Judul: Effectiveness Bio-Fertilizers in the Pre Nursery of Oil Palm
Abstrak: The development of oil palm plantations in Indonesia currently has an impact on the demand for synthetic fertilizers because they contain higher nutrients. Intensive use of synthetic fertilizers needs attention because it can reduce soil quality and soil biodiversity. Therefore, a combination of synthetic fertilizers and bio-fertilizers is needed. The research method used was factorial randomized block design (RBD) with the first factor was fertilizer NPK which consisted of 4 levels of fertilizer doses 0%, 50%, 75%, and 100%. The second factor is biofertilizer which consists of four levels, without biofertilizer, 1ml PHC / L water, 2ml PHC / L water, and 30g mycorrhizae where grups were replicates. The combination treatment of NPK fertilizer at a dose of 50% with twice the recommended dosage of liquid biofertilizer gave the best results on the performance of oil palm in the pre-nursery. Mycorrhizal treatments singly or in combination with NPK fertilizer at doses of 50% and 75% significantly affected the percent of root colonization. The combination of liquid biofertilizer with NPK at a dose of 75% and 100% had a significant effect on the total soil N and plant N. Single treatment of mycorrhizae and its combination with NPK fertilizer at a dose of 75% showed the best results on available soil P.
Keyword: biofertilizer, mycorrhizae, oil palm, pre nursery

Judul: Uji Efektivitas  Pupuk Hayati Fungi Mikoriza Arbuskula (FMA) pada Bibit Kelapa Sawit (Elaeis guineensis Jacq.) di Nursery
Abstrak: Kelapa sawit (Elaeis quineensis Jacq.) merupakan salah satu tanaman perkebunan penghasil minyak nabati yang menjadi komoditas unggulan di Indonesia. Pemberian pupuk hayati menjadi salah satu alternatif untuk membantu meningkatkan pertumbuhan bibit kelapa sawit. Penelitian ini bertujuan menganalisis pengaruh penggunaan pupuk hayati mikoriza terhadap pertumbuhan tanaman kelapa sawit di Nursery, menganalisis infeksi akar dan jenis spora oleh mikoriza serta mengkaji pengaruh pemberian pupuk hayati terhadap sifat biologi tanah dan kimia tanah. Penelitian menggunakan rancangan acak lengkap (RAL) faktor tunggal dengan 6 taraf perlakuan dan 10 ulangan, sehingga total satuan percobaan adalah 60 polibag. Perlakuan pengujian pupuk hayati berdasarkan Peraturan Menteri No.1 Tahun 2019 yaitu kontrol; pupuk NPK standar (15-15-15) 2,5 g; 20 g pupuk hayati; NPK standar + 20 g pupuk hayati; 3/4 NPK standar + 20 g pupuk hayati; dan 1/2 NPK standar + 20 g pupuk hayati. Perlakuan kombinasi 3/4 NPK standar + 20 g pupuk hayati memberikan hasil pertumbuhan bibit kelapa sawit paling baik pada parameter tinggi, diameter, dan jumlah daun. Nilai Relative Agronomic Effectiveness (RAE) pada perlakuan 3/4 NPK + 20 g pupuk hayati mikoriza menunjukkan hasil yang paling efektif secara agronomi dan ekonomi. Perlakuan mikoriza mampu membentuk kolonisasi pada akar sebesar 100% dan jenis spora yang paling banyak ditemukan berasal dari jenis Acaulospora dan Glomus. Pemberian pupuk hayati mikoriza berpengaruh nyata dalam meningkatkan populasin total mikrob tanah, respirasi tanah, serta adanya peningkatan ketersediaan fosfor dalam tanah., Oil palm (Elaeis quineensis Jacq.) is one of the vegetable oil-producing plantation crops that is a leading commodity in Indonesia. The application of biological fertilizers is an alternative to help improve the growth of oil palm seedlings. This study aims to analyze the effect of the use of mycorrhizal biofertilizers on the growth of oil palm plants in the Nursery, analyze root infection and spore types by mycorrhiza and examine the effect of biofertilizers on soil biological and soil chemical properties. The study used a single-factor Completely Randomized Design (CRD) with 6 treatment levels and 10 replications, so that the total experimental units were 60 polybags. Biofertilizer test treatments based on Ministerial Regulation No.1 of 2019 are control; standard NPK fertilizer (15-1515) 2,5 g; 20 g biofertilizer; standard NPK+20 g biofertilizer; 3/4 standard NPK+20 g biofertilizer; and 1/2 standard NPK+20 g biofertilizer. The combination treatment of 3/4 standard NPK+20 g biofertilizer gave the best growth results of oil palm seedlings in the parameters of height, diameter, and number of leaves. The Relative Agronomic Effectiveness (RAE) value in the 3/4 NPK+20 g mycorrhizal biofertilizer treatment showed the most effective results agronomically and economically. The mycorrhiza treatment was able to form colonization on the roots by 100% and the types of spores found were mostly from the Acaulospora and Glomus. The application of mycorrhizal biofertilizer has a significant effect in increasing the total population of soil microbes, soil respiration, and an increase in the availability of phosphorus in the soil.
Keyword: mycorrhiza, oil palm, relative agronomic, regosol

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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