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正确测定土壤含水量至今仍是土壤分析工作者颇感困难的问题。特别是野外测定,其精确度更难满足研究工作的要求。 几十年来,不少研究者致力于发展土壤、植物、矿物及其他材料中含水量的测定方法,诸如重量法、化学方法、电学方法、吸收法、原子能法、X射线强度测量法以及其他等等。然而由于种种原因,在土壤分析中,室内通常多采用烘干失重法(控温105-110℃,分次恒重或连续一次烘8小时称重)。此法误差来源庞杂:含腐质多的土壤烘到恒重颇为困难;某些有机质(如有机碳)和还原性矿物(如FeO),将因长久烘焙而氧化增重;而某些盐类又将由于烘焙中分解(如重碳酸盐)或失去结晶水(如石膏CaSO_4·2H_20)以致减轻重量。因而烘干法既费时而又欠准确,但到目的为止,仍一直被采用作实验室的标准方法。 野外限于设备及其他条件,通常采用酒精燃烧失重法或不控温的烘干法,其粗放程度更可想见。尤其含有机质多的土壤,误差更为惊人;且费酒精,成本高,材料也有困难。因此寻觅一个适于野外测定,既有相当精确度而又简捷的方法,是土壤分析工作者共同的
Correct determination of soil moisture is still a difficult issue for soil analysis workers. Especially in the field, its accuracy is more difficult to meet the requirements of research work. For decades, researchers have focused on the development of methods for determining the water content of soils, plants, minerals and other materials such as gravimetric methods, chemical methods, electrical methods, absorption methods, atomic energy methods, X-ray intensity measurements and others Wait. However, due to various reasons, in the soil analysis, drying indoors is usually used more weight loss method (temperature 105-110 ℃, constant weight or continuous baking 8 hours weighing). This method has a lot of sources of error: it is quite difficult to dry the soil with more humus to constant weight; some organic matter (such as organic carbon) and reducing minerals (such as FeO) will oxidize and gain weight due to long-term baking; and some salts Which in turn will lose weight due to decomposition during baking (eg bicarbonate) or loss of water of crystallization (eg gypsum CaSO 4 · 2H_ 20). The drying method is therefore time-consuming and inaccurate, but by the time it is still used as a laboratory standard method. The field is limited to equipment and other conditions, usually using alcohol combustion weight loss method or drying method is not controlled temperature, the extent of its more predictable. In particular, the soil contains more organic matter, the error is even more alarming; and the cost of alcohol, high cost, materials are also difficult. Therefore, looking for a method that is suitable for field measurement, which is both fairly accurate and simple, is common to soil analysis workers