Vicky BoydFor every 1,000 pounds of almond kernels harvested, as much as 80 pounds of potassium is removed, according to University of California studies.Overland Park, Kan.-based Great Salt Lake Minerals has launched a tool designed to help almond growers and pest control advisers balance orchard potassium requirements with crop yields.
The calculator tool can either be downloaded free from the Apple store for use on iPads or accessed online at http://www.textbookalmonds.com, according to a news release.
The app is not available for users of iPhones or other smartphones.
A version for Android-based tablets is available free from Google.
Users simply type in their number of almond acres, the previous year's per-acre yield and this year's estimated per-acre yield.
Using a constant figure of 96 pounds of potassium removed per 1,000 pounds of kernels harvested, the calculator then provides users with the total estimated potassium removed from the soil.
At the same time, it also shows the amount of sulfate of potash, or K2O, needed to replenish supplies.
Maintaining adequate potassium levels in orchards is crucial to producing healthy crops, according to the release.
A 2001 study by University of California, Davis, plant sciences professor Patrick Brown and colleagues found that trees with less than 1.4 percent of potassium in a July leaf sample had a 27 percent increase in spur mortality and a 30 percent decrease in return bloom of fruiting spurts the following year.
“When the almond crop depletes the soil of nutrients that could be compared to withdrawing money from the bank,” David Doll, a UC Cooperative Extension farm adviser in Merced County, said in the release. “You have to replace that amount in order to avoid future potassium deficiency in the orchard. You have to build up your potassium credit.”