CAJ | 학술논문

利用PVC顶盖埋管原位培育法测定了北京东灵山地区一个油松纯林和一个油松-辽东栎落叶阔叶混交林生态系统土壤无机氮库、氮素净矿化/硝化速率的季节动态以及年度净矿化/硝化量。结果发现：1）两个生态系统的土壤无机氮库和氮素净矿化/硝化速率都存在比较明显且比较一致的季节动态，但个别时期也存在较大差异；2）纯林与混交林土壤NH+4-N浓度在各月都没有显著差异，而NO-3-N浓度，除了1995年11月和1996年8月纯林显著高于混交林外，其它月份也都差异不显著；3）无论是年度净矿化总量（纯林，22.7kg.hm-2；混交林，55.5kg.hm-2）及其占总全N量的百分比（纯林，0.694%；混交林，2.128%），还是年度净硝化总量（纯林，26.7kg.hm-2；混交林，44.6kg.hm-2）及其占总全N量（纯林，0.815%；混交林，1.707%）的百分比，油松针阔混交林生态系统均显著大于油松纯林，高达后者的两倍左右，而净硝化氮占净矿化氮的百分比则相反，油松纯林（100%）显著高于油松-辽东栎混交林（80.2%）。上述结果表明：油松-辽东栎针阔混交林生态系统土壤的氮素有效性（即土壤的供氮能力）以及维持土壤中植物可利用氮素的能力都显著高于油松纯林。物种构成及在其影响下所产生的林下微生境和人为干扰活动可能是造成这种差异的主要原因。
이용PVC정개매관원위배육법측정료북경동령산지구일개유송순림화일개유송-료동력락협활협혼교림생태계통토양무궤담고、담소정광화/초화속솔적계절동태이급년도정광화/초화량。결과발현：1）량개생태계통적토양무궤담고화담소정광화/초화속솔도존재비교명현차비교일치적계절동태，단개별시기야존재교대차이；2）순림여혼교림토양NH+4-N농도재각월도몰유현저차이，이NO-3-N농도，제료1995년11월화1996년8월순림현저고우혼교림외，기타월빈야도차이불현저；3）무론시년도정광화총량（순림，22.7kg.hm-2；혼교림，55.5kg.hm-2）급기점총전N량적백분비（순림，0.694%；혼교림，2.128%），환시년도정초화총량（순림，26.7kg.hm-2；혼교림，44.6kg.hm-2）급기점총전N량（순림，0.815%；혼교림，1.707%）적백분비，유송침활혼교림생태계통균현저대우유송순림，고체후자적량배좌우，이정초화담점정광화담적백분비칙상반，유송순림（100%）현저고우유송-료동력혼교림（80.2%）。상술결과표명：유송-료동력침활혼교림생태계통토양적담소유효성（즉토양적공담능력）이급유지토양중식물가이용담소적능력도현저고우유송순림。물충구성급재기영향하소산생적림하미생경화인위간우활동가능시조성저충차이적주요원인。
Soil net N mineralization and nitrification were determined usingthe PVC tube closed-top in situ incubation method in one pure pine stand and one pine-oak coniferous/deciduous broad-leaved mixed forest in Dongling Mountain region in SW Beijing City. Seasonal variation in the inorganic N pools and net mineralization/nitrification rates and the annual net N mineralization/nitrification were investigated. The results showed that: 1) there were obvious and consistently seasonal variations in soil inorganic N pools and the net N mineralization/nitrification in the two forest ecosystems except for some quite large differences in certain months; 2) there were no significant differences in NH+4-N concentration between the two ecosystems in any sampling dates, whereas NO-3-N concentration did differ, being higher in the pure pine stand than in the pine-oak mixed forest in Dec. 1995 and Aug. 1996; 3) both the annual net N mineralization (55.5 kg.hm-2) and the percentage of annually mineralized N of total N (2.13%) were much higher in pine-oak mixed forest than in pure pine stand (22.7 kg.hm-2 and 0.69%), respectively, with the former nearly being two times of the latter; 4) both the annual net N nitrification (44.6 kg.hm-2) and the percentage of annually nitrified N of total N (1.71%) in the pine-oak mixed forest were also much higher than in the pure pine stand (26.7 kg.hm-2 and 0.82%), while the percentages of nitrified N of mineralized N between the two forest ecosystems were quite different, with the pure pine stand (100%) being higher than pine-oak mixed forest (80.2%). These results indicate that the ability to supply available N to plants (i.e., soil N availability) and to prevent inorganic N loss was higher in the pine-oak mixed forest ecosystem than the pure pine forest ecosystem. Difference in species composition, microhabitats created by the different species and the intensity of human perturbation between the two forests might have accounted for the observed differences in our study.