Potency of Rhizosphere Bacteria to Promote Rice Growth Under Saline Condition

Saline soil is a common problem in coastal paddy field, especially in Indonesia. Salinity affects rice growth and the activities of soil functional microbes, including functional bacteria, which play roles in plant growth. Some of these microbes are associated with rice plants and are able to survive under saline condition. The presence of functional microbes is also important to improve soil quality. Nitrogen and phosphate are essential soil nutrients and is available in soil due to the activities of nitrogen-fixing bacteria and free-living plant-associated bacteria. The objective of the present study was to obtain nitrogen-fixing, phosphate solubilizing and Indole Acetic Acid (IAA)-producing bacteria that are able to survive and promote the growth of rice under saline conditions. From rice and peanut rhizosphere, Ca-phosphate (Ca-P) solubilizing and nitrogen-fixing bacteria were isolated separately using specific media. Then, the Ca-P solubilizing ability, phosphomonoesterase activity and IAA-producing ability were quantitatively examined. Based on the abilities, 20 strains were selected and identified as Burkholderia cepacia-complex, Burkholderia anthina, Burkholderia cenocepacia, Bacillus cereus-complex (three strains), Achromobacter spanius, Azospirillum sp. (four strains), Azotobacter sp. (three strains), Rhizobium leguminosarum, Rhizobium sp. (two strains), and Pseudomonas sp. (three strains). The inoculation of several single strains or the mixture of the selected strains promoted the growth of rice under saline conditions. These inoculants could be potential as biofertilizer in saline paddy fields

Pengaruh Inokulasi Bakteri Terhadap Pertumbuhan Awal Jarak Pagar (Jatropha Curcas L.)

Bacterial inoculants affect the early growth of Jatropha (Jatropha curcas L). Genera ofAzotobacter, Bacillus, Chromobacterium, Citrobacter, Nitrosomonas, Rhizobium, andSpaerotillus natans were soil bacterial isolates. The soil was collected from numerous placesaround Pontianak, West Kalimantan. Those isolates were used as inoculants, and formulatedto single and mixed bacterial inoculants, then used to stimulate the early growth of jatrophaseedling in 15 weeks at greenhouse condition. Bacterial inoculations caused better growthperformance compared to its control as pure soil garden medium without inoculations, andneither to bare soil dresses with compost. In the presence of inoculants, plant height wasaccelerated quickly while other inoculants affected to stalk diameter development. Daily growthperformance of jatropha peaked in 8 and 11 weeks after inoculation of Citrobacter andNitrosomonas bacterial component were used as single inoculant, respectively. The increasingof shoot biomass accumulation was three times as caused by single inoculants (Bacillus sp),and the highest one up to four times of biomass weight caused by a mixture inoculants asconsortium of Azotobacter, Bacillus, and Nitrosomonas spp. That selective inoculant hasopportunity to be used for jatropha farming, and this basic study is meaningful to jatropacultivation for standing to bio-fuel resources.Keywords: Jatropha curcas L., inoculants, Azotobacter, Bacillus, Chromobacterium,Citrobacter, Nitrosomonas, Rhizobium , Spaerotillus natans

Pengaruh Introduksi Kompos Plus terhadap Produkasi Bobot Kering Daun Kumis Kucing (Orthosiphon Aristatus) pada Tiga Macam Media Tanah

A green house experiment were conducted to study the application of “compost plus” on the growth of Orthosiphon aristatus. The experiment was designed in Complete Randomized Design with factorial and five replicates. The first factors were fertilizer application (compost plus, compost, and control). The second factors were 3 kinds of soil (i.e. soil from Cibinong, Ciomas, and Sukabumi). The result showed that compost plus application increased 113.90 gram/pot of dry weight of Orthosispon aristatus leaves compared with compost application and control in 3 kinds of soil

Pengaruh Air Laut terhadap Populasi Bakteri Biofertilizer, P Tersedia dalam Tanah, dan Pertumbuhan Bayam (Amaranthus SP.)

Pemanfaatan pupuk hayati merupakan salah satu upaya untuk mengembangkan pembudidayaan tanaman yang ramah lingkungan. Penelitian bertujuan mengetahui ketahanan bakteri pelarut fosfat dan bakteri pengikat nitrogen nonsimbiosis terhadap salinitas dan peranannya dalam menyediakan P dan N untuk pertumbuhan tanaman bayam. Penelitian dilaksanakan di Laboratorium dan Rumah Kaca Mikrobiologi, LIPI Cibinong, Bogor, Jawa Barat, sejak bulan Februari sampai dengan Desember 2013. Penelitian menggunakan rancangan acak lengkap faktorial dengan tiga ulangan. Faktor pertama, yaitu plant growth promoting rhizobacteria (PGPR) dalam pupuk organik hayati yang terdiri atas: A, B, C, D (A+B), E (A+C), F (B+C), G (A+B+C), H (ABC+TSP+ KCl+ Urea+kompos), I (TSP+KCl+Urea+ABC), dan J (kompos+ABC), serta kontrol (K1 = kompos, K2 = tanpa pupuk, K3 = TSP+KCl+Urea). Faktor kedua, penyiraman yaitu, (1) air laut dan (2) air tawar. Tanaman bayam (Amaranthus sp.) ditumbuhkan dalam media tanah menggunakan pot di dalam rumah kaca. Peubah yang diamati mencakup tinggi tanaman, berat segar bayam, pH tanah, salinitas tanah, populasi bakteri, PME-ase tanah, dan P tersedia dalam media tanah, pada 7 dan 28 hari setelah tanam (HST). Hasil penelitian menunjukkan bahwa air laut dengan kadar garam 30 dS/m berpengaruh nyata terhadap populasi bakteri, produksi enzim PME-ase, P-tersedia, tinggi, dan berat segar tanaman bayam. Semua bakteri tahan terhadap kondisi salin dan bakteri Azotobacter lebih tahan salin daripada Azospirillum. Masing-masing isolat yang terkandung dalam inokulan B, H, dan J mampu bertahan pada salinitas sebesar 2,03; 4,0; dan 4,0 dS/m, dengan populasi bakteri sebesar 27,88 dan 79 x 105sel g/tanah, mampu memproduksi PME-ase sebesar 0,60; 0,62; dan 0,55 mg pnitrofenol/ml, P tersedia sebesar 5,96; 8,95; dan 7,30 ppm serta berdampak positif terhadap tinggi tanaman (14,47; 21,50; dan 25,83 cm) dan berat segar tanaman bayam (12,50; 79,56; dan 102,63 g/pot). Aplikasi bakteri tersebut pada lahan-lahan salin akan bermanfaat untuk pembudidayaan sayuran

Soil organic carbon fractions in oil palm management systems

Conversion of deforested areas into oil palm plantation has been suggested as a means to improve soil quality and carbon sequestration capacity in forest margin areas. Soil organic carbon fractions, such as particulate organic carbon is the most sensitive indicator in improving soil organic matter and soil quality. We determined particulate organic matter - carbon (POM-C) and mineral associated carbon (MAC) in Bengkulu and West Java Provinces Indonesia. The study areas were grain crop fields, secondary forest, 5 yr-oil palm plantation, 10 yr-oil palm plantation, 15 yr-oil palm plantation and 25 yr-oil palm plantation. Soil organic carbon fraction magnitudes varied in the surface of 0 to 30 cm of grain crop fields, secondary forest and oil palm plantations. Twenty five year- oil palm plantation provided the largest total organic carbon, while 5 yr-oil palm plantation and grain crop fields contained similar amount of total organic C. Both POM-C and MAC fractions were increased in the plantation sites with oil palm trees and secondary forest compared to the grain crop fields. The plantation sites had a larger POM-C content than grain crop fields, but the increase of POM-C was limited to the surface of 0 to 10 cm of soil. Carbon stock in 0-30 cm under oil palm plantations were reduced up to 20% compared to secondary forests and 28% compared to rubber plantations in Bengkulu and West Java Provinces. On average, converting forest to plantations led to a loss of 10 Mg C/ha after about 10 years of conversion. However, the C stock in the subsoil was similar under the forest and the plantations in Bengkulu. Further, limited C input from litter would eventually cause more losses of SOC in oil palm plantations compared to rubber plantations. In conclusion, investigating the deeper profiles and soil erosion may be an important tool to unfold the trends of soil organic carbon fraction dynamics and magnitudes after the conversion of natural ecosystems to intensive plantations

Pengaruh Salinitas Dan Inokulan Bakteri Terhadap Pertumbuhan Tanaman Terung (Solanum Melongena L.) [the Effect of Salinity and Bacteria Inoculant on the Growth of Eggplant (Solanum Melongena L.)]

Nitrogen fixing dan phosphate solubilizing bacteria are important PGPR bacterial in addition of plant nutrients by increasing N and P, especially in saline soils. Experiments were conducted to observe the effects of soil salinity and bacterial inoculant on growth eggplant (Solanum melongena) at green house of Microbiology division, Research Center for Biology, The Indonesian Institute of Sciences, Cibinong. Experiment laid out as factorial based randomized complete design with three replications. Five levels of watering consisted of (1). Fresh water, (2). NaCl 0.1%, (3). NaCl 1%, (4). Sea water 75 %+25% fresh water, (5). Sea water 100% as first factors. Five levels of inoculations/biofertilizers consisted of (1).control without fertilizer (K), (2). NPK (P), (3). Nitrogen Fixing bacteria (BPN1), all treatments was repeated 3 times BPN2, mixed inoculation (BPN1 + BPN2 + Phosphate Solubilizing Bacteria/BPF) as second factors. Results showed that biofertilizer application increased growth and yield of eggplant in various levels of salinity at about 21.56%-53.35% compared to uninoculated plant