Soil under enrichment planting : assessing soil properties at reforestation sites of Sabal Forest Reserve

The assessment on relationship between soil properties and edaphic factors in the reforestation site is important to provide information on soil productivity and type of species preferences on degraded site. Hence, this information was vital for planning rehabilitation program at degraded area. The objective of this study were to identify the soil properties at reforestation sites for rehabilitation purpose in Sarawak and to differentiate the soil properties at the reforestation sites of different age stands planted with Shorea macrophylla. For the purpose of this study, study sites were established at a reforestation site located at Sabal Forest Reserve (SFR). Three study plots with the size of 50 m x 50 m were constructed at reforestation sites with planted Shorea macrophylla and at different age stands (31 years, 4 years and 3 years after establishment). In each study plot, soil samples were collected at 0-10 cm and 30-40 cm from random points located at on the lines planting using soil auger. Soil physicochemical analysis involved in this study includes soil texture analysis and soil bulk density (BD), pH (water), total carbon (TC), total nitrogen (TN), total organic carbon (TOC), exchangeable Aluminum and available phosphorus. The results showed that, all the soil at the studied site were sandy and strongly acidic in nature. The soil physicochemical properties showed the clear differences between the SB11, SB10 and SB83 sites and generally showed the differences with the age stand, respectively. The soil at SB83 site was strongly acidic and higher soil organic matter as well as higher available phosphorus as compared with the soil at SB11 and SB10. Meanwhile, soil at SB11 site has higher sand content than SB83 site. The Principal Component Analysis categorized the soil properties into three principal components which explained 84.4% of the total variation. In this study, the PC analysis only showed the trend of the physicochemical properties of the soil at the studies sites. This study also suggested that Shorea macrophylla is the suitable species for reforestation activities in the future as it is fast growing species and improved soil physicochemical properties