|Payne, Jerry - ARS RETIRED|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 1996
Publication Date: N/A
Interpretive Summary: Zinc deficiency is a major production limiting problem of pecan in the southeastern U.S. and is difficult to quickly correct with soil applications of Zn. While there are several Zn sources available, it is the relatively expensive sulfate source that is typically utilized. This research demonstrated that the less expensive oxide form can perform as well as the sulfate form and can correct severe deficiencies by two years after application. This work affects the pecan industry insomuch that it identifies an equally effective alternative method of correcting zinc deficiencies and does so using a zinc form (oxide) that costs about one-half of the commonly used method; thus, offering an option that can save growers substantial money in management costs.
Technical Abstract: Ground application of ZnO, to quickly correct severe Zn deficiency of large mature pecan trees in orchards possessing an acidic soil but with an artificially induced slightly alkaline soil surface zone, was at least as effective as was ZnSO4 for rapidly correcting foliar Zn deficiencies, improving in-shell nut production and maintaining kernel quality of pecan. Under such soil conditions, light disking of 160 kg of Zn/ha from ZnO elevated foliar Zn above the sufficiency level by the second growing season after application; whereas an absence of disking delayed substantial uptake from ZnO until the fourth growing season. These data also indicate that ZnO, a usually far less expensive Zn source, can be as effective as is ZnSO4 for correcting Zn deficiencies via broadcast ground application and that rapid correction of such deficiencies was best accomplished by foliar sprays of ZnSO4 rather than by soil applications of either source.