Soil organic carbon pool under native tree plantations in the Caribbean lowlands of Costa Rica
Background
This study focuses on the role of native tree plantations in enhancing the soil organic carbon (SOC) pool on degraded pastures in the Caribbean lowlands of Costa Rica. SOC is a critical carbon reservoir, influencing atmospheric and soil carbon dynamics. Conversion of tropical forests to agriculture has historically depleted SOC pools, but restoration through tree plantations can reverse this trend. Four native species (Hieronyma alchorneoides, Vochysia guatemalensis, Calophyllum brasiliense, and Stryphnodendron excelsum) were planted on a degraded 2.6 ha pasture in 1991. The goal was to assess the SOC concentration, pool, and associated soil physical and chemical properties 14 years post-plantation, providing insights into land restoration potential in tropical regions.
Goals and Methods
The study aimed to quantify SOC distribution by depth, evaluate variations in SOC pools among tree species and pastures, and understand SOC's relationship with soil properties. Researchers used a randomized block design and soil sampling to 50 cm depth, analyzing bulk density, aggregate size distribution, and SOC in various particle-size fractions. Statistical tools like ANOVA and principal component analysis (PCA) were employed to compare treatments and identify key factors influencing SOC variability. The results were analyzed to determine how tree plantations affect SOC compared to degraded pastures.
Conclusions and Takeaways
The SOC concentration decreased with depth across all treatments, with the highest values observed under H. alchorneoides and V. guatemalensis. These species also demonstrated higher total SOC pools compared to degraded pastures, though differences were not statistically significant. Soil aggregation and biological activity were critical factors in SOC stabilization, influenced by vegetation type. The study highlighted that native tree plantations contribute to SOC enhancement, but changes are gradual and affected by factors like litter production and soil texture. It underscores the importance of long-term monitoring for understanding carbon sequestration in tropical ecosystems and promoting sustainable land management practices.
Reference:
Soil organic carbon pool under native tree plantations in the Caribbean lowlands of Costa Rica. Forest Ecology and Management. 2007;241(1-3):134 - 144. doi:10.1016/j.foreco.2007.01.022.
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