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- Author or Editor: E. J. Hogue x
Layering is a common commercial method of propagating plant material, particularly plants such as currants and gooseberries, which reproduce naturally in this manner. European nurserymen have used layering extensively for the propagation of ornamental schrubs and trees (5). Mound or stool layering (stooling) is a method which involves cutting a plant back to the ground during the dormant season and mounding soil or other media around the base of the newly developing shoots to encourage roots to form on them (1, 2). Stooling is the most common method of propagating clonal rootstocks (4) especially for material, such as some East Mailing, Malling-Merton and Malus robusta apple stocks that are not always easily rooted as cuttings.
For prompt germination the seed of Russian olive (Elaeagnus angustifolia L.) required 9 to 12 weeks of after-ripening at a temperature of 5° C. When fruit and endocarp were removed, 50–60% of the non-after-ripened seed germinated. Complete germination was obtained by removing the endocarp and the seed coats. The germination inhibition appeared to be related to non-leachable inhibitors in both of these structures, and their influence was almost entirely restricted to the radicle end of the embryo. Kinetin was very effective in breaking the dormancy linked to the seed coats but did not influence dormancy when the endocarp was present.
Growth of Zn-deficient apple seedlings (Malus domestica Borkh. cv. McIntosh) grown in the greenhouse responded equally well to chelated or mineral Zn foliar sprays of the same Zn concentration. Absolute leaf Zn uptake, but not leaf Zn concentration, was a good measure of growth response. Foliar sprays with a concentration greater than 2.5 × 103 µg Zn/ml were required to correct Zn deficiency and adequately support growth of severely deficient seedlings for a month.
Zinc-deficiency symptoms and relatively low mid-terminal leaf Zn concentrations were observed in apple seedlings (Malus domestica Borkh. ‘McIntosh’) grown in a minus-Zn Long Ashton solution comprised of reagent grade but unpurified chemicals. Leaf Zn concentration increased as the initial concentration of added Zn increased through the range 0 to 4 μm. Zinc was highest in seedlings grown in solutions with both high Zn and high P concentrations. High leaf P concentrations were associated with inadequate Zn nutrition.
The application of (2-chloroethyl)phosphonic acid (ethephon) on pickling cucumber (Cucumis sativus L.) in the 2 to 3 leaf stage both at 100 and 400 ppm significantly increased the yield and farm value of this crop. A proportionately greater increase in value of the crop was obtained by decreasing the plant spacing from 30 × 30 cm, to 23 × 23 cm or 15 × 15 cm. The treatment yielding the highest value crop was obtained with the plant spacing of 15 × 15 cm and 400 ppm ethephon application.
The effects of various nonfumigant planting-hole treatments on growth and yield of apple (Malus domestics Borkh.) trees were measured during the first 3 years after planting. Eight orchards diagnosed as having a replant problem were monitored. First-year shoot growth, the number of blossoms in the second year (inmost orchards), and first-year trunk cross-sectional area increment (TCAI) in 50% of test orchards were increased by monoammonium phosphate (MAP) fertilizer+ peat, MAP+ mancozeb, or MAP + peat + a bacterial antagonist. By the end of year 3, TCAI generally was not affected by treatments, but treatments resulted in more blossoms by the third season in two of seven orchards that blossomed in the second season. Cumulative yield after 3 years increased significantly in only three orchards, with the best treatment, MAP+ peat, resulting in cost recovery in only one orchard. Inadequate K or Cu nutrition may have reduced growth in some of the orchards, which were characterized by a wide range in yields, independent of planting-hole treatment.
Five sets of basic tillage operations were carried out for 5 consecutive years on an organic soil, each followed by seeding on the flat or on raised beds to determine the cultural methods that would provide the best yield of quality fresh market carrots (Daucus carota L.) without adversely affecting the soil structure. Raised beds offered no yield advantage in a wet season and no yield reduction in a dry season. In a wet season, the bed system favored harvesting operations by reducing soil moisture and rendering the field surface firmer. Minimum tillage consisting of a fall and a spring disking did not reduce yields or increase soil bulk density as compared to spring plowing and rototilling.
Application of high rates of P in the year of planting increased the number of flower clusters and fruit set the subsequent year on newly planted `Macspur McIntosh', `Summerland Red McIntosh', `Jonagold', and `Jonamac' apple (Malus domestica Borkh.) on dwarfing rootstock (M.26 and M.9) in three separate experiments. The effect occurred whether P was applied at rates of 36 or 48 g P/tree as granular monoammonium phosphate (11 N-23.6 P-0K) uniformly mixed with 100 or 180 liter of soil in the planting hole or at rates of 17.5 and 35 g P applied as soluble ammonium polyphosphate (10N-14.6P-0K) with the irrigation water. A leaf P concentration range between 0.20% and 0.36% was associated with the acceleration of fruiting.
Mature ‘Golden Delicious’ apple trees (Malus domestica Borkh.) were subjected for 3 years to factorial combinations of 3 rates of N fertilization applied in April and 3 degrees of orchard floor management. Tree N nutrition was affected more by vegetation management than by rate of N fertilizer applied. Significant reduction in leaf N and trunk diameter, and superior fruit skin color and firmness at commercial harvest occurred consistently when the orchard floor was sod. Increased leaf N and reduced fruit skin color and firmness at harvest were measured at the highest N (180 kg N ha-1) in only 1 year while tree growth was not increased by this rate of N. Increased fruit Ca associated with smaller fruit and increased leaf Mg and leaf K were measured under sod in 2 of 3 years. Leaf Mn was affected only by rate of N fertilization and was consistently high at 180 kg N ha-1.
Zinc supplied as a fulvic-based Zn compound was absorbed and retranslocated to unsprayed new growth as effectively as zinc sulphate in apple seedlings of low Zn status grown hydroponically in the greenhouse. Similarly, fulvic- and humic-based compounds were as effective as zinc sulphate at improving short-term growth and Zn uptake into new tissues in Zn-deficient apple seedlings, with the best growth occurring at spray concentrations of Zn at 500 mg·L-1. Under field conditions, Zn concentration of peeled and washed `Jonagold' apples at harvest was increased, without phytotoxicity, by two or four postbloom sprays of fulvic Zn. It is therefore possible to use this material safely as an effective Zn-source after bloom. However the mobility of the foliar-applied Zn is limited and any yield response by treated apple orchards of marginal Zn nutrition is unlikely to occur in the short term (within two growing seasons).