• 作者： 洪崑煌; 景種; 劉天斌
• 作者服務機構： 國立臺灣大學農業化學系
• 中文摘要： 將銨飽和離子交換樹脂或盤脫土做為基肥全量一次施用之效果，較全施氮量分二十次以硫酸銨施用於水稻之效果為差，但較全量分四次以硫酸銨施用之效果為佳。由此可知交換性銨在水田中可存留較久之時間。土壤溶液中較高之銨濃度會阻礙無機氮之有機化作用，減少硝化－脫氮之損失，但同時亦阻礙礦化作用。稻田中局部性之高濃度銨之存在，則可能由於此種微生物作用之減少而有利於水稻之生長。 初步試驗結果示，基肥中之銨態氮在插秧後三星期內即因吸收及其他變化而消失。肥料氮被水稻吸收利用之期間有限。以較低濃度而源源不斷地供給大量之氮，似為達成稻穀豐收之必要條件。
• 英文摘要： Exchangeable ammonium supplied as ammo-nium saturated resin or bentonite was appliedin one dose as basal placement gave rice grainyields lower than the pots receiving the sameamount of nitrogen in the form of ammoniumsulfate applied in 20 split doses, but better thanthe pots receiving it in 4 split doses. It isapparent that exchangeable ammonium remainslonger in the paddy field condition available tothe rice plants. High ammonium ion concentra-tion in the soil solution can retard its immobil-ization and decrease nitrification-denitrificationlosses, but at the same time it also retards themineralization process. High ammonium con-centration at localized spots may prevent lossesdue to these microbial processes and may bebeneficial to the growth of rice crop. Preliminary experiment indicates that ammo-nium nitrogen applied as basal placement is lost ortaken up by the rice plants in a period of aboutthree weeks after transplanting. The fertilizernitrogen applied to the paddy field remainsavailable to the rice plants within a limitedtime period. A successful fertility managementin the rice culture appears to require that acontinuous supply of ammonium nitrogen at alow concentration is to be maintained but shouldallow the rice plants to absorb a large quantityfor producing a high yield of grains.
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