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碱化土壤是我省东部及北部地区广泛分布的一种低产土壤,对其改良利用是提高该地区农业生产水平的重要措施之一。碱化土壤的分级,各国采用的标准不一。目前,国际上多采用美国的标准,即将钠碱化度(交换性钠占交换量的百分率,简称ESP)大于15%、pH超过8.5为划分碱土的标准。苏联则是以ESP20%作为划分碱土的标准。不论标准如何,交换性钠是划分碱土的重要依据。测定交换性钠的方法较多,如石膏ED TA法、石灰法和碳酸氢钙法,皆采用容量法或重量法,操作手续繁冗,干扰因素和限制条件较多,且不适合于含有石膏的土壤。因此,碱化土壤交换性钠的测定方法,必须审慎地运用。我们对近年来国内所采用的
Alkalized soil is a widely distributed low-yielding soil in the eastern and northern parts of the province, and its improved utilization is one of the important measures to improve the agricultural production in this area. Alkaline soil classification, the standards adopted by different countries. At present, the United States to adopt more international standards, namely the degree of sodium (sodium exchange rate of exchange accounted for the percentage, referred to as ESP) greater than 15%, pH over 8.5 for the division of alkaline earth standards. The Soviet Union is based on ESP20% divided alkaline earth standard. Regardless of the standard, sodium exchange is an important basis for the division of alkaline earth. Determination of exchangeable sodium are many, such as gypsum ED TA method, lime method and calcium bicarbonate method, are used volume or gravimetric methods, redundant procedures, interference factors and restrictions are more, and is not suitable for containing gypsum soil. Therefore, alkalized soil exchangeable sodium determination method, we must carefully use. We used in recent years in China