Variations of Soil Properties on Post Shifting Cultivation area in Primary Forest

Shifting cultivation in tropical forest was presumed as the major cause of soil degradation and soil nutrient depletion, and need several years -namely forest-fallow periods- to be recovered. Soil properties dynamic monitoring has been done in the tropical forest in Central Kalimantan at one, five and ten year after abandonment, and compared to primary forest, to predict the time for soil recovery in term of Calcium (Ca), Magnesium (Mg), Potassium (K), Natrium (Na) content and cation exchange capacity (CEC). The soil properties status can be beneficial for rehabilitation activities through practicing agroforestry by the forest dwellers. The results showed that soil properties (i.e. Ca, Mg, K, CEC) were significantly different among soil depth (P<0.05), but not for Na. Highest value of Ca, Mg, K and Na were observed in the soil surface (0-20 cm), Soil nutrient contents were significantly changed with the time of abandonment, the highest value of CEC, Ca, K, and pH were found in five years after the abandonment. It suggested that soil nutrients were distributed in the soil surface composed from litter of pioneer trees. The research suggested that soil recovery was probably occurred during early fallows, and agroforestry can be practiced at five year after the abandonment.