“Overall, it turned out to be a pretty good crop on the ranches which had enough water for the trees this year. Where the trees didn’t get enough water, the number of closed shells was quite high – as much 80 percent in some blocks.”
Otherwise, Tom Coleman of Fresno rates his crop this year as a pretty good one in terms of closed shells, blanks, kernel size and low insect damage. “Industry-wide, navel orangeworm levels were the lowest in several years,” adds Coleman, who chairs the California Pistachio Research Board.
Some of the ranches he manages that received no deliveries of surface water had only enough ground water to supply about half their needs this season, Coleman reports. In some of those cases, well production declined steadily through the season. For example, some, that were producing 300-gallon-per-minute flows at the start of the season, were pumping only about 100 gallons per minute by harvest time.
“Those trees defoliated to some extent but not as much as you might think,” he says. “However, they didn’t have a healthy, lush look to them.”
Also, lacking enough water, the nuts were much harder to shake loose, Coleman adds.
The rest of the orchards he manages had enough surface and ground water to remain healthy. In the case of his own fields in Fresno County he paid $60 per acre foot to buy a minimum amount of water. He ended up with some unused water, which he was not allowed to transfer or sell to someone else.
In the case of the orchards he owns in Madera County, Coleman was able to supplement his reduced allocation of surface water by purchasing some insurance water last year for use this year at a cost of $418 per acre-foot. Towards the end of this growing season, he bought some subordinate water for $1,000 per acre-foot.
To stretch available water supplies on his own fields, Coleman made two changes in his irrigation management practices. One was to plug the emitters used to irrigate his male trees after they bloomed. Those trees account for about five percent all his total tree numbers. He diverted the water he saved there to his female trees.
The other water-conserving move was to build a four-acre reservoir at one ranch to capture water back-flushed through the filters to remove sand from the water used with his drip system. To prevent the stored water from percolating into the soil, in lined the reservoir with gunite.
Coleman spent $80,000 to build the reservoir and install the gunite. “It was worth the expense,” he says. “It cost less than drilling a new well, and I’m saving as much water as a well would have produced.”