臺灣省水稻田土壤之生成及其特質

Abstract

本報告就本省水稻田土壤之環境，分從地形、母質、氣候、植物、時間數因子討論其土壤之生成，續就全省36代表土壤剖面各層之物理化學分析結果，探討各剖面有否洗入層與洗出層之生成，結果有17土型可為水稻土生成之實例，而以其表土顏色形容其亞類，其餘19土型仍各歸屬於原土類，而以稻田形容其亞類，以別於原土類之旱田土壤。 土壤分類之結果計有5土類，9亞類，35土系，36土型，均各有其鑑別之特徵，詳見表1，其高級分類與美農部第7次土壤分類草案之對照見表2。 綜合討論36代表剖面之物理及化學性質，並比較各亞類各單項理化性之特質，詳見表3至表7，結論列出各亞類之理化性特質包括表、底土之質地及反應，與剖面各層之容重、孔度、游離鐵、錳、有效矽、CEC與C/N比率之範圍及其平均數以至粘土礦物之種類及其強度。 This report included the general review on the soil development in Taiwan according to the factors of environment i.e. relief, parent material, climate, plantship and time of the paddy feild etc. The conclusions were based on the analysis of the physical and chemical properties of the 36 representative soil profiles of the paddy feild. Some evidences had beed found concerning the development of the elluvial horizon and the illuvial horizon. In view of these general findings, the genesis of aquorizem was clarified 17 soil types were found to be the good practical examples of the aquorizems, and the color of the surface soil was used to modified its sub-group. The other 19 soil types were classified according to their original soil groups with their sub-groups in which "paddy" was taken into consideration. 5 soil groups , 9 sub-groups, 35 soil series and 36 soil types were classified and all were characterized by their diagnostic characteristics. It was shown on table 1 and the contrast between the soil classification of this report and the 7th approximation of USDA was shown on table 2. The physico-chemical properties of the 36 soil profiles had been discussed and the comparison on of the single property among the various sub-groups had been made, they were shown on table 3 to table 7. The result of the characteristics of various sub-groups had been described. It included the texture, reaction of the surface and the sub-soil, the range and average of the bulk density porosity, free iron oxide, free manganese oxide, available silica, C. E. C. and C/N ratio of the various layer of the profiles. In addition, the clay minerals were identified and their relative intensities investigated.