Search Results

You are looking at 1 - 10 of 25 items for

  • Author or Editor: G.H. Neilsen x
Clear All Modify Search
Author:

Abstract

‘Delicious’, ‘Golden Delicious’, ‘Spartan’, and ‘Mcintosh’ (Macspur) apple (Malus domestica Borkh.) orchards with low leaf Zn concentration, typical of many orchards in British Columbia, but with otherwise adequate nutrition were monitored for leaf Zn concentration throughout the 1983–85 growing season. Mid-terminal leaf Zn concentration consistently declined from a high of 40 µg·g–1 in early May to values approaching or below the 14 µg·g–1 deficiency concentration, despite annual sprays of dormant Zn.

Open Access
Authors: and

In irrigated apple orchard systems, the magnitude and timing of plant demand for nitrogen (N) and retention of N in the root zone to allow root interception are important factors for efficient management of N fertilizer. Results from five experiments in high-density plantings of apple (Malus domestica) on dwarfing (`Malling 9') rootstocks are reported. All experimental plots received daily drip irrigation and N applied through the irrigation system (fertigation) with different regimes according to experimental design. Labelled fertilizer applications, whole tree excavation and partitioning and removal of N in fruit and senescent leaves were used to assess tree N demand. Nitrogen requirements ranged from 8 to 40 lb/acre (8.8 to 44 kg·ha-1) over the first 6 years after planting and N use efficiency was often low (<30%), likely because supply exceeded demand. Annual growth is supported by N remobilized from storage and taken up by roots. Root uptake of labelled fertilizer was negligible during early spring and the commencement of rapid uptake was associated with the end of remobilization and the start of shoot growth, rendering prebloom fertilizer applications ineffective. Thus timing of N supply to periods of high demand is crucial for improving efficiency. Comparisons were made to determine the effects on N leaching and tree N utilization of irrigation scheduled to meet evaporative demand and irrigation applied at a fixed rate. Water losses beneath the root zone were greater for fixed rate than scheduled irrigation during the coolest months (May, June and September) of irrigation application. Nitrogen leaching followed a similar pattern during times of N fertigation (May and June). Greater N use efficiency was also measured for trees when irrigation was scheduled to meet evaporative demand rather than applied at a fixed rate. The most N efficient management system was for trees receiving a low [50 ppm (mg·L-1)] fertigated N supply, at 0 to 4 or 4 to 8 weeks following bloom with scheduled irrigation.

Full access

Traditionally, broadcast or foliar fertilizer applications sufficed to improve the nutrition of many irrigated, deciduous fruit orchards in western North America. Recent developments, including adoption of low-pressure, micro-irrigation systems and planting at higher densities (especially for apples), have increased interest in controlled application of fertilizers directly with irrigation waters (fertigation). The possibility of using fertigation to synchronize fertilizer application and plant nutrient uptake seems attractive as environmental concerns to minimize leaching of nutrients (especially N) to groundwater increase. Recent fertigation research in western North America will be reviewed and compared to traditional fertilizer application methods to assess the potential of fertigation to overcome inadequate nutrition. Emphasis will be placed on the use of soil solution monitoring to assess changes in soil NPK status. Tree response will be illustrated by studies in high-density orchards where N, P, K, Ca, B, or Zn have been fertigated.

Free access

Traditionally, broadcast or foliar fertilizer applications have been used to improve or sustain the nutrition of many irrigated, deciduous fruit tree orchards in western North America. Recent developments, including adoption of low-pressure microirrigation systems and planting at higher densities [especially for apple (Malus domestica Borkh.)], have increased interest in controlled application of fertilizers directly with irrigation (fertigation). Recent fertigation research in western North America is reviewed, emphasizing results from high-density apple orchards. Fertigation and traditional broadcast application methods are examined with respect to mobility of N, P, and K in the soil and response of fruit trees to application of these nutrients.

Full access
Authors: and

In an apple (Malus domestica Borkh.) orchard with a severe replant problem, tree size was increased by the 2nd year and number of fruit by the 3rd year by treating the planting hole soil with formalin or mancozeb plus monoammonium phosphate (MAP) fertilizer. Growth increases were evident each year for 4 years only for the MAP + formalin treatment. In a second orchard, with a less severe replant problem, planting-hole treatment with formalin or dazomet + MAP increased tree size by year 2. Number of fruit in year 2 was increased by formalin and mancozeb + MAP treatments, although this effect persisted in year 3 only for mancozeb + MAP. Leaf P concentrations were increased to high values in the first year by MAP fertilization but declined in subsequent years. Leaf Mn concentration also increased in one orchard, a consequence of fertilizer-induced acidification of planting hole soil and Mn uptake from the fungicide mancozeb. Chemical names used: tetrahydro-3,5-dimethyl-2 H -l,3,5-thiadiazine-2-thione (dazomet); 37% aqueous solution formaldehyde (formalin); Zn, Mn ethylene dithiocarbamate (mancozeb).

Free access

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).

Free access

`Spartan' apple (Malus×domestica Borkh.) trees on M.9 (T337) rootstock were planted in April 1994 at 1.25 m × 3.5 m spacing. Seven soil management treatments were applied within a 2-m-wide strip centered on the tree row and arranged in a randomized complete-block experimental design. Treatments included a weed-free strip (check) maintained with four annual applications of glyphosate; surface application of 45 t·ha-1 of Greater Vancouver Regional District (GVRD) biosolids applied in 1994 and again in 1997; mulches of shredded office paper; alfalfa (Medicago sativa L.) hay; black woven polypropylene; and shredded paper applied over 45 t·ha-1 GVRD-and Kelowna-biosolids applied in 1994 and 1997. All experimental trees were fertigated with phosphorus (P) in the first year and with nitrogen (N) annually. Cumulative yield for the first five harvests was higher for trees subjected to any soil management treatment relative to check trees. Maximum cumulative yield, exceeding check trees by 80%, was measured for trees grown with a shredded paper mulch with or without biosolids application. Trees from the three shredded paper treatments were the only ones significantly larger than check trees after six growing seasons. No increases in leaf nutrient concentration were consistently as sociated with improved tree performance. Notable effects included increased leaf P concentration associated with biosolids application, increased leaf K concentration after alfalfa mulch application and temporary increases in leaf Zn and Cu concentration associated with application of biosolids high in Zn and Cu. Use of both mulches and biosolids amendments benefits growth of trees in high density plantings despite daily drip irrigation and annual fertigation.

Free access

Direct application of fertilizers in irrigation water (fertigation) is an efficient method of supplying nutrients to fruit trees. Information is needed on the relationship between irrigation and N inputs on N availability in order to target nutrient applications to meet plant demands. Soil solution was collected from permanently installed suction lysimeters and NO3-N concentration was measured over the growing season in three experiments: 1) comparison of sprinkler irrigation + broadcast fertilizer with weekly fertigation + daily drip irrigation; 2) comparison of (NH4)2SO4 or Ca(NO3)2 as N sources under daily fertigation; and 3) comparisons of combinations of irrigation applied at either fixed rates or to meet evaporative demand and fertilizer (Ca(NO3)2) applied daily either at fixed rates or to maintain a given concentration in the fertigation solution in two soil types—loamy sand and silt loam. Trials are located in high density apple plantings of either `Gala' or `Empire' apple (Malus × domestica Borkh.) on M.9 rootstock. Nitrate-N concentration in the soil solution measured at 30 cm deep remained higher, over more of the growing season, for weekly fertigation + daily drip irrigation than for a single broadcast fertilizer application + sprinkler irrigation. With daily Ca(NO3)2 fertigation, soil solution NO3- N concentrations increased and decreased rapidly with the onset and end of fertigation respectively, remained relatively constant during the intervening period and were directly proportional to either the amount of N or the amount of irrigation water added. Daily fertigation with (NH4)2SO4 resulted in less control of NO3-N availability in the root-zone than with Ca(NO3)2, which may be problematic for precise timing of N nutrition. Except for the fixed irrigation rate applied to the loamy sand soil, soil solution NO3-N concentrations at 30 cm beneath the emitter were similar to average concentrations in the fertigating solution, for all methods of irrigation management in both soil types. Elevated NO3-N concentrations in soil solution below the root zone (75 cm deep) were detected in the loamy sand regardless of methods of N application and irrigation although there was some evidence of less leaching to this depth, under scheduled irrigation. In the silt loam soil, considerably lower concentrations of NO3-N were found beneath the root zone than at 30 cm deep for all of irrigation procedures and frequently there was insufficient water moving to 75 cm to provide sample. Tree growth in the loamy sand was less than in the silt loam soil; was limited by low application of irrigation water in 1992 and 1993; was unaffected by NO3-N concentration in the root zone, indicating that N inputs could be minimized by adding N to maintain concentrations of 75 μg·mL-1 or possibly less. Nitrogen inputs may also be reduced if fertilizer N and irrigation water could be retained within the root zone. For coarse-textured soils this will require precise additions of water and possibly soil amendments to improve water holding capacity.

Free access
Authors: and

Abstract

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.

Open Access
Authors: and

Abstract

Field experiments of chelated-or Epsom salt-Mg sprays in 1981 and 1982 on ‘Delicious’ (Red King and Starking strains) and ‘McIntosh’ apple trees (Malus domestica Borkh.) indicated that a minimum of 2 x 2.8 kg Mg/ha, foliar-applied, was necessary to increase leaf-Mg concentration to desired 0.26% levels in ‘McIntosh’. Thus, label-recommended application rates for chelated Mg (2 x 0.56 kg Mg/ha) were too low. ‘McIntosh’ extension growth was increased by adequate foliar-Mg applications, although leaf Ca was reduced in 1 year by the foliar-Mg treatments.

Open Access