Assessment of Deep Percolation in Citrus Orchard

Australian irrigators are under considerable pressure to increase irrigation efficiency and reduce deep drainage, driven by environmental and economic imperatives. Capacitance probe sensors are relatively cheap and popular electromagnetic equipment to measure soil water content. A field experiment was performed with capacitance probe in Mallee area of Australia, to collect the water content dynamics and deep percolation below of root zone. A relationship between these multi-sensor probes and estimates of deep percolation calculated using the Darcy's flux equation. Two empirical models of water retention curve were compared to illuminate the importance of water retention curve in deep percolation. The deep percolation estimate shows considerable daily and seasonal variations of drainage rate.