Drip system testing farmer's ingenuity

“Where do I go to find out an answer to a question?” the grower asks. “Well, I call someone in Texas who’s familiar with drip irrigation. Unfortunately, the experts on drip aren’t familiar with the Delta style of farming. Essentially, once the equipment was set up we’ve been learning on the go.”

The first thing he needs is a proper controller. There are small, white buildings set up around Whittenton’s land that hold a myriad of pumps, hoses, electronics and gizmos. But there’s no unifying unit that prevents Whittenton or a worker from making frequent trips to the sheds.

“When we find a controller we like, we won’t have to worry with the system as much because it will be fully automated. We’re still looking, though.”

“I’ve got a pH pump, a fertilizer pump and different inputs to keep the water that’s going out in good shape. We’ve got a lot of bicarbonates in the water that could build up and clog pipes and tapes up if we don’t watch it closely.”

Many of the aspects related to the system are time-consuming. As mentioned earlier, a lot of the things Whittenton must deal with in the Delta aren’t issues in west Texas where drip irrigation is used much more.

“The fellow we bought this from is from Texas and he told me no one in (the Delta) is trying to work with a drip system like I am. That makes it harder because there’s no one else to bounce ideas off of or find solutions with.”

One thing that is the same: lack of quality water.

“One reason I wanted to try this was because the water situation around here isn’t going to get anything but worse. But that reason is in combination with being able to better conserve resources, manage my operation better and just have a better overall sense and control of what’s going into the fields.”

The water situation is very disturbing to Whittenton. There are operations in western states that are allowed only 25 acre-feet of water per 5-year period. “I can see this area getting to that point. It may not be for another decade or two, but it could happen. Yeah, we don’t have trouble right here on this land but 10 to 15 miles away, there’s a huge problem.

“You can live without a lot of things – but not water. And we all know that if water gets short, farms are the first place water is going to be pulled from. Municipalities are going to get the water and there’s no point in even arguing about it.

“I don’t know if drip is the answer, but I’m willing to look at it and see. I know the groundwater has to be protected regardless. I oppose major regulations governing our water use but I also know that we’re pumping the ground dry and we must do something ourselves or we’re going to be told what to do.”

One hundred percent of the water used on Whittenton’s crops comes off wells that average about 135 feet deep. He says the water level is about 40 feet.

Whittenton grew interested in drip irrigation a few years ago. However, it took a couple of years of searching before he found someone skilled in the practice to come talk. After weighing the benefits, last year Whittenton and several financial partners took the plunge and installed the system.

Under flat ground, irrigation tape sits about 9 or10 inches deep. Roots grow all around it. There is 492 miles of drip tape on 185 drip-irrigated acres Whittenton works. There’s almost 7 miles worth of PVC pipe also tied up in the system.

“The learning curve is steep and I’m not going to sugarcoat it. There have been a lot of bumps getting it set up to work like we need. I’ve learned not to try and do too much too fast.”

Whittenton says the point of drip irrigation is simple: he’s trying to spoon-feed his cotton crop. But there are plenty of roadblocks to making that happen.

“We’ve dealt with things that most folks never think of. We’re treating the water and lowering the pH. We’re using acid to buffer it down and using NpHuric acid as our source. We’re using some chlorine for iron, phosphoric acid for phosphorus and potassium nitrate for potassium.”

Another part of the learning curve with drip irrigation is water quality.

“You think, ‘Man, this water tastes good, it looks good and it sure is coming out of the pivot good. Surely it’ll do good under drip conditions,’” says Whittenton.

But it doesn’t work that way. A grower can put pivot water through a drip line and the line will get stopped up. The bicarbonates are bad to do just that – “that’s why we have to get the pH to around 6 or 6.5.”

Another thing: irrigation timing. On drip, it is preached that it’s best to water on short, frequent intervals. In one 154-acre block, Whittenton has 18 zones. Those zones are then grouped into sets – 4 or 5 zones to a set. Last year, Whittenton watered all the sets in 10 hours – 2 hours each set.

This year, after seeing the yield maps from last year, Whittenton found that lower field areas were coming up short. “We figured we’d run for longer irrigation times at 4 hours and 48 minutes per set. The theory is that the bottom end fills first and pressure backs up to the top. If I’m running short intervals, what we’re doing is overwatering the bottom.”

Why? Because when the pumps are cranked up, the bottom is watered and then, when the system is turned off shortly thereafter, any water built up to the top will drain down and flow out the bottom as well. So Whittenton is going to longer sets to keep a more even flow from top to bottom of a ridge.

Another change from last year was reconfiguring some irrigation zones. “We had some major washes and we made grass waterways to deal with the situation. We had to readjust our zones to make up for it.”

How elaborate the system is can’t be properly appreciated without seeing inside one of the sheds. Imagine a series of pumps, multi-colored hoses and keyboards affixed to the wall. Then, let Whittenton give a short tour.

“This is a Venturi – it pumps the potassium nitrates. We use a booster pump to get the pressure to where we need it. If you read the gauges and readings, it tells us there are 23 minutes of fertilizing to go and 53 minutes of irrigation left. Then the system will switch to watering another zone.

“With the equipment we have, the pH is monitored, and if I had chlorine – which I don’t right now – the system will monitor and turn the pump on and off to achieve, roughly, about one part per million to the end of the irrigation line.

“With the pH part of this, one machine tells how much acid to put in and another reads pH and if it’s below a certain level – 6.9, I think – phosphoric acid is added.

“This is the flow meter. It takes 27,154 gallons of water to make 1 acre-inch.”

By using the system last year, Whittenton figures he saved about a third of the water normally used irrigating under pivot.

Bottom line, what Whittenton really wants to do is maintain three-bale cotton using less water and at less expense.

This year, the varieties he’s growing on drip are: Sure-Grow 105, Stoneville 457, Stoneville 4892, Fibermax 958, and Fibermax 966. He gestures to a field of uniform, pretty cotton.

“We’re trying to find the optimal variety for drip. On this field, we have only 40 pounds of nitrogen on it. The rest of our fields have 110 pounds thus far. We can get away with that because the nitrogen is going straight to the roots.

“It takes 150 pounds of nitrogen to make three-bale cotton conventionally – about 50 pounds per bale. I need to find out how much nitrogen it takes to achieve the same yield while drip irrigating.”

Whittenton says another plus for a drip irrigation system is that TMDL’s (total maximum daily loads) are coming, and the system should help cut fertilizer use. “Believe me, those are going to make everyone sit up and pay attention. If we don’t take care of our business in run-off and excessive use of chemicals, EPA is going to come in and take care of it for us.”

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