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Title: Effect of land management on soil microbial N supply to crop N uptake in a dry tropical cropland in Tanzania
Authors: Sugihara, Soh
Funakawa, Shinya  kyouindb  KAKEN_id  orcid (unconfirmed)
Kilasara, Method
Kosaki, Takashi
Author's alias: 杉原, 創
Keywords: Microbial biomass N
Microbial C:N ratio
Land management
Dry tropical cropland
Sub-Saharan Africa
Issue Date: Jan-2012
Publisher: Elsevier B.V.
Journal title: Agriculture, Ecosystems & Environment
Volume: 146
Issue: 1
Start page: 209
End page: 219
Abstract: In Sub-Saharan Africa, conservation of available soil N during early crop growth, when N loss by leaching generally occurs, is important to improve crop productivity. In a dry tropical cropland in Tanzania, we assessed the potential role of soil microbes as a temporal N sink–source to conserve the available soil N until later crop growth, which generally requires substantial crop N uptake. We evaluated the effect of land management [i.e., no input, plant residue application before planting (P plot) with or without fertilizer application, fertilizer application alone, and non-cultivated plots] on the relationship between soil N pool [microbial biomass N (MBN) and inorganic N] and crop N uptake throughout the ∼120-d crop growth period in two consecutive years. In the P plot, MBN clearly increased (∼14.6–29.6 kg N ha[−1]) early in the crop growth period in both years because of immobilization of potentially leachable N, and it conserved a larger soil N pool (∼10.5–21.2 kg N ha[−1]) than in the control plot. Especially in one year in which N leaching was critical, increased MBN maintained a larger soil N pool in the P plot throughout the experimental period, and a delay of increased MB C:N ratio and a substantial decrease in MBN was observed, indicating better soil microbial N supply for crop N uptake during later crop growth. Therefore, plant residue application before planting should enhance the role of soil microbes as a temporal N sink–source, leading to the conservation of potentially leachable N until later phase of crop growth, especially in years in which N leaching is relatively severe. Although further studies are necessary, our results suggest that plant residue application before planting is a promising option to achieve better N synchronization.
Rights: © 2011 Elsevier B.V.
This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。
DOI(Published Version): 10.1016/j.agee.2011.11.008
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