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Full-Text Articles in Physical Sciences and Mathematics
Multi-Criteria Evaluation Model For Classifying Marginal Cropland In Nebraska Using Historical Crop Yield And Biophysical Characteristics, Andrew Laws
School of Natural Resources: Dissertations, Theses, and Student Research
Marginal cropland is suboptimal due to historically low and variable productivity and limiting biophysical characteristics. To support future agricultural management and policy decisions in Nebraska, U.S.A, it is important to understand where cropland is marginal for its two most economically important crops: corn (Zea mays) and soybean (Glycine max). As corn and soybean are frequently planted in a crop rotation, it is important to consider if there is a relationship with cropland marginality. Based on the current literature, there exists a need for a flexible yet robust methodology for identifying marginal land at different scales, which …
Modeling Gross Primary Production Of Midwest Maize And Soybean Croplands With Satellite And Gridded Weather Data, Gunnar Malek-Madani
Modeling Gross Primary Production Of Midwest Maize And Soybean Croplands With Satellite And Gridded Weather Data, Gunnar Malek-Madani
Department of Geography: Dissertations, Theses, and Student Research
The gross primary production (GPP) metric is useful in determining trends in the terrestrial carbon cycle. Models that determine GPP utilizing the light use efficiency (LUE) approach in conjunction with biophysical parameters that account for local weather conditions and crop specific factors are beneficial in that they combine the accuracy of the biophysical model with the versatility of the LUE model. One such model developed using in situ data was adapted to operate with remote sensing derived leaf area index (LAI) data and gridded weather datasets. The model, known as the Light Use Efficiency GPP Model (EGM), uses a four …
Feasibility Analysis Of Using Inverse Modeling For Estimating Field-Scale Evapotranspiration In Maize And Soybean Fields From Soil Water Content Monitoring Networks, Foad Foolad, Trenton E. Franz, Tiejun Wang, Justin Gibson, Ayse Kilic, Richard Allen, Andrew Suyker
Feasibility Analysis Of Using Inverse Modeling For Estimating Field-Scale Evapotranspiration In Maize And Soybean Fields From Soil Water Content Monitoring Networks, Foad Foolad, Trenton E. Franz, Tiejun Wang, Justin Gibson, Ayse Kilic, Richard Allen, Andrew Suyker
School of Natural Resources: Faculty Publications
No abstract provided.
Quantification And Mapping Of Surface Residue Cover For Maize And Soybean Fields In South Central Nebraska, Vivek Sharma, Suat Irmak, Ayse Kilic, Vasudha Sharma, John E. Gilley, George Meyer, Stevan Z. Knezevic, D. B. Marx
Quantification And Mapping Of Surface Residue Cover For Maize And Soybean Fields In South Central Nebraska, Vivek Sharma, Suat Irmak, Ayse Kilic, Vasudha Sharma, John E. Gilley, George Meyer, Stevan Z. Knezevic, D. B. Marx
School of Natural Resources: Faculty Publications
The area cultivated under conservation tillage practices such as no-till and minimal tillage has recently increased in Midwestern states, including Nebraska. This increase, consequently, resulted in changes in some of the impacts of cropping systems on soil, such as enhancing soil and water quality, improving soil structure and infiltration, increasing water use efficiency, and promoting carbon sequestration. However, there are no methods currently available to quantify the percent crop residue cover (CRC) and the area under conservation tillage for maize and soybean at large scales on a continuous basis. This research used Landsat-7 (ETM+) and Landsat-8 (OLI) satellite data to …
Informative Spectral Bands For Remote Green Lai Estimation In C3 And C4 Crops, Oz Kira, Anthony L. Nguy-Robertson, Timothy J. Arkebauer, Raphael Linker, Anatoly A. Gitelson
Informative Spectral Bands For Remote Green Lai Estimation In C3 And C4 Crops, Oz Kira, Anthony L. Nguy-Robertson, Timothy J. Arkebauer, Raphael Linker, Anatoly A. Gitelson
School of Natural Resources: Faculty Publications
Green leaf area index (LAI) provides insight into the productivity, physiological and phenological status of vegetation. Measurement of spectral reflectance offers a fast and nondestructive estimation of green LAI. A number of methods have been used for the estimation of green LAI; however, the specific spectral bands employed varied widely among the methods and data used. Our objectives were (i) to find informative spectral bands retained in three types of methods, neural network (NN), partial least squares (PLS) regression and vegetation indices (VI), for estimating green LAI in maize (a C4 species) and soybean (a C3 species); (ii) to assess …
Modeling Gross Primary Production Of Maize And Soybean Croplands Using Light Quality, Temperature, Water Stress, And Phenology, Anthony L. Nguy-Robertson, Andrew E. Suyker, Xiangming Xiao
Modeling Gross Primary Production Of Maize And Soybean Croplands Using Light Quality, Temperature, Water Stress, And Phenology, Anthony L. Nguy-Robertson, Andrew E. Suyker, Xiangming Xiao
School of Natural Resources: Faculty Publications
Vegetation productivity metrics, such as gross primary production (GPP) may be determined from the efficiency with which light is converted into photosynthates, or light use efficiency (ϵ). Therefore, accurate measurements and modeling of ϵ is important for estimating GPP in each ecosystem. Previous studies have quantified the impacts of biophysical parameters on light use efficiency based GPP models. Here we enhance previous models utilizing four scalars for light quality (i.e., cloudiness), temperature, water stress, and phenology for data collected from both maize and soybean crops at three Nebraska AmeriFlux sites between 2001 and 2012 (maize: 26 field-years; soybean: …
The Influence Of Different Cover Types On American Robin Nest Success In Organic Agroecosystems, John E. Quinn, Amy I. Oden, James R. Brandle
The Influence Of Different Cover Types On American Robin Nest Success In Organic Agroecosystems, John E. Quinn, Amy I. Oden, James R. Brandle
School of Natural Resources: Faculty Publications
There are many opportunities for biodiversity conservation in organic farm systems. Successful and sustainable conservation efforts in organic systems, however, need to measure appropriate outcomes. In particular, data are needed on the breeding success of associated wildlife species. We measured nesting success of the American Robin (Turdus migratorius) in woodlands embedded within eight organic farms in eastern Nebraska. We modeled daily nest survival rate to identify land use and land cover patterns that optimize conservation of birds in organic farm systems. The percentage of a crop in the fields adjacent to linear woodlands best predicted daily survival rate. …
Gross Primary Production And Ecosystem Respiration Of Irrigated And Rainfed Maize–Soybean Cropping Systems Over 8 Years, Andrew E. Suyker, Shashi B. Verma
Gross Primary Production And Ecosystem Respiration Of Irrigated And Rainfed Maize–Soybean Cropping Systems Over 8 Years, Andrew E. Suyker, Shashi B. Verma
School of Natural Resources: Faculty Publications
The objective of this study is to examine interannual variability of carbon dioxide exchange and relevant controlling factors in irrigated and rainfed maize–soybean agroecosystems. The mean annual gross primary production (GPP) of irrigated and rainfed maize was 1796 ± 92 g C m−2 y−1 (±standard deviation) and 1536 ± 74 g C m−2 y−1, respectively. Mean annual GPP of soybean (average of irrigated and rainfed crops) was about 56% that of maize. Light use efficiency of maize and soybean during clear sky conditions were 1.96 ± 0.10 and 1.37 ± 0.06 g C MJ−1 …
Coupling Of Carbon Dioxide And Water Vapor Exchanges Of Irrigated And Rainfed Maize–Soybean Cropping Systems And Water Productivity, Andrew E. Suyker, Shashi B. Verma
Coupling Of Carbon Dioxide And Water Vapor Exchanges Of Irrigated And Rainfed Maize–Soybean Cropping Systems And Water Productivity, Andrew E. Suyker, Shashi B. Verma
School of Natural Resources: Faculty Publications
Continuous measurements of CO2 and water vapor exchanges made in three cropping systems (irrigated continuous maize, irrigated maize–soybean rotation, and rainfed maize–soybean rotation) in eastern Nebraska, USA during 6 years are discussed. Close coupling between seasonal distributions of gross primary production (GPP) and evapotranspiration (ET) were observed in each growing season. Mean growing season totals of GPP in irrigated maize and soybean were 1738 ± 114 and 996 ± 69 g C m−2, respectively (±standard deviation). Corresponding mean values of growing season ET totals were 545 ± 27 and 454 ± 23 mm, respectively. Irrigation affected GPP …
Leaf Reflectance And Transmittance In Soybean And Corn, Elizabeth A. Walter-Shea, Blaine Blad
Leaf Reflectance And Transmittance In Soybean And Corn, Elizabeth A. Walter-Shea, Blaine Blad
School of Natural Resources: Faculty Publications
No abstract provided.
Respiratory Release Of Co2 In Alfalfa And Soybean Under Field Conditions, S. B. Verma
Respiratory Release Of Co2 In Alfalfa And Soybean Under Field Conditions, S. B. Verma
School of Natural Resources: Faculty Publications
No abstract provided.
Influence Of Windbreak-Shelter On Soybean Growth Canopy Structure, And Light Relations, S.N. Ogbuehi, James R. Brandle
Influence Of Windbreak-Shelter On Soybean Growth Canopy Structure, And Light Relations, S.N. Ogbuehi, James R. Brandle
School of Natural Resources: Faculty Publications
No abstract provided.
Influence Of Windbreak-Shelter On Soybean Production Under Rainfed Conditions, S.N. Ogbuehi, James R. Brandle
Influence Of Windbreak-Shelter On Soybean Production Under Rainfed Conditions, S.N. Ogbuehi, James R. Brandle
School of Natural Resources: Faculty Publications
No abstract provided.
Influence Of Windbreak-Shelter On Soybean Production Under Rainfed Conditions, S.N. Ogbuehi, James R. Brandle
Influence Of Windbreak-Shelter On Soybean Production Under Rainfed Conditions, S.N. Ogbuehi, James R. Brandle
School of Natural Resources: Faculty Publications
No abstract provided.
Reflectorized Soybean Canopy In Relation To Transpiration And Herbicide Phytotoxicity, S.N. Ogbuehi, J.R.C. Leavitt, James R. Brandle
Reflectorized Soybean Canopy In Relation To Transpiration And Herbicide Phytotoxicity, S.N. Ogbuehi, J.R.C. Leavitt, James R. Brandle
School of Natural Resources: Faculty Publications
No abstract provided.
Temperatures Of Alfalfa, Sorghum, Soybean And Grass As Measured With Leaf Thermocouples And An Infrared Thermometer, Silvio Steinmetz
Temperatures Of Alfalfa, Sorghum, Soybean And Grass As Measured With Leaf Thermocouples And An Infrared Thermometer, Silvio Steinmetz
School of Natural Resources: Dissertations, Theses, and Student Research
No abstract provided.
Reflectant Induced Modification Of Soybean Canopy Radiation Balance. V Longwave Radiation Balance, M. W. Baradas, B. L. Blad, N. J. Rosenberg
Reflectant Induced Modification Of Soybean Canopy Radiation Balance. V Longwave Radiation Balance, M. W. Baradas, B. L. Blad, N. J. Rosenberg
School of Natural Resources: Faculty Publications
No abstract provided.
Reflectant Induced Modification Of Soybean Canopy Radiation Balance. Iv. Leaf And Canopy Temperature, M. W. Baradas, B. L. Blad, N. J. Rosenberg
Reflectant Induced Modification Of Soybean Canopy Radiation Balance. Iv. Leaf And Canopy Temperature, M. W. Baradas, B. L. Blad, N. J. Rosenberg
School of Natural Resources: Faculty Publications
No abstract provided.