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All Journal BIOTROPIA - The Southeast Asian Journal of Tropical Biology Jurnal Rekayasa Sipil
Tornando, Hengki
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Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Civil Engineering, Building, Construction & Architecture Engineering Immunology & microbiology Transportation Veterinary

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Karakteristik Kuat Tekan Bebas Stabilisasi Semen Dan Kapur Tanah Cl-Ml Terhadap Siklus Pembasahan Pengeringan Tornando, Hengki; Fatnanta, Ferry; Wibisono, Gunawan
Jurnal Rekayasa Sipil (JRS-Unand) Vol. 16 No. 2 (2020)
Publisher : Civil Engineering Departement, Andalas University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrs.16.2.105-118.2020

Abstract

Menurut grafik Casagrande tanah CL-ML diklasifikasikan tanah yang memiliki nilai indek plastisitas antara 4% - 7%, dan memiliki batas cair berkisar antara 12% - 30%. Beberapa lokasi di Kecamatan Tanayan Raya Kota Pekanbaru terdapat jenis tanah CL-ML, sifat dari tanah CL-ML ini sangat rentan terhadap penambahan kadar air sehingga akan menyebabkan tanah ini menjadi lembek pada musim hujan dan menjadi pecah-pecah pada saat musim kemarau. Dengan adanya sifat ini akan menjadi masalah jika dilakukan suatu konstruksi di atas tanah ini. Salah satu cara untuk memperbaiki  permasalahan ini maka dilakukan stabilisasi tanah. Bahan yang digunakan untuk stabilisasi pada penelitian ini yaitu menggunakan bahan semen dan kapur, siklus pembasahan dilakukan dengan cara merendam sampel pengujian ke dalam air dan siklus pengeringan dilakukan dengan cara sampel pengujian di letakkan (diangin-anginkan) di dalam ruangan terbuka. Hasil penelitian ini menunjukkan bahwa siklus pembasahan dan pengeringan dapat mempengaruhi nilai kuat tekan bebas dari tanah CL-ML. Penambahan 4% kapur dan 3% semen  pada tanah CL-ML meningkatkan nilai kuat tekan bebas. Pada umur pemeraman 0 (nol) hari nilai kuat tekan bebas tanah asli sebesar 133 kPa meningkat menjadi  673 kPa (5 kali lipat), pemeraman 14 (empat belas) hari   dari  142 kPa menjadi 1014 kPa (7 kali lipat), pemeraman 28 (dua puluh delapan) dari 168 kPa menjadi 1513 kPa ( 9 kali lipat).
Soil Microbial Population and Soil Enzyme Activity on PT Bukit Asam Various Reclaimed Land Sites in South Sumatra Tornando, Hengki; Hudi, Firdaus Alam; Prasetyo, Lilik Budi; Santosa, Dwi Andreas
BIOTROPIA Vol. 25 No. 3 (2018): BIOTROPIA Vol. 25 No. 3 December 2018
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (712.192 KB) | DOI: 10.11598/btb.2018.25.3.855

Abstract

Open mining activities result in decreased microbial biomass and negatively impact soil fertility. Soil microbes play a key role in the decomposition of soil organic matter and in nutrient cycling through mineralization mediated by the enzymes they produce. The purpose of this study was to analyze soil fertility levels at PT Bukit Asam’s various reclaimed land sites in Muara Enim Regency, South Sumatra, Indonesia, as determined by microbial populations and soil enzyme activity. The research was conducted using an explorative method across PT Bukit Asam’s reclaimed land sites. Soil samples from seven reclamation areas of different ages were analyzed. Our results showed that soil conditions and enzyme activity vary with reclamation age. At KTU, a 12-year-old reclaimed site, urease enzyme activity was 68.83 mg NH₄⁺·g⁻¹ dm·h⁻¹, with a microbial population of 82.64 × 10⁴ CFU·g⁻¹ soil. The highest phosphatase activity, 95.66 mg pNP·g⁻¹ dm·h⁻¹, was observed at the 9-year-old SP702 reclaimed site, with a soil pH of 5.23. Cellulase activity at the 21-year-old Udongan site was 21.51 mg GE·g⁻¹ dm·h⁻¹, with a cellulolytic microbial population of 1.9 × 10⁴ CFU·g⁻¹ soil, higher than at other reclamation sites. Invertase activity at the 15-year-old Tupak site was 24.37 mg GE·g⁻¹ dm·h⁻¹. Soil enzyme activity can serve as an indicator of soil quality and microbial activity, reflecting biochemical transformations in the soil and exhibiting high sensitivity to environmental changes.
Co-Authors DWI ANDREAS SANTOSA Ferry Fatnanta Gunawan Wibisono Hudi, Firdaus Alam LILIK BUDIPRASETYO