برآورد ابعاد پياز رطوبتي در آبياري قطره اي زير سطحي با استفاده از آناليز ابعادي

Estimating Soil Moisture Pattern in Subsurface Drip Irrigation Using Dimensional Analysis Method

Water Scarcity in arid and semi-arid regions is the major concern for water and agricultural authorities. To confront this problem, high performance irrigation systems, such as drip irrigation and or subsurface drip irrigation, are recommended. In designing a subsurface drip irrigation system for row crops, geometry and dimension of wetted volume are the main factors needed for determining lateralsʹ installation depth as well as emittersʹ spacings. For this purpose several models were developed to demonstrate a good prediction of wetting pattern using emitter discharge, volume of applied water and hydraulic properties of soil. In this paper dimensional analysis method, developed by Singh et al. (2006) was employed due to its simplicity and less input data requirement. Measured data of wetting pattern under subsurface drip irrigation system (Z+, Z- and W, lower, upper and horizontal displacement, respectively) in a clay loam soil with 30 cm emitter depth were compared with output data estimated through the model. A good agreement (R2 - 0.97, 0.99 and 0.97 for z+, z- and r, respectively.) was obtained between measured and estimated data.