Wyniki wyszukiwania - BazTech

1

Volcanic Deposits Thickness and Distance from Mt Semeru Crater Strongly Affected Phosphate Solubilizing Bacteria Population and Soil Organic Carbon

Ustiatik Reni, Ariska Ayu Putri, Hakim Qo'id Luqmanul, Wicaksono Kurniawan Sigit, Utami Sri Rahayu

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 10

360--368

EN

Volcanic eruptions cause large-scale damage and leave piles of volcanic material that destroy plants, agricultural lands, animals, and soil microorganisms, decreasing soil fertility. Therefore, it is necessary to accelerate soil fertility recovery in post-volcanic eruption areas to resume agricultural activities. This study aims to elucidate the effect of volcanic deposits on soil fertility as well as explore tolerant plants and bacteria after Mt Semeru eruption. Soil, volcanic ash, and plant samples were collected from Pronojiwo Sub-regency, Lumajang Regency, East Java, Indonesia. Soil and volcanic ash chemical properties were analyzed (pH, available and total phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca) content). Bacteria were isolated and enumerated, then tested for P solubilization (PSB). The result showed that 3 months after Mt Semeru’s eruption, the first succession was fern, moss, and fungi. Some local plants (banana and coconut) emerge new shoots and recover. A high total P (137.32 mg/kg) with neutral pH 6.8 was found in the volcanic ash. Total P and available P were higher at the closest distance from the crater, and soil pH controlled P availability in the soil covered with volcanic deposits. Also, the thickness and distance from the crater strongly affect organic C, which reduces the PSB population from 103 to 104 CFU/g, compared to unaffected areas. The bacteria exhibited P solubilization activities even under harsh environmental conditions. Thus, accelerating soil fertility restoration by adding organic materials and inoculating beneficial bacteria (such as PSB) in the post-eruption area is essential as the bacteria benefit both soil fertility recovery and agriculture sustainability in degraded lands (e.g., post-eruption).

2

Response of Different Coffee-Based Agroforestry Management on Microbial Respiration and Density

Nugroho R. Muhammad Yusuf Adi Pujo, Ustiatik Reni, Prasetya Budi, Kurniawan Syahrul

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 9

158--170

EN

Coffee agroforestry has become a land use system that provides both ecological and economic benefits, so it is managed in various ways. Pruning and fertilizer management is a combination that is applied for optimal production. However, understanding the effect of combined management on soil respiration and functional microbial populations remains unclear. This study aimed to determine the effect of combining pruning and fertilizer management on soil respiration and functional bacterial populations as well as to elucidate the relationship between tested parameters. The study was conducted in UB Forest. A factorial randomized block design consisting of three factors, i.e., coffee pruning, type of fertilizer, and fertilizer doses was used. The results showed that combining three factors affected the diazotrophic bacterial population and soil respiration, which is sensitive to management changes. Coffee pruning and mixed fertilizer (inorganic + organic) application affected soil respiration and microbial populations, while the dose affected each parameter differently. The conducted study suggests that pruning management with mixed fertilizer application can substitute inorganic fertilizer as more environmentally sustainable management in coffee-based agroforestry.

3

Changes in Essential Soil Nutrients and Soil Disturbance Directly Affected Soil Microbial Community Structure: A Metagenomic Approach

Wiryawan Adam, Eginarta Wahyu Satria, Hermanto Feri Eko, Ustiatik Reni, Dinira Layta, Mustafa Irfan

Journal of Ecological Engineering

|

2022

|

Vol. 23, nr 7

238--245

EN

Soil environment, both biotic (e.g., microbial community) and abiotic (e.g., nutrients and water availability) factors determine soil fertility and health and are directly affected by soil management systems. However, only limited studies evaluate the combined effect of nutrients availability and soil disturbance on the soil bacteria community structure, especially in conventional agricultural practices, on the forests converted to agricultural land. This study aimed to provide a viewpoint of the effect of different soil management systems, i.e., forest soil (natural process) and tilled land, on soil bacteria community structure on forest converted to agricultural land, according to a metagenomics approach. Moreover, each land use was sampled to identify the bacterial community using 16S gene as a biomarker. The sequencing was performed using MinION (Oxford Nanopore Technologies) to read the DNA sequence from each soil sample. Principle Component Analysis (PCA) was performed to comprehend the relationship between availability of nutrients and bacterial diversity. The results revealed that the concentrations of soil micronutrients, such as iron, zinc, and magnesium, were significantly higher in forest soil than in tilled land. According to diversity indices, soil bacteria were more diverse in forest soil than in tilled land. Forest soil had more distinctive taxa than tilled land. Several species comprised the most abundant taxa, such as Candidatus Koribacter versatilis, Candidatus Solibacter usiatus, Rhodoplanes sp., Luteitalea pratensis, and Betaproteobacteria bacterium, were more scarce in tilled land. On the distinctive taxa in each soil sample, Anseongella ginsenosidimutans and Janthinobacterium sp. were the most abundant species in forest and tilled land, respectively. According to PCA analysis, soil management system affected the soil micro-and macronutrients also microbial community structure between forest and tilled land. In conclusion, soil management influences the essential nutrient content and bacterial community structure of soil. Better management should be adopted to maintain soil quality near forest soil.

4

Siderophore Production of the Hg-Resistant Endophytic Bacteria Isolated from Local Grass in the Hg-Contaminated Soil

Ustiatik Reni, Nuraini Yulia, Suharjono, Handayanto Eko

Journal of Ecological Engineering

|

2021

|

Vol. 22, nr 5

129--138

EN

Mercury (Hg)-contaminated soil remediation has become an urgent necessity due to its harmful effect on the environment and living organisms. The use of plant-endophyte partnership for phytoremediation demonstrates an excellent opportunity for cleaning heavy metal contaminated soil. This study aimed to screen and characterize the phenotype of the Hg-resistant endophytic bacteria from local grasses (Cynodon dactylon and Eleusine indica) in the Hg-contaminated soil of West Nusa Tenggara, Indonesia with siderophore-producing traits. Siderophore production of bacteria was qualitatively tested using overlay-chrome azurol S (O-CAS) medium and quantitatively tested using the succinic acid medium. The assay was designed using a Completely Randomized Factorial Design consisting of two factors, i.e., isolate type and incubation time with three replicates. The selected isolates were pathogenicity tested, then they were phenotypically characterized. All tested isolates showed a positive result on changing O-CAS medium color from blue to yellow/brown that indicated hydroxamate type of siderophore. The highest siderophore production was achieved at 72 hours of incubation, by the EI5 and EI6 isolates (62.90% and 35.31%, respectively). In turn, the CD6, EI5 and EI6 isolates achieved high siderophore production at a short incubation period (48 hours). However, during the hemolysis test, only the CD6 and EI6 isolates were not pathogenic. The CD6 and EI6 isolates would be used for phytoremediation on Hg-contaminated soil in the future study. On the basis of the 16S rDNA analysis, it was shown that the CD6 isolate was Jeotgalicoccus huakuii and the EI6 isolate was Bacillus amyloliquefaciens.