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了解小麦生产环节中土壤-作物-大气三者之间的氮素循环系统对于获取高产、优质小麦是很必要的。本文旨在确定氮素的循环并观察土壤和大气氮素的吸收与排放所造成的氮素盈亏的影响,确定植株体内氮素的转运数量。在测取土壤、植株和小气候中氮素数据的同时,还确定了这三者间的氮素转运状况。测定发现,在营养生长初期,植株氮含量达到最大;其后,直到成熟,尽管植株从土壤中持续吸收氮,但植株氮含量仍呈下降趋势。从叶片向籽粒运转的总氮量要比从茎秆转运的多而且转运的也早。同位素全氮研究表明:籽粒中约有一半氮素来自开花后叶片中和茎中,另一半则来自土壤。随着生长时间的推移,有机质矿化氮所占的百分率越来越大。施肥之后及衰老期间,氮以挥发态氨的形式从植株逸出。作者观察到:开花前当土壤氮暂时不能被利用时,植株可从大气中吸收氨;植株逸出氨损失的氮量约占施氮量的21%;在土壤氮不能被利用期间,植株从大气中吸收的氨中的氮量相当于施入氮量的1%。
It is necessary to understand the nitrogen circulation system among the soil-crop-atmosphere in the wheat production process to obtain high-yield and high-quality wheat. The purpose of this paper is to determine the circulation of nitrogen and to observe the effects of nitrogen uptake and loss on soil nitrogen and nitrogen uptake by the atmosphere and to determine the amount of nitrogen transport in the plant. In addition to the data of nitrogen in soils, plants and microclimates, the nitrogen translocation among the three was also confirmed. The results showed that the nitrogen content of the plant reached its maximum at the beginning of vegetative growth. Afterwards, until the maturity, although the plant continued to absorb nitrogen from the soil, the nitrogen content of the plant tended to decline. The total amount of nitrogen transported from the leaves to the grain was much earlier than that transferred from the stalks and transported. Isotope total nitrogen studies show that about half of the nitrogen in the grain comes from the leaves and stems after flowering and the other half comes from the soil. With the growth of time, the percentage of organic matter mineralized nitrogen is more and more big. After fertilization and during aging, nitrogen escapes from the plant in the form of volatile ammonia. The authors observed that when soil N temporarily could not be utilized before flowering, the plant could absorb ammonia from the atmosphere; the amount of nitrogen that the plant escaped from ammonia loss was about 21% of the amount of nitrogen applied; during the period when soil nitrogen could not be utilized, The amount of nitrogen in the ammonia absorbed in the atmosphere corresponds to 1% of the amount of nitrogen applied.