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所谓土壤有效氮指的是易被植株根系吸收的化学态氮。虽然绝大多数土壤有效氮都是以NH_4~+或NO_3~-的形态存在,但是仅以NH_4~+与NO_3~-的数量并不能很好地鉴定出在植株生长期间氮对稻株的有效性。作物的氮素营养取决于一段时期内土壤提供的有效氮,而不是某一时间土壤中NH_4~+与NO_3~-的浓度。因此,研究土壤的供氮能力的测定方法便是多年来许多农业科学家致力探求的重大课题。应用化学的方法和生物的方法都可以测出土壤氮对作物的有效性。生物测定法的优点在于可以直接模拟土壤氮在稻株生长期间的释放,而任何化学剂都无法拟模土壤微生物的活动情况。但是生物方法所费的时间相当长,而化学方法则快得多。本文作者综合了所有有关科技文献中最有把握的土壤氮测定方法,选
The so-called soil effective nitrogen refers to the chemical nitrogen that is easily absorbed by plant roots. Although most soil available nitrogen is in the form of NH_4 ~ + or NO_3 ~ -, only the amount of NH_4 ~ + and NO_3 ~ - can not well identify the effect of nitrogen on rice plants during plant growth Sex. Nitrogen nutrition in crops depends on the available nitrogen supplied by the soil over a period of time rather than the concentration of NH_4 ~ + and NO_3 ~ in the soil at any given time. Therefore, the determination of soil nitrogen availability has been a major issue that many agricultural scientists have been working on for many years. The application of chemical methods and biological methods can be measured soil nitrogen availability of crops. The beauty of bioassays is that they directly simulate the release of soil nitrogen during the growth of rice plants, and none of the chemicals can mimic the activity of soil microbes. However, biological methods take a long time and chemical methods are much faster. The author combines all the most relevant scientific and technological literature soil nitrogen determination method, the election