THE ROLE OF DIFFERENT TYPES OF BIOPORY TECHNOLOGY IN REPAIR OF LAND PROPERTIES AND ROOT GROWTH IN THE PALM OIL PLANTS AREASUGITO LOSO, SUDRADJAT, HARIYADI, SUDIRMAN YAHYA AND ATANG SUTANDI
The improvement of soil characteristics is an important factor to support the growth and yield of oil palm. The technology of biopore can be optimized by utilizing litter around the oil palm disc. This study aimed to determine the best litter type to increase the root volume of oil palms and to improve the physical, chemical, and biological properties of the soil. The study was conducted from October 2014 to December 2016 at Teaching Farm of Oil Palm IPB-Cargill, Bogor, Indonesia. The experiment used one factor arranged in a randomized complete block design consisting of four treatment levels with four replications. The treatments level were the litter from monocotyl plant (S1), the litter from dicotyl plant (S2), the litter from part of oil palm organs (S3), and the litter from S1 + S2 + S3 mixture (S4). The root volume of oil palm increased in each treatment of S4, S2, S3, and S1 at 26 months after treatment (MAT). The root volume of oil palm on S4, S2, S3, and S1 treatments was 305 mL m-3 (312.16%), 207 mL m-3 (276.00%), 175 mL m-3 (177.78%), and 153.5 ml m-3 (143.65%), respectively. The treatment of mixed litter (S4) could improve the physical, chemical, and biological properties of the soils characterized by increasing of soil water content, soil macronutrients, cation exchange capacity (CEC), the number of soil macroorganisms, and the type and number of soil microorganisms. The soil water content decreased from 0-20 cm depth to 40-60 cm as deeper soil layer on sufficient water content condition, while the soil water content in topsoil (0-20 cm) would be lower than in soil depth 20-40 cm and 40-60 cm on long drought period. The treatment of mixed litter (S4) was the best treatment to increase the root volume of oil palm, the soil water content, the soil nutrient contents (N, P, K, Ca, Mg, and C-organic), CEC, the number of soil macroorganisms, and the type and number of soil microorganisms compared to the treatment of monocotyl litter (S1), dicotyl litter (S2), and the litter from part of the oil palm organs (S3).