By Clint Thompson
Maintaining herbicide strips in pecan orchards is an essential management tactic for growers with young trees, says Lenny Wells, University of Georgia Cooperative Extension pecan specialist.
It is not as dire, though, for producers with more mature trees.
“In a mature orchard, the competition is not going to be as hard on the tree, but also if you get enough shade to where if you’ve kept pretty good herbicide strips in the past, that shade will keep (weeds) down somewhat,” Wells said. “Young trees can be hurt pretty bad if you don’t keep the weeds away from them. It’s pretty critical on those.”
Wells addressed the concern in the UGA Extension pecan blog as growers try to reduce production costs. Multiple producers have asked if they really need to maintain a herbicide strip all year long.
“If you’re talking about an orchard with young trees still in the establishment phase or an orchard not yet bearing, you definitely need to maintain a herbicide strip,” Wells wrote. “Weed competition is one of the biggest drains on growth of the tree and length of time to production.
“The two most important things for tree establishment and getting them growing and getting them to bearing size is keeping the weeds away from them and keeping good soil moisture.”
Oklahoma State research has shown a 334% increase in yield by year seven on trees with the largest weed-free area.
Mature, established trees compete well with most grasses and herbaceous plants. The strip’s main benefit in a mature orchard is to make the wind-row harvest process run smoothly, says Wells. Most growers need to burn it down as harvest approaches.
“One confounding factor with this is that too much dead, herbaceous material in the strip can trap nuts when trying to blow them out of the tree row at harvest,” Wells wrote. “If you decide to cut back on the maintenance of your herbicide strip in mature orchards to save money, be sure to mow it (mowing across the rows) prior to the burndown for harvest to try and limit the amount of debris left in the strips which may interfere with harvest.”