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Humic acids containing carboxyl and hydroxyl groups that have the ability to cover the P adsorption site in Typic Hapludults. Molybdate has similarity behaviour with phosphate in theacid soils. Research aim was to study the effects of molybdate and humic acid to the kinetics of phosphate adsorption in Typic Hapludults of Cigudeg, Bogor. Important of kinetics is to get accuration of materials transport, to control influence on anion mobility, that the assessment is needed for the efficient application of Mo and P. Aplication humic acid and molybdate as competitor anion of phosphate was conducted with combination of humic acid and Mo concentration as double anions. Many models describe the kinetics for the adsorption of phosphate by soils i.e. zero order, first order, second order, and Elovich. As ststistically, there was not interaction of humic acid and molybdate on P adsorption. Application of humic acid with rate of 100 mg.L-1 was not effective decrease P adsorption in Typic Hapludults. It was due to the pH of the adsorption system that get near to its pKa of carboxyl gruop about 5. Meanwhile aplication 2 and 5 mmol.L-1 of molybdate significantly decrease of P adsorption. The second order kinetics models apropriate to the adsorptionof P in the Typic Hapludults of Cigudeg, with determination coefficients value (R2) of 0.999-1 and standard error value (SE) of 0.001–0.011.The results suggest that the molybdate as competitor anion affected the kinetics for the adsorption of phosphate due to the charge of molybdate.

The use of chemical insecticide in crop protection around the world has resulted in disturbances of the environment. Therefore, it is necessary to develop for environmentally friendly insect pest management techniques such as the activity of liquid smoke made from tobacco stem waste as an insecticide to Spodoptera litura. Activity of liquid smoke of tobacco stem waste was carried out at the laboratory condition. The results showed that the application of liquid smoke by using the spraying method (direct method) showed better results compared to the results of feeding method (indirect method). Lethal concentration (LC) at 5 days after treatment, LC50 and LC75 values the direct method of 2.9% and 8.87%, while the indirect method of 6,99% and 21.03%. The sub lethal concentration did not cause mortality of S. litura larvae, but inhibited the growth such as indicated by lower weight of larval and pupal in treated larvae than in control. Liquid smoke of tobacco stem waste has activity as an insecticide to S. litura. INTISARIPenggunaan pestisida kimia dalam pengendalian hama di dunia telah menimbulkan gangguan terhadap lingkungan. Maka teknik pengendalian hama yang ramah lingkungan perlu dikembangkan, misalnya aktivitas asap cair limbah batang tembakau sebagai insektisida pada Spodoptera litura. Aktivitas asap cair limbah batang tembakau dilakukan pada kondisi laboratorium. Hasil penelitian menunjukkan bahwa aplikasi asap cair secara langsung (metode semprot) lebih efektif daripada tidak langsung (metode celup pakan). Lethal concentration (LC) pada 5 hari setelah perlakuan, LC50 dan LC75 pada aplikasi langsung sebesar 2,9% dan 8,87%, sedangkan pada aplikasi tidak langsung 6,99% dan 21,03%. Konsentrasi subletal tidak menyebabkan kematian S. litura tetapi mampu menghambat pertumbuhan yang diindikasikan dengan rendahnya bobot larva dan pupa S. litura. Asap cair limbah batang tembakau bersifat insektisida terhadap larva S. litura.