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    Nitrogen release and synchrony in organic and conventional farming systems of the central highlands of Kenya

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    S19ArtMusyokaNitrogenInthomDev.pdf (559.0Kb)
    Date
    2019-03-15
    Author
    Musyoka, M.W.
    Adamtey, N.
    Bünemann, Else K.
    Muriuki, A.W.
    Karanja, E.N.
    Mucheru-Muna, M.
    Fiaboe, K.
    Cadisch, Georg
    Type
    Journal Article
    Target Audience
    Scientists
    Metadata
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    Abstract/Description
    To match Nitrogen (N) supply to crop N demand, it is essential to understand N release and uptake patterns in different farming systems and crops. To assesses the dynamics of N released in organic and conventional systems and potential synchrony and asynchrony in crop N uptake, a study was conducted over three cropping seasons (potato, maize and leafy vegetables) at two sites in the Central Highlands of Kenya. Mineral-N release and synchrony were monitored in conventional and organic systems at high (recommended N, P, pesticides and irrigation) and low input (low N, P, pesticide use and rainfed) systems. Mineral-N release was assessed using in situ buried bags and N synchrony was measured by the daily differences in N fluxes. The percentage of N applied released during potato (38%) and vegetable (44%) cropping seasons were similar between systems. However, under maize strong temporal N immobilization from inputs occurred, particularly at Thika, related to the poor quality of manure and compost (lignin:N ratio > 13). In all systems, excess-asynchrony of available N was pronounced during vegetative stages and at harvest, while insufficient-asynchrony occurred at reproductive stages. During potato cropping season at Thika, Org-High showed highest positive N fluxes (> 20 kg N ha−1 day−1) at planting and tuber bulking stage. At early stages of maize and vegetables Org-Low and Org-High experienced up to 5 times larger negative N fluxes (insufficiency) compared to conventional treatments at Chuka site. The study recommends reducing N applications at planting and increasing N dosages at reproductive stages of crops.
    https://dx.doi.org/10.1007/s10705-019-09978-z
    Multi standard citation
    Permanent link to this item
    https://hdl.handle.net/20.500.12478/5542
    Digital Object Identifier (DOI)
    https://dx.doi.org/10.1007/s10705-019-09978-z
    Agrovoc Terms
    Incubation; Mineralization; Organic; Inputs; Quality
    Regions
    Africa; East Africa
    Countries
    Kenya
    Journals
    Nutrient Cycling in Agroecosystems
    Collections
    • Journal and Journal Articles4835
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