Allometric equations were developed for orchard-grown pecan [Carya illinoinensis (Wangenh.) C. Koch] trees. Trees, ranging in size from 22 to 33 cm in trunk diameter 1.4 m above the ground, were destructively harvested from two sites. The entire aboveground portion of each tree was harvested and then divided into leaves, current season's shoots, and branches ≥1 year old plus trunk. Roots were sampled by digging a trench beginning beneath the trunk and extending to one-half the distance to an adjacent tree, then separating the roots from the soil. Roots were then divided into those less than 1 cm in diameter and those ≥1 cm in diameter. Equations in the form Y = eaXb were developed to estimate dry biomass of most tree components and the whole tree, where Y is the dry weight, e is the base of the natural logarithm, X is the trunk diameter at 1.4 m above the ground, and a and b are coefficients. A linear equation provided the best fit for estimating the weight of the current season's growth. Power equations were also developed to estimate the weights of inner bark and wood for different size trunks or branches.
Michael W. Smith and Bruce W. Wood
M. Lenny Wells and Bruce W. Wood
(cotyledon) filling and shell hardening, resulting in abortion and drop of damaged fruit ≈7 d after splitting ( Wood and Reilly, 1999 ). The WSFS malady is highly erratic with incidence and severity varying depending on cultivar, location, and year
Andrew P. Nyczepir and Bruce W. Wood
symptoms of pecan seedlings induced by root-knot nematode ( Meloidogyne partityla Kleynhans) are correctable by timely foliar Ni application ( Nyczepir et al., 2006 ; Wood et al., 2004 ). Plant Ni nutritional physiology can affect many physiological
M. Leonard Wells and Bruce W. Wood
consistent from year to year ( Wood, 1991 ). Optimum yield for individual trees or orchards may vary considerably from one year to the next; however, for southeastern United States orchards, return fruit set is generally nil to poor when production is ≈2000
Bruce W. Wood, Lenny Wells, and Frank Funderburke
associated with physiological stresses accentuated by “moderate to heavy” crop loads ( Wood et al., 2009 ). Depending on genotype, this drop is complete within ≈3 to 5 weeks (usually by mid-June) after stigmas of pistillate flowers lose receptivity and fruit
R.P. Flynn, C.W. Wood, and E.A. Guertal
A glasshouse study was conducted to evaluate the suitability of composted broiler chicken (Gallus gallus) litter as a potting substrate using lettuce (Lactuca sativa L.). Broiler litters containing wood shavings or peanut bulls as bedding materials were composted with either shredded pine bark or peanut hulls. Composted materials were then combined with a commercially available potting substrate. Greatest fresh weight yield was obtained when peanut bull compost was mixed with commercial potting substrate at a ratio of 3:1. Fresh weight was less with pine bark compost than with peanut hull compost. However, there were no differences in lettuce dry weight among composts except for pine bark composted with wood-shaving broiler litter. The pH of this material was below the lettuce tolerance level for mixes at or above 50% compost. There was no evidence of lettuce physiological disorders resulting from excessive nutrient concentration. Most elements analyzed (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and Al) were within or slightly above sufficiency ranges for Boston-type leaf lettuce. It appears that composting broiler litter for use as a potting substrate or component would be one suitable alternative to land application in the southern United States. We recommend, however, that the pH of substrates be adjusted to suit desired crop requirements.
Bruce W. Wood and Larry J. Grauke
that pecan possesses a relatively high Ni requirement during early spring ( Wood et al., 2004 ), and Ni's associated importance in nitrogen, organic acid, and fatty acid metabolism ( Bai et al., 2006 , 2007 ) has led to modified nutrient management
Bruce W. Wood, Charles C. Reilly, and Andrew P. Nyczepir
The discovery of nickel (Ni) deficiency in field plantings of pecan [Caryaillinoinensis (Wangenh.) K. Koch] (Wood et al., 2004) has led to efforts to identify appropriate management approaches to correct tree deficiency and to identify the causes for Ni deficiency. Evaluation of several inorganic and organic forms of Ni have indicated that solutions from all sources function well to correct deficiencies when timely applied as a foliar spray to affected trees at Ni concentrations >10 mg·L-1. Addition of urea, ammonium nitrate, or nicotinic acid to Ni spray solutions increased apparent foliar uptake from Ni sprays. The lower critical level of Ni, based on foliar analysis, appears to be in the 3-5 mg·L-1 dw range, with the upper critical level appearing to be >50 mg·L-1 dw. The cause of Ni deficiency in soils possessing plenty of Ni is associated with excessive amounts of one or more metals (e.g., Ca, Mg, Fr, Mn, Cu, and Zn) that inhibit Ni uptake and/or utilization. Root damage by nematode feeding and cool/dry soils during early spring also contributes to Ni deficiency. Foliar application of Ni to foliage in the autumn and subsequent appearance of Ni in dormant season shoot tissues indicates that Ni can be mobilized from senescing foliage to dormant season shoots and is therefore available for early spring growth. Evidence indicates that pecan has a higher Ni requirement than most other crop species because it transports nitrogenous substances as ureides. Thus, there is evidence that Ni-metalloenzymes are playing either a direct or indirect role in ureide and nitrogen metabolism. It is postulated that crop species that are most likely to exhibit field level Ni deficiencies are those that transport N as ureides. Candidate crops will be discussed.
Curt R. Rom and Bruce Barritt
The role of spur leaves in bud and fruit development on two spur-type `Delicious' apple strains (Malus domestica Borkh.) and factors affecting spur development were studied. Reducing spur leaf area on vegetative spurs in August reduced the number of spurs that flowered the following year but did not affect flower size. On spurs that did flower, leaf area reduction the previous year did not influence leaf number or area, but the bourse shoot leaf area was reduced. Spur bud diameter, leaf area, size, specific leaf weight (SLW), and leaf dry weight were larger on 2-year-old vegetative spurs than on 1- or 3-year-old spurs. Within each age section of a limb, spur leaf number, area, size, SLW, and bud diameter decreased from the apical to basal positions on the limb. Flower number did not vary within a limb section, but fruit set was lower on the most apical and basal spurs compared to midshoot spurs. Fruit size was largest at the apical end of each limb section and was smallest at basal positions. These relationships were not affected by strain, tree age, or orchard location. Summer pruning at 30 days after bloom tended to increase leaf number, area, size, and spur length compared to unpruned trees or pruning later in the season but did not influence spur bud diameter.
M.A. Woodard, B.C. Bearce, and E.C. Townsend
A recycling nutriculture system was redesigned to improve growth and flowering of Tagetes erecta L., cv., Inca Yellow in four media; loose rockwool (RW), coal bottom ash (CBA), pinewood peelings (PWP) and CBA:PWP (1:1, v/v). Three nutricycle frequencies of 12, 6 and 4 per 12 hour light period were set with a nutricycle duration of 5 minutes. Volume, height and fresh and dry weights of marigolds in CBA, PWP and CBA: PWP were comparable to that of marigolds in RW. Flower diameters of plants in CBA, PWP and CBA:PWP were increased and days to harvest decreased compared to plants in RW. Plants in CBA: PWP increased in fresh weight compared to CBA or PWP plants. No interaction occurred between media and nutricycle frequency at 12 or 4 cycles per 12 hours; however a malfunctioning timer caused prolonged flooding of plant root zones at the 6 cycle setting. This resulted in decreased plant volume and fresh and dry weights at this frequency. These results show that growth and flowering of marigolds in CBA and PWP comparable with that in RW can be achieved with more than 1 nutricycle frequency.