• 作者： 莊作權; 紀秋來; 譚鎮中; 青峰重範
• 作者服務機構： 國立中興大學土壤系
• 中文摘要： 本文乃是就本省中、南部十五處水稻田所採土壤中有機氮素的礦質化與氮素損失情形加以探討，俾使對水田中氮素的變化與氮素供應能力作一初步之瞭解。 本省土壤之氮素潛在肥力一般較低，可能與土壤之比表面積低、氣溫高、有機質含量低，陽離子交換能量低，對銨之吸附能力低有關。某些土壤具第二層，緊接在耕犁層之下，此層具有較高的潛在肥力。長期的浸水似乎會增加A層的厚度。屏東、彰化地區的大部份水田土壤 pH 值隨土壤深度加深而增加，然而對土壤中有機氮素的礦質化影響似乎不大。浸水土壤中，由於氧化還原作用，有大量的氮氣損失，浸水狀況下，氧化區域常顯其重要性，可使水田產生嚴重的脫氮現象。鹼性土壤中氨氣的逸失甚為可觀。孵育後土壤全氮量的損失約等於礦物態氮素的損失；孵育前若將土樣風乾，將使還原作用加強而增加氣素的損失。土壤中加入稻草不能減少氮素的損失，反而增加了浸水土壤表土中氮素的損失。
• 英文摘要： The primary purpose of this study was toinvestigate the changes and potential fertility ofnitrogen in paddy soils by the way of evaluatingthe mineralization rate of soil organic nitrogenand nitrogen loss in incubated soil sampleswhich were collected from 15 rice fields locatedat central and southern areas of Taiwan. Theresults were summarized as follows： 1. Paddy soils in Taiwan show very oftenlow in the potential nitrogen fertility, probablybecause of low specific surface area of soils andhigh temperature in the subtropics. 2. Some soils have the second layer, im-mediately underlying the plowed layer, whichis rather high in the potential nitrogen fertility.It is likely that the flooding for a long periodcauses to the increase of thickness of A-horizon. 3. The pH value of most Ping-tung andChang-hua soils increased with the increase ofsoil depth; however, these pH variations didnot affect the mineralization rate of organic ni-trogen in the soils considerably. 4. The oxidized domain is often dominantunder flooded conditions, suggesting vigorousdenitrification occurring in paddy soils. 5. A very large amount of nitrogen waslost from flooded soils, mainly due to oxidation-reduction processes. 6. Volatilization of ammonia was consi-derably high in alkaline soils. 7. The loss of total-N agreed with the lossof mineral-N, and increased by air-drying thesoils prior to incubation which was due to theactivation of reduction processes. 8. Rice straw could not decrease the lossof nitrogen but increased it in the surface layerof flooded soils.
• 中文關鍵字： --
• 英文關鍵字： --