• Korean Journal of Environmental Agriculture
• /
• v.25 no.2
• /
• pp.164-169
• /
• 2006

This study was conducted for 10 days from 17 July to 26 July in 2005 to measure the amount of xylem sap flow under short-term variation of soil moisture regimes at -20 kPa, -50 kPa and -80 kPa in eight-year-old 'Fuji'/M.9 apple trees with different fruit loads. Fruit load was adjusted as three different treatments with standard (100%), 1/2 times (50%) and 2 times (200%) on the basis of optimum fruiting number per tree as the standard fruit load of Fuji cultivar. Trees with standard fruit load during the experimental period showed higher xylem sap flow at -50 kPa of soil moisture regimes than those of trees with 1/2 times and 2 times fruit load. Trees with 1/2 times and 2 times fruit load had similar patterns of the diurnal changes of xylem sap flow, vapor pressure deficit (VPD), and maximum evapotranspiration (ETm). However, trees with 2 times fruit load at -50 kPa and -80 kPa of soil moisture regimes produced lower amount of xylem sap flow than ETm. Trees with standard fruit load produced $1.06{\sim}3.93$ L/tree more amount of xylem sap flow than ETm at all soil moisture regimes. But xylem sap flow of tees with 2 times fruit load had 21% lower at -50 kPa and $31{\sim}36%$ lower at -20 kPa and -80 kPa of soil moisture regimes, respectively than that of trees with standard fruit load. Shoot growth and leaf area were significantly the highest in trees with standard fruit load while those of trees with 2 times fruit load recorded significantly lowest. Leaf water potential of trees with standard fruit load was lower than that of trees with 1/2 times and 2 times fruit load. It indicated that tees with standard fruit load had higher water use for transpiration than other treatments and tees with 2 times fruit load received more stress for the transpiration process under low soil moisture regimes. Consequently, 'Fuji'/M.9 apple trees, the fruit load and soil moisture should be maintained optimum to increase xylem sap flow and transpiration during higher growth period.

• Journal of Korea Soil Environment Society
• /
• v.4 no.2
• /
• pp.185-192
• /
• 1999

To assess the soil quality of Chonan City, soil analyses were conducted according to the 14 different sampling sites. The soil pH of the agricultural area near the expressway was lower than that of the other farming area, which indicated that this acidification was probably attributed to the acid rain caused by the traffic exhaust gas such as SOx and NOx. Acidification was more severe in the dry farming area than in the rice paddy area. All concentration of 6 different heavy metals (As, Cu, Cd, $Cr^{6+}$, Hg, Pb) and organic contaminants (cyanide, organic-p, PCBs, phenols) were found to be lower than the standard of soil pollution. The concentration of BTEX also lower than the standard of soil pollution. An assessment using the SPI (Soil Pollution Index). which was developed to estimate an overall soil quality, was performed. Each SPC (Soil Pollution Score) were evaluated with the results of the data from this study. The soil quality of most area of Chonan City was determined to Class 1 , which indicated that the soil was healthy.

• Journal of the Korean Chemical Society
• /
• v.47 no.6
• /
• pp.578-584
• /
• 2003

Polychlorinated biphenyls (PCBs) known as environmental contaminants in soil were analyzed by the soil pollution standard process test and the static supercritical $CO_2$ extraction mode. It was shown that the percent average recoveries of PCBs by the soil pollution standard process test were ranged in 25-35% and the corresponding standard deviations were above 10%. In contrast, the percent average recoveries of PCBs by the static supercritical $CO_2$ extraction mode were 2-2.5 times higher and standard deviations were within 7%. These results indicate that static supercritical $CO_2$ extraction mode may be a useful alternative to sample pretreatment certified by the soil pollution standard process test. The increasing supercritical $CO_2$ pressure from 1130 psi to 1996 psi at $40^{\circ}C$ enhanced the recovery of all PCB congeners from soil. However, at same Tc and Pc, the equilibrium time (5 versus 60 minutes) had no effect on the recovery of each PCB congener. Finally, similar PCB recoveries were obtained under the same extraction condition, regardless of the molecular weight and structure (coplanar versus non-coplanar) of PCB congeners.

• Korean Journal of Soil Science and Fertilizer
• /
• v.32 no.3
• /
• pp.274-278
• /
• 1999

Determination of soil texture, particularly the clay fraction, is an important measurement in most researches related with soil. In this study micro-pipette method For soil particle size analysis was compared with the standard hydrometer method. Micro-pipette method can eliminate the need for bulky laboratory equipment and long settling times associated with the standard hydrometer or pipette method. In the results of this investigation, the particle size data obtained with micro-pipette method were in good agreement with those found using standard hydrometer method. And with this method one person could run analysis much larger numbers of soil sample per day than with hydrometer method in relatively small laboratory space.

• Journal of Soil and Groundwater Environment
• /
• v.17 no.5
• /
• pp.20-30
• /
• 2012

In case of analyzing PAHs (EPA 16 compounds) in oil-contaminated soils, the lump of peaks may occur because of the aliphatic and polar compounds in oil. This phenomenon is due to the lower accuracy of the analysis. To solve this problem, evaluation of application of silicagel-alumina multi-layer fraction was performed using standard substances and oil-contaminated soils. As a result of application of silicagel-alumina multi-layer fraction cleanup method using standard substances, recovery rates of surrogate standards (5 compounds including Naphthalene-d8) were 83~100% and those of target standards were 75~129%. These were to meet the target values (60~130%) in this study. When used 4% water-silicagel column analyze PAHs in oil-contaminated soils, Some problems were generated for quantitative analysis of PAHs; concentration of PAHs was underestimated due to an upward baseline of internal standard (recovery rate: less than 60%) and overestimated by the lump of peaks which were not purified (the biggest recovery rate: more than 400%). On the other hand, in case of silicagel-alumina multi-layer fraction cleanup method, recovery rate of surrogate standards were 61~101.6%. Therefore this cleanup method was considered a valid method to improve accuracy of analysis of PAHs in oil-contaminated soils.

• Korean Journal of Soil Science and Fertilizer
• /
• v.36 no.2
• /
• pp.86-91
• /
• 2003

Carbon material such as graphite and activated charcoal can promote the growth of some formsog bacteria. We examined whether this bacterial growth promoting effect can have a positive influence on field crops. Refined graphite was mixed into the standard soil used in rice cultivation. Varying soil graphite mixtures of 0.1%, 0.5% and 1% were used to cultivate rice seedling for 3 weeks. After transplanting in the filed, rice plants were cultivated for 4 months. To observe the effect of graphite(carbon material) during the cultivation of rice, we examined various different growth components in this research. During the transplanting stage, growth promoting effect of carbon was observed in the 0.1% carbon added soil. However, there were not much difference between graphite added soil and standard soil in the other stages. Rice yield was highest in the soil with 0.1% graphite.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.48 no.4
• /
• pp.15-22
• /
• 2006

This study was conducted by the slump test and the consistency test of the cement mixed soil which is soil mixed with cement to investigate and estimate the difficulty degree of work and the proper water content. So I would like to present the fundamental data that establish the work standard of the cement mixed soil. In conclusion, in this study the slump value of the cement mixed soil increases over-all according to the increase of the water content although it has a little difference of the increase range and it is smaller than one of the soil. It is estimated that the aggregating and throwing work of the cement mixed soil which is mixed with 6% and 9% cement would be fine when it has the $25%{\sim}27%$ water content and the wall plastering work is the $30%{\sim}32%$ and the floor plastering work is the $30%{\sim}35%$ and the flowing and pouring work is the $40%{\sim}42%$ water content as well as the mold compacting work is the 20%.

• Journal of Life Science
• /
• v.14 no.5
• /
• pp.778-787
• /
• 2004

Effect of the microbial product made of Bacillus stearothermophilus DL-3, which was isolated from the soil and identified in this study, and rice bran on microorganisms in soil and growth of lettuce (Red skirt lettuce) and Chinese cabbage (Ga rack new No.1 Chinese cabbage) was investigated. Total numbers of microorganisms in the pot with untreated soil, treated with standard amount of microbial product and treated with double amounts of microbial product for growth of lettuce after 6 weeks were 2.78${\times}$10$^{7}$ CFU/g, 2.72${\times}$10$^{8}$ CFU/g and 3.63${\times}$10$^{8}$ CFU/g. Total numbers of microorganisms in the soil without treatment of microbial product and treated with standard amount of microbial product were 2.06${\times}$10$^{8}$ CFU/g and 5.49${\times}$10$^{8}$ CFU/g. Total numbers of microorganisms in the pot with untreated soil, treated with standard amount of microbial product and treated with double amounts of microbial product for growth of Chinse cabbage after 6 weeks were 1.43${\times}$10$^{7}$ CFU/g, 3.42${\times}$10$^{8}$ CFU/g and 7.22${\times}$10$^{8}$ CFU/g. Total numbers of microorganisms in the soil without treatment of microbial product and treated with standard amount of microbial product were 5.75${\times}$10$^{8}$ CFU/g and 7.96${\times}$10$^{8}$ CFU/g. On basis of leaf length, leaf width, leaf number, wet weight and dry weight, the growth of lettuce and Chinese cabbage on the soil treated with microbial product was faster than that on the untreated soil. The treatment of microbial product in the soil resulted in the increase of useful microorganisms, which seemed to enhance the growth of lettuce and Chinese cabbage.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.4
• /
• pp.278-284
• /
• 2015

In general, plant roots accumulate more heavy metals than the above ground organs such as leaf, stem, and fruit. This implies that root medicinal plants would be an issue with excessive heavy metal accumulation. Therefore, the current study was carried out to investigate the distribution of heavy metal (focused on Cd and Pb) concentrations in soils and medicinal plant roots grown in different region of Korea. Total 293 samples for each soil and plant were collected along the national wide. Soil pH, total and phytoavailable metal concentrations (1 M $NH_4NO_3$ extracted) in soils were determined and heavy metal concentrations in root of the medicinal plants were analyzed. Heavy metal concentrations of the soil samples studied were not exceeded standard limits legislated in 'Soil Environmental Conservation Act', except 2 samples for Cu. However, substantial amount of Cd was accumulated in medicinal plant roots with 29% samples exceeding the standard limit legislated in 'Pharmaceutical Affairs Act' while all plant samples were lower than the standard limit value for Pb. Also the current study demonstrated that cadmium concentrations in the roots were governed by the phytoavailable Cd in soils, which decreased as soil pH increased. From this result, application of heavy metal immobilization technique using a pH change-induced immobilizing agents can be suggested for safer root medicinal plant production.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.62 no.1
• /
• pp.117-126
• /
• 2020

The area of facility horticulture in Korea is increasing rapidly, the single-span pipe house which uses galvanized steel pipe as the main rafters occupies 78.7% of the facility area. Lightweight structures such as the single-span pipe house are vulnerable to meteorological disasters such as strong winds, economic losses of the state, local governments and farmers are continuing as construction does not meet the design standards. In order to minimize economic losses in the horticultural specialty facilities sector, the Rural Development Administration has been operating the horticultural disaster resilient standard for horticultural specialty facilities since April 2007. The only standard for the pipe connector is the disaster resilient standard, there is no standard for the uplift capacity of the house pipe foundation and the research on it is also insufficient. The purpose of this study is to investigate the characteristics of uplift capacity according to the foundation type, compaction ratio and embedded depth through soil box test. The results of the maximum uplift capacity according to the type, compaction ratio and embedded depth can be used as the basic data for the basic design of the pipe house conforming to the disaster resilient standard. Due to the limitation of soil box test, it may be different from the behavior of pipe house installed on site. In the future, the field test and the actual pipe house should be made and supplemented by comparing this result with the field test values.