Soil properties and soil carbon storage in the Acacia mangium Willd. and Acacia auriculaeformis A.Cunn. ex Benth. plantations at Northeast Forest Research and Development Center, Nakhon Ratchasima Province

Abstract

This study aims to compare soil properties and carbon storage in soil and study the relationship between soil properties and carbon in the soil of Acacia mangium Willd. and Acacia auriculaeformis A.Cunn. ex Benth. The study was conducted in plantations planted in 1985, 1986, and 1987, ages 33, 32, and 31 years, respectively, with the planting spacing of 2 m x 4 m using a completely randomized design (CRD). A total of 18 sample plots were collected, with three replicate sub-sampling plots of size 20 x 20 m for each sample plot. Soil samples were collected at 0–15 cm and 15–30 cm in each sub-sampling plot. The soil samples were then analyzed for physical properties, chemical properties and carbon storage. The results showed that the texture of all soils is sandy clay loam. The bulk density, particle density and percentage of soil porosity were similar. The pH value was between 3.68-4.21, In the soil map 48, 56 and 62, which is classified as very acidic. Organic matter content is low to high. In the Acacia mangium Willd. The plot for the planting year 1985 had the highest organic matter value, equal to 3.65%. The total nitrogen content varied with the organic matter content. The available phosphorus content was very low to low. Most of the exchangeable potassium, exchangeable calcium and exchangeable magnesium values were not significantly different (p>0.05), Acacia mangium Willd. had the highest carbon storage in soil, equal to 49.62 tons per hectare. The relationship between soil carbon concentration and soil properties was analyzed. The results showed that soil carbon concentration had a positive relationship with porosity, organic matter, total nitrogen, and available phosphorus, but a negative relationship with clay content, bulk density, particle density, pH, and exchangeable calcium.