不同土壤pH和铵硝态氮配比对杉木和木荷幼苗叶片C、N、P化学计量的影响
Effects of different soil pH and ammonium nitrate nitrogen ratio on C,N and P stoichiometry in leaves of Cunninghamia lanceolata and Schima superba seedlings
[目的]研究不同土壤pH和铵硝态氮配比环境下对杉木和木荷幼苗叶片C、N、P化学计量特征的影响,探讨适合杉木和木荷生长的最佳pH和铵硝态氮配比环境,为提高杉木木荷混交林林地生产力提供理论依据。[方法]本研究以一年生杉木和木荷实生苗为研究对象,设置 3个栽培基质pH水平:pH= 4.5、pH= 5.5、pH =6.5,在N素总量相等的条件下设置 5个铵硝配比(NH4+-N∶NO3--N)处理:10:0、7∶3、3∶7、0∶10、5∶5(对照:均一分布组),共计15个处理,由此模拟构建不同pH条件和铵硝配比的养分逆境。[结果](1)不同的铵硝配比和土壤pH条件对杉木和木荷叶片的C、N和P含量产生了显著影响。(2)杉木的C/N整体上随着pH的升高而下降,木荷的C/P整体上在pH=6.5 水平下较低。木荷的N/P整体上在pH=5.5水平下显著高于pH=4.5和pH=6.5水平。(3)pH=4.5水平下,杉木和木荷的C/N随着硝态氮浓度的升高先上升后下降,pH=5.5水平下,杉木的C/N在不同配比处理下没有显著差异,而木荷的C/N在 10:0和 3:7配比下显著高于其他配比。pH=6.5水平下,不同配比处理对两个树种的C/N没有显著影响,但杉木的C/N在 3:7配比下最高,而木荷的C/N在 10:0配比下最高。[结论]杉木在相对较高铵态氮浓度的环境下生长更好,而木荷在相对较高硝态氮浓度的环境下生长更好,在土壤pH值为 4.5～5.5的环境下,为杉木增施铵态氮,为木荷增施铵态氮,最终提高针阔混交林林地生产力。
[Objective]The effects of different soil pH and ammonium nitrate nitrogen ratio on the C,N and P stoichiometric characteristics of leaves of Cunninghamia lanceolata and Schima superba seedlings were studied,and the optimal pH and ammonium nitrate nitrogen ratio environment suitable for the growth of C.lanceolata and S.superba seedlings was discussed,providing a theoretical basis for improving the forest productivity of C.lanceolata and S.superba mixed forest.[Method]In this study,annual C.lanceolata and S.superba seedlings were selected as the research objects,and pH levels of three cultivation substrates were set:pH= 4.5,pH= 5.5,pH= 6.5.Under the condition of equal total N content,five ammonium and nitrate ratios(NH4+-N∶NO3--N)were set for treatment:10:0,7∶3,3∶7,0∶10,5∶5(control group:uniform distribution group),a total of 15 treatments,so as to simulate the nutrient stress of different pH conditions and ammonium nitrate ratio.[Results](1)The contents of C,N and P in leaves of C.lanceolata and S.superba were significantly affected by different ammonium and nitrate ratios and soil pH conditions.(2)As a whole,the C/N of C.lanceolata decreased with the increase of pH,and the C/P of S.superba was lower at the pH=6.5 level.The N/P of S.superba at pH=5.5 was significantly higher than that at pH=4.5 and pH=6.5.(3)At pH=4.5,the C/N of C.lanceolata and S.superba first increased and then decreased with the increase of nitrate nitrogen concentration.At pH=5.5,there was no significant difference in the C/N of C.lanceolata under different ratio treatments,while the C/N of S.superba under 10:0 and 3:7 ratio treatments was significantly higher than other ratios.At pH=6.5,the C/N of the two tree species was not significantly affected by different ratio treatments,but the C/N of C.lanceolata was the highest at 3:7 ratio,while that of S.superba was the highest at 10:0 ratio.[Conclusion]C.lanceolata grows better under relatively high ammonium nitrogen concentration,while S.superba grows better under relatively high nitrate nitrogen concentration.In the soil pH value of 4.5～5.5,the increased application of ammonium nitrogen for C.lanceolata and ammonium nitrogen for S.superba ultimately improves the forest productivity.
程聪;王立冬;梁海燕;王燕茹;全小强;李小玉;闫小莉;
福建农林大学林学院,福建,福州 350002;福建农林大学林学院,福建,福州 350002;福建农林大学林学院,福建,福州 350002;福建农林大学林学院,福建,福州 350002;福建农林大学林学院,福建,福州 350002;福建农林大学林学院,福建,福州 350002;福建农林大学林学院,福建,福州 350002;
Cunninghamia lanceolata Schima superba ammonium and nitrate ratio stoichiometric characteristics.
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