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All Journal AGROTEKBIS Jurnal Penelitian Pendidikan IPA (JPPIPA) Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) FLUIDA Electrices : Jurnal Otomasi Kelistrikan dan Energi Terbarukan JITEL (Jurnal Ilmiah Telekomunikasi, Elektronika, dan Listrik Tenaga) Jurnal Pepadu AGROTEKBIS: Jurnal Ilmu Pertanian Agroland: Jurnal Ilmu-ilmu Pertanian
Danang Widjajanto
Sekretariat Unit Penelitian dan Pengabdian kepada Masyarakat (UP2M) Politeknik Negeri Jakarta Gedung Direktorat Lt.2, Telp.(021) 7270036 Psw. 236 Fax (021)7270034 Kampus Baru Universitas Indonesia Depok, DEPOK 16425 Email: politeknologi_pnj@yahoo.co
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Dynamics of Soil Organic Carbon at Different Elevations in Cocoa Land-Use Systems Widjajanto, Danang; Zainuddin, Rachmat; Rois; Rahman, Abdul; Khaliq, Moh. Adnan; Hasanah, Uswah; Gailea, Rosmaniar; Fera
Jurnal Penelitian Pendidikan IPA Vol 11 No 7 (2025): July
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v11i7.11999

Abstract

Soil organic carbon (SOC) is essential for sustaining soil quality, especially in sloped agricultural landscapes prone to erosion and degradation. This study aimed to analyze SOC dynamics across different elevations (400, 600, and 800 meters above sea level) in cocoa-based land-use systems and examine its relationships with some key physical properties. Soil sampling was conducted using a stratified random design, and laboratory analyses were carried out using standard methods. The results showed that SOC increased with elevation due to cooler temperatures, slower organic matter decomposition, and higher surface litter accumulation. Polynomial regression revealed non-linear relationships between SOC and soil properties, with significant coefficients of determination: SOC vs. bulk density (R² = 0.82), SOC vs. penetration resistance (R² = 0.44), and SOC vs. saturated hydraulic conductivity (R² = 0.37). Moderate SOC levels (around 2.3% – 3.0%) were associated with improved soil structure, lower bulk density, higher hydraulic conductivity, and reduced penetration resistance. However, excessive organic inputs beyond the optimum may reduce these benefits due to incomplete decomposition. A similar curvilinear pattern was found between surface litter and SOC content. These findings highlight the importance of optimizing organic matter management in cocoa systems on sloped lands to enhance soil physical conditions and promote sustainable agriculture.
Ketersediaan Air Tanah dan Karbon Organik pada Lahan Semak Belukar dan Budidaya Bawang Merah di Wilayah Tropika Kering Zainuddin, Rachmat; Widjajanto, Danang
Agroland: Jurnal Ilmu-ilmu Pertanian Vol 32 No 2 (2025): Agustus
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/agrolandnasional.v32i2.2690

Abstract

Konversi lahan semak belukar menjadi lahan budidaya intensif di daerah iklim kering tropika memengaruhi dinamika sifat fisik dan kimia tanah. Penelitian ini bertujuan untuk menganalisis perbedaan ketersediaan air tanah dan kandungan karbon organik pada dua jenis penggunaan lahan, yaitu semak belukar dan bawang merah. Sebanyak 21 sampel tanah dikumpulkan untuk dianalisis sifat fisik, seperti bobot isi, konduktivitas hidraulik jenuh, kadar air kapasitas lapang, dan kimia seperti kapasitas tukar kation (KTK) dan karbon organik. Hasil penelitian menunjukkan bahwa lahan semak belukar memiliki nilai ketersediaan air dan kandungan C-organik yang lebih tinggi dibandingkan lahan budidaya. Hubungan bobot isi tanah dengan air tersedia dan konduktivitas hidraulik mengikuti pola kuadratik (R² = 0,72 dan R² = 0,62), sementara hubungan antara C-organik dan KTK menunjukkan korelasi sangat kuat (R² = 0,78). Sebaliknya, tekstur tanah tidak menunjukkan hubungan yang berarti terhadap perilaku air dan KTK. Penurunan kualitas tanah akibat konversi lahan dapat ditekan melalui peningkatan kandungan bahan organik dan praktik konservasi. Hasil penelitian ini penting digunakan sebagai dasar pengetahuan pengelolaan tanah berkelanjutan di wilayah tropika kering.
PENURUNAN TINGKAT KEMATIAN IKAN GURAMI MELALUI PENURUNAN KEKERUHAN AIR KOLAM DENGAN PROSES ELEKTROKOAGULASI   Widjajanto, Danang; Saepudin, Endang
Jurnal Pepadu Vol 6 No 3 (2025): Jurnal Pepadu
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/pepadu.v6i3.7928

Abstract

The turbidity of the water used for cultivating gourami fish by the Mina Lestari Fish Farmers group reaches 68 NTU and oxygen solubility is about 2.5 mg/L, while the maximum turbidity permitted for fish farming is 50 NTU and oxygen solubility more than 5 mg/L. Insufficient oxygen can cause the death of fish. To reduce water turbidity can be treating water using electrocoagulation. This community service activity aims to implement aelectrocoagulation process to reduce water turbidity, thereby increasing dissolved oxygen levels and reducing gourami mortality in RW 05, Duren Mekar, Depok. The methods used include site surveys, problem identification, partner coordination, program outreach, water reservoir for electrocoagulation process construction, coagulant producer construction, elctrocoagulation processing and evaluation. The electrocoagulation water reservoir for electrocoagulation process is made from concrete with 3m long, 1.5 m wide, and 1.2 m high. It is equipped with one 4-inch PVC pipe for the inlet and three 3-inch PVC pipes for the outlet. The electrocoagulation process is carried out by flowing 5 liters per minute of coagulant from coagulant storage to the water in reservoir. The electrocoagulation process was able to reduce water turbidity from 68 NTU to 43 NTU and increase dissolved oxygen from 2.5 mg/L to 5.6 mg/L as well as reduce the gourami fish deaths from 20 to 5 from a cultivation of 100 fish for 5 months. The conclusion is that the electrocoagulation process of pond water is able to produce water with turbidity that meets the requirements for cultivating gourami fish.
Pengaruh Komposisi Media Tanam Terhadap Sifat Fisika Tanah dan Pertumbuhan Bibit Gaharu (Aquilaria malaccensis) Monde, Anthon; Rahman, Abdul; Widjajanto, Danang; Somba, Bunga Elim; Frahastuti, Frahastuti
Agroland: Jurnal Ilmu-ilmu Pertanian Vol 31 No 2 (2024): Agustus
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/agrolandnasional.v31i2.2222

Abstract

Gaharu merupakan komoditas hasil hutan non kayu yang bernilai komersial tinggi. Untuk mendukung tersedianya bahan tanam dalam upaya pembudidayaan tanaman Gaharu berkualitas, maka salah satu upaya dalam penyedian bibit perlu didukung oleh tersedianya media tanam bibit yang baik dan tepat Penelitian ini bertujuan untuk mengetahui pengaruh komposisi media tanam terhadap sifat fisika tanah dan pertumbuhan bibit gaharu. Penelitian ini dilaksanakan di Persemaian BPDASHL di Kampus Universitas Tadulako Palu. Penelitian dimulai Februari sampai Juni 2023. Penelitian ditata dan dianalisis dengan Rancangan Acak Kelompok (RAK), dengan perlakuan yang dicobakan adalah: M1 = tanah, sekam padi bakar, pupuk kandang kambing 1:0:0 v/v; M2 = dengan perbandingan 1:1,25:0,25 v/v; M3 = 1:1,5:0,5 v/v; M4 = 1:1,75:0,75 v/v; dan M5 = 1:2:1 v/v. dengan ulangan 4 kali. Pengamatan yaitu pertumbuhan tinggi tanaman, jumlah daun, berat kering tanaman, bobot isi tanah, porositas tanah dan kadar air kapasitas lapang. Hasil analisis menunjukkan perlakuan M3= 1:1,5:0,5 v/v, meningkatkan pertambahan tinggi tanaman hingga 27,47 cm, jumlah daun 12,33 helai, dan berat kering tanaman 5,13 g. Analisis sifat fisika tanah diperoleh bobot isi tanah perlakuan kontrol dengan kriteria berat (1,65 g/cm3) dan semakin tinggi dosis arang sekam maka bobot isi tanah menurun (M5 = 0,88 g/cm3), sebaliknya porositas tanah semakin meningkat (M5 = 66,47%), peningkatan dosis pupuk kandang meningkatkan kadar air kapasitas lapang tanah.
The Use of Organic Fertilizer to Enhance Soil Water Availability and Promote the Growth of Tomatoes in Sandy Loam Soils Rahman, Abdul; Widjajanto, Danang
Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) Vol. 14 No. 3 (2025): June 2025
Publisher : The University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtep-l.v14i3.1034-1039

Abstract

The use of organic fertilizer has been shown to improve soil structure and promote plant root growth, particularly in critical areas with limited water resources for agricultural activities. This study aimed to evaluate the effect of organic fertilizer application on the soil’s water holding capacity and the growth performance of tomato. The experiment was conducted using a randomized complete blocs design with six treatments, each replicated three times. The treatments included P0 (0 Mg/ha), P1 (5 Mg/ha), P2 (10 Mg/ha), P3 (15 Mg/ha), P4 (20 Mg/ha), and P5 (25 Mg/ha). The findings revealed that organic fertilizer application significantly influenced soil organic carbon levels, bulk density, hydraulic conductivity, and soil water availability. Additionally, the increased soil organic carbon led to noticeable improvements in shoot dry weight, total root length, and root dry weight of tomatoes. This study found that the availability of organic carbon has very strong correlation with tomatoes growth and soil water availability. Keywords: Organic Carbon, Sandy Soils Texture, Soil Structure, Water Retention.
Effect of Changes Turbidity on Oxygen Solubility in Fish Pond Water Electrocoagulation Process Sutanto, Sutanto; Supriyanto, Toto; Widjajanto, Danang
Fluida Vol. 16 No. sp1 (2023): FLUIDA x IRWNS Special Edition
Publisher : Department of Chemical Engineering, Politeknik Negeri Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35313/fluida.v16isp1.5596

Abstract

The water used for fish farming by the Mina Lestari is very dirty, because many soil particles are dissolved in water. The water with high dirty in generally has very high turbidity. So that oxygen is difficult to dissolve in water and is not sufficient for fish life. So many fish die, due to insufficient oxygen for breathing. To reduce water turbidity is treated by electrocoagulation process combined with the aeration process. The aim of the research was to study the effect of changes in turbidity on dissolved oxygen in water. The study began by measuring the turbidity using a turbidimeter and dissolved oxygen using a DO meter. Furthermore, pour 10 liters of water into the electrocoagulation process tank. The electrocoagulation was carried out at 12 volt or 0,3 ampere for 10 minutes. The process was stopped, then the water flowed into the settling tank and left for 30 minutes to precipitate of the dirt. The water flowed into a holding tank and followed aeration process by flowing air at a rate of 500 cc per minute for 30 minutes. Then followed measuring turbidity by turbidimeter and dissolved oxygen by DO meter. Subsequent studies were carried out using the same procedure with an interval of 10 minutes processing time for electrocoagulation process. The results showed that an increase in processing time can reduce water turbidity from 68 NTU to 45 NTU or 33.82% and increase dissolved oxygen from 2.8 mg/L to 5.3 mg/L or 89.29% at 50 minutes processing.
Swallow Droppings for The Chemical Properties of Alluvial Soil As Growing Medium For Ebony (Diospyros Celebica) Rahman, Abdul; Monde, Anthon; Widjajanto, Danang; Khaliq, Moh. Adnan; Adrianton; Oktavina, Trisni
Jurnal Penelitian Pendidikan IPA Vol 10 No 8 (2024): August
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v10i8.7856

Abstract

This study aimed to determine the effects of swallow bird droppings bokashi on several soil chemical properties such as pH, C-Organic, N, P, K, CEC, and to determine the appropriate dosage of bokashi fertilizer for the growth of ebony seedlings. This research was conducted at Permanent Nursery located at Tadulako University. This study was conducted using a completely randomized design with 5 treatments and 4 replications, 20 experimental units as: P0 (control), P1 (7 tons/ha), P2 (14 tons/ha), P3 (21 tons/ha), and P4 (28 tons/ha). The results showed that the swallow droppings bokashi fertilizer was able to improve: soil pH 7.18 to 7.55 with a neutral status, P from 41.34 to 65.06 with very high status, K from 46.26 to 53.87 with high status, C-Organic from 5.30 to 10.25 with high to very high status, and N-Total from 0.12 to 0.34 although in low status in the soil. The application of swallow droppings bokashi into the soil was very much needed. C-Organic content in swallow droppings bokashi was 50.23%, N (4.26). The application of swallow droppings bokashi with a treatment of 21 tons/ha (61.25 g/pot) was the best dose for the growth (height) and the increase number of leaves of ebony seedlings.
Co-Authors A.A. Ketut Agung Cahyawan W Abdul Rahman Adrianton Ahmad , Virzha Rafiq Anthon Monde Aulia, Windi Bintoro, Ahmad Bunga Elim Somba Endang Saepudin, Endang Fera Frahastuti, Frahastuti Ilham Bakri Abdul Rahim Thaha,Isrun, Ilham Bakri Isrun Isrun Jusman Jusman Khaliq, Moh. Adnan Kusumastuti, Sri Lestari Liana Liana Nadhiroh, Nuha Nuraqil, Noufal Nurfadila Nurfadila, Nurfadila Oktavina, Trisni Patadungan, Yosep Soge Prahastuti, Sri Wahidah Rois Rosmaniar Gailea Sely Limbong Rara Setiana, Hatib Sutanto Sutanto Toto Supriyanto Uswah Hasanah Yuspita, Opi Isra Zainuddin, Rachmat