Judul: Potensi Oligochitosan, Vitazyme, dan Biofertilizer dalam Meningkatkan Efisiensi Pemupukan, Pertumbuhan, dan Produksi Padi (Oryza sativa L.)
Abstrak: Efficiency of nutrient uptake by rice plants is still low. Various attempts have been made to improve the efficiency of nutrient absorption so that fertilizers are added are not wasted, pollute the environment and save farmers’s expenditures. Oligochitosan, Vitazyme, and Biofertilizer can be an alternative way in order to improve the efficiency of nutrient uptake in rice plants. This study aimed to evaluate the ability of Oligochitosan, Vitazyme, and Biofertilizer in improving fertilization efficiency, growth, and yield of rice plants. This study consisted of pot and field research. The treatments used in pot research were using NPK fertilizer, Oligochitosan Japan, Oligochitosan BATAN, Biofertilizer Azozo and Vitazyme, while field research only used NPK fertilizer, Oligochitosan Japan and Biofertilizer Azozo as treatments. The results showed that pot study at Cihideung Udik Village on 100% NPK treatment, significantly increased the yield of rice compared with 50% NPK. Combinations treatment between 50% NPK fertilizer with Oligochitosan, Vitazyme, and Biofertilizer, significantly increased the yield of rice compared with 50% NPK use only. The yield improvement on these treatment combinations showed that Oligochitosan, Vitazyme, and Biofertilizer were able to increase the efficiency of nutrient uptake by plants more than 100% NPK fertilizer. Oligochitosan and Biofertilizer application on field research in the Cihideung Udik and Situ Gede Village were not significantly different in supporting the growth and production of rice, except on rice panicle length parameter in Situ Gede Village. The growth and production in all treatments at each replication showed the same result. This was apparently due to the lack appropriate of basis fertilizer application on field trials, so that causing the effect on each treatment hard to be evaluated.
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Judul: Increased Rice Yield (Oryza sativa L.) with Application of Organic Fertilizer Enriched with Microbes
Abstrak: Produktivitas padi Indonesia beberapa tahun terakhir mengalami penurunan. Pemupukan yang sesuai dengan kondisi tanah dan kebutuhan tanaman mampu meningkatkan produksi tanaman. Aplikasi pupuk organik diperkaya dapat meningkatkan kesuburan tanah. Mikroba yang hidup di perakaran tanaman atau PGPR dalam pupuk dapat meningkatkan ketersediaan hara dalam tanah dan mensintesis hormon pertumbuhan tanaman melalui aktivitas biologisnya. Penelitian ini bertujuan untuk mempelajari pengaruh aplikasi pupuk organik diperkaya terhadap peningkatan hasil padi sawah dan pengurangan dosis pupuk anorganik. Rancangan yang digunakan adalah rancangan kelompok lengkap teracak satu faktor yaitu dosis pupuk dengan 4 ulangan. Penelitian dilaksanakan di Kebun Pendidikan Sawah Baru IPB. Analisis tanah dan analisis kandungan pupuk dilaksanakan di Laboratorium Kimia dan Kesuburan Tanah, Departemen Ilmu Tanah dan Sumber Daya Lahan, Laboratorium Pengujian Departemen Agronomi dan Hortikultura, serta Laboratorium Tanah, Tanaman, Pupuk, Air, Balai Penelitian dan Pengembangan Pertanian. Pelaksanaan penelitian dimulai pada November 2020 hingga April 2021. Pengamatan dilakukan terhadap pertumbuhan, hasil, dan komponen hasil padi sawah. Hasil penelitian ini menunjukkan aplikasi pupuk organik diperkaya secara umum tidak meningkatkan pertumbuhan dan hasil per tanaman maupun hasil per hektar padi sawah. Aplikasi pupuk organik diperkaya dapat mengurangi 25% penggunaan pupuk anorganik dengan nilai efektivitas agronomi relatif sebesar 108,8%., Rice productivity in Indonesia has decreased in recent years. Fertilization that is suitable for soil conditions and plant needs can increase crop yield. The application of bioorganic fertilizer would be able to increase soil fertility. Microbes that live in plant roots could increase the availability of nutrients in the soil and synthesize plant growth hormones through their biological activities. The research aims to study the effect of the application of organic fertilizer enriched with microbes on increasing growth, yield, and yield components of lowland rice and the reduction of the dose of inorganic fertilizer. The experimental design used was a randomized complete group design with one factor, namely the dose of fertilizer with 4 replications. The research was carried out at the Sawah Baru Teaching Farm, IPB. Soil analysis and analysis of fertilizer content were carried out at the Laboratory of Chemistry and Soil Fertility, Department of Soil Science and Land Resources, Testing Laboratory of the Department of Agronomy and Horticulture, and the Laboratory of Soil, Plants, Fertilizer, Water, Agricultural Research and Development Center. The experiment was conducted from November 2020 until April 2021. The observations made were observations of vegetative and generative characters, as well as yields. Results shows, the application of enriched organic fertilizers did not increase growth and yield per plant or yield per hectare of lowland rice. Application of enriched organic fertilizers, however, could reduce 25% of inorganic fertilizers usage with a relative agronomic effectiveness value of 108.8%.
Keyword: effectiveness, organic fertilizer, PGPR, rice, yield

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh.
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.