Humic and Fulvic Acids of Gliricidia and Tithonia Composts for Aluminium Detoxification in an Ultisol

A laboratory experiment was conducted to elucidate roles of Gliricidia sepium and Tithonia diversifolia composts and their extracted humic and fulvic acids on aluminum concentration in an Ultisol. Those composts and humic and fulvic acids extracted from them mixed with soil were arranged in a complete randomized design with three replicates, and incubated for 90 days. Al concentration and pH of the soil were measured at 0, 3, 10, 20, 30, 45, 60, 75 and 90 days after incubation. Results of the study showed that the highest decrease in exchangeable Al concentration (90.5%) was observed for Tithonia fulvic acid treatment during 90 days, followed by Tithonia compost (88.4%), Gliricidia fulvic acid (82.3%), Gliricida compost (82.2%), Tithonia humic acid (75.66%), and Gliricidia humic acid (73.46%) treatments, whereas control only decreased exchangeable Al concentration by 0.9%. The rate of change in exchangeable Al concentration was fast for the first 45 days, but it then slowed down for the second 45 days (45-90 days). This was particularly observed with organic acid treatments, whereas compost treatment still showed a subsequent decrease. Patterns of Al chelate and pH were very similar to that of exchangeable Al. It was thus concluded that roles of humic and fulvic acids in reducing exchangeable Al was only short term, whereas compost played roles in the long term

PENGARUH UMUR DAN SISTIM PENANAMAN AKAR WANGI (Vetiveria zizanioides L.) DALAM PERBAIKAN KUALITAS LIMBAH CAIR PABRIK TAPIOKA

A series of experiment had been conducted to elucidate the effects of age and planting system of fragrant root (Vetiveria zizanoides) in improving quality of tapioca industry liquid waste. Eight treatments generated from two planting systems, i.e. hydroponics system (To) and wetland system (T1), and four levels of plant age, i.e. 7 days after planting (LiV1), 45 days after planting (L1V45), 60 days after planting (L1V60), and 75 days after planting (L1V75), were arranged in a randomized block design with three replicates. pH, BOD, COD, DO and CN values were measured periodically for 61 days. Results of the study showed that various age of fragrant root plant were capable of reducing BOD, COD and CN concentrations, as well as increasing DO concentration and pH value for the two planting systems. During remediation process, the LiV75 treatment at wetland system produced better quality of tapioca liquid waste than that of hydroponics syste