国立研究開発法人 国際農林水産業研究センター | JIRCAS

Dynamics of Fertilizer Nitrogen Applied to Sweet Sorghum (<i>Sorghum bicolor</i> (L.) Moench) in the Semi-Arid Tropics

JARQ : Japan Agricultural Research Quarterly
ISSN
00213551
書誌レコードID(総合目録DB)
AA0068709X
本文フルテキスト

Although sweet sorghum is in focus as a promising multi-purpose crop in semi-arid tropical regions, information on optimum nitrogen (N) management remains rather limited. To determine and understand the N dynamics in sweet sorghum-soil ecosystem, we evaluated the N recovery of applied fertilizer in the Alfisol field during the 2009 and 2010 rainy seasons. Sweet sorghum was grown under six N rates (0, 30, 60, 90, 120 and 150 kg N ha-1) with split application (at 0, 30 and 60 days after sowing) and N concentration and N recovery efficiency (NRE) were measured. In addition, to determine the fate of basal and topdressed N, 15N-labeled urea was applied at each application timing within main plots of 90 kg N ha-1. There was no significant difference in NRE calculated by the difference method between six N rates and N uptake rose with increasing N rate. The total dry weight and sugar yield increased at rates up to 90 kg N ha-1 and higher N rates did not significantly affect sorghum productivity. As a total of basal and topdressing applications, 33% of the applied 15N-labeled urea was absorbed by the sorghum plant, while 36 and 30% remained in the soil and unaccounted for, respectively. The NRE calculated by the isotopic method was about 39 and 37% for topdressings at 30 and 60 days after sowing, respectively. The distribution ratio of absorbed N in leaves was higher for basal applications and topdressing at 30 days after sowing, while that in grains was higher for topdressing at 60 days after sowing, compared to the other application timings. In contrast to topdressings, the NRE was very low (13%) for basal N application: about 70% of the basal applied N remained in the soil at the physiological maturity. The results imply that the NRE might be increased by improving the ways in which basal N is applied.

刊行年月2015-10-01
作成者UCHINO HiroshiWATANABE TakeshiRAMU KarriSAHRAWAT Kanwar L.MARIMUTHU SubramanianWANI Suhas P.ITO Osamu
著者キーワード

15N-labeled urea

fertilizer application timing

nitrogen recovery efficiency

公開者Japan International Research Center for Agricultural Sciences
データ作成日2015-10-01
国立情報学研究所メタデータ主題語彙集(資源タイプ)Journal Article
49
4
開始ページ409
終了ページ418
DOI10.6090/jarq.49.409
権利Japan International Research Center for Agricultural Sciences
言語eng