CAJ | 학술논문

通过原位模拟氮沉降的试验研究了长白山阔叶红松林土壤呼吸及其对氮沉降的响应。分别在6、7、8月的月初采用喷洒尿素进行施氮处理，处理水平为对照、低氮（23 kg· hm－2· a－1）、中氮（46 kg· hm－2· a－1）和高氮（69 kg· hm－2· a－1）（以氮素质量计），每月用红外分析法测定各处理水平的土壤呼吸速率3、4次。结果显示：在生长季内长白山阔叶红松林土壤呼吸有明显的季节变化，10月份最低（0．72μmol· m－2· s－1），7月份最高（2．27μmol· m－2· s－1）；低、中氮处理提高了土壤呼吸速率，分别比对照高出55．4％和60．3％，高氮则降低了土壤呼吸速率，比对照低21．7％；模拟氮沉降没有改变土壤呼吸的昼夜变化趋势，其变化趋势与土壤温度一致，土壤呼吸速率与5cm 土壤温度呈显著的指数关系；模拟氮沉降增加改变了土壤呼吸对温度的敏感性，对照、低氮、中氮和高氮处理的Q10值分别为1．93、2．34、2．94和1．54。结果表明，在我国北方温带森林地区，未来氮沉降增加会促进土壤呼吸排放，并增加呼吸的温度敏感性，但过高的氮沉降会抑制土壤呼吸并降低呼吸的温度敏感性。
통과원위모의담침강적시험연구료장백산활협홍송림토양호흡급기대담침강적향응。분별재6、7、8월적월초채용분쇄뇨소진행시담처리，처리수평위대조、저담（23 kg· hm－2· a－1）、중담（46 kg· hm－2· a－1）화고담（69 kg· hm－2· a－1）（이담소질량계），매월용홍외분석법측정각처리수평적토양호흡속솔3、4차。결과현시：재생장계내장백산활협홍송림토양호흡유명현적계절변화，10월빈최저（0．72μmol· m－2· s－1），7월빈최고（2．27μmol· m－2· s－1）；저、중담처리제고료토양호흡속솔，분별비대조고출55．4％화60．3％，고담칙강저료토양호흡속솔，비대조저21．7％；모의담침강몰유개변토양호흡적주야변화추세，기변화추세여토양온도일치，토양호흡속솔여5cm 토양온도정현저적지수관계；모의담침강증가개변료토양호흡대온도적민감성，대조、저담、중담화고담처리적Q10치분별위1．93、2．34、2．94화1．54。결과표명，재아국북방온대삼임지구，미래담침강증가회촉진토양호흡배방，병증가호흡적온도민감성，단과고적담침강회억제토양호흡병강저호흡적온도민감성。
This study was conducted in broadleaved Korean pine forest in Changbai Mountains to explore the effects of nitrogen deposition on soil respiration.The levels of nitrogen deposition were control (CK), low nitrogen (23 kg· hm-2· a-1), medium nitrogen (46 kg· hm-2· a-1) and high nitrogen (69 kg· hm-2· a-1) by adding urea at the beginning of June , July and August since 2011.Soil respiration was measured by three to four times at mid month from May to October by using infrared gas analyzer .Soil respiration showed a strong seasonal variation with the lowest rates occurred in October ( 0.72μmol· m-2· s-1) and the highest rates in July (2.27μmol· m-2· s-1).Low and medium nitrogen deposition promoted soil respiration significantly with the increase by 55.4%and 60.3%, respectively, while high nitrogen deposition inhibited soil respiration and the rates decreased by 21.7%.However , the diurnal pattern of soil respiration didn ’ t show significant difference between each treatment , and their trends were consistent with the seasonal course of soil temperature .The soil respiration rates of all treatments exhibited significant positive exponential relationship with soil temperature at 5 cm depth. The enhanced nitrogen deposition changed temperature sensitivity of soil respiration , and Q10 of CK, low nitrogen, medium nitrogen and high nitrogen were 1.93, 2.34, 2.94 and 1.54, respectively.The moderate nitrogen deposition can increase soil respiration rates and its temperature sensitivity , while high level of nitrogen deposition can reduce soil respiration rates and its temperature sensitivity in temperate forests in North China .