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<table border="1" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top" width="456"><p><em>Citronella grass (</em>Cymbopogon nardus var genuinus<em> L) is an essential oil-producing plant known as "Citronella Oil of Java". Oil is </em><em>resulted</em><em> from leaf distillation. The fertilization of N, P, K and Mg was expected to enhance herb productivity and oil yield of citronella grass. The research was conducted at Cicurug Experimental Garden, Sukabumi from August 2016 - February 2017. The objective of this research was to determine the proper dosage of NPKMg fertilizer on citronella grass in Latosol</em><em> soil type</em><em>. The study was arranged in a Randomized Block Design with 6 fertilization treatments and 4 replications. Fertilizer treatments were (1) without fertilizer (control), (2) NPKMg (12:12:17:2): (2) at the dosage of 141 kg.ha^-1,(3) 281 kg.ha^-1, (4) 421 kg.ha^-1, (5) 526 kg.ha^-1, and (6) Urea 150 kg.ha^-1, SP-36         50 kg.ha^-1 and KCl 125 kg.ha^-1 (as comparison). The NPKMg fertilization on citronella grass enhanced plant growth and increased the productivity of biomass and oil yield.  The application of NPKMg fertilization (12:12:17:2) 141 kg.ha^-1 produced 23 tons of herbs, increased by 30.8 % compared to NPK fertilization without Mg. The dosage of NPKMg fertilizer (12-12-17-2) at 281 kg.ha^-1 indicated the best growth and the highest herb production (24 ton.ha^-1</em><em>),</em><em> increased by 39 %, while the highest oil content (1.4 %) was shown by 421 kg.ha^-1NPKMg (12-12-17-2) <em>treatment, although the oil yield was insignificant compared to 281 kg.ha^-1. Thus, the dosage of 281 kg.ha^-1NPKMg (12:12:17:2) can be recommended for citronella <ins cite="mailto:ASUS" datetime="2019-06-17T09:10"> grass</ins> cultivated at Latosol<ins cite="mailto:ASUS" datetime="2019-06-17T09:10"> soil type</ins></em></em></p></td></tr></tbody></table>

Black pepper cultivation in Bangka Belitung is commonly followed a shifting cultivation method. This is due to the low soil fertility. The study aimed to obtain the best combination and concentration of indigenous rhizosphere and endophytic bacteria to improve soil fertility and enhanced growth and yield of black pepper. The study was set up in a complete randomized block design, 9 treatments and 3 replications. The treatments were the combinations of the types and concentrations of the bacterial isolates, i.e. (1) Control, (2) Endophytic bacteria A, (3) Combination of Endophytic bacteria B + Bb. chosinensis+ Rhizobacteria A, (4) Combination of Rhizobacteria B + Endophytic bacteria A+ Endophytic bacteria C, (5) Combination of Endophytic bacteria B + Endophytic bacteria C + Endophytic bacteria D at 105 and 108 cpu ml−1 respectively. Endophytic bacteria were capable to boost the growth and yield of black pepper, also improved the soil chemical properties. The best treatment combinations were the mixture of of bacteria, i.e. (1) Psedomanas sp.+ Brevibacillus sp+Mesorhizobium sp., (2) Bb. sp1 +Bb. sp2+Bacillus sp., and (3) Brevibacillus sp +Bb sp1+Bacillus sp. The study implies that rhizosphere and endophytic bacteria are potential to be developed for reducing fertilizer use in black pepper cultivation.

Artemisia contains secondary metabolites with antioxidants properties. The study aimed to obtain the type and concentration of effective solvents to produce Artemisia extract with maximum antioxidant activity. The research was conducted at the Laboratory of Indonesian Spices and Medicinal Crops Research Institute in 2015. The Artemisia used for the research came from Lembang, West Java. The study was arranged in a randomized block design, 7 treatments, and 2 replications. The treatment consisted of a combination of two solvents (ethanol and methanol) and three solvent concentrations (50, 70, and 96%) and water as control. Artemisia was processed into powder and then extracted following the treatments. The extract obtained was then tested for its antioxidant activity using the DPPH method. The type and concentration of solvent had a significant effect on the yield and antioxidant activity of Artemisia extract. The use of ethanol solvent resulted in higher extract yield and antioxidant activity than methanol. The higher the solvent concentration, the smaller the extract yield. The antioxidant activity of Artemisia ethanolic extract was stronger than methanolic extract. The IC50 value of the Artemisia ethanolic and methanolic extract were 20.61 ppm, and 25.06 ppm. The most effective solvent concentration to extract Artemisia was ethanol 70%.