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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Nutrient cycling in agroecosystems 33 (1992), S. 239-247 
    ISSN: 1573-0867
    Keywords: Al ; apple orchard ; Ca ; Fertigation ; K ; Mg ; Mn ; sandy loam ; soil pH ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Changes in soil pH, exchangeable aluminium (Al), calcium (Ca), magnesium (Mg), and potassium (K) and extractable manganese (Mn) were investigated after urea fertigation of a sandy loam soil in an apple orchard in New Zealand. Urea at three rates (0, 25, 50 kg N ha−1 yr−1 or 0, 16.9, 33.8 g N emitter−1 yr−1) was applied in 4 equal fertigations. Soil cores at 4 profile depths (0–10, 10–20, 20–40 and 40–60 cm) directly below and 20 cm from the emitter were sampled approximately 4 weeks after each fertigation and in the following winter. Results obtained showed that the largest changes in soil pH and cations occurred in soils directly below the emitter in the 50 kg N ha−1 yr−1 treatment where the soil pH decreased by 1.6 pH units at all soil depths. The lowest pH of 4.3 was observed at a depth of 27 cm. Exchangeable Al and extractable Mn levels increased to 11 meq kg−1 and 78µg g−1 respectively. Estimated losses of Ca, Mg and K from the upper soil profile depth (0–10 cm) represented 23, 63 and 27% of their respective total exchangeable levels. At lower profile depths (〉20 cm), accumulation of displaced K was evident. Variable, and generally non-significant, chemical changes recorded in soils 20 cm from the emitter were attributed to restricted lateral water movement, and therefore urea movement, down the profile. The present study showed that one season of urea fertigation by trickle emitters, applied to a sandy loam, at half the rate conventionally applied to apple orchards (50 kg N ha−1 yr−1) resulted in pH and mineral element imbalances which were potentially and sufficiently severe to inhibit tree growth.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5036
    Keywords: Ca ; Cation leaching ; Exchangeable bases ; K ; Mg ; Mn ; Na ; Soil management ; Soil pH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Observations from a soil management trial conducted on a previously grassed down orchard showed that after 3 years the pH of the surface soil (0–10 cm) whether measured in distilled water or 1N KCl was significantly lowered in herbicided and cultivated treatments in comparison with plots under continued grass sod. The drop in pH was accompanied by a decrease in base saturation and a consequent increase in exchange acidity. This was attributed to the leaching of Ca and also Mg from the surface soil of the non-grassed plots. In a subsequent laboratory leaching study, cubic soil blocks (16 cm3) were leached with distilled water at two weekly intervals for 24 weeks. It was found that over the experimental period, the cumulative quantity of cations leached (in milli-equivalents) per soil block from the herbicided and cultivated treatments was approximately 3.5 times that leached from the grassed treatment.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 56 (1980), S. 445-457 
    ISSN: 1573-5036
    Keywords: Apple orchard ; Biogeochemistry ; Ca ; Cl ; K ; Mg ; N ; Na ; Nutrient budget ; P ; S
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Data on the dry matter distribution and nutrient reserves (N, P, S, Cl, K, Ca, Mg and Na) in the standing biomass of a grassed-down 14 year-old apple orchard are presented together with mean estimates of nutrient inputs, returns and losses over a 2 year period. The major inputs of N P K and S were through fertilizer additions. The major inputs of Na and Cl were in bulk precipitation plus irrigation whilst both sources were important for Mg and Ca. Total inputs by precipitation plus irrigation plus fertilizer in kg/ha/yr were: N, 81; P, 20; S, 42; Cl, 58; K, 64; Ca, 35; Mg, 10 and Na, 33. Nutrient returns to the orchard floor were dominated by those from returns of herbage clippings orginating from the mowing of the orchard pasture. Autumn leaf fall also contributed significant quantities to the total nutrient returns. Total nutrient returns to the orchard floor through petal fall, fruit drop, leaf fall, foliar leaching (includes leaf washing) and pasture clippings in kg/ha/yr were: N, 545; P, 33; S, 41; Cl, 107; K, 442; Ca, 147; Mg, 35 and Na, 16. The major loss of Na, Mg, Ca, Cl and S was through leaching (this may include a certain amount of chemical weathering). In contrast, the major loss of P and K was in the harvested fruit crop, while for N, losses were about equally divided between the fruit crop and leaching. Total nutrient losses from the orchard by removal of the fruit crop and pruning wood plus leaching losses were estimated in kg/ha/yr at: N, 58; P, 5; S, 28; Cl, 81; K, 124; Ca, 55; Mg, 39 and Na, 80. Inputs minus losses in kg/ha/yr were positive for N, P and S(+23, +16 and +14 respectively and negative for Cl, K, Ca, Mg and Na (−24, −60, −19, −30 and −47 respectively).
    Type of Medium: Electronic Resource
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