promise for corn ( Zea mays L.) N fertilization. However, among‐field and within‐field spatial variability of this test is unknown and sampling recommendations have not been defined. The objectives of this study were to estimate the spatial variability and structure of the ISNT to provide sampling recommendations and to determine the short‐term effect of N fertilizer on this test. Soil samples were collected on 14 production fields and analyzed for the ISNT. Data was analyzed with traditional statistics and with geostatistical techniques. In the short term, N fertilization did not have a significant effect on the ISNT ( p 〉 0.3). The ISNT was normally distributed in 12 fields and showed a relatively low coefficient of variation (18% on average). Field mean ISNT ranged from 98 to 255 mg kg −1 and tended to be higher in Mollisols than in Alfisols. On average across fields, at least 10 samples are required to determine the mean ISNT for a given field with a precision of 24 mg kg −1 . The geostatistical analysis revealed that the ISNT has strong spatial structure, as indicated by the bounded variograms, the relatively low nugget/sill ratio ( 〈 30% in 10 fields) and the mean range of 150 m. The spatial variability indicates that the ISNT can be mapped with a relatively sparse sampling grid and with a low number of samples, critical characteristics when assessing the economic implication for variable and uniform rate N fertilization.
    Type of Medium: Online Resource
    ISSN: 0002-1962 , 1435-0645
    URL: Article
    DOI: 10.2134/agronj2004.0323
    Language: English
    Publisher: Wiley
    Publication Date: 2005
    detail.hit.zdb_id: 1471598-3
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  • 2
    Online Resource
    Online Resource
    Sequential Pyroxasulfone Applications with Fluxofenim Reduce Sorghum Injury and Increase Weed Control
    Wiley ; 2018
    In:  Agronomy Journal Vol. 110, No. 5 ( 2018-09), p. 1915-1924
    Details
    In: Agronomy Journal, Wiley, Vol. 110, No. 5 ( 2018-09), p. 1915-1924
    Abstract: Selective control of weedy grasses is difficult in grain sorghum due to the presence of wild relatives. Pyroxasulfone provided greater weed control than S ‐metolachlor but caused more crop injury. Sorghum protection from pyroxasulfone provided by fluxofenim was dependent on the environment. Split applications of pyroxasulfone equal to the highest single rate provided similar weed control. Controlling weeds selectively is a challenge when producing grain sorghum [ Sorghum bicolor (L.) Moench]. Pyroxasulfone, a preemergence (PRE) herbicide, has demonstrated excellent grass and broadleaf control in maize ( Zea mays L.) and soybean [ Glycine max (L.) Merr]. However, pyroxasulfone is not labeled for grain sorghum because crop injury is a major limitation. Our first objective was to evaluate five herbicide safeners in the greenhouse to determine their ability to protect sorghum from pyroxasulfone. Growth data indicated seed‐applied fluxofenim provided the highest level of protection to emerging seedlings. A second objective was to evaluate fluxofenim for protecting sorghum from single and sequential pyroxasulfone applications in the field. A split‐plot in a randomized complete block design evaluated six pyroxasulfone (whole plot) and two fluxofenim treatments (subplot) in 2015 and 2016. A single PRE treatment of S ‐metolachlor, an untreated‐weedy control, and weed‐free control were compared with pyroxasulfone to assess weed control, crop injury and stand count, and grain yield. Pyroxasulfone provided greater weed control than S ‐metolachlor. However, as pyroxasulfone rates increased both weed control and crop injury increased, regardless of safener. In contrast, sequential pyroxasulfone applications (90/120 or 120/90 g ai ha −1 ) did not elicit as much crop injury or stand reductions as a single PRE application at the same total rate (210 g ai ha −1 ) and maintained weed control, which resulted in higher yields. Despite increased crop tolerance and yield with sequential relative to single pyroxasulfone applications, these findings indicate a more effective herbicide safener for pyroxasulfone in grain sorghum is required.
    Type of Medium: Online Resource
    ISSN: 0002-1962 , 1435-0645
    URL: Article
    DOI: 10.2134/agronj2018.01.0014
    Language: English
    Publisher: Wiley
    Publication Date: 2018
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  • 3
    Online Resource
    Online Resource
    Design of on‐farm precision experiments to estimate site‐specific crop responses
    Wiley ; 2021
    In:  Agronomy Journal Vol. 113, No. 2 ( 2021-03), p. 1366-1380
    Details
    In: Agronomy Journal, Wiley, Vol. 113, No. 2 ( 2021-03), p. 1366-1380
    Abstract: Application of geographically weighted regression estimate site‐specific responses. On‐farm Precision Experiment designs can be compared with simulation studies. Systematic treatment assignments are more favorable than random treatment assignment. Medium to smaller plots size increase trial performance compared with large plot size. Prior knowledge of spatial structure improves the performance of the experimental design.
    Type of Medium: Online Resource
    ISSN: 0002-1962 , 1435-0645
    URL: Issue
    URL: Article
    DOI: 10.1002/agj2.v113.2
    DOI: 10.1002/agj2.20572
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 1471598-3
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  • 4
    Online Resource
    Online Resource
    Forage and Energy Sorghum Responses to Nitrogen Fertilization in Central and Southern Illinois
    Wiley ; 2012
    In:  Agronomy Journal Vol. 104, No. 4 ( 2012-07), p. 1032-1040
    Details
    In: Agronomy Journal, Wiley, Vol. 104, No. 4 ( 2012-07), p. 1032-1040
    Abstract: Recently introduced forage and energy sorghums ( Sorghum bicolor L. Moench) have potential as cellulosic biofuel feedstocks in the Midwest. The objectives of this study were to evaluate the effect of N fertilization on biomass yield and to determine the relationship between biomass yield and plant height, leaf development, and leaf area index (LAI) on two forage and two energy sorghum hybrids in four central and southern Illinois (IL) environments. Sorghum hybrids were evaluated in Urbana in 2009 under four N rates and in Urbana, Dixon Springs, and Perry in 2010 under five N rates. Forage sorghums harvested twice (summer and fall) annually produced less biomass than the energy sorghums harvested once in the fall both in 2009 and 2010. Averaged across all environments in 2010, maximum biomass yields were 30.1 Mg DM ha −1 for the energy sorghums and 19.2 Mg DM ha −1 for the forage sorghums at the 224 kg N ha −1 application rate. Biomass yields, LAI, and plant‐height responses to N applications were observed up to 150 kg N ha −1 in 2009 and up to 224 kg N ha −1 in 2010. Leaf development was linearly related to growing‐degree days and the average number of fully expanded leaves on the energy sorghum reached 28 in Perry‐10 with the longest growing season. Photoperiod‐sensitive energy and forage sorghums have potential in central and southern IL as bioenergy feedstocks because these grasses continue vegetative growth until late September, and therefore, produce large amounts of biomass.
    Type of Medium: Online Resource
    ISSN: 0002-1962 , 1435-0645
    URL: Article
    DOI: 10.2134/agronj2011.0408
    Language: English
    Publisher: Wiley
    Publication Date: 2012
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  • 5
    Online Resource
    Online Resource
    Modeling Rye and Hairy Vetch Residue Decomposition as a Function of Degree‐Days and Decomposition‐Days
    Wiley ; 2003
    In:  Agronomy Journal Vol. 95, No. 4 ( 2003-07), p. 900-907
    Details
    In: Agronomy Journal, Wiley, Vol. 95, No. 4 ( 2003-07), p. 900-907
    Abstract: Temperature and precipitation affect crop residue decomposition rate. Degree‐days (DGD) and decomposition‐days (DCD) are used to account for the effect of temperature and precipitation, but little information is available about winter cover crop (WCC) residue decomposition as a function of DCD or DGD. This study was conducted to model the decomposition of rye ( Secale cereale L.) and hairy vetch ( Vicia villosa Roth) residues and the subsequent release of C and N under field conditions using DGD and DCD. Rye and hairy vetch WCCs were planted during the fall either in monoculture or biculture and killed before corn ( Zea mays L.) planting. Grab samples of WCC residues were taken six times during the corn growing season. A single‐pool exponential decay function was used to model biomass decomposition and C and N release. Most decay models showed coefficients of determination ( r 2 ) larger than 0.7. Both DGD and DCD were equally effective as time scales. Winter cover crops differed in their initial biomass and C content and in their biomass decomposition and C and N release rates. At corn V6 stage, 33 and 75% of the initial N content had been released from rye and hairy vetch residues, respectively. At the end of the growing season, hairy vetch had almost completely decomposed while 5% of the initial biomass of rye remained undecomposed. Decomposition dynamics of hairy vetch residue indicate that it is a potential source of N while decomposition dynamics of rye indicate that it is more useful in soil conservation.
    Type of Medium: Online Resource
    ISSN: 0002-1962 , 1435-0645
    URL: Article
    DOI: 10.2134/agronj2003.9000
    Language: English
    Publisher: Wiley
    Publication Date: 2003
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  • 6
    Online Resource
    Online Resource
    Experimental Designs and Estimation Methods for On‐Farm Research: A Simulation Study of Corn Yields at Field Scale
    Wiley ; 2019
    In:  Agronomy Journal Vol. 111, No. 6 ( 2019-11), p. 2724-2735
    Details
    In: Agronomy Journal, Wiley, Vol. 111, No. 6 ( 2019-11), p. 2724-2735
    Abstract: On‐farm experimentation using Precision Agriculture technology enables farmers to make decisions based on data from their fields. Results from on‐farm experiments depend on the experimental design and statistical analyses performed. Detailed information about the accuracy of the treatment effect estimates, and Type I error rates of hypothesis testing under different spatial structure scenarios attained by alternative experimental designs and analysis is required to improve on‐farm research experiments. Three thousand yield data sets were drawn from 15 random fields simulated by unconditional Gaussian geostatistical simulation technique and were modeled by applying 10 experimental designs and three estimation methods with experimental units ranging from 138 to 9969 m 2 . No effect of spatial structure, experimental design, and estimation methods was observed on overall mean yield and treatment bias. Unaddressed changes of nugget/sill ratio and range of variogram had a significant effect on estimator efficiency and accuracy with Type I error rates above the nominal rate, which increased with higher spatial autocorrelation. Spatial methods were robust to changes in spatial structure regardless of the design. Randomization of treatment increased the uncertainty of model estimators. In general, the accuracy of treatment effect estimates increased with the number of replications of smaller size. The opposite trend was observed between those estimates and the size of the plots. Analyses showed that the best designs for testing the overall treatment effect in two‐treatment experiments would be split‐planter, strip‐plots, and chessboard because of their size and number of experimental units. Core Ideas Spatial autocorrelation increases grand mean estimator variance in any design or method. Spatial autocorrelation reduces treatment effect estimator efficiency if not modeled. Spatial autocorrelation increases Type I error if not modeled. Designs with small experimental units (strip plots or chessboard) performed better.
    Type of Medium: Online Resource
    ISSN: 0002-1962 , 1435-0645
    URL: Article
    DOI: 10.2134/agronj2019.03.0142
    Language: English
    Publisher: Wiley
    Publication Date: 2019
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  • 7
    Online Resource
    Online Resource
    Soil Quality and Corn Yield under Crop–Livestock Integration in Illinois
    Wiley ; 2009
    In:  Agronomy Journal Vol. 101, No. 6 ( 2009-11), p. 1503-1510
    Details
    In: Agronomy Journal, Wiley, Vol. 101, No. 6 ( 2009-11), p. 1503-1510
    Abstract: Compared with traditional cropping systems, integrated crop–livestock systems have shown greater efficiency in improving soil quality and crop yield. The objective of this study was to determine how an integrated crop–livestock system affected soil properties and corn ( Zea mays L.) yield when compared with continuous corn (CC). The study was conducted from 2004–2008 on a large‐scale research farm located near Pana, IL, USA. We evaluated the following soil and crop variables: soil organic matter (SOM) fractions, total nitrogen (TN) and total organic carbon (TC), soil microbial biomass carbon (SMBC), water aggregate stability, soil penetration resistance (PR), and corn yield. Three treatments were used in this study: winter cover crops (WCCs) and cool‐season pastures (CSP), considered integrated system treatments and a nonintegrated CC monoculture. In the integrated system, CSP and WCC treatments combined, had significantly higher TN ( P = 0.0926) than CC. Water aggregate stability was also higher in the integrated system ( P = 0.0039). Greater percentages of TC and TN were represented by particulate organic matter (POM) POM‐N and POM‐C in the WCC treatment, followed by CSP, and CC. The PR for CSP (928 kPa) was not significantly different than WCC (921 kPa). However, both were significantly different than CC (655 kPa). Averaged across years, corn grain yield for WCC (11.5 Mg ha −1 ) was significantly higher than CC (10.8 Mg ha −1 ) ( P = 0.0780). These results confirm that WCC and CSP used within integrated crop–livestock systems should improve soil quality, SOM dynamics, and crop yield despite moderate soil compaction caused from cattle presence.
    Type of Medium: Online Resource
    ISSN: 0002-1962 , 1435-0645
    URL: Article
    DOI: 10.2134/agronj2009.0068
    Language: English
    Publisher: Wiley
    Publication Date: 2009
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  • 8
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    Online Resource
    Corrigendum to “Assessing the impacts of cover crops on maize and soybean yield in the U.S. Midwestern agroecosystems” [Field Crops Res. 273 (2021) 108264]
    Elsevier BV ; 2022
    In:  Field Crops Research Vol. 277 ( 2022-03), p. 108404-
    Details
    In: Field Crops Research, Elsevier BV, Vol. 277 ( 2022-03), p. 108404-
    Type of Medium: Online Resource
    ISSN: 0378-4290
    URL: Article
    DOI: 10.1016/j.fcr.2021.108404
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2022
    detail.hit.zdb_id: 2012484-3
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  • 9
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    Online Resource
    Detection of Occult Urinary Tract Infections in Dogs With Diabetes Mellitus
    American Animal Hospital Association ; 2002
    In:  Journal of the American Animal Hospital Association Vol. 38, No. 6 ( 2002-11-01), p. 541-544
    Details
    In: Journal of the American Animal Hospital Association, American Animal Hospital Association, Vol. 38, No. 6 ( 2002-11-01), p. 541-544
    Abstract: Dogs with diabetes mellitus may develop occult urinary tract infections. In this study, diabetic dogs with negative and positive bacterial urine cultures were compared. Records from 51 dogs with diabetes mellitus were reviewed at the University of Illinois. No difference was identified between the groups in urine specific gravity, pH, glucose, ketones, protein, red blood cells, white blood cells, or epithelial cells. Dogs with occult urinary tract infection did have an increased incidence of bacteriuria, but this was not a consistent finding. Therefore, the urine on all diabetic dogs should be cultured to accurately identify the presence or absence of bacterial urinary tract infections.
    Type of Medium: Online Resource
    ISSN: 0587-2871 , 1547-3317
    URL: Article
    DOI: 10.5326/0380541
    Language: English
    Publisher: American Animal Hospital Association
    Publication Date: 2002
    SSG: 22
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  • 10
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    Online Resource
    Reply to: Brazilian ethanol expansion subject to limitations
    Springer Science and Business Media LLC ; 2019
    In:  Nature Climate Change Vol. 9, No. 3 ( 2019-3), p. 211-212
    Details
    In: Nature Climate Change, Springer Science and Business Media LLC, Vol. 9, No. 3 ( 2019-3), p. 211-212
    Type of Medium: Online Resource
    ISSN: 1758-678X , 1758-6798
    URL: Article
    DOI: 10.1038/s41558-019-0423-y
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2019
    detail.hit.zdb_id: 2603450-5
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