Fuzzy modeling of soil water distribution using buried porous clay capsule irrigation from a subsurface point source

摘要

Water distribution in soil is important for the design, operation, and management of irrigation system for arid and semi-arid regions. The present paper has attempted to estimate the wetted radius and vertical depth from Buried porous clay capsule irrigation using fuzzy model. A fuzzy reasoning algorithm is used to define the relationship between the saturated hydraulic conductivity, discharge, porosity, water volume applied and hydrostatic pressure head and the surface wetted radius and vertical depth. Singleton fuzzyfier, minimum Mamdani inference engine and centriod defuzzyfier are selected to determine soil water distribution using observed data of calcareous soil with clay loam texture in TMU. To obtain porous clay capsules with different discharge, we mixed 200, 400, 600 and 800 gram fine sand per kilogram clay loam and then baked porous clay capsules about 900 0C temperatures in a kiln. Water discharge from porous capsules included 200, 400, 800, 1200, and 2000 (cm3 /hr) in 2.5 meter hydrostatic pressure head. The surface wetted radius and vertical depth values of this model were also compared in the field by the analysis of residual errors. The results show a significant relation between measurement and estimation of the surface wetted radius and vertical depth of wetted zone. Also results shows that the wetted radius and vertical depth values in 2.5 meter pressure with low discharge were about 13.5 and 22 centimeter, respectively. These parameters were 14 and 45 centimeters with high discharge, respectively.