It's irrigation season. All around me, the neighbors are running their wheel lines and center pivots. Here at Prairie Heritage Farm, we have flood irrigation - essentially the practice of using gravity to move water across the surface of a field. It is a very old method of irrigation and requires no external power (no pumps, no motors) besides a little bit of hand work with the shovel. The water is dammed from the main canal which fills in a ditch running east and west. Through a series of dammed and undammed culverts using boards and hand-set canvas dams, the water is moved to the proper series of ditches that will flood a particular field. My 15-acre field is the furthest from the main canal, so the water had to first travel east, then dammed so it would travel along a northern ditch, then dammed again to head northeast and east along the southern edge of the field. All along this ditch, I would set a dam then cut out sections of the ditch to allow the water to flow through a portion of the field.
Me setting a dam.
I would then walk the field to monitor how far the water had traveled, moving the dam and digging new cutouts when the water from the first set had reached the end of the field. I continued this - set dam, dig cutouts, monitor, move and reset dam, etc. - until the whole field had been irrigated. It was basically a great way to play in the water and mud.
A set dam.
One downside to flood irrigation is crops can suffocate if water stays on the ground for too long. The head of the field slopes slightly west, so no matter where my dam was set, water tended to pool in my milk thistle, especially the closer I got the dam to it. This is what happened:
Drowned milk thistle.
Wow. This one has brought a myriad of questions. 1. How long does it take for the water to move? 2. How much water do you lose to evaporation in the process? 3. How often is this done? 4. Is your back killing you? 5. Isn't drowned thistle a good thing? (I'm assuming it's not a crop, but you know what assuming does...)
ReplyDeleteFascinating. I'm impressed...
Pretty interesting.
ReplyDeleteAs a child, moving irrigation was one of the early morning things to do. I haven't run across folks doing it this way for quite a while. Nice that you can skip over pumps and motors... and leaking irrigation pipes that need fixing.. which required shutting the whole production down, a dad getting mad and children late for any summertime fun.
Enjoying your blog.. fellow Montanan.. Sarah
Camie
ReplyDelete1. The speed at which the water moves depends on the amount of water in the ditch. For me, it took anywhere from 15-24 hours for each set (a dam and 3 or 4 cutouts).
2. I don't know how much is lost to evaporation, but I've been told it's a lot less than overhead irrigation, where a fine mist is sprayed into the hot air. There is a lot more waste water in flood irrigation, though. But a farmer friend pointed out that the waste water off the field will eventually find its way into the Marias River then into the Missouri River.
3. I will likely only flood my field once this season, but there is a chance I will irrigate once more in the fall to recharge the soil.
4. My back is fine. Maybe I've just been lucky.
5. The milk thistle is actually a crop. We'll harvest the seed which you then eat whole, grind, or make tea out of. It's a liver detoxifier.
You mean to tell me that I've got a pharmacy growing in one of the flower beds? Who would've known? Just kidding...I don't think I have the right kind of thistles. Go figure.
ReplyDeleteWow, thanks for answering my questions. I am so enjoying your blog. I learn something new at every turn.
As far as your back is concerned - maybe it's not luck. Maybe it's that it's young(ish)...