Soil–atmosphere exchange of greenhouse gases in a Eucalyptus marginata woodland, a clover‐grass pasture, and Pinus radiata and Eucalyptus globulus plantations

Abstract

Soils provide the largest terrestrial carbon store, the largest atmospheric CO 2 source, the largest terrestrial N 2 O source and the largest terrestrial CH 4 sink, as mediated through root and soil microbial processes. A change in land use or management can alter these soil processes such that net greenhouse gas exchange may increase or decrease. We measured soil-atmosphere exchange of CO 2 , N 2 O and CH 4 in four adjacent land-use systems (native eucalypt woodland, clover-grass pasture, Pinus radiata and Eucalyptus globulus plantation) for short, but continuous, periods between October 2005 and June 2006 using an automated trace gas measurement system near Albany in southwest Western Australia. Mean N 2 O emission in the pasture was 26.6 lg N m À2 h À1 , significantly greater than in the natural and managed forests (o2.0 lg N m À2 h À1 ). N 2 O emission from pasture soil increased after rainfall events (up to 100 lg N m À2 h À1 ) and as soil water content increased into winter, whereas no soil water response was detected in the forest systems. Gross nitrification through 15 N isotope dilution in all land-use systems was small at water holding capacity o30%, and under optimum soil water conditions gross nitrification ranged between o0.1 and 1.0 mg N kg À1 h À1 , being least in the native woodland/eucalypt plantation opine plantation opasture. Forest soils were a constant CH 4 sink, up to À20 lg C m À2 h À1 in the native woodland. Pasture soil was an occasional CH 4 source, but weak CH 4 sink overall (À3 lg C m À2 h À1 ). There were no strong correlations (Ro0.4) between CH 4 flux and soil moisture or temperature. Soil CO 2 emissions (35-55 mg C m À2 h À1 ) correlated with soil water content (Ro0.5) in all but the E. globulus plantation. Soil N 2 O emissions from improved pastures can be considerable and comparable with intensively managed, irrigated and fertilised dairy pastures. In all land uses, soil N 2 O emissions exceeded soil CH 4 uptake on a carbon dioxide equivalent basis. Overall, afforestation of improved pastures (i) decreases soil N 2 O emissions and (ii) increases soil CH 4 uptake.

An Evaluation of Short Term Greenhouse Gas Emissions from Soil and Atmosphere Exchange in Response to Controlling Edaphic Factgors of Eucalyptus Plantation, Gujarat, India

“…Moreover, CH 4 uptake is dominated by aeration of the soil profile (Khalil and Baggs, 2005). with the estimates from other forest studies (Castaldi et al 2006;Livesley et al 2009), but is less than that measured in some moist tropical or boreal forests (Hall et al 2004;Werner et al 2007). Moreover, our results revealed the soil N 2 O emission is predominantly controlled by soil pH (Stevens et al 1997), soil moisture (Merino et al 2004), soil C and N stocks (Li et al 2005), soil inorganic N contents (Merino et al 2004) and C:N ratio of litter and soil (Werner et al 2007).…”

“…(Wang et al 2006), subtropical forests (Tang et al 2006), and tropical rain forests (Sotta et al 2004). Soil CO 2 annual mean emission was lower than in broadleaf plantations (between 56.38 and 72.15 mg C m−2h−1), as observed by Livesley et al (2009) in coniferous broadleaf forest/plantations. Soil CO 2 emission, could be the result of soil respiration generates mainly from autotrophic (root) and heterotrophic microbial activity (Janssens et al 2001).…”

Fonction puits de carbone des taillis d'eucalyptus à Madagascar

“…Concernant les Ges non CO 2 , ce sont surtout les sols des forêts tempérées qui constituent un puits important de CH 4 et une source d'un peu de N 2 O lors du recyclage des nutriments (Dalal et al, 2008 ;Livesley et al, 2009 À Madagascar, l'eucalyptus est une espèce massivement adoptée par les populations malgaches en raison de son ancienne diffusion, de sa capacité à constituer une alternative à la dégradation des forêts naturelles, mais aussi pour l'appropriation foncière (Carrière, Randriambanona, 2007 L'objectif de cette étude est de quantifier la contribution réelle des plantations d'eucalyptus à la constitution du stock de C dans les différents compartiments (aérien, racinaire, litière, matière organique du sol) au regard du mode de gestion et de comparer la capacité des vieilles souches à fixer du C avec deux autres modes d'usage des terres : la pseudosteppe (système originel) et la rotation culture/jachère. …”

Implications of urbanization related land use change on the Carbon and Nitrogen cycle from subtropical soils

“…Soil mineral N in the SERF forest was generally low and dominated by NH 4 + , and while less seasonally variable throughout the year than NO 3 -, still responded to rainfall. The overall mineral N reported from temperate eucalypt forest soils was double the annual SERF average of 17.6 kg N ha -1 with up to 38.1 kg N ha -1 (Fest et al 2009;Livesley et al 2009;Fest et al 2015a). However, the greater NO 3 -proportion in the sandy SERF soil of 3.9 kg N ha -1 compared to 0.8 kg N ha -1 of temperate sandy forest soils ) indicates a higher mineral N availability in the subtropics.…”

“…Urban populations worldwide now exceed rural populations and will account for For example, land use change from intact biomes to agricultural use can lead to a loss in soil quality (structure and nutrient losses) and quantity (erosion), increase greenhouse gas (GHG) emissions, and reduce soil potential for carbon sequestration (Grover et al 2012;Livesley et al 2009). Given the large areas worldwide undergoing these land use changes, the implications for ecosystem functionality and health are significant.…”