臺灣土壤肥力之研究　1．臺灣稻田土壤有效性磷素測定方法之研究

A Study on the Methods of Determining Available Phosphorus of Paddy Soils in Taiwan

曾憲鼎(H. D. Tseng) ； 王接皇(C. H. Wang)

《中華農業研究》 8卷3&4期 (1959/12) Pp. 11-20

摘要

本試驗之目的在檢討影響土壤有效性磷素測定之因子及土壤有效性磷素速測方決之應用範圍，茲將其試驗結果及摘要如下：
1．由Bray氏法及Troug氏，Olsen氏及Peech氏四種方法測定臺灣稻田土壤有效性磷素之比較研究結果，指示Peech氏法及Olsen氏法抽出土壤有效性磷素量過低，在臺灣不適於作土壤有效性磷素速測之用。
2．Bray氏及Troug氏二法應用之溶提液為強酸，對土壤有效性磷素溶解力強，各土壤中有效性磷素量之差異變域大，易於比軾及判斷土壤中之含磷情形。因此二法較適合於臺彎稻田土壤速測之用，惟Troug氏法需大量溶提液，過濾需時，較為不適於作速測之用。Bray氏法即無此缺點。
3．Bray氏及Troug氏二法所抽出來之有效陸磷素量甚為相近，但在紅黃壤上Bray氏溶提液抽出來之磷素量一般的較Troug氏法所測者為高，但在粘板岩沖積土則不盡然。
4．Bray氏及Troug氏二法測定臺灣粘板岩沖積土之有效陸磷素量不能與臺彎紅黃壤或砂頁岩仲積土之有效性磷素量作同等之比較，蓋因此三類土壤中有效性磷酸所存在之形態不同。
5．Bray氏法測定有效性磷素受溫度及振盪時間之影響甚大，應用此法測定有效性磷酸，則須對此項因子予以嚴密控制。

並列摘要

The factor affecting the reproducibility of the determined values of available phosphorus of soils was studied and four methods were compared in determining the available phosphorus of paddy soils of Taiwan.
Analytical results indicated that Peech's method and Olsen's method extracted too small amount of available phosphorus for accurate estimation of the status of soil phosphous. Bray's method and Troug's method were found to be more adaptable for routine test. The latter two methods may extract larger amount of phosphorus and are able to distinguish clearly the different status of soil phosphorus. Troug's methos employs a larger amount of extrating solution and is more time-consuming in filtration to undertake routine test than Bray's method. The amounts of phosphorus extracted by both methods from paddy soils of Taiwan were mutually correlated. Bray's method extracted more phosphorus from lateritic soils than Troug's method, but this is not always true from calcareous soils due to the different forms of phosphate existing in the respective soils. Bray's method, only when temperature and shaking time were restrictly controled, can yield reproducible results.