The most common irrigation method for alfalfa on the US West coast is flood irrigation. But lately (since about 2017) drip irrigation systems are gaining more and more popularity and for a good reason we’ll touch on them later in this post.
Flood Irrigation
First, in a few words about flood irrigation. Flood irrigation is the simplest and oldest crop irrigation method. And as mentioned above, it is still commonly used today, mostly for row crops. Water is delivered to the plant by ditch, pipe, etc. and flows over the field irrigating the crop. Although flood irrigation is effective, it is not efficient when we are comparing it to other irrigation systems, because only about half of the water applied ends up irrigating the crop. Flood irrigation is best used in areas where water is easily accessible and cheap, and fields are graded with drainage slope between 0.1 percent and 0.5 percent.
Drip Irrigation
Drip Irrigation has many benefits when compared to flood irrigation but comes with higher installation / setup cost. Today drip irrigation is a common choice for permanent and vegetable crop growers. Drip systems can also be partially or fully automated, saving on operational costs.
Here are just some of the benefits:
- Conserving water and energy
- Increasing plant health
- Design flexibility
- Can irrigate uneven fields
- Delivers water closer to the plant
- Use recycled water safely
- Eliminating transpiration loss due to evaporation and runoff
Drip Irrigation for Alfalfa
Ok, let’s get back to the original subject of this post – drip irrigation for alfalfa. Yes, drip systems do come with higher installation costs. But since drip saves water, chances are that there are grants available (USDA, SWEEP, etc.). If you are a farmer, I recommend you reach out to your local USDA office or talk to the company which helps you with farm compliance to see if there are any grants available.
Here is a comparison I made for alfalfa yields grown on drip irrigation versus flood. Full details of this study, you will find it in this pdf file.
