Subsurface Irrigation
Practice Overview
Similar to a controlled drainage system, control structures manage the water table through the field. However, water can be supplied to the system from a ditch or storage pond to ensure the water table is always at an ideal level. Excess water from rainfall can still be drained through the system.
Benefits
- Reduced nutrient loss
- Higher, consistent yields (+30% to 50%)
- Less evaporation loss
- Less energy and water needed to irrigate compared to other irrigation systems
How It Works
Water is supplied to an otherwise controlled drainage system to ensure that the water table is always at an ideal level. Water can be pumped from a nearby well, ditch, or storage pond (“Drainage Water Recycling”) to each control structure, or to an upstream mainline/manifold and allow the water to work with gravity to fill the water table to desired WCS height. A combination of floats, pumps, and automatic valves can be used to automate and optimize the system.
Installation Considerations
- Most effective on flat fields
- Soil must have high water holding capacity
- Soil profile must have an impermeable layer to prevent deep infiltration .
- Lateral spacing about 65% closer than traditional drainage
Costs
Varies depending on water source, field topography, crop water needs, etc.