Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/27358
標題: 本省主要土類土壤鉀有效性之評估
Evaluation on K availability of the major group soils in Taiwan
作者: 顏正中
Yen, Cheng-Chung
關鍵字: K availability
鉀有效性
K fixation
Liming
Availability index
鉀固定
石灰施用
有效性指標
出版社: 土壤學系
摘要: 土壤中鉀的固定作用常是造成短期內土壤中鉀有效性降低的主 要原因,故欲評估本省主要土類之土壤鉀有效性,必需先對鉀在土壤中之 固定特性有深入的瞭解o 鉀肥施入土壤後,將導致土壤不同型態鉀之消長 ,繼而影響土壤中鉀有效性的變化,而各種型態鉀對土壤鉀有效性之相對 貢獻,亦有待釐清o 決定土壤鉀有效性的測定方法甚多,何者較適用於作 為本省土壤的鉀有效性指標,亦有待評估之o 石灰施用為增進強酸性土壤 生產力之重要對策,唯其對強酸性土壤鉀有效性的影響評估仍屬欠缺,誠 應予以探究之o 本論文探討 (1)本省主要土類土壤之鉀固定特性及與土壤 性質間之關係; (2)鉀肥施用對土壤鉀有效性及對甘藍生育的影響; (3)七種土壤鉀有效性指標測定法之適宜性評估;以及 (4)施用石灰對強 酸性土壤之鉀固定能力及鉀有效性的影響o 藉由土壤鉀固定能力指標 和土壤相關性質之測定及其相關性分析得知,本省主要土類土壤鉀固定能 力以石灰性沖積土大於非石灰性沖積土及其他強風化土壤,而黏土礦物的 種類與其相對含量及土壤pH是造成鉀固定能力差異的主要因子o 試驗結果 亦顯示,鉀固定能力較低的大肚山及中寮土壤在鉀肥施用後較鉀固定能力 強之善化土壤能提供更多的速效性鉀,而後者則固持較多量的鉀,且土壤 中鉀型態之消長特性並不會因培育期的長短而有顯著的差異o 由盆 栽試驗證實,土壤中非交換性鉀在甘藍鉀吸收之貢獻上實不容忽視o 鉀有 效性測定方法的適宜性評估結果顯示,在鉀固定能力葚強之善化土壤中, 沸騰硝酸,中性醋酸銨,Mehlich I,Bray I,Mehlich III以及AB-DTPA 等鉀有效性測定法皆能反映甘藍鉀吸收之狀況;其中以沸騰硝酸法與甘藍 鉀吸收之相關性最高,且可反映非交換性鉀對甘藍鉀吸收之貢獻,唯非交 換性鉀的釋放速率恐太慢而無法及時供甘藍吸收利用,固在兼顧 "量" 的 衡量下,Mehlich III 應為最適切之鉀有效性測定方法o 在以石 灰施用來增進強酸性土壤生產力的策略下,將會促進土壤對溶液鉀的固持 ,而當土壤pH低於6.0 時,鉀在表面吸附的增加為鉀固持增加的主因,然 隨石灰施用量的增加,鉀固定作用則逐漸成為土壤鉀固持的主因o 藉 Barber-Cushman養分吸收模式的評估結果,發現在強酸性土壤,當石灰施 用量愈高時,則土壤中可為作物所吸收的鉀相對地將減低o 同時,石灰施 用會提高土壤的鉀固定能力而降低鉀肥施用效率o 由此可見,在施用石灰 改良強酸性土壤之際,誠需顧及鉀有效性之變化,並適度調整鉀肥管理策 略為宜o
Potassium (K) fixation has been suggested to be the main factor in reducing K availability in soil. Therefore, it is necessary to investigate the characteristics of K fixation in the main groups of soil in Taiwan in order to evaluate their K availabilities. The relative change in the forms and the availabilities of K in the soils could be altered by K fertilization, and the effect of each forms of K on K availability should be determined. Several methods have been used to determine K availability in soils, but their suitability needed to be evaluated. Liming is an important mean in improving the productivity of acid soils, however, its effect on K availability still confused and should be studied. The purposes of this study were to (1)study the relationship between K fixation capacity and soil properties of those main soil groups in Taiwan, (2)determine the effects of K fertilization on soil K availability and cabbage growth, (3)evaluate the suitability ofseven methods in determining K availability, and (4)investigate the effect of liming on the fixation capacity and availability of K in acid soil. Basedon the relationships between K fixation capacity and soil properties, calcareous eluvial soils had higher K fixation capacity than those of noncalcareous eluvial soils and others strongly weathered soils. It was concluded that the K fixation capacity of soils was largely governed by the kinds and the content of clay minerals and soil pH. Results also showed that theith lower K fixation capacity resulted in more readily availableK released, and the relative changes in the forms of K was not significantly influenced by the time of incubation. The results of pot experiment clearly indicated that nonexchangeable did play a very important role on the K uptake by cabbage. The boiling HNOз, neutral NH4OAC, Mehlich I, Bray I, Mehlich III , and AB-DTPA method all were suitable in determining K availability of Shan Wha soil which has strong K fixation capacity . Furthermore, the method of boiling HNOз had a best relationwith the K uptake by cabbage, but the relase rate of nonexchangeable K was too slow to provide cabbage absorption. Therefore, the Mehlich III was the most suitable method in determining K availability in soils as the quantity of K was considered. There had been a distinct increase in the K retention as liming acid soils, and surface adsorption was the main mechanism of K retention as pH below 6.0, however, K fixation was gradually important with more lime was added. According the amount of K uptake by maize calculated by using the Barber-Cushman nutrient uptake model, K availability in soils was decline with liming in the acid soils. In addition, liming caused a increase in K fixation capacity and decrease in the efficiency of K fertilization. It suggested that the changes of K availability in soils, and the adjustment of the K fertilization management need to be consider when acid soils were liming.
URI: http://hdl.handle.net/11455/27358
Appears in Collections:土壤環境科學系

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