Session 26. Scheduling of Microirrigation System
A Simple Optimal Microirrigation Scheduling
I.P. Wu
Microirrigation can achieve more than a 90% uniformity coefficient (or less than 10% in coefficient of variation) if plugging can be controlled to less than 5%. Microjets and some turbulent flow emitters with proper filtration can maintain these ranges of plugging. For this high uniformity situation, the water application can be expressed by a linearized straight line function which, for a required irrigation depth, the volumes of deficit and deep seepage as well as application efficiency and storage efficiency can be expressed by simple algebraic equations. An optimal irrigation scheduling was developed by optimizing the total return considering the cost of water, loss of yield in the deficit area and damage caused by the deep seepage, including the potential for groundwater contamination. The optimal solution indicated, at a possible range of the costs (or price) of irrigation water for the crops, fertilizer and chemical losses and remediation of groundwater contamination, that the amount of irrigation application can be set as the same amount required. Under this condition, deficit, deep seepage, irrigation application, efficiency and storage efficiency can be expressed by the uniformity of the microirrigation application only.
Keywords: Microirrigation, Optimal Solution, Groundwater Contamination, Water Quality, Deep Seepage
Abstract taken from paper found on pages 781 to 786 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Real-Time Expert System for Citrus Microirrigation Management
J. N.Xin, F. S. Zazueta, A. G. Smajstrla, T. A. Wheaton
A prototype of a real-time expert system (CIMS) for citrus irrigation management was developed for microirrigation water application, cold protection, and fertigation control. The system integrates water management and control technologies into an effectively control system which can be used as a tool by irrigators. Data from soil-moisture sensors and an automated weather station were used as inputs to the computer. The system, based upon expert knowledge, activates irrigation, fertigation and cold protection. The users can also define their own schedules for implementation by the controller.
Keywords: Knowledge base, control, irrigation, fertigation, cold protection
Abstract taken from paper found on pages 787 to 791 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Scheduling Microirrigations for Wine Grapes Using CIMIS
Donald Pitts, Mary Bianchi, and Kelly Clark
This study describes an efficient and accurate method of microirrigation scheduling using the California Irrigation Management Information System (CIMIS) and published crop coefficients. Reference evapotranspiration (ETo) from CIMIS was combined with crop coefficients, a canopy coefficient, a soil-water availability coefficient, soil and irrigation system parameters to accurately predict soil-water content under full-irrigation and deficit-irrigation conditions. The water budgeting computations were performed with a spreadsheet computer program. The irrigation scheduling method was calibrated and verified by comparing predicted soil-water content to measured soil-water content under replicated field conditions.
Keywords: Irrigation systems, Irrigation management, Computer-based water-budget, Neutron probe, Evapotranspiration
Abstract taken from paper found on pages 792 to 798 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Irrigation Scheduling of Microirrigation Systems Using the SCS-Scheduler
V. F. Bralts, W. H. Shayya and T. Lei
Over the past several years, a computer package called SCS-Scheduler was developed to schedule irrigation water applications using real time weather data. The SCS-Scheduler software can assist irrigation districts and individual farmers keep track of available soil water. The purpose of this paper and poster presentation is to introduce the Scheduler software and describe how the program can be used with microirrigation systems.
Keywords: Microirrigation, Irrigation scheduling, SCS-Scheduler
Abstract taken from paper found on pages 799 to 805 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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High-Frequency Microirrigation for Environmental Control and Increased Water Application Efficiency
V. I. Sardo, C. Germanà
Experiments conducted with a spray irrigation system in an orange grove in Sicily showed the possibility of smoothing peak values in temperature (T) and relative humidity (RH) and therefore also in vapor pressure deficit (VPD). Since former experiences by the same authors evidenced the remarkable amount of evaporation losses when irrigating during the warmest hours of the day, the possibility of achieving a climatizing effect through a daily night-time irrigation, thus reducing evaporation losses, was explored. Results showed that daily night-time irrigation was effective in controlling environmental conditions, while water loss to evaporation was appreciably reduced.
Keywords: Climate control, Spray irrigation, Citrus irrigation, Irrigation efficiency
Abstract taken from paper found on pages 806 to 811 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Microirrigation for Artificial Revegatation Bed Soil Focused on arid Lands
S. Segawa, T. Yamamoto, A. Tanaka, M. Inoue, S. Yokotsuka
An irrigation scheduling experiment for revegetation was carried out on an artificial revegetation bed soil. In the experiment, a revegetation method, Texsol Green (TG) method, which is commercial name, was used. Its characteristics are a high water holding capacity and a high potential of protecting soil surface layer. Irrigation methods used were perforated pipes in 1992 and biwall type drip tubes in 1993 and plants used were itachi-hagi (Amorph fruticosa L.) and tall fescue kentucky 31 (Fesyuca arundinacea Schred).
As a result, (1) Artificial bed soils such as TG bed soil which showed the high water holding capacity had smaller percolation loss and had larger soil surface evaporation. (2) A sand mulching reduced soil surface evaporation and surface run off. (3) Better plant growth can be obtained by the use of an artificial bed soil.
Keywords: Artificial revegetation bed soil, Irrigation schedule, Arid lands, Soil water, slope
Abstract taken from paper found on pages 812 to 817 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
