Optimum nitrogen fertilization of
Wentao ZOU,Ruifeng JIA,Jinchang YANG,Rongsheng LI,Guangtian YIN
Frontiers of Agricultural Science and Engineering
2016,
Volume 3,
Issue 4,
Pages 368-374
doi:
10.15302/J-FASE-2016120
Abstract:
A greenhouse pot experiment was conducted to study the effects of nitrogen fertilization on seedlings grown with 0, 50, 100, 150, 200, 300, 400 and 600 mg N per seedling according to exponential functions. Seedling height, root collar diameter, leaf area and total biomass increased with increasing fertilization from 0 to 200 mg N per seedling and decreased with further increase in fertilization from 300 to 600 mg N per seedling. The net photosynthetic rate, stomatal conductance, intercellular CO concentration and transpiration rate of seedlings showed a unimodal parabolic trend, with peak values of 7.29 mmol·m ·s , 0.071 mol·m ·s , 220 mmol·mol and 1.34 mmol·m ·s , respectively, when the rate of fertilization was 200 mg N per seedling. Photosynthetic gas exchange parameters were significantly different among nitrogen treatments. Based on the critical values of leaf N and P concentration and N/P ratio, the optimum amount of nitrogen of seedlings was 200–400 mg per seedling for leaf N and P concentration, and 100–400 mg per seedling for N/P ratio. It was concluded that 200–400 mg N per seedling was the most suitable nitrogen range for seedlings.
Keywords：
Calophyllum inophyllum
growth
nitrogen fertilization
nutrient status
photosynthesis
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