Irrigation
What is Irrigation?
Due to increasingly erratic weather and sparse or spotty rainfall, many farmers can’t rely on rain alone for their crops. Recently, weather patterns have leaned toward extremes, from heavy rainfall over the course of a day to periods of drought stretching one or two weeks. While the weather has always been an assumed cost of the trade, the years in which weather is more unpredictable are years in which farmers tend to struggle when it comes time to measure yield.
Irrigation functions act as a reliable, secondary water source, providing farmers with flexibility and control over the amounts of water they’re able to apply to their fields at the exact moments water is needed. While this doesn’t address the periods of intense rainfall during times when intense rainfall may be a detriment to crops, it does address those periods of drought that, at best, diminish yield, and at worst, decimate it. The key, though, is that irrigation, via years of innovation and growth into its many forms, works. To illustrate, nearly 80% of the nation’s water consumption is used for agricultural irrigation, and in Illinois, approximately 600,000 acres are irrigated.
Differing Forms of Irrigation
Flood or furrow irrigation is an old, trusted practice through which water is carried to a location through gated aluminum or plastic pipe, and covers the entire soil surface through furrows or troughs between rows of the crop.
Drip irrigation, or micro-irrigation, is where tubes or pipes with little holes are installed in a field. The slow and steady drip of water allows for localized application and complete absorption.
Spray or sprinkler irrigation is a controlled technique with the intention of mimicking rainfall. Often, a predetermined layout of conveyance pipes is necessary to connect multiple sprinklers. The most common sprinkler used is center pivot, to which water is brought through a pump that connects to a local water source, like a dam, well, or larger piping infrastructure. Water then travels through pipes up to the pivot point, or the main control system of the sprinkler. Water is then dispersed from the sprinkler ends by formulated drop sizes to generate that rainfall effect.
Benefits
Drip:
Efficient
Less water waste
Direct plant root zone application
Low-pressure (won’t damage crop)
Nutrient-loss minimized
Flood:
Low-cost
Low-tech
Low-pressure (won’t damage crop)
Runoff water can be collected and reused
Sprinkler:
Very terrain versatile
Less water waste
Large-scale
Equal water distribution
Balance Between Irrigation & Drainage
Just as water is important to the success of crops, drainage is also an equally crucial element. When natural precipitation is awry, proper water management including irrigation and drainage can create stable crops year after year. When the underground water table is too high, surface level flooding occurs. Meanwhile, underground, the root of the produce can’t absorb the oxygen it needs to live and can drown.
To address this, drainage tile may be implemented to manage wet soil while lowering the water table. When perforated pipe is placed below the soil surface, it allows for excess water to be drained from the root zone to ensure greater crop health. Tile is designed to allow water to enter the pipe and then flow at a specified grade to an outlet. When these strategically placed pipes are installed, they can benefit specified wet areas. They can also be installed in a pattern to drain an entire field. When the process is complete, the water table is lowered, and greater soil aeration is achieved.
The key is balance: a water management plan that considers the risks of too little water with the benefits of an appropriately designed irrigation system, and one that considers the negative impact of too much water. Spending time on the design of these systems while considering their interplay is crucial to getting the most from both, and probably the most cost-effective way to approach management in a field.