紫色土的色度特征与系统分类

Soil color is one of the morphological features of human initially see, is important diagnostic markers of series of physical, chemical properties, and has important significance in soil genesis and classification study. Purplish soils widely distributed, with large-area, high productivity, and unique color, have attracted the many of Chinese and foreign soil science scholars, especially soil taxonomists. However, their classification has not been satisfactorily resolved. Currently, the controversial item in Chinese Soil Taxonomy is about the color definition of "Lithologic Characters of Purplish Sandstones and Shales". In this project, modern colorimetry theory and color measurement instruments were used for quantitative and objective colorimetric characteristics study of purplish soils and their parent rocks or parent materials with various colors sampled from Sichuan and other regions. In addition, correlation and regression analysis between color index and coloring ingredients were conducted to ascertain the color features of the purplish soils and their parent rocks or parent materials, their control factors, and scientific definition of "Lithologic Characters of Purplish Sandstones and Shales" in Munsell colorimetric system (H,V,C). On this basis, the taxonomic status of the purplish soils were evaluated finally. This project can improve the Chinese Soil Taxonomy.

土壤颜色是人们最初看到的土壤形态特征之一，是系列物理、化学性质的重要诊断标志，在土壤发生、分类研究中具有重要意义。紫色土分布广，面积大，生产力高，颜色独特，一直吸引着中外广大土壤学者，尤其是土壤分类学者，但其分类问题一直未得到圆满地解决，目前争议较大的是系统分类中“紫色砂、页岩岩性特征”颜色的界定。本项目借助现代色度学理论与测色仪器，对从四川及其他地区采集的、各种颜色的紫色土及其母岩（母质）样品，开展色度参数的客观、定量测定，并通过着色成分淘汰与添加，及色度参数与着色成分含量的相关与回归分析，弄清紫色土及其母岩（母质）的颜色特征及其控制因素，科学界定“紫色砂、页岩岩性特征”的Munsell色度参数H、V、C，在此基础上，进一步确定其系统分类地位。本项目可促进中国土壤系统分类体系的完善。

土壤颜色是人们最初看到的土壤形态特征之一，是系列物理、化学性质的重要诊断标志，在土壤发生、分类研究中具有重要意义。紫色土分布广，面积大，生产力高，颜色独特，一直吸引着土壤学者的关注，但其分类问题一直未能得到圆满地解决，目前争议较大的是系统分类中“紫色砂、页岩岩性特征”颜色的界定。本项目借助现代色度学理论与测色仪器，对从川中丘陵、盆周山地、川西南山地等地区采集的多种侏罗系、白垩系等地层母岩及其风化发育的紫色土样品，开展色度参数的客观、定量测定，并通过着色成分淘汰与添加，及色度参数与着色成分含量的相关与回归分析，探讨紫色土及其母岩的颜色特征及其控制因素，科学界定“紫色砂、页岩岩性特征”的Munsell色度参数H、V、C，在此基础上，进一步确定紫色土的系统分类地位。.研究结果表明，现代分光测色仪测定的紫色土及其母岩样品无RP色调，即无满足中国土壤系统分类中“紫色砂、页岩岩性特征”现有限定条件的紫色湿润雏形土或紫色正常新成土存在。综合分析紫色土去除或添加着色成分后颜色变化的模拟试验结果及自然样品颜色与铁锰形态及有机质的相关与回归关系，紫色土颜色主要受铁锰形态及含量的影响；腐殖质虽然可以改变紫色土色调，但主要影响紫色土的明度和彩度。结合20世纪90年代以前中国土壤学者制定的土色标准及人类肉眼对紫色的判断等因素，“紫色砂、页岩岩性特征”的Munsell色调可调整为 2.5RP～10RP；或2.5R～5YR，干态明度为 3～6，干态彩度为 2～4。根据调整后的“紫色砂、页岩岩性特征”对颜色的限定，可以扩大紫色湿润雏形土或紫色正常新成土范围，更符合人们对紫色土的认识。