五種台灣農地土壤鉀的交換特性

K為植物生長所需的主要元素之一，然而土壤K的供應受到許多因子所限制，其中K-Ca交換反應之KG值是用來解釋K供應予植物的重要影響因子之一，本研究乃探討KG與EP值（可交換性K比率）間的關係，接著求出恆定KG值，比較五種土壤的KG值，配合CEC值探討土壤K的緩衝能力，本研究之最終目的在探討EP與鉀吸附比（PAR=[K^+]/([Ca^(2+)+[Mg^(2+)])^(1/2)）間的關係。由結果顯示：（1）五種土壤KG值隨EP值及交換性K飽和度的增加而有下降的趨勢，在高K飽和度情況下最後達到一定值。（2）善化系土壤CEC及KG均高，為K緩衝能力較大的土壤；將軍系土壤CEC及KG均屬中等值。二林系土壤雖然CEC高，但KG值低，因此其K緩衝能力並不高。牛尿港系土壤CEC雖低，但KG尚屬中等，因此K緩衝能力亦屬中等值。（3）五種農地土壤在不同CaCl2濃度處理下其EP與PAR間均呈良好線性相關。

關鍵字

Gapon選擇性係數；可交換性鉀比率；鉀吸附比；鉀的緩衝容量

並列摘要

K is one of the primary elements of plants. However, the supply of K is limited by many factors. The Gapon exchange coefficient, KG, for K-Ca exchange reaction, may be considered as one of the important influential factor to explain the K availability of a soil to plants. At first, This study explored the relationship between KG versus EP (exchangeable potassium ratio), then used KG and CEC to predict K buffering capacity. The objective of this study was to examine the relationship between EP and potassium adsorption ratio (PAR=[K^+]/([Ca^(2+)]+[Mg^(2+)]) ^(1/2)) The results show that (1) In five soils, there is the same trend of KG decreasing with increasing in K saturation of the soil, which levels reach constant value at a higher degree of K saturation. (2) The CEC and KG of Sanghua soil are high so that its buffering capacity is high, too; The KG and CEC of Chianjing soil show moderate values. Although the CEC of Erling soil is high, but its KG is low so that its K buffering capacity is not high. Although the CEC of Nieuniokang soil is low, but KG is in range of value, thus buffering capacity has also in the moderate value, and (3) The correlation between EP and PAR is shown linear relationship at three different CaCl2 concentrations of five farm soils tested.

並列關鍵字

Gapon selectivity coefficience ； Exchangeable potassium ratio ； Potassium adsorption ratio ； K buffering capacity

國際替代計量

五種台灣農地土壤鉀的交換特性

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