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: Uji Penanaman Menggunakan Teknik Direct Seeding di Lahan Bekas Tambang Batu Kapur, Gunung Putri, Bogor
Abstrak: Kegiatan reklamasi dan rehabilitasi penting dilakukan untuk mengembalikan daya dukung lahan agar berfungsi kembali sesuai dengan peruntukannya. Inovasi dalam kegiatan reklamasi dan rehabilitasi lahan bekas tambang perlu dilakukan untuk mempercepat dan meningkatkan keberhasilan dalam mengembalikan fungsi lahan sesuai peruntukannya. Salah satu bentuk kegiatan reklamasi dan rehabilitasi lahan bekas tambang adalah revegetasi. Direct seeding adalah teknik penanaman dengan menggunakan benih yang ditanam langsung di lapangan tanpa melalui tahapan pembibitan di persemaian. Penting untuk menganalisis pertumbuhan tanaman yang ditanam menggunakan teknik direct seeding dan penanaman menggunakan semai. Kedua teknik tersebut diujicoba untuk merehabilitasi lahan bekas tambang batu kapur PT. Solusi Bangun Indonesia di Bogor. Benih dan bibit yang digunakan dalam penelitian ini adalah merbau (Intsia bijuga), ketapang (Terminalia catappa), jengkol (Archidendron jiringa), bisbul (Diospyros blancoi), dan nangka (Artocarpus heterophyllus). Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap (RAL) dengan kombinasi metode penanaman dan pemupukan serta lima jenis tanaman sebagai perlakuan. Benih dan bibit kelima tanaman tersebut ditanam di lahan bekas tambang batu kapur dengan kondisi tanah yang didominasi fraksi pasir. Hasil penelitian menunjukkan bahwa tanaman yang ditanam dengan teknik direct seeding memiliki persentase bertahan hidup dan rata- rata pertumbuhan tanaman yang sama bahkan cenderung lebih baik dibandingkan dengan tanaman yang ditanam menggunakan bibit polybag. Jenis tanaman yang dapat ditanam menggunakan teknik direct seeding di lahan terbuka bekas tambang batu kapur adalah nangka dan merbau, sedangkan jengkol kurang mampu bertahan pada kondisi lingkungan yang kering, ketapang yang ditanam menggunakan teknik direct seeding rentan terhadap serangan hama yang menyebabkan benih gagal berkecambah, dan bisbul yang memiliki pertumbuhan kurang baik walaupun persentase hidup dan daya berkecambahnya tinggi. Penanaman menggunakan teknik direct seeding mampu menghemat biaya penanaman dibandingkan menggunakan bibit tanaman hingga 65%. Berdasarkan uraian diatas dapat disimpulkan bahwa teknik direct seeding menggunakan jenis nangka dan merbau dapat dilakukan untuk mempercepat reklamasi dan rehabilitasi lahan bekas tambang batu kapur dan menghemat biaya operasional penanaman., Reclamation and rehabilitation activities are carried out to restore the land function according to its designation. Innovations in reclamation and rehabilitation of ex-mining land need to be carried out to accelerate and increase success in restoring land functions. One form of reclamation and rehabilitation of ex-mining land is revegetation. The direct seeding technique is a planting method using seeds planted directly in the field without going through nursery stages. It is important to analyze and find out wether the direct seeding technique has better plant growth when compared to planting using seedlings. The technique was tested to rehabilitate ex-limestone mining of PT. Solusi Bangun Indonesia in Bogor. The seeds and seedlings used in this study were Merbau (Intsia bijuga), ketapang (Terminalia catappa), jengkol (Archidendron jiringa), bisbul (Diospyros blancoi), and jackfruit (Artocarpus heterophyllus). This experiment design used was a completely randomized design (CRD) with combination of planting methods and fertilizer as well as five tree species as treatments. The seeds and seedlings are planted on ex-limestone mining land which has soil with a dominant sand fraction. The results showed that plants grown using the direct seeding technique had a higher survival rate than seedlings, except for ketapang. The growth of plants grown using the direct
Keyword: Direct seeding, Ex-limestone mining land, Reclamation, Seedlings

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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