To improve production grapes, Fresno County, Calif. farmer Don Hornor has been deep-ripping his alkaline soils and drilling deeper for better quality groundwater.

Hornor Farms produces 800 acres of Thompson seedless, 300 acres of Ruby Red and 120 acres of Zante currants near Kerman.

Alkaline soils, poor quality well water and a clay pan combined to cut raisin production by more than half on some blocks over several years. The clay pan prevented leaching of salts brought in with the irrigation water, leading to a salt buildup.

“You could see the vines dying back in the middle of summer,” Hornor recalls.

Three years ago he re-leveled one vineyard to more evenly distribute the water and then applied 5 tons of gypsum per acre. Then, he ran a Caterpillar D9 dozer pulling three shanks down every row, ripping 3 feet deep to break up the clay pan and improve water infiltration.

Hornor has been re-leveling his vineyards at the rate of 80 acres each winter. Where alkalinity levels are relatively low, he’s ripping up every other row. Deep ripping and applying the gypsum costs about $300 per acre. It also knocks production back for two years before yields start to recover.

But, the results are worth the costs, Hornor says. This year he’s looking for production from that initially-treated block of grapes to be back to more than 2 tons of raisins per acre.

“Probably 80 percent of the vines in the treated blocks are looking the best they have in about five years,” he says. He still has some “bad spots where alkaline is still high,” and plans deeper ripping there.

With increasing demand on well water and the third year of below normal rainfall to recharge groundwater, Hornor had to abandon, two wells, one 250-feet deep, another 280-feet, because they stopped producing water. Production from a third well, also 280-feet deep, has dropped significantly.

He just completed drilling a new 400-foot well. “This one should produce more than three of our older wells combined,” he says. A 200-horsepower diesel engine will bring the water to the surface. The diesel engine will eliminate the threat of electricity brownouts, which have burned up switch boxes and motors on his electric pump, and caused total blackouts.

“If diesel fuel goes back up to $3.50 to $4.00 a gallon like last year, I’ll look at an electric motor for the new well,” Hornor says. “Until then, I‘m better off with a diesel engine.”