大气CO2浓度升高和氮肥水平对麦田土壤有机碳更新的影响  

EFFECT OF ELEVATED ATMOSPHERIC pCO_2 AND NITROGEN LEVEL ON REPLACEMENT RATE OF SOIL ORGANIC CARBON IN WINTER WHEAT FIELD

作　　者：寇太记[1,2] 朱建国[1] 谢祖彬[1] 刘钢[1] 曾青[1] 

机构地区：[1]土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008 [2]河南科技大学农学院,河南洛阳471003

出　　处：《土壤学报》2009年第3期459-465,共7页Acta Pedologica Sinica

基　　金：国家重点基础研究发展规划项目(CCDMCTE-2002CB412502);中国科学院知识创新重要方向项目(KZCX3-SW-440);国家自然科学基金重点基金项目(40231003、40110817、40271061)联合资助

摘　　要：依托FACE(Free air carbon dioxide enrichment)技术平台,采用稳定^(13)C同位索法,通过将C_3作物小麦种植于长期单作玉米的C_4土壤上,研究了大气CO_2浓度升高和不同氮肥水平对水稻-小麦轮作制中冬小麦生长季土壤有机碳更新的影响。结果表明,种植一季小麦后土壤有机碳的δ^(13)C值显著降低,小麦生长改变了土壤有机碳的组成,大气CO_2浓度增加促进作物向土壤中输入更多的碳。大气CO_2浓度升高增加了麦田土壤有机碳的更新率,使土壤有机碳的更新率由3.61%(施氮量为150 kg hm^(-2),LN)～4.59%(施氮量为250 kg hm^(-2),HN)提高至6.72%(LN)～8.55%(HN),分别增加72.7%和86.1%。结果表明,大气CO_2浓度升高和提高氮肥用量将加快农田土壤有机碳的更新。With the aid of the Free-Air Carbon Dioxide Enrichment （FACE） system and the isotope ^13C technique, effects of elevated atmospheric pCO2 and nitrogen fertilization on replacement rate of soil organic carbon （SOC） in wheat field, through planting wheat （ Triticum aestivum L. ev Yangmai 14） under a rice/wheat rotation system in a C4 soil, on which only maize had been planted for years. Results show that after one crop of wheat, the value of δ^13C in SOC fell significantly, suggesting that wheat growth had altered the composition of SOC, and that elevated atmospheric pCO2 stimulated the crop to transfer more organic carbon into the soil, thus increasing the SOC replacement rate in the wheat field from 3.61% to 6.72% when the nitrogen application rate was 150 kg hm ^-2, LN and from 4.59% to 8.55% , when the application rate was 250 kg hm^-2, HN, or by 72.7% and 86. 1% , respectively. It is quite obvious that elevated atmospheric pCO2 and higher nitrogen application rate will accelerate SOC replacement in farmland soil.

关 键 词：CO2浓度升高 冬小麦 有机碳 土壤有机质 更新率 氮肥 

分 类 号：S161[农业科学—农业气象学] X171[农业科学—农业基础科学]