不同指数施肥方法下长白落叶松播种苗的需肥规律

为了探讨长白落叶松苗木的最适N含量和供N速率,应用3种不同指数施肥方法在大田条件下进行试验。结果表明:经过111d的生长,供N总量为30mg.株-1的指数施肥处理下的苗木可以获得相对较高的生物量积累和N含量水平,该处理还可以使得苗木在103d的生长中获得0.29 m.g株-.1d-1的N添加速率。在该速率下,苗木生物量、N含量和N吸收效率分别可以达到637.80 m.g株-1、8.10 m.g株-1和41.77%。根据生物量和N含量随着供N量增加的二项式回归拟合结果,在111d的生长过程中24.3—33.7m.g株-1的供N总量可以使得苗木获得较高的生物量积累水平和N利用效率。试验设置的总供N量为30 m.g株-1的处理优于60 m.g株-1或70 m.g株-1。

Nutrient upkate of Larix olgensis seedlings in response to different exponential regimes

The aim of this paper was to determine the optimum seedling N content and rate of N fertilizer application for Larix olgensis in a field culture experiment conducted with three exponential N fertilization regimes. The treatment that resulted in both the greatest seedling biomass and the highest seedling N content after 111 days of growth applied a total of 30mg N plant-1 at an exponentially increasing rate. This treatment resulted in a average optimum N application rate of 0.29 mg plant-1 d-1 over 103 days of growth. In this treatment, seedling biomass, N content and N uptake efficiency were 637.80 mg plant-1, 8.10 mg N plant-1 and 41.77%, respectively. Based on binomial regression of the biomass and N content growth curves from the three N fertilization treatments, 24.3 to 33.7 mg plant-1 N supplied in 111d resulted in the greatest biomass and highest N efficiency. We conclude that the treatment with 30 mgN plant-1 supplied produced better seedlings than either 60 mgN plant-1 or 70 mgN plant-1 treatments.