Progress 04/19/16 to 09/30/20
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Dr. Irmak has separated from UNL
Publications
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:State and federal agency personnel, including USDA-NRCS, Natural Resources Districts, Department of Natural Resources, Irrigation Disricts, producers, crop consultants, graduate and undergraduate students, researchers/scientists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The NEBFLUX project sites are used as training for international and national scientists, researchers, extension personnel, graduate and undergraduate students and domestic and international interns. How have the results been disseminated to communities of interest?The project progress, findings, and data have been presented in numerous local regional, national, and international meetings, conferences (e.g., American Society of Agricultural and Biological Engineers Annual International Conference), and other educational platforms (including teaching NEBFLUX functions in graduate and undergraduate level courses). The flux data have been used as part of high level education and scientific analyses, including MS and PhD students' programs. What do you plan to do during the next reporting period to accomplish the goals?We will continue to maintain our towers for good quality data collection, graduate student education, and disseminating the information and data. We will continue to quantify basal and normal crop coefficients for different surfaces; and we will continue analyze and disseminate climate variables trends and magnitudes and their potential implications on agrculture.
Impacts
What was accomplished under these goals?
Background and Rationale: Availability of freshwater resources for agro-ecosystems has been an important issue for the sustainability of agricultural production in the U.S.A. and around the world. Despite of extensive water resources activities and significantly large areas of agro-ecosystem settings in Nebraska, a network of actual evapotranspiration (ETa) measurement infrastructure to provide short and long-term and improved ETa data for water resources policy-makers, planners, regulators, and users on a continuous basis does not exist. The Nebraska Water and Energy Flux Measurement, Modeling, and Research Network (NEBFLUX) was established in 2004 for filling this important gap. The NEBFLUX is a network of micrometeorological tower sites that uses mainly Bowen ratio energy balance systems (BREBS) to measure surface water vapor and energy fluxes between terrestrial agro-ecosystems and microclimate. At present, eleven BREBSs and eddy covariance systems are operating on a long-term and continuous basis tilled and untilled irrigated and rainfed croplands, irrigated and rainfed grasslands, to Phragmites-dominated cottonwood and willow stand plant communities, irrigated alfalfa and irrigated and rainfed grasslands. NEBFLUX provide data and information that aids in better managing state's water resources. In addition to the scientific and research functions, information/data dissemination to educate the general public and youth is another important objective and output of the network. NEBFLUX is having significant positive impacts and resulting in change in knowledge and/or condition as it enables the use of scientific and research-based data in management decisions. Numerous graduate students (MS, PhD, and undergraduate) use NEBFLUX data for their research. The NEBFLUX data and information are being used by state water management agencies for their water management plans. Information and data gathered by NEBFLUX are also being used to calibrate and validate crop models, climate analyses, and other water management-related analyses. NEBFLUX progress, data, and information are disseminated in numerous local, regional, national, and international platforms.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Zhu, Y., S. Irmak, A.J. Jhala, M.C. Vuran and A. Diotto. 2019. Time-domain and frequency-domain reflectometry type soil moisture sensor performance and soil temperature effect in fine- and coarse-textured soils. Applied Engineering in Agriculture 35(2):117-134. https://doi.org/10.13031/aea.12908.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Mohammed, A.T., S. Irmak, W.L. Kranz, S. van Donk and C.D. Yonts. 2019. Grain yield, crop and basal evapotranspiration, production functions and water productivity response of drought-tolerant and non-drought-tolerant maize hybrids under different irrigation levels, and population densities: Part I. In western Nebraskas semi-arid environments. Applied Engineering in Agriculture 35(1):65-81. https://doi.org/10.13031/aea.12870.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Kukal, M., and S. Irmak. 2019. Comparative canopy growth dynamics in four row crops and their relationships with allometric and environmental determinants. Agronomy Journal 111(4):1799-1816. doi:10.2134/agronj2019.01.0017.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Sandhu, R., and S. Irmak. 2019. Assessment of AquaCrop model in simulating maize canopy cover, soil-water, evapotranspiration, yield and water productivity for different planting dates and densities under irrigated and rainfed conditions. Agricultural Water Management 224, 105753. https://doi.org/10.1016/j.agwat.2019.105753.
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:State and federal water management agency personnel (including Department of Natural Resources, Natural Resources Districts), agricultural producers, irrigation district personnel, crop consultants, university faculty and students. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The NEBFLUX project sites are used as training for international and national scientists, researchers, extension personnel,graduate and undergraduate students and domestic and international interns. How have the results been disseminated to communities of interest?The project progress, findings, and data have been presented in numerous local regional, national, and international meetings, conferences (e.g., American Society of Agricultural and Biological Engineers Annula International Conference), and other educational platforms (including teaching NEBFLUX functions in graduate and undergraduate level courses). The flux data have been used as part of high level education and scientific analyses, including MS and PhD students' programs. What do you plan to do during the next reporting period to accomplish the goals?We will continue to maintain our towers for good quality data collection, graduate student education, and disseminating the information and data. We will continue to quantify basal and normal crop coefficients for different surfaces; and we will continue analyze and disseminate climate variables trends and magnitudes and their potential implications on agrculture.
Impacts
What was accomplished under these goals?
Background and Rationale: Availability of freshwater resources for agro-ecosystems has been an important issue for the sustainability of agricultural production in the U.S.A. and around the world. Despite of extensive water resources activities and significantly large areas of agro-ecosystem settings in Nebraska, a network of actual evapotranspiration (ETa) measurement infrastructure to provide short and long-term and improved ETa data for water resources policy-makers, planners, regulators, and users on a continuous basis does not exist. The Nebraska Water and Energy Flux Measurement, Modeling, and Research Network (NEBFLUX) was established in 2004 for filling this important gap. The NEBFLUX is a network of micrometeorological tower sites that uses mainly Bowen ratio energy balance systems (BREBS) to measure surface water vapor and energy fluxes between terrestrial agro-ecosystems and microclimate. At present, eleven BREBSs and eddy covariance systems are operating on a long-term and continuous basis tilled and untilled irrigated and rainfed croplands, irrigated and rainfed grasslands, to Phragmites-dominated cottonwood and willow stand plant communities, irrigated alfalfa and irrigated and rainfed grasslands. NEBFLUX provide data and information that aids in better managing state's water resources. In addition to the scientific and research functions, information/data dissemination to educate the general public and youth is another important objective and output of the network. NEBFLUX is having significant positive impacts and resulting in change in knowledge and/or condition as it enables the use of scientific and research-based data in management decisions. Numerous graduate students (MS, PhD, and undergraduate) use NEBFLUX data for their research. The NEBFLUX data and information are being used by state water management agencies for their water management plans. Information and data gathered by NEBFLUX are also being used to calibrate and validate crop models, climate analyses, and other water management-related analyses. NEBFLUX progress, data, and information are disseminated in numerous local, regional, national, and international platforms. Goals/Objectives, Progress, Accomplishments, and Impacts: The NEBFLUX project has a wide range of goals and objectives. Some of the specific objectives are: 1. The fundamental premise of the NEBFLUX is to measure continuous and long-term (at least ten complete annual cycles for each surface) exchange of water vapor and energy fluxes for various vegetation surfaces/cropping systems. Accomplishments: Flux towers have been operating continuously for aforementioned vegetation surfaces for the calendar year, collecting hourly data on surface energy fluxes and other environmental variables. A large, good quality, and a unique datasets have ben continued to be gathered for various surfaces that provide contributions to the scientific literature and to water management professionals in practical application. 2. Measure/update crop coefficient (Kc) values for maize, soybean, winter wheat, grasslands, alfalfa, seed corn, cover crops, black turtle bean, popcorn, riparian vegetation. Accomplishments: Hourly and daily normal and basal crop coefficients have been developed for maize and soybean for full and limited irrigation as well as for rainfed conditions and disseminated through journal articles and other platforms. Cover crop normal and basal crop coefficients have been developed and published in scientific journals, which are some of the first (if not the first) cover crop coefficients in the literature. Crop coefficients for other surfaces will be developed. 3. Measure and develop techniques to predict evaporative losses during the non-growing season. Accomplishments: The magnitudes, trends, and contribution to the nocturnal surface energy balance of various microclimatic variables (air temperature, Ta; vapor pressure deficit, VPD; relative humidity, RH; and wind speed at 3 m, u3) and surface energy fluxes (ETcnight ; soil heat flux, G; sensible heat flux, H; and net radiation, Rn); were quantified and interpreted for a non-stressed and subsurface-drip-irrigated maize canopy. The nighttime evaporative losses were high early in the season during partial canopy closure because of increased surface soil evaporation and were also high later in the season during and after leaf aging, physiological maturity, and leaf senescence. The seasonal average nighttime evaporative losses for year 1 and 2 were 0.19 and 0:11 mm/night, respectively. Losses of 0.50 mm or more occurred in 2005 and 2006 on eight and seven nights, respectively. 4. In addition to flux and environmental interactions, the impact(s) of change in climate variables on agro-ecosystem productivity and water resources are investigated. Climate impacts on maize, sorghum, and soybean yields and effect of irrigation for individual counties in this region were evaluated by employing extensive crop yield and climate datasets from 1968-2013. Variability in crop yields was a quarter of the regional average yields, with a quarter of this variability explained by climate variability, and temperature and precipitation explained these in singularity or combination at different locations. Observed temperature trend was beneficial for maize yields, but detrimental for sorghum and soybean yields, whereas observed precipitation trend was beneficial for all three crops. Irrigated yields demonstrated increased robustness and an effective mitigation strategy against climate impacts than their non-irrigated counterparts by a considerable fraction. The information, data, and maps provided can serve as an assessment guide for planners, managers, and policy- and decision makers to prioritize agricultural resilience efforts and resource allocation or re-allocation in the regions that exhibit risk from climate variability.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Irmak, S., V. Sharma, A.T. Mohammed, and K. Djaman. 2018. Impacts of cover crops on soil physical properties: Field capacity, permanent wilting point, soil-water holding capacity, bulk density, hydraulic conductivity, and infiltration. Transactions of the ASABE 61(4):1307-1321. https://doi.org/10.13031/trans.12700.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Sharma, V., S. Irmak, and J. Padhi. 2018a. Effect of cover crops on soil quality: Part I: Soil chemical properties ⿿ organic C, total N, pH, EC, organic matter content, NO3-N, and P. J. Soil and Water Conservation 73(6):637-651. doi:10.2489/jswc.73.6.637.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Sharma, V., S. Irmak, and J. Padhi. 2018b. Effect of cover crops on soil quality: Part II. Soil exchangeable bases (K, Mg, Na, Ca) and soil micronutrients (Zn, Mn, Fe, Cu, and B). J. Soil and Water Conservation 73(6):652-668. doi:10.2489/jswc.73.6.652.
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:State and federal water management agency personnel (including Department of Natural Resources, Natural Resources Districts), agricultural producers, irrigation district personnel, crop consultants, university faculty and students. Changes/Problems:Funding to sustain this very important network is always a challenge. What opportunities for training and professional development has the project provided?The NEBFLUX project sites are used as training for international and national scientists, researchers, graduate students. How have the results been disseminated to communities of interest?The project progress, finsings, and data have been presented in numerous locall regional, national, and international meetings, conferences (e.g., American Society of Agricultural and Biological Engineers Annula International Conference), and other educational educational platforms (including teaching NEBFLUX functions in graduate and undergraduate level courses). The flux data have been used as part of high level education and scientific analyses, including MS and PhD students' programs. What do you plan to do during the next reporting period to accomplish the goals?We will continue maintain our towers for good quality data collection, graduate student education, and disseminating the information and data. We will continue to quantify basal and normal crop coefficients for different surfaces; and we will continue analyze and disseminate climate variables trends and magnitudes and their potentialimplications on agrculture.
Impacts
What was accomplished under these goals?
Background and Rationale: Availability of freshwater resources for agro-ecosystems has been an important issue for the sustainability of agricultural production in the U.S.A. and around the world. Despite of extensive water resources activities and significantly large areas of agro-ecosystem settings in Nebraska, a network of actual evapotranspiration (ETa) measurement infrastructure to provide short and long-term and improvedETadata for water resources policy-makers, planners, regulators, and users on a continuous basis does not exist. The Nebraska Water and Energy Flux Measurement, Modeling, and Research Network (NEBFLUX) was established in 2004 for filling this important gap. The NEBFLUX is a network of micrometeorological tower sites that uses mainly Bowen ratio energy balance systems (BREBS) to measure surface water vapor and energy fluxes between terrestrial agro-ecosystems and microclimate. At present, eleven BREBSs and eddy covariance system are operating on a long-term and continuous basis tilled and untilled irrigated and rainfed croplands, irrigated and rainfed grasslands, to Phragmites-dominated cottonwood and willow stand plant communities, irrigated alfalfa and irrigated and rainfed grasslands. NEBFLUX provide data and information that aids in better managing state's water resources. In addition to the scientific and research functions, information/data dissemination to educate the general public and youth is another important objective and output of the network. NEBFLUX is having significant positive impacts and resulting in change in knowledge and/or condition as it enables the use of scientific and research-based data in management decisions. Numerous graduate students (MS, PhD, and undergraduate) use NEBFLUX data for their research. The NEBFLUX data and information are being used by state water management agencies for their water management plans. Information and data gathered by NEBFLUX are also being used to calibrate and validate crop models, climate analyses, and other water management-related analyses. NEBFLUX progress, data, and information are disseminated in numerous local, regional, national, and international platforms. Goals/Objectives, Progress, Accomplishments, and Impacts: The NEBFLUX project has a wide range of goals and objectives. Some of the specific objectives are: 1. The fundamental premise of the NEBFLUX is to measure continuous and long-term (at least ten complete annual cycles for each surface) exchange of water vapor and energy fluxes for various vegetation surfaces/cropping systems. Accomplishments: Flux towers have been operating continuously for aforementioned vegetation surfaces for the calendar year, collecting hourly data on surface energy fluxes and other environmental variables. A large, good quality, and a unique datasets have ben continued to be gathered for various surfaces that provide contributions to the scientific literature and to water management professionals in practical application. 2. Measure/update crop coefficient (Kc) values for maize, soybean, winter wheat, grasslands, alfalfa, seed corn, cover crops, black turtle bean, popcorn, riparian vegetation. Accomplishments: Hourly and daily normal and basal crop coefficients have been developed for maize and soybean for full and limited irrigation as well as for rainfed conditions and disseminated through journal articles and other platforms. Cover crop normal and basal crop coefficients have been developed and published in scientific journals, which are some of the first (if not the first) cover crop coefficients in the literature. Crop coefficients for other surfaces will be developed. 3. Measure and develop techniques to predict evaporative losses during the non-growing season. Accomplishments: The magnitudes, trends, and contribution to the nocturnal surface energy balance of various microclimatic variables (air temperature, Ta; vapor pressure deficit, VPD; relative humidity, RH; and wind speed at 3 m, u3) and surface energy fluxes (ETcnight ; soil heat flux, G; sensible heat flux, H; and net radiation, Rn); were quantified and interpreted for a non-stressed and subsurface-drip-irrigated maize canopy. The nighttime evaporative losses were high early in the season during partial canopy closure because of increased surface soil evaporation and were also high later in the season during and after leaf aging, physiological maturity, and leaf senescence. The seasonal average nighttime evaporative losses for year 1 and 2 were 0.19 and 0:11 mm/night, respectively. Losses of 0.50 mm or more occurred in 2005 and 2006 on eight and seven nights, respectively. 4. In addition to flux and environmental interactions, the impact(s) of change in climate variables on agro-ecosystem productivity and water resources are investigated. Quantification of Spatial distribution of annual, growing season, and monthly precipitation Long-term (1968-2013) average annual, growing season and monthly precipitation were calculated from daily weather records and the results were depicted on a spatial basis for 834 counties in the Great Plains region. Precipitation, irrespective of the period, showed a similar spatial nature where the amount increased gradually from west to east. The maps created (not shown) can be instrumental in determining average precipitation amounts in any geographical location in the region. Averaged across all the counties in the region, annual and growing season precipitation amounts were 24.3 and 13.7 inches, respectively. County-specific average precipitation amounts were calculated and it was found that the annual average precipitation ranged from 8.4 inches for Big Horn County, Wyoming to 57.4 inches for Orange County, Texas. Similarly, it was found that average growing season precipitation amounts varied from 4.8 inches for Big Horn County, Wyoming to 27.9 inches for Orange County, Texas. The site-specific maximum and minimum precipitation amounts observed across the region, were slightly different from the county-averaged amounts. The regional extremes in average annual precipitation were 6.4 and 58.5 inches, whereas those for average growing season precipitation were 3.9 and 29.3 inches, respectively. Averaged by state, the peak annual precipitation was observed in Oklahoma (35 inches), followed by Iowa (34.4 inches), while the minimum magnitude was observed in Wyoming (12.5 inches). Temporal Changes in Annual, Growing Season, and Monthly Precipitation Temporal trends in annual and growing-season precipitation amounts during the period 1968-2013 across the Great Plains region were calculated and their nature (whether increasing or decreasing) and statistical significance (whether a trend is large enough to be qualified as a trend by statistical definition) were investigated. These characteristics of temporal trends are reported by maps (not shown). For the annual precipitation, 61% of the counties in the region showed increasing trends and the rest (39%) showed decreasing trends. All the counties in North Dakota and South Dakota showed positive trends. In Nebraska, except the East Central and Southeast region which showed negative trends, all other counties showed positive trends. Similarly, in Iowa, all counties showed positive trends, although there are some counties in Southwest, South Central, Southeast, Central and East Central region, which showed negative trends. In Kansas, North Central, West Central, Central and South central regions showed positive trends, while the rest of the state shows negative trends. In Wyoming, the counties along the border of South Dakota, Nebraska and Colorado showed positive trends, and the rest of the state was dominated by negative trends. Southwest and Central Colorado comprise of some counties which show negative trends, with the remainder of the state showing positive trends.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Kukal, M., S. Irmak, and A. Kilic. 2017. Long-term spatial and temporal maize and soybean evapotranspiration derived from ground and satellite-based NDVI datasets over the USA Great Plains. J. Irrigation and Drainage Engineering 143(9):04017031. doi:10.1061/(ASCE)IR.1943-4774.0001212.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Sharma, V., and S. Irmak. 2017. Soil-water dynamics, evapotranspiration, and crop coefficients of cover crop mixtures in seed maize-cover crop rotation fields: Part II. Grass- and alfalfa-reference single (normal) and basal crop coefficients. J. Irrigation and Drainage Engineering 143(9): 04017033. doi:10.1061/(ASCE)IR.1943-4774.0001215.
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Progress 04/19/16 to 09/30/16
Outputs
Target Audience:State and federal water management agency personnel (including Department of Natural Resources, Natural Resources Districts), agricultural producers, irrigation district personnel, crop consultants, university faculty and students. Changes/Problems:No major changes or problems to report. What opportunities for training and professional development has the project provided?The NEBFLUX project sites are used as training for international and national scientists, researchers, graduate students. How have the results been disseminated to communities of interest?Yes, I have preseented several seminars to disseminate project progress and results in different educational platforms. What do you plan to do during the next reporting period to accomplish the goals?We will continue maintain our towers for good quality data collection, graduate student education, and disseminating the information and data.
Impacts
What was accomplished under these goals?
All towers continue to measure all surface energy balance components, including evapotranspiration, sensible heat flux, soil heat flux, soil moisture, soil temeprature, and other variables. We continue to manintain all towers on a wekly or two week basis.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Kukal, M., and S. Irmak. 2016. Long-term patterns of air temperatures, daily temperature range, precipitation, grass-reference evapotranspiration and aridity index in the USA Great Plains: Part I. Spatial trends. Journal of Hydrology. 542:953-977. dx.doi.org/10.1016/j.jhydrol.2016.06.006.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Kukal, M., and S. Irmak. 2016. Long-term patterns of air temperatures, daily temperature range, precipitation, grass-reference evapotranspiration and aridity index in the USA Great Plains: Part II. Temporal trends. Journal of Hydrology. 542:978-1001. dx.doi.org/10.1016/j.jhydrol.2016.06.008.
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