The nuts in Tom Coleman’s pistachio orchards begin to fill near the end of June, which puts the trees pretty much on schedule for a normal harvest start around September 5-6.
Based at Fresno, Calif., Coleman Farming Co. manages 900 acres of its own orchards and another 3,000 or so acres of pistachios for other owners in Madera and Fresno Counties. The trees range in age from first leaf to those that have been in his orchards for 27 years.
Following a good size crop last year, Coleman expects his 2012 production will be no more than average. Results between individual orchards, or even within the same field, could differ significantly up or down, he notes.
“As has been the case for the last several years, there’s a lot of variability among the trees this year,” he says. “Some have a heavy crop, while just a short distance away others have virtually no crop.”
He attributes this to frost damage in low areas of his fields several years ago, which induced an alternate bearing cycle within the orchards.
To meet the nutrient needs of his trees, including the spike in demand as nuts fill, Coleman applies most of the fertilizer through drip irrigation systems. He feeds younger-producing trees a total of about 100 units of nitrogen annually, while the oldest trees get up to 200 units of nitrogen each. He applies it beginning with the first irrigation, usually around the first of May and continuing through July. During this time, he also runs a total of 125 units of potassium and about 4 pounds of boron per acre through the drip systems.
To improve zinc uptake and save the cost of a soil-applied copper material, he makes a foliar application of these nutrients in the spring. He includes a little nitrogen, which helps the leaves absorb the fertilizers, Coleman says.
This spring he sprayed for botrysphaeria and botrytris in orchards with a history of the fungal diseases; other than that, diseases haven’t been a threat this season.
“We haven’t dealt with alternaria in a long time,” he says. “Years ago, we had some problems with that disease in some low areas, so we reduced our irrigation and that seems to have corrected the problem.”
In May, Coleman applied an insecticide to kill any plant bugs or navel orangeworms. Now, he’s waiting for the first hulls to split, usually in early August, before he treats all of his trees again to control navel orangeworm.
“It’s not a concern at this point,” he says. “But, no matter how much effort we make to clean up mummies in the winter, we’ll still find some that didn’t get disked under. So, I know they’re out there.”
Coleman’s usual start of his month-long harvest in the first week of September is earlier than many growers begin. This minimizes the risks of naval orangeworm damage, which increases the longer nuts stay on the tree. And, the value of the damage-free nuts, he says, outweighs the cost of shaking trees a second time to harvest nuts that weren’t maturing when the first shake was made.
“As soon as nuts are ready to come off, it’s time to harvest them,” he says. “I feel I’m getting better quality and making more money in the long run.”
Coleman has Class II water rights for his largest pistachio ranch, located in Madera County. This subordinate right means he can get water from the local irrigation district only after Class I users have received their annual supplies. This year, those users are scheduled to receive only 55 percent of the full allotment, which leaves none for Coleman and other subordinate users.
“I can’t afford not to have water,” he says, “so each winter I pre-purchase water for insurance.”
He could have bought the water he needed this past December at a cost of $275 per acre, but based on high water levels in reservoirs at the time due to last year’s ample rainfall, he decided to wait. By the time it became apparent that the snowpack in the mountains and winter rainfall in the valley would fall far short of normal and he made the decision to buy the water he needed, the price had risen to $340 an acre foot.
Even at that price, the water was worth it, Coleman says. “We should be OK for water this season. Later, the district received a little more water, which I could have bought for $400 an acre-foot, but I didn’t need it.”
Meanwhile, in the other districts where he farms and has Class I water rights, Coleman expects to receive surface water deliveries until the end of August.