Soil Respiration of Natural Forest, Forest Plantation and Agricutural Incubated Soils

Abstract

Recently, scientists have focused attention on soil as a major source and sink for atmospheric CO2. Three replications of two-depth soils from eleven different ecosystem types from Sakaerat Environmental Research Station (SERS), Sakaerat Silvicultural Research Station (SSRS) and Suranaree University of Technology (SUT), Nakhon Ratchasima were collected during the first week of March, 2010. The soils were then incubated at 25°C for three days and measured their respiration rates. The highest soil respiration rate was found in sunflower with 0.823 μmol CO2 g-1 h-1 while the lowest was found in eucalyptus plantation in SUT with 0.005 μmol CO2 g-1 h-1. Additionally between two natural forests at SERS, the respiration rate of dry evergreen forest was higher than in dry dipterocarp forest with the value of 0.037 and 0.016 μmol CO2 g-1 h-1 respectively. Whereas the soil respiration rate at SSRS forests was highest in the eucalyptus plantation (0.048 μmol CO2 g-1 h-1) and lowest in acacia plantation (0.027 μmol CO2 g-1 h-1). The overall respiration rate was higher for soils from 0-5 cm than 5-15 cm, but not statistically significant difference. Soil water content and pH were positively significant related with soil respiration (p<0.01). Soil carbon, however, was also positively significant related with soil respiration but in lesser degree (p<0.05). Therefore soil water content and pH should be major driving forces for soil respiration.