MOP 70 is a comprehensive reference to estimating the water quantities needed for irrigation of crops projects based upon the physics of evaporation and evapotranspiration (ET).
This book covers topics on the basic models, assessments, and techniques to calculate evapotranspiration (ET) for practical applications in agriculture, forestry, and urban science. This simple and thorough guide provides the information and techniques necessary to develop, manage, interpret, and apply evapotranspiration ET data to practical applications. The simplicity of the contents assists technicians in developing ET data for effective water management.
This Task Committee report provides standardized equations for calculating reference evapotranspiration (ET) from weather data and procedures for quality assessment and control of weather data. The purpose of the standardized reference ET equation and calculation procedures is to bring commonality to the calculation of reference ET and to provide a standardized basis for determining or transferring crop coefficients for agriculture and landscape use. The basis of the standardized reference ET equation is the ASCE Penman-Monteith (ASCE-PM) method Manual 70. Along with applications for the ASCE-PM method, this report includes recommended calculations for vapor pressure, net radiation and wind speed adjustment, and guidelines on assessing weather data integrity and estimating values for missing data. The development of this standardized report by the Environmental and Water Resources Committee (EWRI) of ASCE, was made at the request of, and has been endorsed by, the Irrigation Association.
Irrigated agriculture produces about 40% of all food and fibre on about 16% of all cropped land. As such, irrigated agriculture is a productive user of resources; both in terms of yield per cropped area and in yield per volume of water consumed. Many irrigation projects, however, use (divert or withdraw) much more water than consumed by the crop. The non-consumed fraction of the water may cause a variety of undesirable effects ranging from water-logging and salinity within the irrigated area to downstram water pollution. This book discusses all components of the water balance of an irrigated area; evapotranspiration (Ch.2), effective precipitation (Ch.3) and capillary rise from the groundwater table (Ch.4). Chapter 5 then combines all components into a water management strategy that balances actual evapotranspiration (and thus crop yield) with the groundwater balance of the irrigated area (for a substainable environment). Chapter 6 presents CRIWAR 3.0, a simulation program that combines all water balance components into a single simulation procedure. The chapter describes the use of the CRIWAR software for developing water requirement tables and other useful information based on the selected water management strategy. This version greatly expands upon the capabilities of previously published programs.