• Journal of Microbiology and Biotechnology
• /
• v.21 no.4
• /
• pp.341-346
• /
• 2011

To study the effects of salinity-sodicity on bacterial population and enzyme activities, soil samples were collected from the Bay of Yellow Sea, Incheon, South Korea. In the soils nearest to the coastline, pH, electrical conductivity ($EC_e$), sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) were greater than the criteria of saline-sodic soil, and soils collected from sites 1.5-2 km away from the coastline were not substantially affected by the intrusion and spray of seawater. Halotolerant bacteria showed similar trends, whereas non-tolerant bacteria and enzymatic activities had opposite trends. Significant positive correlations were found between EC, exchangeable $Na^+$, and pH with SAR and ESP. In contrast, $EC_e$, SAR, ESP, and exchangeable $Na^+$ exhibited significant negative correlations with bacterial populations and enzyme activities. The results of this study indicate that the soil chemical variables related with salinity-sodicity are significantly related with the sampling distance from the coastline and are the key stress factors, which greatly affect microbial and biochemical properties.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.31 no.1
• /
• pp.96-105
• /
• 1989

This laboratory study was performed to produce basic data for the estimation of water requirements for desalinization, through analyzing changes of the electrical conductivity and the exchangeable sodium percentage during the desalinization of reclaimed tidelands. Desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The results obtained from this study were summarized as follows : 1. The sample soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. Changes of the electrical conductivity and the exchangeable sodium percentage with water requirements for desalinization showed a similar tendency in the desalinization experiment by the same water management practice. 3. The regression equation between the relative electrical conductivity(EC/EC) and water requirements for desalinization(Dw/Ds) could be described by Dw/Ds=O. 29x(EC/EC.) -0.982 (Leaching method), Dw/Ds=3. 678X0. 030(EC/EC ) (Rinsing method). 4. The regression equation between the relative exchangeable sodium percentage (ESP/ESP ) and water requirements for desalinization (Dw/Ds) could be expressed in Dw/Ds = 0.039 x (ESP/ESP. ) - 1. 134 (Leaching method), Dw/Ds=7. 197X0. 024(ESP/ESP ) (Rinsing method). 5. It was estimated that water requirements for the adequate desalinization would be Dw/Ds=0.3 (Leaching method) and Dw/Ds=3.0 (Rinsing method)

• Korean Journal of Agricultural Science
• /
• v.42 no.2
• /
• pp.93-98
• /
• 2015

This study was conducted to evaluate the efficacy of herbicide in winter cereal crops, barley and wheat. The efficacy of soil-applied herbicides, linuron EC and pendimethalin, thiobencarb GR was greater than that of butachlor EC. Linuron EC controlled average 95% and pendimethalin, thiobencarb GR controlled average 97% within 150 days after soil-applied treatment. When compared with untreated control, no visual injuries were detected at single and double dosage of linuron EC and pendimethalin, thiobencarb GR. The yield of barley increased in linuron EC and wheat increased in pendimethalin, thiobencarb GR treatments when compared with butachlor EC. The efficacy of foliage treatment, bentazone+propanil ME was greater than that of bentazone SL. Bentazone+propanil ME controlled average 96% in barley and 97% in wheat, within 30 days after foliage treatment. When compared with untreated control, no visual injuries were detected at single and double dosage of bentazone+propanil ME. The yield of barley and wheat increased in bentazone+propanil ME treatments when compared with bentazone SL. Based on these data, combinations of these herbicides could be applied to provide effective weed management in barley and wheat field.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.3
• /
• pp.394-399
• /
• 2011

This study evaluated the effect of using waste nutrient solution (WNS) and reclaimed wastewater (WW) on the growth of Chinese cabbage and soil quality. The pH and electrical conductivity (EC) values of waste nutrient solution were 6.3 and $1.5dS\;m^{-1}$ and being 6.8 and $0.4dS\;m^{-1}$ in reclaimed WW, respectively. WNS found to be included more than $10g\;m^{-2}$ of $NO_3^-$, $K^+$, $SO_4^{2-}$ and $Ca^{2+}$, thereby enhancing Chinese cabbage growth. However, $Cl^-$ and $Na^+$ contents were higher than other nutrients in WW. Among the three irrigation resources, no significant differences were found for the growth of Chinese cabbage plants. On the other hand, pH was decreased in WNS-treated soil when compare to that in WW-treated soil which pH was increased. In spite of the uptake of nutrients by the growing plants, irrigation of the WNS led to an increase in available $P_2O_5$ and exchangeable cations such as $K^+$ and $Mg^{2+}$ in the soil when compared to soil that irrigated by groundwater or WW. Taken together, the use of WNS can remarkably reduce the amount of the chemical fertilizer for Chinese cabbage production; however, WNS can possibly cause a problem as nutrients accumulation in soil.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.24 no.4
• /
• pp.5-10
• /
• 2022

After ginseng seeds were planted in sand, the first experiment was conducted by germinating seeds with a nutrient concentration of 0 to 2.5. The average germination rate was highest in EC 1.0 with a nutrient concentration of 87%, followed by the comparative group with EC 1.5, 82%, EC 2.0, 78%, EC 2.5, 72%, EC 0.5, 71%, and con, 68%. Ginseng seeds were sown in the sandy soil, grown for 60 days were transferred to the ginseng soil, and the second growth experiment was conducted 30 days later. As a result of the experiment, at the nutrient concentration of EC 1.5, it grew from 11.64cm to 15.54cm, the average total length(cm)increased the most from 3.90cm. At the EC 1.0, nutrient concentration, the average total weight(g)increased the most from 0.42g to 0.75g to 0.33g. At the EC 0.5, nutrient concentration, the average total root width(mm) increased the most from 4.06mm to 5.52mm to 1.46mm.

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.4
• /
• pp.381-387
• /
• 2016

The scientific information on the microbial differentiation according to the changes in chemical properties of paddy soil in reclaimed tidal lands is not enough to understand the reclamation processes. The changes in microflora based on the chemical properties of paddy soils at the same sites of reclaimed tidal lands (21 samples from Nampo, Ewon, Sukmoon and Shihwa sites) were investigated in 2013 and 2015. In general, organic matter in paddy soils increased whereas pH decreased with the reclamation time. The electrical conductivities (EC) of soil samples were closely related to the exchangeable $Na^+$. With an increases in EC of paddy soils from 0.39 to $48.9dS\;m^{-1}$, the ratios (%) of halotolerant and halophilic bacteria to mesophilic bacteria proportionally increased from 0.2% to 102,000%. The population of halotolerant and halophilic bacteria in total microflora was also differentiated with the changes in EC of the same sites from reclaimed tidal soils within 2 years. The population of mesophilic bacteria decreased with an increase in EC above $5dS\;m^{-1}$. The microflora including halotolerant and halophilic bacteria could be a candidate as a biological parameter in evaluating the reclamation processes in addition to the chemical index of EC.

• Journal of Bio-Environment Control
• /
• v.16 no.4
• /
• pp.328-332
• /
• 2007

This study was conducted to investigate the effects of high concentrations of salts in soil on the growth, yield, quality, photosynthetic rate, and mineral uptake of tomato ('House Momotaro') in pot cultivation. The growth of tomato such as plant height, top plant weight and root weight decreased as the concentrations of salts in soils increased. Yield decreased by 31% and 41% in EC 5.0 and $7.5dS{\cdot}m^{-1}$, respectively compared with the salt concentration of EC $1.5dS{\cdot}m^{-1}$. Yield reduction was caused by low mean weight and number of fruit if at high salt concentration in soil, and affected by low photosynthetic rate and water potential in leaf, The rate of blossom-end rot was highest (16.7%) in EC $7.5dS{\cdot}m^{-1}$ and increased as the concentrations of salts in soils increased. The contents of soluble solids and titratable acids showed a tendency to increase with increasing the concentrations of salts in soils. Photosynthetic rate, water potential and stomatal conductance in leaf decreased as the salt concentration in soil increased. The higher the salt concentration in soil, the lower the mineral uptake such as T-N, P, K, Ca and Mg but, the higher the content of Na.

• Korean Journal of Organic Agriculture
• /
• v.21 no.4
• /
• pp.647-657
• /
• 2013

This experiment was done to evaluate the effects of green manure cropping in green house soil on the changes of soil nutrients and soil microorganisms. The biomass of green manure crop was the highest in ryegrass and nitrogen absorption was the highest in hairy vetch. After cropping, soil phosphate content was the lowest in ryegrass, however, biomass C was the highest of all the green manures. Nitrogen uptake of plant and nitrogen content of the soil after the experiment showed a negative correlation. Total N content of soil was increased in hairy vetch plot, but decreasing tendency showed in the ryegrass and common crabgrass plots. In this results are summarized that green manure cropping greatly reduced salt accumulation in green house.

• Journal of Korean Society of Forest Science
• /
• v.89 no.1
• /
• pp.55-64
• /
• 2000

This study was carried out to analyze the characteristics of pH and electrical conductivity(EC) at each stand and soil depth by the artificial acid rain sprinkling in the upper watershed of Mt. Palgong and furthermore to clarify the relationships between forest soil and water purification function. The results obtained in the experimental sites of Quercus acutissima and Larix leptolepis were summarized as follows ; 1. The average soil pH at each soil layer(0~5cm, 0~10cm, 0~20cm in depth) were 4.8, 4.3 and 4.5 for the Quercus acutissima soil and 5.15, 5.19 and 5.21 for the Larix leptolepis soil. The soil pH of Larix leptolepis stand was higher than that of Quercus acutissima stand. In addition, the deeper soil depth was, the higher soil pH was. 2. The soil solution pH of Larix leptolepis stand was higher than that of Quercus acutissima stand. It was due to the high soil pH of Larix leptolepis stand itself and the difference of humus layer thickness. 3. It took time to show the pH buffer capacity of forest soil after application of artificial acid rain in the forest soil. The pH value of soil solution in each experimental site was maximum at this time and then did not increase pH value any more. 4. Soil solution EC increased slowly with pH 3.0 treatment, but it decreased slowly with pH 5.0 treatment over time. It was assumed that the amount of the leached cation and the ions leading buffer action changed at the stands with ranges of acidity treatment. 5. From the trend of soil solution EC at each soil depth, it seemed that the water buffer capacity of the forest soil increased as the soil depth increased.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.4
• /
• pp.262-268
• /
• 2014

The management of soil chemical properties is very important to sustainable agriculture of many horticultural crops, including cucumber. This study was conducted to find the optimal soil properties of environmentally friendly agriculture in controlled horticulture. Soil chemical properties of 267 samples were collected from soil in Chungnam Province. The average of pH, EC, OM, available $P_2O_5$, exchangeable K, Ca, and Mg was 6.1, $5.38dS\;m^{-1}$, $34g\;kg^{-1}$, $1,321mg\;kg^{-1}$, $1.50cmol_c\;kg{-1}$, $10.3cmol_c\;kg{-1}$, and $3.4cmol_c\;kg{-1}$, respectively. The organic matter content in silty clay loam was significantly higher than in the other soil textures, whereas the pH, EC, exchangeable K, and Mg in loamy fine sand showed significantly lower among soil textures. The EC value and exchangeable Mg concentration were highest in mountain foot-slope soils. The frequency distribution within optimum range of soil chemical properties was 26.2%, 30.3%, 2.3%, 3.8%, 3.4%, and 6.7% for pH, OM, available $P_2O_5$, exchangeable K, Ca, and Mg, respectively. Especially, excessive portion of available $P_2O_5$ and exchangeable Ca were 94.0% and 94.4%, respectively. The EC value and organic matter content of soil samples were positive correlation with all chemical properties except soil pH. In principle component analysis of chemical properties in soil samples, the percentage of variance explained by PC 1 was 52.2%, while PC 2 explained 21.3% of the variance, for a cumulative total of 73.5%. In conclusion, these results are considered to improve soil nutrient management for sustainable controlled horticulture.