An Acrylamide-degrading Bacterial Consortium Isolated from Volcanic Soi

In soil, polyacrylamide is a key source of acrylamide because it slowly decomposes into acrylamide. There has been a modest but steady rise in worldwide interest in microbe-mediated acrylamide decomposition as a bioremediation method. A bacterial consortium isolated from the volcanic soil of Mount Marapi, West Sumatra, Indonesia, was able to thrive on acrylamide in this study. Acrylamide-degrading bacteria grew best in the presence of 1 %(w/v) glucose with acrylamide as the sole nitrogen source. Optimum growth occurs in between 300 and 500 mg/L of acrylamide, pH between 6.5 and 8.0, and temperatures between 30 and 35 °C. The consortium can also grow on acetamide as the sole nitrogen source. Toxic heavy metals, such as mercury, silver and copper slowed down the growth of this consortium on acrylamide. This is the first report of an acrylamide-degrading consortium isolated from volcanic soils.

The unique and extreme vineyards of Santorini Island (Cyclades)

Own-rooted and phylloxera-free vines have been cultivated on the volcanic soil of Santorini for thousands of years. All this time, vines have been cultivated by using two traditional training systems, the ‘Κouloura’, and the ‘Κladeftiko’, which are well-adapted to the specific climatic conditions of the island. This first report aims to share the scarce existing knowledge on Santorini’s training and pruning systems, looking at some important quantitative and qualitative ripening parameters over four consecutive seasons (2017-2020) and revealing similarities regarding their adaptation to climate conditions on the island.

Effect of Beneficial Soil Microbes on Growth and Yield of Celery in Volcanic Soil of West Java

Soil beneficial microbes have a critical role in plant growth. Inoculating biofertilizer is suppose essential for supporting the plant performance and hence plant yield. The objective of field experiment was to verify the growth and production of celery (Apium graveolens L.) after biofertilizers application. The experiment had been performed in a plastic house in the mountainous area of tropical volcanic soil of West Java, Indonesia. The field trial was carried out in a Completely Randomized Block Design to test two microbial-coated urea formulas and a mixed biofertilizer. The control treatment was Nitrogen-Phosphorous-Potassium (NPK) compound fertilizer. All treatments were replicated three times. The celery was growing in low Nitrogen but high Phosphor and Potassium soil during the dry season. The field trial verified that plant height and biomass as well as yield of celery didn’t depend on fertilizer treatments. Nonetheless, this trial founded that both microbial-coated urea and mixed biofertilizer can replace the NPK fertilizer to produce a same yield of celery.

Improvement of the Shear Strength Parameters of a Granular Volcanic Soil Using Type I Portland Cement

The purpose of this research is to improve the parameters of shear strength in granular volcanic soil, by adding a percentage of Portland type I cement. The first step for this research was to classify the soil through a Granulometry test, according to the Unified Soil Classification System (USCS), the result was considered as a poorly graded sand with gravel also considered by The American Association of State Highway and Transportation Officials (AASHTO) as “A-1-b”. In addition, the compaction curve of the volcanic soil has a Maximum Dry Density (MDD) of 1.21 kg/cm2 and an optimum moisture content of 17.8%. Also, the friction angle of 33.5° and a cohesion of 0 kg/cm2, and the results of the Direct Shear Test indicate the Residual Stresses of 0.63, 1.34 and 2.65 kg/cm2 according to the Normal Stresses 1, 2 and 4 kg/cm2, respectively. The second step was to apply a Modified Proctor Test as following: one sample for natural soil and four samples adding 3%, 5%, 7% and 9% of cement. Finally, applied the Direct Shear Test: one sample for natural soil and three samples adding 3%, 5%, and 7% of cement after 7 days of curing, then three more samples are taken adding 3, 5% and 7% of cement at 14 days of curing. The results of the Modified Proctor Test of the volcanic soil with the addition of 5% cement has a maximum peak of a Maximum Dry Density of 1.33 kg/cm2 and with an Optimal Moisture Content of 22.7%, improved the MDD by 10% in regard to the natural soil. And the results of the Direct Shear Test shown in each sample an increase from 14.6% to 79.1% in the friction angle in comparison with the natural soil from 25.8% to 161.5% in shear strength. Likewise, the behavior of the volumetric deformation is shown, presenting a greater contraction when a normal stress of 1 kg/cm2 is applied and a greater expansion when a normal stress of 4 kg/cm2 is applied. Also, the volcanic soil at 7 days of curing with 7% cement addition increases its resistance by 67.34% and the volumetric variation decreases by 50% and the volcanic soil at 14 days of curing with 5% addition of cement increases its resistance by 103.40% and the volumetric variation decreases by 25%.

Aluminum Toxicity in Sweet Cherry Trees Grown in an Acidic Volcanic Soil

Chile is the world’s largest exporter of sweet cherries. New plantings have been shifted to southern regions, where aluminum (Al) phytotoxicity could be a serious constraint on establishing orchards in acidic volcanic soils. This study investigated the effects of soil Al on growth and macronutrient uptake in non-bearing ‘Bing’ on Gisela®6 trees grown in 120 L pots containing volcanic soil with four concentrations of exchangeable Al (0.12, 0.40, 0.60, and 1.24 cmol kg−1). At the end of the first and second seasons after planting, the trees were destructively harvested, and individual organs were analyzed for dry weight, Al concentration, and macronutrient concentration. Increasing soil Al concentrations had a detrimental effect on nutrient uptake and growth, particularly in the second season. However, fine-root growth was significantly reduced from the first season and from low soil Al concentrations. In sweet cherry trees, Al was preferentially accumulated in root tissues and its translocation to aerial organs was restricted. In addition, Al accumulation in fine roots, in conjunction with a reduction in root growth, severely restricted the uptake of N, P, K, Mg, and, particularly, Ca. Therefore, soil acidity must be corrected to ensure the successful establishment of sweet cherry orchards in southern Chile.