Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Fate of 15N-labelled nitrogen fertilizer applied to kiwifruit (Actinidia deliciosa) vines (1992)
    Springer
    Plant and soil 147 (1992), S. 49-57 
    Details
    ISSN: 1573-5036
    Keywords: ammonium ; field ; kiwifruit ; 15N ; nitrogen fertilizer ; recovery ; soil nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The fate of 15N-labelled ammonium fertilizer applied once to six-year-old field-grown kiwifruit (Actinidia deliciosa ‘Hayward’) vines was measured over three years. The three main treatments were nitrogen (N) applied singularly at 100 or 200 kg N ha−1 in early spring (two weeks before bud burst) or split with 100 kg N ha−1 (unlabelled) in early spring and 100 kg N ha−1 (15N-labelled) ten weeks later. All N treatments were applied to vines with a history of either 50 or 200 kg N ha−1 yr−1. For three years after 15n application, components of the vines and soil (0–600 mm depth) were sampled at harvest in late autumn and the N and 15N contents determined. By the first harvest, all plant uptake of 15N had occurred and this represented 48–53% of the 15N applied. There was no significant effect of current N fertilizer treatment or of N history on 15N recovery by vines. Removal of 15N in harvested fruit was small at 5–6% in the first year and 8% over 3 years. After 2–3 years, most plant 15N occurred in the roots and this component declined only slowly over time. In contrast, there was a large temporal decline in 15N in above-ground plant components due to the annual ‘removal’ in leaf fall and pruning. An associated experiment showed that when 15N-labelled prunings and leaves were mulched and returned to the soil, only about 9% was recovered by plants within 2 years. Almost all remaining mulched material had been immobilised into the soil organic N. In all treatments, about 20% of the added 15N remained in soil at the first harvest. This was almost entirely in organic fractions (〈0.4% in inorganic N) and mostly in the surface 150-mm layer. The 15N content in soil changed little over time (from 20 to 17% between the first and third harvests respectively) and indicated that most of the N had been immobilised into stable humus forms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009370
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Influence of time of application on the utilization of nitrogen fertilizer by asparagus, estimated using 15N (1992)
    Springer
    Plant and soil 147 (1992), S. 41-47 
    Details
    ISSN: 1573-5036
    Keywords: asparagus ; Asparagus officinalis ; nitrogen fertilizer ; 15N ; plant uptake ; soil nitrogen fractions ; time of application
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of nitrogen (N) fertilizer on the production of a 6-year-old asparagus (Asparagus officinalis L.) crop was examined over 2 years by the application of 0, 50 or 100 kg N ha−1 as ammonium sulphate at three times; 1) prior to fern growth (9 months before harvest), 2) prior to harvest, or 3) early-harvest prior to the main period of spear production. The utilization of N fertilizer was examined by applying 15N-enriched ammonium sulphate to 2 m×2.5 m microplost within the 50 kg N ha−1 treatments. There was a 12% response in spear production to added N in the first harvest year only and there was no significant effect of rate or time of N application. Plant uptake of added 15N by the end of the first harvest period was 25, 11 and 4% of the total applied for the pre-fern, pre-harvest and early-harvest treatments respectively. About 60% of the 15N applied pre- or early-harvest remained in the soil at the end of the first harvest period. Most of the 15N in soil in the pre-harvest treatment occurred as inorganic N and had been leached into the 150–600 mm soil depth. In contrast, most of the 15N that remained in soil from the early-harvest application was in the 0–75 mm depth and 40% of this had been immobilized into organic N. In the short-term (less than one year), utilisation of 15N-labelled N fertilizer by asparagus was greatest when applied prior to fern growth. However, after 2 years there was no difference between treatments in 15N recovery in plant or soil. Thus, time of application of N fertilizer had no long-term effect on production or utilization of N fertilizer by asparagus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009369
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Nitrogen inputs and losses from New Zealand dairy farmlets, as affected by nitrogen fertilizer application: year one (1996)
    Springer
    Plant and soil 181 (1996), S. 65-69 
    Details
    ISSN: 1573-5036
    Keywords: ammonia volatilization ; denitrification ; grazed pasture ; leaching ; nitrogen ; N2 fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inputs and losses of nitrogen (N) were determined in dairy cow farmlets receiving 0, 225 or 360 kg N ha-1 (in split applications as urea) in the first year of a large grazing experiment near Hamilton, New Zealand. Cows grazed perennial ryegrass/white clover pastures all year round on a free-draining soil. N2 fixation was estimated (using 15N dilution) to be 212, 165 and 74 kg N ha-1 yr-1 in the 0, 225 and 360 N treatments, respectively. The intermediate N rate had little effect on clover growth during spring but favoured more total pasture cover in summer and autumn, thereby reducing overgrazing and resulting in 140% more clover growth during the latter period. Removal of N in milk was 76,89 and 92 kg N ha-1 in the 0, 225 and 360 N treatments, respectively. Denitrification losses were low (7–14 kg N ha-1 yr-1), increased with N application, and occurred predominantly during winter. Ammonia volatilization was estimated by micrometeorological mass balance at 15, 45 and 63 kg N ha-1 yr-1 in the 0, 225 and 360 N treatments, respectively. Most of the increase in ammonia loss was attributed to direct loss after application of the urea fertilizer. Leaching of nitrate was estimated (using ceramic cup samplers at 1 m soil depth, in conjunction with lysimeters) to be 13, 18 and 31 kg N ha-1 yr-1 in a year of relatively low rainfall (990 mm yr-1) and drainage (170–210 mm yr-1). Drainage was lower in the N fertilized treatments and this was attributed to enhanced evapotranspiration associated with increased grass growth. Nitrate-N concentrations in leachates increased gradually over time to 30 mg L-1 in the 360 N treatment whereas there was little temporal variation evident in the 0 (mean 6.4 mg L-1) and 225 (mean 10.1 mg L-1) N treatments. Thus, the 360 N treatment had a major effect by greatly reducing N2 fixation and increasing N losses, whereas the 225 N treatment had little effect on N2 fixation or on nitrate leaching. However, these results refer to the first year of the experiment and further measurements over time will determine the longer-term effects of these treatments on N inputs, transformations and losses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011293
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...