Carbon, water and nutrient balances of a Eucalyptus grandis plantation in Brazil over 5 years
Eucalyptus grandis plantations in Brazil are among the most productive forests of the world, reaching mean annual increments of about 50 m3/ha/yr over short (6 yr) rotations. Carbon, water, and nutrients budgets in one of these plantations were investigated through continuous eddy-covariance measurements of water vapor and CO2 fluxes over a 5-yr period encompassing two successive rotations (2 yr before and 3 yr after harvesting and replanting), with measurements of water table depth, soil water content to a depth of 10 m, and concentrations of nutrients in soil solutions. Before clearcutting, fine roots were found to a depth of 16 m. No seepage occurred below 5 m. Actual evapotranspiration (AET) was approximately equal to annual precipitation (1350 mm). Clearcutting resulted in a strong decrease in AET, a recharge of deep soil layers, and a rise in the water table. By the third year after replanting, the rapid increase in AET supported by the fast expansion of roots led to soil water depletion to a depth of 10 m. Clearcutting turned the forest from a strong C sink (net ecosystem productivity of about 1 tonne C/ha/month) into a C source, but the plantation turned back to a C sink from 7 months after replanting onwards.
| Main Authors: | , , , , , , , , , |
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| Format: | article biblioteca |
| Language: | eng |
| Subjects: | F60 - Physiologie et biochimie végétale, Eucalyptus grandis, bilan hydrique, équilibre nutritif (plante), plantation forestière, évapotranspiration, analyse de covariance, http://aims.fao.org/aos/agrovoc/c_2693, http://aims.fao.org/aos/agrovoc/c_8311, http://aims.fao.org/aos/agrovoc/c_35711, http://aims.fao.org/aos/agrovoc/c_3048, http://aims.fao.org/aos/agrovoc/c_2741, http://aims.fao.org/aos/agrovoc/c_28833, http://aims.fao.org/aos/agrovoc/c_1070, |
| Online Access: | http://agritrop.cirad.fr/596000/ http://agritrop.cirad.fr/596000/1/596000.pdf |
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| Summary: | Eucalyptus grandis plantations in Brazil are among the most productive forests of the world, reaching mean annual increments of about 50 m3/ha/yr over short (6 yr) rotations. Carbon, water, and nutrients budgets in one of these plantations were investigated through continuous eddy-covariance measurements of water vapor and CO2 fluxes over a 5-yr period encompassing two successive rotations (2 yr before and 3 yr after harvesting and replanting), with measurements of water table depth, soil water content to a depth of 10 m, and concentrations of nutrients in soil solutions. Before clearcutting, fine roots were found to a depth of 16 m. No seepage occurred below 5 m. Actual evapotranspiration (AET) was approximately equal to annual precipitation (1350 mm). Clearcutting resulted in a strong decrease in AET, a recharge of deep soil layers, and a rise in the water table. By the third year after replanting, the rapid increase in AET supported by the fast expansion of roots led to soil water depletion to a depth of 10 m. Clearcutting turned the forest from a strong C sink (net ecosystem productivity of about 1 tonne C/ha/month) into a C source, but the plantation turned back to a C sink from 7 months after replanting onwards. |
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