Now, however, drip is so inexpensive and the price of cotton much improved, growers are justifying it for cotton alone.

About 80 percent of Cameron’s crops are on drip, including most of the trees and all of the vines. He still must use sprinklers on carrots and onions, and 40 percent of his 700 acres of cotton is on drip.

That will eventually be 100 percent, he says. “Water has become too expensive not to use drip. We must be more efficient with water and fertilizer, which we can deliver via drip. Nitrogen through the drip system goes directly to the roots.”

“I was on a trip to western China a few years ago, looking at processing tomatoes, and I saw growers gravity feed drip lines with water from ditches and no filters. I said we can do that, but improve on it with a pump and a simple filter.”

He utilizes buried main lines with above-ground disposable, recyclable, lay-flat 6 mil drip tape to deliver water to cotton and other crops. Well water is filtered through self-flushing $2,500 screen filters. It cost him only about $250 per acre.

“We can manage plants so much better — uniformity is amazing, and water efficiency is more than 90 percent. Virtually every drop of water is used by the plants. There is no stress unless you manage for stress.”

He irrigates based on a simple evapotranspiration formula that tells him the daily plant water use. All well water is metered so he knows exactly how much is being applied.

It was not uncommon in the past to use 4 or even 5.5 acre feet of water on cotton, Cameron says. Today, he can grow 3-bale cotton with 2.5 acre feet of water or less.

“Drip makes so much sense. We can grow 60-ton tomatoes where we could grow maybe 45 without drip. You’re talking 15 tons more tomatoes per acre on 20 percent less ground than you would with furrow or sprinklers.”

He grows many organic crops, and is one of only two or three organic Pima growers in the U.S. He had 190 acres of organic Pima last year.

Cotton is probably the most challenging crop to grow organically, he says, primarily because of weed control costs.

It was costing $450 to $600 per acre for hand weeding of furrow-irrigated, organic Pima. When he switched to drip, it cut his weeding bill to $227 in 2009. Unfortunately, early spring rains in 2011 sprouted many more weeds and the hand-weeding cost jumped back to $563 per acre.

He has to germinate weeds and mechanically take them out before planting organically certified cotton. Weeds continue to be a challenge after establishment, but with drip, he says, there are far fewer weeds to contend with during the season.