Seed yield response to N fertilization and potential of proximal sensing in Italian ryegrass seed crops

Tim Vleugels, Georges Rijckaert, René Gislum

    Research output: Contribution to journalA1: Web of Science-articlepeer-review

    Abstract

    Italian ryegrass (Lolium multiflorum L.) seed crops are often routinely fertilized with a predetermined amount of
    nitrogen (N) fertilizer in spring. However, nitrate leaching and increasing N fertilizer prices require rationalized
    fertilizer applications without compromises in seed yield. The objectives of this study were (1) to determine the
    seed yield response to N fertilization, and (2) to evaluate if NDVI values can reliably predict the N status in
    Italian ryegrass seed crops. During eight years, field trials were conducted with two cultivars ‘Melclips’ and
    ‘Melquatro’, and seven N strategies applied after the forage cut as single or split application: 0, 60, 60 +30, 90,
    90 + 30, 120 and 150 kg N ha−1. NDVI values were obtained with a ‘GreenSeeker’ optical sensor. Maximum
    seed yield was attained at 141 kg N ha−1 total available N (92 kg N ha−1 fertilized). Higher fertilizations only
    increased NNI values but not seed yield. Split-application strategies were equal to single-applications in terms of
    seed yield, which indicates that remedial fertilizations at the two-three node stage are effective. NNI values at all
    growth stages predicted seed yield adequately: maximum seed yield was attained at NNI values of 0.86 in the
    2–3 node stage, 0.72 at the beginning of heading, and 0.59 at full ear emergence. NDVI values were correlated
    with NNI values, but were also heavily influenced by trial year. Therefore, is it impossible to establish NDVI
    thresholds to decide on remedial N fertilization.
    Original languageEnglish
    JournalField Crops Research
    Volume211
    Pages (from-to)37-47
    Number of pages11
    ISSN0378-4290
    Publication statusPublished - 2017

    Keywords

    • B390-plant-breeding

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