Judul: The Seedball Usage on (Samanea saman) Plantation on Ex-Bauxite Mining Land
Abstrak: Kegiatan reklamasi lahan pascatambang bertujuan memulihkan kembali fungsi lingkungan di areal bekas tambang dan sekitarnya. Salah satu jenis tanaman pionir yang mampu beradaptasi di lahan pascatambang adalah trembesi (Samanea saman). Seedball diaplikasikan pada benih dengan melapisi benih dengan media yang mendukung benih untuk berkecambah. Penelitian ini bertujuan untuk menganalisis pengaruh pengunaan seedball terhadap perkecambahan benih dan pertumbuhan trembesi di lahan bekas tambang serta menganalisis pengaruh metode tanam terhadap perkecambahan dan pertumbuhan seedball trembesi. Penelitian ini menggunakan rancangan acak lengkap (RAL) faktorial dengan dua faktor yaitu penggunaan media seedball dan metode tanam. Hasil penelitian menunjukkan bahwa perlakuan seedball tidak berpengaruh nyata pada diameter, tinggi, dan jumlah daun trembesi. Perlakuan P2Q2 memberikan hasil tertinggi pada persen kecambah (78%), persen hidup (100%), dan nilai kecambah (7,12%/hari), sedangkan perlakuan P1Q1 memberikan hasil terendah pada persen kecambah (8%), persen hidup (30%), dan nilai kecambah (0,08%/hari). Faktor penggunaan media seedball menunjukkan hasil tertinggi pada persen kecambah yaitu antara 65% (P2Q1) hingga 78% (P2Q2), serta nilai kecambah antara 2,86%/hari (P2Q1) hingga 7,12%/hari (P2Q2)., Post-mining land reclamation activities aim to restore environmental functions in the ex-mining area and its surroundings. One type of pioneer plant that is able to adapt to post-mining land is trembesi (Samanea saman). Seedballs are applied to seeds by coating the seeds with a medium that supports the seeds to germinate. This study aims to analyze the effect of the use of seedball on seed germination and growth of trembesi on ex-mining land and analyze the effect of planting method on germination and growth of trembesi seedball. This study used a factorial completely randomized design (CRD) with two factors, namely the use of seedball media and planting methods. The results showed that the seedball treatment had no significant effect on the parameters of diameter, height, and number of trembesi leaves. The P2Q2 treatment gave the highest yield at percent sprouts (78%), percent live (100%), and sprout value (7.12%/day), while the P1Q1 treatment gave the lowest yield at percent sprouts (8%), percent live (30 %), and germination value (0.08%/day). The factor of using seedball media showed the highest yield on the percentage of sprouts, which was between 65% (P2Q1) to 78% (P2Q2), and the sprout value was between 2.86%/day (P2Q1) to 7.12%/day (P2Q2).
Keyword: seedball, Samanea saman, bekas tambang, metode tanam

Judul: Seedball and Bioenzyme Application for Land Reclamation Post Limestone Mining, Gunung Putri, Bogor.
Abstrak: Mining causes a decrease in land carrying capacity and soil fertility, so it is necessary to reclaim ex-mining land. To accelerate and reduce the cost of ex-mining land reclamation activities, it is necessary to make technological breakthroughs. Forest rehabilitation using seedball has been widely reported, but has not yet been tested on ex-mining land. Seedball is a technique of seed wrapping to protect seeds from predators and extreme environmental conditions, and provide initial nutrition to seeds after germination. Bioenzymes and manure are needed to support seedling growth in ex-mining lands, which are generally nutrient-poor. The purpose of this study was to find the right composition of seedball ingredients for planting durian (Durio zibethinus), jackfruit (Artocarpus heterophyllus), bisbul (Diospyros blancoi), merbau (Intsia bijuga) and gmelina (Gmelina arborea) seeds on lime ex- mining land, analyzed the effect of seedball and bioenzyme application on plant growth used and analyzed mycorrhizal colonization on plant roots used in limestone ex-mining land. The seedball formulation test used three formulations, namely Formula A (clay and compost), Formula B (clay, compost, and insecticide), and Formula C (clay, sawdust, vermicompost, and bone meal). The design used was a factorial Completely Randomized Design (CRD) with 2 factors. The first factor is the seedball formula, and the second factor is the type of plant where each treatment combination was repeated 3 times. After the best formula was obtained, a planting test was carried out on PT SBI's ex-mining land using the best formula. At the age of 12 weeks after planting (MST) the seeds were given bioenzymes and manure with a Split Plot design. Furthermore, the parameters of germination, germination rate, seedling height, stem diameter, number of leaves, and mycorrhizal colonization on seedling roots were observed by staining method. The result of this research is the best seedball’s formulations is formula C. The results of the planting test on the ex-mining land of PT SBI were the seeds that grow well are jackfruit and merbau. The best fertilization treatment is a combination of bioenzymes and manure. The roots of all plant species in the study area were also colonized by mycorrhizae, and the highest colonization was found in gmelina with a colonization percentage 80.95%. Based on the description above, it can be concluded that the best compositions for making seedballs are clay, sawdust, vermicompost, and bone meal (8:8:2:1), and the seedball technique, application of bioenzymes and manure using jackfruit and merbau types can be used to accelerate the reclamation and rehabilitation of ex-limestone mining land., Pertambangan menyebabkan penurunan daya dukung lahan dan kesuburan tanah, sehingga perlu dilakukan reklamasi lahan bekas tambang. Upaya untuk mempercepat dan menekan biaya kegiatan reklamasi lahan bekas tambang diperlukan terobosan teknologi. Rehabilitasi lahan menggunakan seedball telah banyak dilaporkan, tetapi belum diujicobakan di lahan bekas tambang. Seedball merupakan teknik pembungkusan benih untuk melindungi benih dari predator dan kondisi lingkungan yang ekstrim, serta untuk memberikan nutrisi awal pada benih setelah berkecambah. Bioenzim dan pupuk kandang diperlukan untuk mendukung pertumbuhan bibit di lahan bekas tambang yang miskin hara. Tujuan dari penelitian ini adalah menemukan komposisi bahan pembuat seedball yang tepat untuk menanam
Keyword: seedball, bioenzymes, rehabilitation, degraded land, plant growth

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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