Week 8 Newsletter

After a very wet spring it has been a dry summer on the farm so far, which has its advantages and disadvantages. We always say it is easier to put water on the fields than take it off. We haven’t ever tried to take water off the fields, but our friends at Angelic Organics in Illinois did that last week. They received 5.25 inches of rain in four days. Some of their fields were completely under water so they dug some holes in the low spots in the field and installed a trash pump and sucked out over 1000 gallons of water. This isn’t a lot of water but enough to save the vegetables growing in the low spots in the field. We empathize with them and hope the weather is kinder to them over the coming weeks.
We have watched storm after storm go north or south of the farm and on Saturday evening the storm went both north and south leaving about a 2-mile wide dry patch just over us. This means Jean-Paul and John have been on irrigation duty over the past three weeks. When it doesn’t rain we try to put ¾ inch of water on each field every week. We call this maintenance irrigation. Most conventional agricultural guides recommend that you put 2 inches of rain on your crops each week. We don’t follow this advice for a number of reasons. We don’t want to coddle our plants, having 2 inches of water on them each week would keep their roots shallow and their growth really soft. We want our plants to have deep roots to access the water that is deeper down in the soil. We also don’t want to wash away the nutrients in the soil. Adding 2 inches of water each week implies that you also add more fertilizer each week which is not an option for us anyway.
Another reason we don’t want to put on 2 inches of water is disease prevention. To put on that much water the plants would be wet for hours at a time. For example, Alternaria blight reproduces with spores that require wet conditions to open and disperse the blight. The spores only need to be wet for 4 to 5 hours to open up which would easily happen if we irrigated for 2 inches of water. Organic farmers don’t have any effective options to control Alternaria blight once it occurs. Other diseases and blights follow similar patterns.
We have an irrigation reel with a traveling gun (the huge sprinkler that shoots out the water) and an underground irrigation line so that one person can move the irrigation set up in about an hour. The irrigation reel has an 850 ft. long hose that we pull out and then it reels itself in with the water pressure. We can irrigate about five acres with each “pull”. The irrigation hose reels
itself in at about 40 meters per hour. When we irrigate the field with 850 ft. long beds it takes about 7 to 8 hours to irrigate four acres. At this rate it takes about 7 days to irrigate the whole farm. Then if it doesn’t rain we start all over again.
We also have about 6 acres of crops grown with drip irrigation. We cover the soil with a layer of biodegradable “plastic” mulch (made of corn starch so it isn’t really plastic) and bury a plastic tube with very small holes in it under the soil. The water slowly trickles out of the tube putting the water right at the plants’ roots. The layer of plastic on top of the soil reduces evaporation keeping the soil moist around plants’ roots for much longer than in bare ground. We run the drip irrigation for about 6 hours to give the plants the right amount of water. We can only use the drip tube and the mulch one season which adds quite a bit to the cost of this irrigation method. If we could discount the use of plastic for the drip tube and the cornstarch mulch it is a much more efficient method of watering. Some farms put the drip tube on top of the soil but that causes problems if you want to do this on a large scale. Each time you want to cultivate or weed you have to pick up the drip tube and then lay it back down. This is a very time consuming project that also puts nicks and holes into the drip tube if you can even manage to roll it up without creating a huge mess of knots. The farm that grows our green beans tried this method and he even had a machine to roll up the drip tape. The benefits they received from the drip tube were too small in comparison to the time and energy it took to make it work so they quit doing this after a season or two.
We chose our two types of irrigation because for our size farm they are the most efficient use of time and fuel. We pump the water from the Kinderhook Creek with a pump that is run by one of our tractors. This is more fuel efficient than our large pump with its own engine. The traveling gun shoots out 170 gallons of water per minute. With the tractor running the pump we can irrigate for 12 hours on one tank of fuel. This means we can pump 122,000 gallons of water with one tank of diesel (30 gallons) or with 1 gallon of diesel we can pump about 4000 gallons of water. All these numbers mean it costs us about $1100 worth of fuel a week if we have to irrigate the whole farm (or about $1.00 per member for a week’s worth of irrigation which does not include the cost of the equipment).
Right now Jean-Paul is starting the irrigation rotation over again. The gun is set up in the carrots, parsnips, celeriac, beets, and a planting of sweet corn. The forecast is calling for rain today and tomorrow. So, we haven’t turned it on, hoping the much needed rain will fall and Jean-Paul and John will get a few days break from the irrigation gun. (P.S. After I wrote this we received about 1 inch of rain on Sunday night.) ~ Jody