Changes in carbon stocks in Eucalyptus globulus Labill. plantations induced by different water and nutrient availability

Abstract Changes in the carbon stocks under different soil water and nutrient conditions were studied in Eucalyptus globulus Labill. stands in a field experiment, at Obidos (central Portugal). The treatments were irrigation plus a complete fertiliser solution to simulate ‘near optimal’ nutrition (IF), irrigation only (I), and fertilisers added to rain-fed plots (F). The control (C) received neither water nor fertilisers (except a small amount at planting). The production of biomass (aboveground), the litterfall and the soil chemical composition were evaluated regularly during the experiment. Root biomass was estimated at the end of the experiment. Carbon in biomass, litterfall and soil, increased significantly when water and/or nutrients were supplied, in comparison to the control. The amount of carbon accumulated in the system, 6 years after planting, was 8.22, 10.22, 11.23 and 13.76 kg C m −2 in the control, F, I and IF treatments, respectively. The increase of carbon in the system during the same period was 5.86, 7.86, 8.87 and 11.40 kg C m −2 in the control, F, I and IF treatments, respectively. This rise in carbon resulted from the accumulation of long-lived woody biomass, which represented between 77.7 (in IF) and 82.9% (in the control) of the total rise in carbon. Although water was the main limiting factor for biomass accumulation, the allocation of carbon to the soil was mainly related to nutrient supply, irrespective of water availability. The amount of carbon stored belowground, i.e. soil and forest floor, plus stumps and roots, reached 4.2, 4.7, 4.8 and 6.3 kg C m −2 in the control, F, I and IF treatments, respectively. The increase in C in the mineral soil regarding the initial state was, in the same order as above, 0.21, 0.75, 0.58 and 1.21 kg C m −2 . These values were 3.6, 9.6, 6.6 and 10.6% of the C accumulated in the whole system, during the experimental period.

[1]  S. Linder,et al.  Optimization of Biomass Production in Eucalyptus Globulus Plantations. — A Case Study , 1989 .

[2]  E. Axelsson,et al.  Changes in carbon allocation patterns in spruce and pine trees following irrigation and fertilization. , 1986, Tree physiology.

[3]  R. Lal,et al.  Land use and soil C pools in terrestrial ecosystems. , 1998 .

[4]  D. Binkley,et al.  Ecology and Management of Forest Soils , 2000 .

[5]  R. Marrs,et al.  Nutrient Cycling in Terrestrial Ecosystems, Field Methods, Applications and Interpretation. , 1990 .

[6]  D. Baldocchi,et al.  The carbon balance of tropical, temperate and boreal forests , 1999 .

[7]  Rattan Lal,et al.  Soil processes and the carbon cycle. , 1998 .

[8]  J. Pereira,et al.  Plant Responses to Drought Under Climate Change in Mediterranean-Type Ecosystems , 1995 .

[9]  H. Keith,et al.  Allocation of carbon in a mature eucalypt forest and some effects of soil phosphorus availability , 1997, Plant and Soil.

[10]  J. Turner,et al.  Change in organic carbon in forest plantation soils in eastern Australia. , 2000 .

[11]  E. Steen,et al.  Root mass in plantations of Eucalyptus globulus in portugal in relation to soil characteristics , 1987 .

[12]  Walter C. Oechel,et al.  Global Change and Mediterranean-Type Ecosystems , 1995, Ecological Studies.

[13]  J. Pereira,et al.  Productivity, nutrient immobilization and soil chemical properties in an Eucalyptus globulus plantation under different irrigation and fertilization regimes , 1990 .

[14]  C. C. Grier,et al.  Above- and below-ground net production in 40-year-old Douglas-fir stands on low and high productivity sites , 1981 .

[15]  T. Kätterer,et al.  Fine-root dynamics, soil moisture and soil carbon content in a Eucalyptus globulus plantation under different irrigation and fertilisation regimes , 1995 .

[16]  H. Persson,et al.  The distribution and productivity of fine roots in boreal forests , 1983 .

[17]  N. H. Ravindranath,et al.  Land Use, Land-Use Change, and Forestry: A Special Report of the Intergovernmental Panel on Climate Change , 2000 .

[18]  J. J. Landsberg,et al.  Biomass production by fast-growing trees. , 1989 .

[19]  Rattan Lal,et al.  Land Use, Land-Use Change and Forestry , 2015 .

[20]  M. Bonneau,et al.  Constituants et Propriétés du Sol , 1979 .

[21]  Isric.  FAO - Unesco Soil map of the world : revised legend with corrections and updates , 1997 .

[22]  B. A. Stewart,et al.  Advances in Soil Science , 1986, Advances in Soil Science.

[23]  R. Lal,et al.  Soil Carbon Dynamics in Canadian Agroecosystems , 2018 .

[24]  P. Ineson,et al.  Methods of studying root dynamics in relation to nutrient cycling. , 1990 .

[25]  H. N. Chappell,et al.  Additional carbon sequestration following repeated urea fertilization of second-growth Douglas-fir stands in western Washington , 2000 .