Abstract. Sunarpi, Jupri A, Kurnianingsih R, Julisaniah NI, Nikmatullah A 2010. Effect of seaweed extracts on growth and yield of rice plants. Nusantara Bioscience 2: 73-77. Application of liquid seaweed fertilizers on some plant species has been reported to decrease application doses of nitrogen, phosphorus, and potassium on some crop plants, as well as stimulating growth and production of many plants. It has been reported that there are at least 59 species of seaweeds found in the coastal zone of West Nusa Tenggara Province, 15 of those species weres able to stimulate germination, growth, and production of some horticultural and legume plants. This research aims to investigate the effect of seaweed extracts obtained from ten species on growth and production of rice plants. To achive the goal, seaweed (100 g per species) wasextracted with 100 mL of water, to obtain the concentration of 100%. Seaweed extract (15%) was sprayed into the rice plants during vegetative and generative stages. Subsequently, the growth and yield parameters of rice plants were measured. The results showed that extracts of Sargassum sp.1, Sargassum sp.2, Sargassum polycistum, Hydroclathrus sp., Turbinaria ornata, and Turbinaria murayana, were able to induce growth of rice plants. However, only the Hydroclathrus sp. extract could enhance both growth and production of rice plants.

Abstrak: Keanekaragaman jenis tumbuhan di Indonesia pada dasarnya juga diikuti dengan beragamnya potensi pemanfaatan jenis-jenis tumbuhan, termasuk di antaranya tanaman pangan dan obat-obatan. Penggunaan obat tradisional oleh masyarakat adakalanya masih menjadi prioritas utama dalam mengobati beberapa jenis penyakit. Selain berkhasiat, obat-obatan berbahan alam tidak memiliki efek samping sebesar obat-obatan medis, asalkan digunakan sesuai dosis yang dianjurkan. Selain itu juga relatif lebih ekonomis dan beberapa jenis di antaranya mudah dijumpai di lingkungan sekitar tempat tinggal. Lahan pekarangan masyarakat merupakan lokasi yang potensial untuk membudidayakan tanaman pangan dan obat-obatan, setidaknya untuk keperluan dalam skala rumah tangga. Namun kendala yang sering dihadapi adalah terbatasnya lahan pekarangan karena telah digunakan untuk keperluan lainnya, selain juga adanya kendala lain yang menyebabkan masyarakat belum giat melakukan penanman di sekitar lahan pekarangan. Oleh karena itu diperlukan teknik bertanam yang tidak banyak memakan tempat, yang bahkan bisa juga diterapkan pada jenis tanaman lain misalnya tanaman sayur-sayuran untuk keperluan rumah tangga. Tujuan kegiatan ini adalah untuk memberikan sosialisasi dan pelatihan pada warga masyarakat agar memiliki pengetahuan dan keterampilan dalam melakukan optimalisasi lahan pekarangan, dengan penanaman tanaman sayur dan tanaman obat menggunakan teknik vertikultur. Diharapkan hal ini dapat membantu upaya pemeliharaan kesehatan dan ketersediaan pangan untuk skala rumah tangga. Kata kunci: Pekarangan; Tanaman Sayur; Tanaman Ibat; Vertikuktur

City parks, apart from having an aesthetic function as a place for recreation, also have an ecological function with vegetation components to soften the microclimate. Vegetation analysis was carried out in six city parks in Mataram City to determine the vegetation structure. Microclimate factors of the park, namely light intensity, air temperature and humidity inside and outside the park during the day and observations of sound attenuation at night have been carried out. Climatic data is carried out to determine the park's ability to reduce heat and air temperature, increase air humidity and reduce noise and determine the park's environmental discomfort index. Of the six urban parks observed in the city of Mataram, namely the parks of Ampenan, Malomba, Udayana, Sangkareang, Mayura, and Selagalas, it is known that there are three groups of vegetation structures, namely trees-shrubs, shrubs-trees, and shrubs. Vegetation with various compositions of life forms in each city park only controls 40 to 60% of the land area of the park. Urban parks in Mataram City have a low level of ability to soften the microclimate, which is below 5%. In reducing heat and air temperature, and increasing air humidity. City parks are also known to have a low ability to reduce noise. The city parks of Ampenan, Udayana and Sangkareang have an environmental comfort level equivalent to the discomfort felt by more than 50% of the population, while the Malomba, Mayura, and Selagalas parks have a level of comfort equivalent to the discomfort felt by less than 50% of the population. The existence of urban park vegetation is only able to reduce the discomfort index of 7 to 9%.

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.

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