Central Michigan grower Gary Carmichael irrigates his alfalfa and alfalfa-grass fields to get higher yields and greater returns per acre. He uses movable center pivots; lake, spring and swamp water; plus nearly five miles of underground pipe to accomplish those two goals.
“We have a five-month growing season from May through September in Michigan, and I want to maximize that. I want to put my farm under greenhouse conditions. If I’ve got the seed and fertilizer and don’t have the moisture, I’ve made all that investment for what? Maybe half or two-thirds of a crop,” he says.
Carmichael Farms, near Evart, raises and markets about 2,000 acres of alfalfa and alfalfa-grass, low-potassium dry-cow hay, horse hay and alpaca hay.
“We’re looking at alfalfa as a 30-day crop. We know that about every 30 or 35 days we need to be cutting it,” he says. “We know that alfalfa uses 0.2-0.3” of water per day. So in a 30-day growing season, we’re going to need 6-9” either in the soil or in rainfall.”
But average rainfall is 2.5-3.5” per growing-season month in his county. The first cutting does just fine, because there is less heat and no evaporation, but the later two or possibly three cuttings need water, he says.
“I can easily lose 1 ton in a 30-day period with low rainfall,” he says. Irrigating practically guarantees he will get 1½ tons and sometimes 2 tons/acre each cutting.
Carmichael figures that 10 days of hot weather is all that separates his land from getting too much or too little rain. If a field had adequate moisture one week and 85° the next week onward, it would probably be out of moisture within seven days.
So he monitors the amount of rain that falls as well as soil moisture. “Up to a point, you can bank water from one cutting to another. Remember, alfalfa’s deep-rooted but grasses are shallow-rooted and will run out of water sooner.”
Carmichael uses one stationary and three movable center pivots and two water systems. One takes water pumped into a pond from springs and a cedar swamp and the other uses a farm lake. In both cases, water moves by underground pipe to pivots.
“I laid a lot of pipe – I have five miles of pipe underground – so I wasn’t tied to one location. The movables give me flexibility, especially in hay. I cut the hay, run a pivot four times around the field and put on 4-5” of water and then move that pivot to the next field and do the same thing.
“That spreads my costs out. I invest in a pivot to do two to three fields. A lot of people don’t realize the logistics that you can pump water two to three miles underground with the right-size pipe, do it economically and not have too much pressure loss. As an example, we pump 500 gallons/minute, which is standard. I pump that almost two miles and only lose 15-20 lbs of pressure.”
But before he invested in the equipment, he took a long, hard look at his production costs, what it would cost per acre to irrigate and what irrigation system would be most efficient.
He also came up with several possible scenarios and costs that he shares in talks with other growers:
1) A $40,000 pivot used at one 38-acre location with a 500-gallon/minute well costing $35,000 pencils out at $1,974/acre. “That’s pretty high,” he says.
2) A 40-acre movable pivot costing $45,000 used in two locations totaling 76 acres, with the same size well at the $35,000 price, would average $1,052/acre.
3) A 160-acre center pivot at $65,000 used in one 150-acre location with a $35,000, 500-gallon/minute well would cost $667/acre.
4) A 160-acre pivot at $65,000, covering 150 acres on a river with an engine pump costing $6,000 and $5,000 worth of plastic pipe, would total $507/acre.
“If I took that same pivot and put in a 25’-deep $8,000 horizontal well, and I know guys who have run three pivots off of one, the cost spreads out more,” Carmichael says.
Growers also have to consider fuel costs to run the equipment. The higher the pressure, the more fuel is required, he says.
“It costs me 5 gallons per hour to get 120 lbs of pressure on a hard-hose traveler, but if I go down to 60 lbs on a pivot, I run the cost down to 2-3 gallons.”
The cost to run a diesel- or gas-run pivot pumping 60 psi from a 500-gallon/minute well at a 2-gallon/hour rate, at $3/gallon, would total $6/hour (figured at 1” of water per 1 acre/hour). If 4” would be needed, the cost would run to $24/acre. If 3 gallons/hour were used at $3/gallon to get a 4” watering, the total fuel cost would be $36/acre.
If run on electricity, pumps would average $7.68/acre at a $1.92/inch rate (19.2 kilowatts/hour x 10¢/kilowatt). “Electricity is so much cheaper right now,” he says. “When, in 2000, we put an irrigation system in, gas was cheap; I could buy gas or diesel for $1.18.”
Even with fluctuating fuel costs, Carmichael comes out ahead by irrigating.
“Our seeding costs are still the same, our operating costs at harvest are going to be the same. Fertilizer is still going to be the same if based on tons harvested per acre. I’m going over that same ground – what if I only get 1 ton or ¾ ton or, if we have a very dry year, a half-ton yield?
“With farmland at $2,000-3,000/acre, when I look at the cost of putting water on it and increasing my yields and guaranteeing my crop, $600-800/acre is much cheaper than buying an extra acre. So look at what farmland is costing in your area,” he urges growers. “Are you maximizing your land? What would irrigation cost to do that?”