In addition to his work in the field, Coleman chairs the California Pistachio Research Board which funds research on pistachio production and is vice chair of the Administrative Committee for Pistachios, a federal marketing order. The pistachio industry is coming off the biggest crop in history. Last year, California growers brought in 521 million pounds (inshell) of nuts. Meanwhile, Arizona and New Mexico farmers produced 8 million pounds for a total 2010 crop of 529 million pounds. The previous record was the 415-million-pound harvest in 2007.

Like producers of other California tree nuts, Coleman and his fellow pistachio growers are profiting from continued growth in pistachio demand worldwide. Pistachio prices are at a record high of around 2.50 per pound. That’s up more than 40 percent from the roughly $2.22 per pound growers received for their 2009 pistachios. Some of that increase reflects expectations earlier in the 2010 crop year for a much smaller crop – in the mid-300 million-pound or even lower range – than was actually harvested. Pistachio growers normally sign contracts to sell their nuts before harvest. The higher prices processors offered growers last August were based on the lower, pre-harvest production estimates.

As an alternate bearing tree, the size of the pistachio crop fluctuates from one year to the next. Coleman was satisfied with his 2010 off-year yields that ranged from about 3,000 to 4,000 pounds per acre. In the on-year of 2009, production averaged around 3,500 pounds per acre, with his better orchards producing as much as 5,000 pounds per acre.

This past winter he pruned his trees a little heavier than the previous winter to prepare for the expected higher 2011 production. “Going into an on-year like this one, pistachio trees seem to overcome the loss of buds from pruning,” Coleman says. “The remaining buds are more viable with a higher rate of pollination and produce more nuts.”

His trees are planted 16 feet apart within rows, which rows are spaced 20 feet apart. The more common spacing is 17-by-19 feet. “I’d rather crowd the trees a little in the row and keep the middles open more,” he explains. “Otherwise, the trees can get pretty tight between rows. If you’re not careful when going down the middles with equipment you end up knocking nuts off the trees.”

Coleman’s spacing results in 135 trees per acre. That’s close enough to get a large number of trees, but not so dense that trees have to be pulled out because of crowding, he adds.

Except for that one invasion by grasshoppers, Coleman’s insecticide program has kept insect pressures very low, he reports. From time to time over the years, Botryosphaeria panicle and shoot blight have infected some of his older trees during wet weather at bloom. Alternaria, another fungal disease, can pose problems for pistachio trees from spring through July. It hasn’t caused growers in his area of the San Joaquin Valley as much trouble as it has farther south, he reports.

Coleman fertiligates his trees, all on drip systems, with nitrogen, potassium and boron. Some of the boron as well as copper and zinc are sprayed on the leaves. “Getting enough zinc for our trees on the Madera County ranches is a constant battle,” he says. He tries to finish the nitrogen applications by the end of July and continues applying the remaining nutrients until the end of August.

Unlike some growers who apply large quantities of nutrients two or three times a year, Coleman feed his trees smaller amounts more frequently throughout the season, starting with the first irrigation. “I think the trees are better able to take up the nutrients when you spoon-feed them a little at a time and always with water rather than dumping on a whole lot a few times a year.”

Also, he says, this approach helps improve water infiltration on his surface-irrigated fields, where salts in the fertilizers impede water movement in the soil. “Smaller, consistent fertilizer applications with water seem to work just as well as gypsum in keeping the soil loose,” he says. “Also, it’s easier to do.”