Mullahingamise dünaamika Vihterpalu ja Nõva põlengualade näitel
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Kuupäev
2014
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Käesoleva uurimistöö eesmärk on anda ülevaade tule mõjust mulla süsiniku (C)
sisaldusele ja mullahingamisele. Selleks analüüsiti põlengujärgset mullahingamist ning
C ja lämmastiku (N) sisaldust mullas.
Vihterpalus (põleng 2008. aastal) ja Nõval (põleng 1992. aastal) teostati mõõtmisi 12
püsiproovitükil (20x40m), kus mõõdeti mullahingamist, mulla temperatuuri ning võeti
mullaproove. Nii Vihterpalus kui Nõval olid kuuest proovitükist: (a) kaks kontrollala
(NU), kus põlengut ja raiet ei ole toimunud; (b) kaks põlenud ja põlengujärgselt puudest
koristatud ala (BC) ning; (c) kaks põlenud ja puudest koristamata ala (BU). Igale
proovitükile paigaldati mullahingamise mõõtmiseks neli polüpropüleen püsirõngast.
Mullahingamist mõõdeti kaasaskantava gaasianalüsaatoriga CIRAS-2 koos suletud
süsteemiga mullahingamiskambriga SRC-1, igal proovitükil tehti neli mõõtmist
vegetatsiooniperioodi jooksul. Mullatemperatuur mõõdeti termomeetriga püsirõnga
lähedusest ning igalt proovitükilt võeti kolm mullaproovi mulla C ja N sisalduse
määramiseks.
Teostatud analüüside põhjal leiti, et NU aladel on mullahingamine kõrgem kui BU ja
BC aladel, samas puude põlengujärgne eemaldamine (BU või BC) mullahingamist ei
mõjutanud. Samuti ei leitud, et põlengust möödunud ajal oleks oluline mõju
mullahingamisele. Mullatemperatuuri mõju mullahingamisele käesolevas töös ei olnud
oluline. Leiti, et keskmised mullatemperatuurid on kõrgemad BC aladel, kuna puude
võrad ei piira valguse ligipääsu ning maapind soojeneb intensiivsemalt.
C ja N sisaldus mullaproovides oli kõrgeim ülemises kihis ehk kõduhorisondis,
kusjuures kõduhorisondi C ja N näitajad olid kõrgemad 1992. aasta põlengualal
võrreldes 2008. aastal põlenud alaga. Mulla N sisaldus oli NU aladel suurem kui BU ja
BC aladel. Mullahingamise ja mulla N sisalduse vahel seost ei leitud.
Mullahingamise uuringuid põlengualadel on vajalik jätkata mõistmaks paremini
mullahingamise dünaamikat.
The goal of this thesis was to study fire influence on soil C stock and soil respiration. Soil respiration, soil C and N were analysed in fired damaged areas. In Vihterpalu (fire in 2008) and Nõva (fire in 1992) soil respiration and soil temperature were measured and soil samples were taken in 12 permanent sample plots (20x40m). In both areas three different management cenarios were separated: (a) two control sample plots (NU) where no disturbance occured; (b) two sample plots of burned and cleaned areas (BC) and; (c) two sample plots of burned and uncleaned areas (BU). Four permanent polypropylen collars were installed on every sample plot for measuring soil respiration. Soil respiration was measured with infrared gasanalyser CIRAS-2 combined with colosed bath soil respiration chamber SRC-1. In every sample plot four soil respiration measurements were done within growing season. Soil temperatures were measured near the collars and three soil samples were taken from each plot for soil C and N analyses. Results of statistical analysis showed, that in NU areas, the soil respiration was highest. Management at burned areas (BC and BU) did not affect soil respiration. Also no difference in soil respiration was found of time since fire. The soil temperature had no influence on soil respiration. Although average soil temperatures were higher in BC areas (compared to BU) because removed trees do not limit the access of sunlight to ground. Soil C and N stock were the highest in organic layer, also the soil C content was higher in areas which were burned in 1992, compared to recently burned areas. Soil N was highest in NU areas compared to BU and BC areas. Correlation between soil N and soil respiration did not occure. The continuation of the soil respiration studies at fire damaged areas would provide us better understanding of soil C dynamics.
The goal of this thesis was to study fire influence on soil C stock and soil respiration. Soil respiration, soil C and N were analysed in fired damaged areas. In Vihterpalu (fire in 2008) and Nõva (fire in 1992) soil respiration and soil temperature were measured and soil samples were taken in 12 permanent sample plots (20x40m). In both areas three different management cenarios were separated: (a) two control sample plots (NU) where no disturbance occured; (b) two sample plots of burned and cleaned areas (BC) and; (c) two sample plots of burned and uncleaned areas (BU). Four permanent polypropylen collars were installed on every sample plot for measuring soil respiration. Soil respiration was measured with infrared gasanalyser CIRAS-2 combined with colosed bath soil respiration chamber SRC-1. In every sample plot four soil respiration measurements were done within growing season. Soil temperatures were measured near the collars and three soil samples were taken from each plot for soil C and N analyses. Results of statistical analysis showed, that in NU areas, the soil respiration was highest. Management at burned areas (BC and BU) did not affect soil respiration. Also no difference in soil respiration was found of time since fire. The soil temperature had no influence on soil respiration. Although average soil temperatures were higher in BC areas (compared to BU) because removed trees do not limit the access of sunlight to ground. Soil C and N stock were the highest in organic layer, also the soil C content was higher in areas which were burned in 1992, compared to recently burned areas. Soil N was highest in NU areas compared to BU and BC areas. Correlation between soil N and soil respiration did not occure. The continuation of the soil respiration studies at fire damaged areas would provide us better understanding of soil C dynamics.
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