东北师大生物地球化学课题组在SBB上发表土壤氮磷循环对干湿交替的响应

点击上方“蓝字”关注我们

气候变化会引起降水格局发生改变，从而导致干湿交替模式发生改变，进而可能会影响陆地生态系统中土壤氮、磷循环。土壤干旱会抑制土壤微生物活性，并且随着干旱强度的增加，土壤微生物和根系可能会死亡。随后的再湿润会通过破坏土壤结构、从土壤矿物表面解吸有机和无机氮和磷、对土壤微生物施加渗透压以及改变根系生长等途径影响土壤养分循环。由于土壤氮和磷在陆地生态系统中起着至关重要的作用，因此全面了解其对干湿交替的响应变得越来越重要。

Fig. 1. The distribution of drying and rewetting experiments worldwide in this meta-analysis.

东北师范大学生物地球化学组对土壤氮、磷循环的各个库和通量对干旱和再湿润的响应进行了整合分析。基于来自79个研究的1882个观测数据，整合分析结果显示，干湿循环中的干旱处理使土壤铵态氮、可提取有机氮和有效磷分别显著提高22%、27%和72%；相比之下，土壤硝态氮、酶活性、微生物量、净硝化作用和N₂O的排放量分别显著降低37%、13-21%、21-28%、39%和93%。再湿润后，土壤可提取有机氮、可提取有机磷、净氮矿化、硝化作用、磷酸酶活性、可溶性有机氮淋溶、可溶性无机磷淋溶和N₂O排放分别显著增加59%、27%、19%、15%、12%、60%、116%和218%，而土壤硝态氮和硝态氮淋溶分别显著降低9%和74%。土壤微生物氮和磷以及酶活性能在土壤再湿润后恢复到干旱前的水平。土壤氮磷对干湿交替处理响应值的大小通常会随着干旱强度的增强而增大，这也可能是室内实验中这个响应值大于野外实验的主要原因。另外，我们还发现，土壤有效磷对干湿交替处理的响应强于无机氮强对干湿交替处理的响应，从而导致在干湿交替处理土壤氮和磷之间的不平衡，这一现象在森林土壤的表现比农业土壤中更为明显。

Fig. 1.Effects of drying and rewetting on variables of the nitrogen (N) and phosphorus (P) cycles. Error bars stand for 95% bootstrapped confidence intervals (CIs). If the 95% CI of the did not overlap with zero, the effect of drying or rewetting treatment was considered significant. The sample sizes for drying and rewetting treatments are shown on the left and right of the figure, respectively. Closed black and open red symbols indicate drying and rewetting effects on soil N and P cycles, respectively. The response ratio (ln R) represents the “effect size”. Abbreviations: TN, total nitrogen; EON, extractable organic nitrogen; DON, dissolved organic nitrogen in publications extracted with H2O; DIN, dissolved inorganic nitrogen; MBN, microbial biomass nitrogen; Net N min, net N mineralization; Net nit, net nitrification; EOP, extractable organic phosphorus; DOP, dissolved organic phosphorus in publications extracted with H2O; MBP, microbial biomass phosphorus;. DIP leaching, dissolved inorganic phosphorus leaching.

Fig. 3. Responses of terrestrial ecosystem nitrogen (N) and phosphorus (P) pools, their transformation processes and fluxes to drying and rewetting. Abbreviation: TN, total nitrogen; Org. N, organic nitrogen; EON, extractable organic nitrogen; MBN, microbial biomass nitrogen; Net N 1min, net N mineralization; Immo, immobilization; Net nit, net nitrification; Deni, denitrification; EOP, extractable organic phosphorus; Ava P, available phosphorus; MBP, microbial biomass  phosphorus; D-RW: drying-rewetting. The red numbers and ↑ stand for significant increases by drying or rewetting treatment. The blue numbers and ↓ represent significant decreases by drying or rewetting treatment. →, no significant change; ?, current researches data are not sufficient to be analyzed.

Fig. 7. Relationships between the effect size of rewetting on soil nitrogen (N) and phosphorus (P) variables and the effect size of drying on soil moisture. Other variables have no significant correlation with the effect size of drying on soil moisture. A positive relationship indicates an 1increasing negative response of soil parameters with an increasing intensity of drying. A negative relationship indicates an increasing positive response of soil parameters with an increasing intensity of drying. The response ratio (ln R) represents the “effect size”. The effect size of drying on soil moisture reflects the magnitude of drying, the response ratio (ln R) of soil moisture in the drought and control treatment.

东北师范大学高德才为文章的第一作者，白娥教授为通讯作者。该研究得到了国家重点研发项目、国家自然科学基金和国家青年拔尖人才计划的支持。

生态笔记 Econote

想要了解更多，一定要去下载原文阅读噢~~

https://doi.org/10.1016/j.soilbio.2020.107896

原文报道于东北师范大学官网

http://geo.nenu.edu.cn/info/1097/5143.htm

喜欢就转发、点赞、点“在看”