relation: https://orgprints.org/id/eprint/36379/
title: Nitrogen release and synchrony in organic and conventional farming systems of the Central Highlands of Kenya
creator: Musyoka, Martha W.
creator: Adamtey, Noah
creator: Bünemann, Else K.
creator: Muriuki, Anne W.
creator: Karanja, Edward N.
creator: Mucheru-Muna, Monica
creator: Fiaboe, Komi K.M.
creator: Cadisch, Georg
subject:  Soil quality
subject:  Composting and manuring
subject: Africa
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.
date: 2019
type: Journal paper
type: NonPeerReviewed
identifier:    Musyoka, Martha W.; Adamtey, Noah; Bünemann, Else K.; Muriuki, Anne W.; Karanja, Edward N.; Mucheru-Muna, Monica; Fiaboe, Komi K.M. and Cadisch, Georg   (2019) Nitrogen release and synchrony in organic and conventional farming systems of the Central Highlands of Kenya.   Nutrient Cycling in Agroecosystems, 113 (3), pp. 283-305.        
relation: https://doi.org/10.1007/s10705-019-09978-z
identifier: https://doi.org/10.1007/s10705-019-09978-z
identifier: urn:ISSN:online: 1573-0867, Print: 1385-1314
identifier: info:doi/https://doi.org/10.1007/s10705-019-09978-z