Abstract:

This field study was conducted to assess the effects of phosphorus on nitrogen absorption, translocation as well as utilization in dryland flax. We set four phosphorus (P₂O₅) levels of 0, 45, 90 and 135 kg/hm², planted two flax varieties (‘Lunxuan 2’ and ‘Dingya 22’) in 2017 and 2018 at Dingxi, and adopted a completely random block group design. The results showed that phosphorus had an influence on nitrogen absorption and translocation of the above ground parts and the physiological utilization efficiency of nitrogen in dryland flax, and the difference between the years was significant. Year, variety and phosphorus interaction showed significant impact on nitrogen absorption in the above ground parts at anthesis and maturity, nitrogen absorption and distribution rate in seeds at maturity, and total nitrogen translocation amount, translocation efficiency, rate of contribution and physiological utilization efficiency of stems, leaves and other parts. The application of phosphorus averagely increased nitrogen absorption in the above ground parts at anthesis and maturity by 76% and 82% respectively, nitrogen absorption and distribution rate in seeds at maturity by 127% and 25% respectively, and nitrogen translocation and translocation efficiency in stems and leaves and other parts by 556%, 102%, 237%, and 16% respectively compared with no application of phosphorus. The physiological utilization efficiency of nitrogen significantly increased with increased phosphorus rate of ‘Lunxuan 2’, however, physiological utilization efficiency of nitrogen of ‘Dingya 22’ showed no difference between 90 kg/hm² and 135 kg/hm². The correlation analysis indicated that the phosphorus application amount had significantly positive correlation with nitrogen absorption translation and utilization in dryland flax.

Key words: phosphorus, flax, nitrogen, absorption, translocation, utilization