Exessive use of inorganic fertilizers in rice production systems, causes various negative effects in the environemnt, such as reducing soil fertility and increases pollution, which disturbs agricultural sustainability. Understanding raw materials for developing organic fertilizers which are cheap and adaptive to our environment, is an important study recently. Many researchers reported that brown algae could increase growth and yield of several species of plants. This due to brown algae extract contain plant growth hormone and essential elements to stimulate growth and production of plants. This article report growth and yield of rice plants suplied with mixtured extract of brown algae. Several species of brown algae were collected in coastal beach of Lombok. The seaweeds were cutted into small peaces, extracted with boiled water for 30 minute and filtered using filter whatman no.1 to get solid and liquid extract. Mixtured solid extracts were added in soil media. On the other hand, the mixtured liquid extracts were sprayed to rice plants during vegetative growth. The results shown that mixtured solid extracts increased growth and yield of rice plants. However, mixtured liquid extract did not stimulate growth and yield of rice plants. This suggests that brown algae is a potential raw material for development of organic fertilizers, which are adaptive to environment to support sustainable agriculture.

Chlorophyll is a green pigment in leaves that functions to absorb light energy for photosynthesis. The value of chlorophyll concentration in leaves indicates the health status of a plant and healthy plants will produce more fruit. The purpose of this study was to determine the effect of chemical fertilizer (CF) and solid algae fertilizer (SAF) with different doses on the concentration of chlorophyll in paddy leaves. This research is important to do to determine the potential of macroalgae in reducing the dose of chemical fertilizer use in agricultural activities. In this study, paddy plants were given four different treatments, namely control (without CF and SAF); 100% chemical fertilizer (CF); 100% solid algae fertilizer (SAF); 50% chemical fertilizers and 50% solid algae fertilizers (CF+SAF). Each treatment consisted of ten pots. The results showed that the administration of SAF in the form of a combination of SAF 50% and CF 50% had a significant effect on the increase of chlorophyll b content of the leaves of paddy plants. However, there were no significant difference in chlorophyll a content between CF and CF+SAF group. Current results show that addition of SAF could potentially increase growth quality in paddy plants due to the increase of chlorophyll b content which absorbs higher frequency of blue light for photosynthesis.

Marine sponge Stylissa flabelliformis is a marine sponge species that is widely found in Indonesia. Marine sponges have been proven to have pharmacological activities including wound healing, cytotoxicity and antimicrobial activity. All these activities are related to its antioxidant potential. Antioxidants are important for human health due to its ability to protect cell damage caused by free radicals. The aim of this research was to study the antioxidant activity of marine sponge (Stylissa flabelliformis) and to observe the phytochemical compound of the marine sponge such as the phenolic and flavonoid content. Extraction was performed using cold maceration with 96% ethanol solvent and continued by rotary evaporator to get the concentrated extract. Antioxidants activity was analysed using DPPH (2,2-diphenyl-1-picrylhydrazyl) method, which examines the inhibitory concentration (IC50) of the ethanol extract. Total phenolic content (TPC) was examined using Gallic acid as the standard, while total flavonoid content (TFC) was examined using quercetin as the standard. The result showed a concentration-dependent antiradical activity by reduction of DPPH with an IC50 value 2000 µg/mL. Total phenolic content was 152,67 mg GAE/g, while the total flavonoid content was 155,79 mg QE/g.

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The coastal areas of Lombok has very high diversity of macroalgae which are largely unexplored. Among them are the brown macroalgae Sargassum species which are well known for their biological potentials. In this study, we aim to evaluate 4 Sargassum species, S.cristaefolium, S. crassifolium, S. polycystum, and S. aquifolium for their antioxidant potential of Sargassum species found the west coastal Aare of Lombok, Indonesia. To determine the antioxidant capacity of macroalgal extracts, 2,2-diphenyl-1-picrylhydrazyl (DPPH) as well as total phenolic content (TPC) were measured. Extracts of the brown macroalgae are well known to have very active antioxidant activity. Among them S. cristaefolium and S.crassifolium provide stronger antioxidant activity compared to S.aquifolium and S.polycystum. Furthermore, correlations were found between TPC macroalgal and their DPPH scavenging activity. This indicates an important role of polyphenols as antioxidants. Overall, brown macroalgae from Lombok coastal area may be a good source of natural bioactive compounds.