Your search found 8 records
1 Buchleiter, G. W.; Farahani, H. J.; Ahuja, L. R.. 1995. Model evaluation of groundwater contamination under center pivot irrigated corn in Eastern Colorado. In Heatwole, C. (Ed.), Water quality modeling: Proceedings of the International Symposium, April 2-5, 1995, Hyatt Hotel Orlando, Orlando, Florida. St. Joseph, MI, USA: ASAE. pp.41-50.
Groundwater ; Water pollution ; Evaluation ; Simulation models ; Sprinkler irrigation ; Maize ; Evapotranspiration ; Nitrogen ; Leaching ; Percolation / USA / Colorado
(Location: IWMI-HQ Call no: 333.91 G000 HEA Record No: H018693)
The USDA/ARS Root-Zone-Water-Quality-Model (RZWQM) is a multi-modular physically-based model that simulates the many processes in the soil-crop- atmosphere continuum on a daily basis. The study evaluates the potential of the RZWQM to simulate a typical center pivot irrigated corn production system in Eastern Colorado. At the evaluation site, the coarse textured soils having low water holding capacities, require frequent irrigation which increases the potential for deep percolation of water and solutes below the root zone. Minimizing deep percolation of irrigation water increases nitrogen use efficiency and decreases water quality degradation from nitrates. Predicted values were compared with measured values for one growing season to parameterize the model. In the following year, deviations of the parameterized model's predictions from independently measured values for the 7 performance criteria ranged from 5-22%, indicating acceptable model performance.
2 Farahani, H. J.; Ahuja, L. R.; Buchleiter, G. W.; Peterson, G. A. 1995. Mathematical modelling of irrigated and dryland corn production in Eastern Colorado. In Clean water - Clean environment - 21st century: Team agriculture - Working to protect water resources: Conference proceedings, March 5-8, 1995, Kansas City, Missouri. Volume III: Practices, systems and adoption. St. Joseph, MI, USA: ASAE. pp.97-100.
Mathematical models ; Irrigated farming ; Maize ; Crop production ; Dry farming ; Water quality ; Simulation ; Groundwater ; Water pollution ; Sprinkler irrigation ; Sandy soils ; Soil water / USA / Colorado
(Location: IWMI-HQ Call no: 333.91 G000 CLE Record No: H018790)
3 Cameira, M. R.; Sousa, P. L.; Farahani, H. J.; Ahuja, L. R.; Pereira, L. S. 1996. Simulation of water and nitrates in level basin fertigated maize using RZWQM. In Ragab, R.; El-Quosy, D. E. D.; van den Broek, B.; Pereira, L. S. (Eds.), Crop-water-environment models: Selected papers to the workshop organized by the ICID Working Group on "Sustainable Crops and Water Use" at the occasion of the 16th Congress of the International Commission on Irrigation and Drainage at Cairo, Egypt. Cairo, Egypt: ICID. Egypt National Committee. pp.42-53.
Water quality ; Simulation models ; Nitrogen ; Fertilizers ; Maize ; Basin irrigation ; Soil moisture / Portugal / Sorraia River
(Location: IWMI-HQ Call no: 631.7.1 G000 RAG Record No: H019364)
This study concerns the evaluation of the ability of Root Zone Water Quality Model (RZWQM) to simulate the seasonal water and nitrate movement in a level basin irrigated corn field under three different fertilizer treatments by comparing simulated and measured soil moisture and nitrate profiles for the growing season. The treatments were a single broadcast application of Urea, a single fertigation with UAN through the first irrigation, and multiple UAN fertigations through all irrigations. First, the model was parameterized for maize using data from the single fertigation treatment. Evaluation runs, using the parameterized model, were conducted for the other two treatments. The model simulated water and nitrate transport well for the season, with the seasonal mean of measured and predicted values differing by less than 5%. Computer requirements: an 80386 or better CPU with math coprocessor; IBM PC-DOS or MS-DOS, Version 5.0 or later; at least 4 megabytes of RAM.
4 Farahani, H. J.; Bausch, W. C.; Aiken, R. M.; Ahuja, L. R.. 1996. Evapotranspiration in system-wide agricultural models. In Camp, C. R.; Sadler, E. J.; Yoder, R. E. (Eds.), Evapotranspiration and irrigation scheduling: Proceedings of the International Conference, November 3-6, 1996, San Antonio Convention Center, San Antonio, Texas. St. Joseph, MI, USA: ASAE. pp.673-678.
Evapotranspiration ; Mathematical models ; Simulation models ; Assessment ; Maize ; Cropping systems ; Experiments / USA / Colorado
(Location: IWMI-HQ Call no: 631.7.1 G000 CAM Record No: H020645)
5 Hanson, J. D.; Ahuja, L. R.; Shaffer, M. D.; Rojas, K. W.; DeCoursey, D. G.; Farahani, H.; Johnson, K. 1998. RZWQM: Simulating the effects of management on water quality and crop production. Agricultural Systems, 57(2):161-195.
Simulation models ; Computer models ; Water quality ; Crop production ; Plant growth ; Pesticide residues ; Irrigation water ; Tillage ; Infiltration ; Evapotranspiration ; Soil properties ; Nitrogen
(Location: IWMI-HQ Call no: PER Record No: H022465)
6 Ahuja, L. R.; Timlin, D. J.; Heathman, G. C. 1991. Modelling soluble chemical transfer from soil to overland flow and its transport through macropores to groundwater. In Nachtnebel, H. P.; Kovar, K. Hydrological basis of ecologically sound management of soil and groundwater. Wallingford, UK: IAHS. pp.3-11.
(Location: IWMI-HQ Call no: 551.48 G000 NAC Record No: H029741)
7 Ahuja, L. R.; Ma, L.; Andales, A. A.; Saseendran, S. A. 2004. Agricultural system models in field research and technology transfer. In Singh, P.; Ahlawat, I. P. S.; Gautam, R. C. (Eds.), Second International Agronomy Congress “Balancing Food and Environmental Security: A Continuing Challenge,” New Delhi, India, 26-30 November 2002 - Proceedings. pp.226-233.
(Location: IWMI-HQ Call no: 630 G000 SIN Record No: H037786)
8 Ahuja, L. R.; Ma, L.; Hanson, J. D. 1998. Application of the root zone water quality model for environment-water management in agricultural systems. In Pereira, L. S.; Gowing, J. W. (Eds.). Water and the environment: Innovation issues in irrigation and drainage: Selected papers of the 1st Inter-Regional Conference “Environment-Water: Innovative Issues in Irrigation and Drainage,” Lisbon, Portugal, Sept. 1998. London, UK: E & FN Spon. pp.3-11.
(Location: IWMI-HQ Call no: 631.7.1 G000 PER Record No: H039011)
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