I turned water onto the first hayfield this evening. Most years we have already irrigated the hay twice by July. But most years we don’t get the volume of rain and snow we had this year.
In this first field I use siphon tubes to pull water over the bank of a ditch that comes out of West Boulder River. These are 3-inch shaped PVC tubes about six feet long.
We have 9 of these tubes – we place them about eight feet apart, and move them every 8-12 hours until we have gotten across the whole field. We are soaking an area about seventy feet wide and the width of the field, and it takes about a week to go from one end to another.
In the next field we have “gated pipe’ – twelve-inch PVC that lies along the length of the upper side of the field. There is a little rubber slide-gate every thirty inches along the pipe, and we open gates across a 120-foot section – again for 8-12 hours depending on how long it takes the water to run across the field.
These are both methods of “flood irrigation”. This works well for us on the fields that are below the ditches because the high volume of water quickly fills the soil profile with moisture and it requires no power to run. Much more common in the west is sprinkler irrigation.
“Pivots “are long steel pipes supported by towers on wheels which rotate around the center-pivot where the water is piped in. These may be up to a half mile long, and irrigate about 600 acres in a huge circle. Not only are they expensive to build, but they also use a lot of electricity to pump the water and keep the wheels turning. They mostly run themselves, however, and don't require any labor to operate.
Wheel lines are also common in the west. These are generally steel or aluminum pipes that are four or five inches in diameter, supported by a four or five foot wheel every sixty feet. The water must be shut off to a wheel line twice a day and the pipes drained. A small gas motor rolls the unit to the next set sixty feet away, and the pump is started again. These have “RainBird” style sprinklers along the length of the pipe.
It took about an hour standing in the river this afternoon to shovel away the accumulation of silt which had nearly buried the headgate. My face was perspiring as my feet were getting numb in the cold mountain water that was still snow 24 hours ago.
I will try to be out the door by five o’clock in the morning to move my siphon tubes, then go to baling while there is still some humidity in the hay from the night air. This wet summer has been a nice respite from our normal irrigation routine which is last thing at night and first thing in the morning, sometimes beginning in May.
We usually plan for the alfalfa to re-grow for a second cutting, but I doubt we will get one this year. The frost comes early at our elevation of 5200 feet, and with the late start we got this year the hay will likely freeze before it is ready to cut again.