Direct and Indirect Methods of Soil Microbial-Biomass Determination: Weakness and Strength

Dalam dua dasawarsa terakhir ini telah terjadi peningkatan minat para pakar ilmu tanah dan lingkungan dalam menentukan jumlah total mikroorganisme dalam contoh tanah. Minat tersebut muncul karena para pakar menyadari pentingnya peranan mikroorganisme tanah di dalam berbagai proses biokimia yang terjadi di dalam sistem tanah, proses retensi dan pelepasan hara serta energi dalam tanah. Setiap usaha untuk menentukan aliran hara dan energi dalam sistem tanah harus mempertimbangkan peranan dari mikroorganisme tanah.Dalam dua dasawarsa terakhir ini telah terjadi peningkatan minat para pakar ilmu tanah dan lingkungan dalam menentukan jumlah total mikroorganisme dalam contoh tanah. Minat tersebut muncul karena para pakar menyadari pentingnya peranan mikroorganisme tanah di dalam berbagai proses biokimia yang terjadi di dalam sistem tanah, proses retensi dan pelepasan hara serta energi dalam tanah. Setiap usaha untuk menentukan aliran hara dan energi dalam sistem tanah harus mempertimbangkan peranan dari mikroorganisme tanah

Isolation and Activity Test of Acidophilic Iron and Sulfur Oxidizing Bacteria from Black Water Ecosystem of Central Kalimantan

The acidophilic iron and sulfur-oxidizing bacteria were isolated from the black water ecosystem, an 'extreme' ecosystem affected indirectly or directly by peatland Isolation and selection were done on minimal media (liquid and solid). All selected strain of bacteria (BB 179, OM 349, AH 41, TB 23, TB 27, TP 3, NN 323, and SI 188) were identified as Thiobacillus ferrooxidans. Biooxidation and bio-leaching tests were accomplished using the isolated bacteria. The results showed the capability of the isolated bacteria to oxidize ferrous-salt and to leach the low qualities of sulfide ores. Keywords: Acidophilic, bioleaching, biooxidation, Thiobacillus ferrooxidansThe acidophilic iron and sulfur-oxidizing bacteria were isolated from the black water ecosystem, an 'extreme' ecosystem affected indirectly or directly by peatland Isolation and selection were done on minimal media (liquid and solid). All selected strain of bacteria (BB 179, OM 349, AH 41, TB 23, TB 27, TP 3, NN 323, and SI 188) were identified as Thiobacillus ferrooxidans. Biooxidation and bio-leaching tests were accomplished using the isolated bacteria. The results showed the capability of the isolated bacteria to oxidize ferrous-salt and to leach the low qualities of sulfide ores. Keywords: Acidophilic, bioleaching, biooxidation, Thiobacillus ferrooxidan

Slow- Release Fertilizer Formulation Using Acrylic and Chitosan Coating

The low-efficiency problem in fertilizer application can be overcome by controlling fertilizer solubility, i.e. by rendering the fertilizer to be released gradually; such material is also known as slow-release fertilizer (SRF). This research was aimed to formulate SRF by coating technique using acrylic and chitosan as the coating material, and to evaluate fertilizer resistance to too fast disintegration, and rate of nutrient release method. The results demonstrated that fertilizer formulation containing  N, P, K, Fe, Cu, and Zn with granulation technique yielded 74% of granules with 2-5 mm in diameter. The SRFs (formulated fertilizer with acrylic or chitosan coating) were more resistant to water pounding than non-SRF. Furthermore, shaking test with distilled water or 2% citric acid, or by percolation test with distilled water showed that the SRFs had lower nutrient solubility than the non-SRFs. The results of shaking test also specifically indicated that coating with acrylic made the fertilizer more resistant to the citric acid,suggesting that this coating material would be more suitable in acidic soils. The SRFs formulated with the addition of chitosan during blending of micronutrients prior to mixing with macronutrients, granulation, and final coating exhibited lower nutrient solubility than the SRFs without the pre-coating chitosan addition. [How to Cite: Lili H, G Djajakirana, Darmawan, and CP Munoz. 2015. Slow- Release Fertilizer Formulation Using Acrylic and Chitosan Coating. J Trop Soils 19: 37-45. Doi: 10.5400/jts.2015.20.1.37][Permalink/DOI: www.dx.doi.org/10.5400/jts.2015.20.1.37

The Diversity and Abundance of Springtail (Collembola) on Forests and Smallholder in Jambi

Harapan forests is the first restoration forest in Indonesia, includes several different ecosystems. Different ecosystems have different characteristic to affect the diversity and abundance of Collembola. In the ecosystem, Collembola have an important role in biocontrol, decomposition, soil nutrient distribution, stimulation of soil microbial activity and as an alternative feed for predators. This study was aimed to investigate the diversity and abundance of Collembola in four ecosystems at Harapan forest, i.e. secondary forest, rubber forest, rubber smallholder and oil palm smallholder. To achieve the objective, soil samples were taken at 48 observation points in the four ecosystem. The soil samples were then extracted by Kempson Extractor. The diversity and abundance of Collembola in four ecosystems were categorized as medium to high. The total of individual and population of Collembola in the secondary and rubber forest ecosystems were likely to be higher than in the rubber and oil palm smallholders. This study had also identified four orders, 14 families and 31 genera of Collembola, where Isotomiella and Proisotoma dominated the genus of Collembola in the four ecosystems. [How to Cite: Widrializa, R Widyastuti, DA Santosa and G Djajakirana. 2015. The Diversity and Abundance of Springtail (Collembola) on Forests and Smallholder in Jambi. J Trop Soils 20: 173-180. Doi: 10.5400/jts.2015.20.3.173]

The Solubility of Nickel on Mixed Ultramafic Soil with Peat Soil at Saturated and Unsaturated Water Condition

Gambut tropik dengan bobot isi yang rendah berdampak pada berkurangnya kemampuan tanah gambut dalam menopang tanaman. Untuk meningkatkan bobot isi gambut maka dilakukan pencampuran tanah mineral dengan tanah gambut. Namun sumber tanah mineral yang dekat ke lahan gambut adalah tanah berbahan induk ultrabasa dengan kandungan logam Nikel (Ni) yang tinggi mencapai 5000 ppm. Karakter lahan gambut yang asam dan berada pada topografi yang rendah menjadi dugaan akan meningkatkan kelarutan Ni saat terjadi banjir. Oleh karena itu pencampuran bahan-bahan tanah dan perlakuan air bertujuan untuk mengukur kelarutan Ni pada kesetimbangan pH setelah pencampuran dan diekstrak menggunakan larutan NH4OAc 1.0 N pH 7.0; 4.8; 4.2, HCl 1.0 N; 0.1 N, dan H2SO4 1.0 N. Kesetimbangan pH setelah pencampuran bahan tanah berada pada pH 5.2 – 6.1 yang berarti kelarutan Ni ditunjukan oleh hasil ekstrak larutan NH4OAc 1.0 N pH 7.0 - 4.8. Pada rentang kesetimbangan pH tersebut nilai kelarutan Ni pada perlakuan penjenuhan (J) dan pengeringan (K) tidak berbeda nyata pada uji taraf 5%. Namun kelarutan Ni pada setiap penambahan bobot gambut berbeda nyata pada kondisi penjenuhan yang dikeringkan sampai kondisi lembab (JK).Tropical peat with low bulk density affects the ability of peat soil to support plant growth. To improve the bulk density of peat, mineral soil is mixed to peat soil. However, mineral soil sources near peatlands are typically ultrabasic parent material with high nickel (Ni) content up to 5000 ppm. The acidic peat condition and low topography of peatlands may increase the solubility of Ni if in flooding condition. Therefore, mixing soil materials and water treatments are aimed at measuring Ni solubility at pH equilibrium after mixing and extracting using NH4OAc 1.0 N pH 7.0; 4.8; 4.2, HCl 1.0 N; 0.1 N, and H2SO4 1.0 N. The pH equilibrium after mixing soil materials was at pH 5.2-6.1, indicating Ni solubility is shown by the results of NH4OAc 1.0 N pH 7.0 - 4.8 extraction. Within this pH range, the Ni solubility value in the saturation (J) and drying (K) treatments did not differ significantly at a 5% level of significance. However, the Ni solubility with each addition of peat weight differed significantly under the saturated and moist-dried conditions (JK)

Aplikasi Kombinasi Biochar dan Pupuk Hayati pada Tanaman Jagung di Lahan Kering Kabupaten Pandeglang: Application of Biochar and Biofertilizer Combination on Corn in Up Land Pandeglang Regency

Biochar is an alternative amendment for improving soil is to rehabilitate degraded land, especially dry land. In addition, biochar serves as a habitat for soil microbes that play an important role in the availability of nutrients for plants. The use of biofertilizers in agriculture is part of the support for sustainable agriculture because it is environmentally friendly. This study aimed to examine effect of application biochar and biofertilizers combination on chemical and biological properties of soil as well as growth and yield of maize in an up land, Pandeglang Regency. The experimental design in this study was a factorial completely randomized design with two factors. The first factor was biochar with 3 levels (0; 2.5; 5 tons ha-1) and the second factor was combination of  biofertilizer (PHC) and NPK with 5 types (100% PHC, 100% NPK, 25% PHC + 75% NPK, 50% PHC + 50% NPK, and 75% PHC + 25% NPK). Each treatment was replicated 3 times so there were 45 experimental units. The results of this study showed that the application of biochar dose of 5 tons ha-1 (B2) significantly increased K-available in soil and plant height. The combination of 75% biofertilizer and 25% NPK (P4) significantly increased the population of N2-fixing bacteria and cellulolytic bacteria. The combination of biochar dose 2 with 100% NPK fertilizer (B2P1) is the best treatment combination in improving soil nutrient status. On the other hand, the combination of application of biochar dose 1 (2.5 ton ha-1) with 50:50 concentration of biofertilizer and NPK (B1P3) has the opportunity to support the growth and yield of maize.Biochar merupakan bahan alternatif pembenah tanah dari pemanfaatan limbah biomassa berpotensi sebagai bagian dari upaya rehabilitasi lahan terdegradasi, khususnya lahan kering. Biochar juga berfungsi sebagai habitat mikrob tanah yang berperan penting dalam ketersediaan unsur hara bagi tanaman. Pemanfaatan pupuk hayati di bidang pertanian merupakan bagian dari dukungan terhadap pertanian berkelanjutan karena bersifat ramah lingkungan. Berdasarkan latar belakang tersebut, penelitian ini bertujuan untuk mengkaji pengaruh aplikasi kombinasi biochar dan pupuk hayati terhadap sifat kimia dan biologi tanah serta pertumbuhan dan hasil tanaman jagung di lahan kering Kabupaten Pandeglang. Percobaan ini merupakan percobaan faktorial dua faktor yang ditempatkan dalam rancangan acak lengkap. Faktor pertama adalah biochar dengan 3 taraf (0; 2.5; 5 ton ha-1) dan faktor kedua adalah kombinasi pupuk hayati cair (PHC) dengan pupuk NPK terdiri atas 5 macam (100% PHC, 100% NPK, 25% PHC + 75% NPK, 50% PHC + 50% NPK, dan 75% PHC + 25%NPK). Masing-masing perlakuan diulang sebanyak 3 kali sehingga terdapat 45 satuan unit percobaan. Hasil penelitian ini menunjukkan aplikasi biochar dosis 5 ton ha-1 (B2) nyata meningkatkan K-tersedia dalam tanah dan tinggi tanaman. Kombinasi pemupukan 75% pupuk hayati cair dan 25% pupuk NPK (P4) nyata meningkatkan jumlah populasi bakteri penambat N2 dan bakteri selulolitik. Kombinasi biochar dosis 2 dengan 100% pupuk NPK (B2P1) merupakan kombinasi perlakuan yang paling baik dalam memperbaiki status unsur hara tanah. Di sisi lain, kombinasi aplikasi biochar dosis 1 dengan pemupukan pupuk hayati cair dan pupuk NPK konsentrasi 50:50 (B1P3) memiliki peluang untuk mendukung pertumbuhan dan hasil tanaman jagung

Slow- Release Fertilizer Formulation Using Acrylic and Chitosan Coating

The low-efficiency problem in fertilizer application can be overcome by controlling fertilizer solubility, i.e. by rendering the fertilizer to be released gradually; such material is also known as slow-release fertilizer (SRF). This research was aimed to formulate SRF by coating technique using acrylic and chitosan as the coating material, and to evaluate fertilizer resistance to too fast disintegration, and rate of nutrient release method. The results demonstrated that fertilizer formulation containing  N, P, K, Fe, Cu, and Zn with granulation technique yielded 74% of granules with 2-5 mm in diameter. The SRFs (formulated fertilizer with acrylic or chitosan coating) were more resistant to water pounding than non-SRF. Furthermore, shaking test with distilled water or 2% citric acid, or by percolation test with distilled water showed that the SRFs had lower nutrient solubility than the non-SRFs. The results of shaking test also specifically indicated that coating with acrylic made the fertilizer more resistant to the citric acid,suggesting that this coating material would be more suitable in acidic soils. The SRFs formulated with the addition of chitosan during blending of micronutrients prior to mixing with macronutrients, granulation, and final coating exhibited lower nutrient solubility than the SRFs without the pre-coating chitosan addition. [How to Cite: Lili H, G Djajakirana, Darmawan, and CP Munoz. 2015. Slow- Release Fertilizer Formulation Using Acrylic and Chitosan Coating. J Trop Soils 19: 37-45. Doi: 10.5400/jts.2015.20.1.37][Permalink/DOI: www.dx.doi.org/10.5400/jts.2015.20.1.37

Fluks Metana dan Karakteristik Tanah pada Beberapa Macam Sistem Budidaya

Methane (CH4) is an important greenhouse gas that has a high heat trapping capacity thus potentially contribute to the global-warming.  Agriculture is considered among the responsible emission sources of CH4. Relationship among soil characteristics, soil microbes, and CH4 flux is very important in understanding the mechanism involved in the mitigation effects of certain agriculture practices. Results of this research showed that rice field produced the highest CH4 flux (7.4976 ± 0.5299 mg CH4-C m-2 h-1, n=3), while vegetable, sweet potato, yam bean and corn cropping produced lower CH4 flux (-0.7708 ± 0.6434 to 0.4605 ± 0.5255 mg CH4-C m-2 h-1, n=3). Nitrifier population among cropping systems was 3.13x103 to 3.17x104  MPN g-1 soil (dry weight), while denitrifier population was 3.77x103 to 1.17x105 MPN g-1 soil (dry weight).  There were no specific dominance proportion of nitrosomonas, nitrobacter, denitrifier and total propagule among cropping systems. The CH4 flux had highly correlation to soil water content (r = 0.951), soil pH (r = 0.852) and soil Eh (r = -0.982). Denitrifier had significantly correlation to soil pH (r = -0.635) and soil ammonium content (r =  -0.681).   Key words :  CH4 flux, cropping system, soil characteristic, soil microbe