摘要
采用室内模拟培养和^(13)C同位素标记技术相结合的研究方法,探讨了在葡萄糖与无机氮肥共施的条件下,土壤有机碳矿化及其激发效应对外源磷添加的响应,以揭示土壤有机碳矿化的碳磷耦合调控机制.结果表明:外源磷的输入加快了CO_2的释放,但抑制了CH_4的释放;在整个土壤淹水培养期间,磷添加抑制了土壤碳矿化释放CH_4总量的53.1%,其中外源葡萄糖-^(13)C矿化成^(13)CH_4的总量降低了70.5%;磷添加促使通过微生物转化的葡萄糖-^(13)C向易利用态碳库的分配比例增加了3.6%,显著提高土壤有机碳快库矿化速率,缩短土壤碳矿化周期.土壤培养前期,外源有机质的添加表现为短暂的负激发效应;随着葡萄糖不断矿化分解,CO_2累积激发效应(PE_(CO_2))总体上呈现先增加后下降的趋势,而CH_4累积激发效应(PE_(CH_4))稳步增加最终保持基本稳定状态;培养结束时(100 d),在磷添加条件下,PE_(CO_2)增强32.3%,PE_(CH_4)显著降低93.4%.冗余分析和Pearson分析表明,电导率、氧化还原电位和溶解有机碳对稻田土壤碳矿化的影响最为显著;速效磷与^(13)CH_4、PE_(CH_4)呈极显著负相关.在外源有机质添加条件下,磷的添加能够抑制CH_4排放及其激发效应,促进土壤有机质的矿化和养分释放,提高土壤原有有机碳的可利用性,促进稻田土壤有机碳循环.
To understand the coupled controlling of carbon （C） and phosphorus （P） on the mineralization of soil organic carbon and amended substrates in paddy soil, we investigated the effects of P addition on the decomposition of organic carbon and its induced priming effect by using 13Cisotope probing technique in microcosm. The results showed that P addition accelerated the release of CO2 but inhibited the release of CH4, leading to 53.1% reduction of total accumulated CH4 and 70.5% reduction of the13CH4 derived from exotic glucose13C. P addition altered the carbon distribution during the microbial turnover progress, with 3.6% of glucose13C being transferred into the labile carbon pool, therein significantly increased potential of the mineralization rate of exogenous C. A transient negative priming effect was observed in the early stage of incubation. With timeprolonging, the priming effect on CO2 emission （PECO2） generally increased and then decreased after a peak. The priming effect on CH4 emission （PECH4） kept increasing and finally fluctuated at a relative stable value until the end of the experiment （100 days）. P addition increased PECO2 by32.3% but reduced PECH4 by 93.4%. Results from the RDA and Pearson analysis showed that electricconductivity, oxidationreduction potential and dissolved organic carbon significantly affected soil C mineralization. There were significantly negative correlations between available phosphorus （Olsen-P） and 13CH4, and between Olsen-P and PECH4. In conclusion, with the addition of exogenousorganic matter, P application could reduce CH4 emissions and inhibit its priming effect, accelerate the mineralization of SOC, probably improve the nutrient supply, and thus enhance the availability of organic C and promote C cycling in paddy soil.
出处
《应用生态学报》
CAS
CSCD
北大核心
2018年第3期857-864,共8页
Chinese Journal of Applied Ecology
基金
本文由国家自然科学基金项目(41430860,41371304)、中国科学院战略性先导科技专项(XDB15020401)和湖南省自然科学基金项目(2016JJ3132)资助
关键词
稻田土
有机碳矿化
磷添加
激发效应
paddy soil
organic carbon mineralization
phosphorus addition
priming effect.
