To provide potential implications of species selection for carbon plantation, differences in carbon sequestration pattern and net ecosystem production (NEP) were determined between two 36-year-old plantations of broad...To provide potential implications of species selection for carbon plantation, differences in carbon sequestration pattern and net ecosystem production (NEP) were determined between two 36-year-old plantations of broadleaved species, Castanopsis kawakamii and Cunninghamia lanceolata, in Sanming, Fujian. Annual net carbon sequestration was 13.639 and 6.599 t C·hm -2 a -1 , respectively, in the C. kawakamii and the C. lanceolata, among which the annual biomass C increment and the litterfall production was evenly distributed. To the annual net carbon sequestration, the contribution of stem (wood plus bark) increment was much lower, and that of branch increment was much higher in the C. kawakamii than in the C. lanceolata (26.6% versus 40.3%, and 11.5% versus 0.3%). In both plantation, the above and belowground litterfall accounted 60% and 40% respectively for the annual litterfall production, which was estimated 7.183 t C·hm -2 a -1 in the C. kawakamii and 3.554 t C·hm -2 a -1 in the C. lanceolata. Annual soil heterotrophic respiration was responsible for a C loss of 5.983 and 2.984 t·hm -2 a -1 from soil to atmosphere in the C. kawakamii and the C. lanceolata, respectively. Carbon balance analysis showed there were a positive net ecosystem production (C sink), 7.656 and 3.615 t C·hm -2 a -1 , for the C. kawakamii and the C. lanceolata, respectively. For the purpose of carbon management, C. kawakamii might be a more suitable species than C. lanceolata in local region.展开更多
采用FACE(Free air carbon dioxide enrichment)技术,研究了不同施氮水平下,大气CO_2浓度升高对水稻/小麦轮作土壤速效钾的影响。结果表明,相对于对照处理,在不同氮水平下CO_2浓度升高使作物生物量增加,导致作物生长季对土壤钾的吸收增...采用FACE(Free air carbon dioxide enrichment)技术,研究了不同施氮水平下,大气CO_2浓度升高对水稻/小麦轮作土壤速效钾的影响。结果表明,相对于对照处理,在不同氮水平下CO_2浓度升高使作物生物量增加,导致作物生长季对土壤钾的吸收增加,但并没有降低作物主要生长期土壤(0—5、5—15 cm土层)速效钾的含量;CO_2浓度升高使土壤速效钾增加的幅度在作物根际达6.3%～22.3%,在行间达3.7%～11.2%,且土壤速效钾增加的幅度在小麦季大于水稻季。表明根系对土壤速效钾的影响很大,因此,短期内土壤钾含量不会成为限制因素而影响作物对高CO_2浓度的响应,反而会增加土壤钾的有效性。但在土壤肥力较低的土壤上可能会产生消极影响。展开更多
文摘To provide potential implications of species selection for carbon plantation, differences in carbon sequestration pattern and net ecosystem production (NEP) were determined between two 36-year-old plantations of broadleaved species, Castanopsis kawakamii and Cunninghamia lanceolata, in Sanming, Fujian. Annual net carbon sequestration was 13.639 and 6.599 t C·hm -2 a -1 , respectively, in the C. kawakamii and the C. lanceolata, among which the annual biomass C increment and the litterfall production was evenly distributed. To the annual net carbon sequestration, the contribution of stem (wood plus bark) increment was much lower, and that of branch increment was much higher in the C. kawakamii than in the C. lanceolata (26.6% versus 40.3%, and 11.5% versus 0.3%). In both plantation, the above and belowground litterfall accounted 60% and 40% respectively for the annual litterfall production, which was estimated 7.183 t C·hm -2 a -1 in the C. kawakamii and 3.554 t C·hm -2 a -1 in the C. lanceolata. Annual soil heterotrophic respiration was responsible for a C loss of 5.983 and 2.984 t·hm -2 a -1 from soil to atmosphere in the C. kawakamii and the C. lanceolata, respectively. Carbon balance analysis showed there were a positive net ecosystem production (C sink), 7.656 and 3.615 t C·hm -2 a -1 , for the C. kawakamii and the C. lanceolata, respectively. For the purpose of carbon management, C. kawakamii might be a more suitable species than C. lanceolata in local region.
