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土壤中的氮素绝大部分呈有机形态存在,必须经过微生物的作用转化为矿质氮后,才能被作物吸收利用,而这个过程受气侯、土壤和农业措施的影响变化很大。因此,土壤中氮素动态变化的测定,对于指导农业生产有着十分重要的意义。目前,一般认为土壤中水解性氮与田间作物生长的相关性较密切,测定土壤水解性氮就基本能反映土壤氮素的供应状况。 土壤水解性氮的测定,过去一直沿用硫酸浸提的丘林法;以后改用碱解蒸馏法和扩散吸收法。但这些方法都不适宜于田间现场测定,因而不能及时指导施肥。
Most of the nitrogen in the soil is in an organic form and must be absorbed and utilized by the crop after it has been converted to mineral nitrogen by the action of microorganisms. However, this process is greatly affected by climate, soil and agricultural practices. Therefore, the determination of the dynamic changes of nitrogen in soil is very important for guiding agricultural production. At present, it is generally believed that the correlation between hydrolysable nitrogen in the soil and crop growth in the field is relatively close. Determination of soil hydrolyzable nitrogen basically reflects the supply status of soil nitrogen. Determination of soil hydrolyzable nitrogen, the past has been followed by sulfuric acid extraction Qiu Lin law; later converted to alkaline hydrolysis and diffusion absorption method. However, these methods are not suitable for field measurements, which can not be timely guidance fertilization.