Agricultural Field Scale Irrigation Requirements Simulation (AFSIRS) Model. Version 5.5. Technical Manual

摘要

The Agricultural Field Scale Irrigation Requirements Simulation (AFSIRS) Model is a numerical simulation model which allows the user to estimate irrigation requirements (IRR) for Florida crops, soils, irrigation systems, growing seasons, climate conditions and irrigation management practices. IRR for crop production is the amount of water, exclusive of precipitation, that must be applied to meet a crop's evapotranspiration (ET) requirements without significant reduction in yield. IRR, as defined in this model, does not include leaching, freeze protection, or crop cooling requirements, even though water for these purposes may be applied through an irrigation system. The AFSIRS model is based on a water budget of the crop root zone and the concept that crop ET can be estimated from potential evapotranspiration (ETp) and crop water use coefficients. The water budget includes inputs to the crop root zone from rain and irrigation, and losses from the root zone by drainage and ET. The water storage capacity in the crop root zone is defined as the multiple of the water-holding capacity of the soil and the depth of the effective root zone for the crop being grown. This manual presents the technical basis for the AFSIRS model. It documents the computational techniques and sources of data used in the model. It presents the assumptions used in the model development and discusses why these assumptions were required. Finally, this manual contains listings of the computer program code and the crop and soil coefficient data bases.