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- Author or Editor: Ray E. Worley x
Abstract
Correlations between pecan yield, quality, tree growth, and various nutritional variables were studied over an 8-year period. Yield was negatively correlated with yield the previous year, but yield was positively correlated with yield accumulated over several years. Terminal shoot growth and nuts/lb. varied in a pattern similar to yield. Soil and leaf analysis was not often correlated with yield, nut quality, or tree growth. Degree of leaf retention in a heavy crop year was positively correlated with yield the following season.
Nitrogen at rates of 112 or 224 kg·ha-1 was applied to nonirrigated and drip irrigated mature pecan trees for 9 years. Some irrigated trees received 224 kg·ha-1 N either all broadcast or ½ through the drip irrigation. Other drip irrigated trees received only 112 kg·ha-1 all through the drip irrigation system. Fertigation was in 4 equal monthly doses beginning April 1. Irrigation increased yield for 2 years for Schley and 3 years for Stuart. Nut size was increased by irrigation in 6 years for Schley and 8 years for Stuart. Applying ½ N through the irrigation system caused no detrimental effect on yield or nut quality. The lower rate of N all applied through the drip irrigation system gave yield and nut quality as good as the higher rate either all broadcast or ½ broadcast and ½ fertigated.
Abstract
Zinc uptake by pecan leaves as affected by Zn sources and methods of application was compared for young and old pecan trees. Sources of Zn used were ZnSO4, ZnO, ZnHEDTA, and ZnEDTA. Methods of application were broadcast, in holes, and foliar sprays. Chelates were applied at 1/5 - 1/10 the rate of Zn used for ZnSO4 or ZnO. Leaf Zn from trees treated with ZnO broadcast was either equal to or greater than that from trees treated with ZnSO4 broadcast when both were applied every year. On young Zn deficient trees, ZnEDTA entered the tree earlier than the other sources when broadcast. Zinc deficiency symptoms appeared when leaf Zn was 40 ppm or less. Foliar sprays of ZnSO4 caused erratic and temporary increases in leaf Zn.
Staminate and pistillate flower maturity of 80 cultivars of young (<15 years old) pecan [Carya illinoinensis (Wangenh.) K. Koch] trees are presented. These patterns show that pollination and receptivity windows within the flowering season can be divided into very early, early, mid, late, and very late season protandrous (Type I) and protogynous (Type II) types. This system therefore provides a seasonally based 30-class Type I and Type II alternative to the standard two-class Type I and Type II system, thus offering enhanced resolution of flowering intervals and an improved means of selecting cultivars to ensure cross-pollination of yard and orchard trees. Scott-Knott cluster analysis of budbreak, nut ripening date, and date of autumn leaf drop segregated cultivars into one of several categories.