• The Plant Pathology Journal
• /
• v.38 no.6
• /
• pp.679-684
• /
• 2022

Rice blast is one of the most destructive diseases of rice worldwide, and the causative agent is the filamentous ascomycete Magnaporthe oryzae. With the successful cloning of more and more avirulence genes from M. oryzae, the direct extraction of M. oryzae genomic DNA from infected rice tissue would be useful alternative for rapid monitoring of changes of avirulence genes without isolation and cultivation of the pathogen. In this study, a fast, low-cost and reliable method for DNA preparation of M. oryzae from a small piece of infected single rice leaf or neck lesion was established. This single step method only required 10 min for DNA preparation and conventional chemical reagents commonly found in the laboratory. The AvrPik and AvrPi9 genes were successfully amplified with the prepared DNA. The expected DNA fragments from 570 bp to 1,139 bp could be amplified even three months after DNA preparation. This method was also suitable for DNA preparation from M. oryzae strains stored on the filter paper. All together these results indicate that the DNA preparation method established in this study is reliable, and could meet the basic needs for polymerase chain reaction-based analysis of M. oryzae.

• Journal of Applied Biological Chemistry
• /
• v.65 no.1
• /
• pp.1-6
• /
• 2022

Urea is one of the most common nitrogen fertilizer, but nitrogen use efficiency by crop is low because of rapid hydrolysis of urea and loss of nitrogen in environments. Therefore, it is important to control the nitrogen release from nitrogen fertilizers. In this study, pyroligneous acid (PA) was used as a mean to inhibit urease in soil and prevent excessive nitrogen release from urea. Active ingredient in PA (AI) inhibited ammonification of urea in soil by reducing extracted ammonium nitrogen at 79.7% compared to the soil without PA. In order to evaluate the effect of PA on fertilization efficiency of urea, Chinese cabbage (Brassica campestris var. Pekinensis) was cultivated in soil treated with urea and PA both in pot and field. For PA treatment, half amount of urea was used compared to the amount of urea conventionally applied to Chinese cabbage. The PA treatment with half amount of urea resulted in similar Chinese cabbage biomass to the conventional urea application. Nitrogen concentration in Chinese cabbage was less in PA treatment indicating that Chinse cabbage effectively used nitrogen. Consequently, fertilization of urea with PA will reduce amount of fertilizer and frequency of application.

• New & Renewable Energy
• /
• v.19 no.4
• /
• pp.35-45
• /
• 2023

Global efforts are focused on achieving carbon neutrality due to the increases in the levels of greenhouse gases. Moreover, the greenhouse gases generated from the disposal of municipal solid waste (MSW) are the primary sources of emissions in South Korea. In this study, we conducted the biological conversion of syngas (CO, H₂, and CO₂) generated from MSW gasification. The MSW-derived syngas was used as a feed source for cultivating Eubacterium limosum KIST612, and pressurization was employed to enhance gas solubility in culture broth. However, the pH of the medium decreased owing to the pressurization because of the CO₂ in the syngas and the cultivation-associated organic acid production. The replacement of conventional HEPES buffer with a phosphate buffer led to an approximately 2.5-fold increase in acetic acid concentration. Furthermore, compared with the control group, the pressurized reactor exhibited a maximum 8.28-fold increase in the CO consumption rate and a 3.8-fold increase in the H2 consumption rate.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.24 no.4
• /
• pp.77-83
• /
• 2016

The objectives of this study was to investigate the difference between organic-farming and conventional-farming soils relatives to soil chemical properties and microbial flora. Fifteen soil sampling sites were chosen from the certified organic upland farm, considered with its location, crop and application of organic compost types. Soil chemical properties were analyzed by standard methods established by National Institute of Agricultural Sciences, Rural Development Administration. For the soil chemical properties, the values of pH were ranged from 4.5 to 7.3. The values of electrical conductivity (EC) in the sampling sites were below 2 dS/m of convention cultivation soil. For analyzing the microbial flora, the bacillus(16S rDNA) and cladothricosis(18S rDNA) were analyzed by using PCR-DGGE (Denaturing Gradient Gel Electrophoresis) in the soil of 15 sampling sites. Cluster analysis of biodiversity index was performed by using pattern of DGGE. DGGE patterns and clustering analysis of bacterial DNA from soil extracts revealed that the bacterial community was differentiated between less than 5 years and more than 5 years depending on the cultivation history. But there was no consistent tendency between cultivation history and regional trend in the case of molds. Therefore, it would be very effective to analyze bacterial clusters of organically cultivated soils in long - term cultivated soil for more than 5 years.

• Korean Journal of Soil Science and Fertilizer
• /
• v.29 no.4
• /
• pp.342-346
• /
• 1996

Field experiments were conducted to investigate the mode of changes in exchangeable K contents in the soil under the continued(for three years) application of different levels of K fertilizer(KCl) with and without application of conventional compost(CC) and chicken-dung derived compost (CDC) for red pepper cultivation at two field parcels with different exchageable K contents on Gopyong silty loamy soil. The application of KCl at standard rate for red-pepper resulted in the increase in exchangeable K in the soil after each harvest of the crop. while no application of K and the application of KCl at one half of the standard rate tended to lower the exchangeable K in top soil with the cultivation of the crop. The application of compost in addition to KCl ammplified the difference in exchangeable K in the soil before and after the harvest of each crop. An equation could resonably well predict the exchageable K content in top soil after the years of crop cultivation, under different treatments. were developed.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.5
• /
• pp.725-732
• /
• 2012

There is relatively high vulnerability of soil erosion in slope highland agriculture due to a reclamation of mountain as well as low surface covering during early summer with high rainfall intensity. Especially, in soybean cultivation, soil disturbance by conventional tillage and exposure of topsoil at the early stage of soybean have intensified soil loss. The aim of this study was to evaluate various surface covering methods for reducing soil loss in highland soybean cultivation. The experiment was conducted in 17% sloped lysimeter ($2.5m{\times}13.4m$) with 8 treatments. Amount of runoff water and eroded soil, and soybean growth were investigated. Surface covering through sod culture and plant residue showed 3.4~45.0 runoff water amount with $177{\sim}2,375m^3\;ha^{-1}$ compared with control ($5,274m^3\;ha^{-1}$). And the amount of eroded soil was also reduced by 95% in surface covering treatment with $0.02{\sim}1.94Mg\;ha^{-1}$ than control with $40.72Mg\;ha^{-1}$. Yields of soybean pod showed $0.3Mg\;ha^{-1}$ in rye sod culture, $1.3Mg\;ha^{-1}$ in Ligularia fischeri var. spiciformis Nakai, $0.7Mg\;ha^{-1}$ in Aster koraiensis Nakai, $0.2Mg\;ha^{-1}$ in red clover and $2.0Mg\;ha^{-1}$ in non-covering, on the other hand, covering with cut rye showed $3.8Mg\;ha^{-1}$. Conclusively, covering the soil surface with cut rye were beneficial for reduction of soil loss without decreasing soybean yield in highland sloped fields.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.5
• /
• pp.744-748
• /
• 2012

This study was carried out to investigate the incorporation effect of green manure crops (GMC) such as the hairy vetch on improvement of soil environment in reclaimed land during sorghum${\times}$sudangrass hybrid (SSH) cultivation over the past three years from 2009 to 2011. Plots consisted of conventional fertilization (CF) and incorporation of GMC were divided by rates of additional nitrogen fertilizer ($100kg\;ha^{-1}$) and decreased percentage of 30 50 70 100 fertilization in addition to non nitrogen fertilization (NNF). Soil physico-chemical properties, growth and yield potential were examined. The results were as follows. The testing soil was showed strong alkaline saline soil with low organic matter contents and less available phosphate while exchangeable sodium and magnesium were higher. Soil salinity was increased during cultivation of summer crop. However, SSH was not affected by salt content. The fresh weight of GMC at incorporation time was $18,345kg\;ha^{-1}$. Content of total nitrogen at incorporation time was 3.09% and the C/N ratio was 12.8. Fresh and dry matter yield of SSH were higher in the order of 30%, CF, N50%, N70%d, N100%, and NNF. Fresh and dry matter yield of SSH increased in the order of CF ($55,050kg\;ha^{-1}$, $16,250kg\;ha^{-1}$), N contents from 30% to 9%. Soil physical properties, such as bulk density were decrease with incoporation of GMC, while porosity was increased. Soil chemical properties, such as pH was decreased while content of exchangeable calcium, available phosphate, and organic matter were increased. Also contents of exchangeable sodium and potassium were decreased with incorporation of GMC than those before experiment. Thus, we assumed that incorporation of hairy vetch was more effective that can lead to reduce chemical nitrogen fertilizer and to improve soil environment in cultivating SSH on Saemangeum reclaimed land.

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.2
• /
• pp.102-108
• /
• 2006

It is very important to improve fertilizer use efficiency for the saving of fertilizers and for environmental purposes as well. However, there was no effective ways for the fertilization in the mid of growth under the plastic film mulching cultivation so far. For this, a Band Spotty Fertilization (BSF) machine was developed recently. So, we tried to establish a low input fertilization technique using this BSF machine in the vinyl mulching cultivation of onion (Allium cepa L.). Fertilization efficiency, soil properties, and crop yield were examined and compared among treatments from 2000 to 2001. The content of exchangeable K in soils were higher after fertilization but that of available $P_2O_5$ was lower than before the experiment in all plots. The content of nitrate-N was highest at the early growth stage, and higher in BSF plots than that of conventional fertilization (CF). BSF plot showed higher growth rate, and uptake amount of nitrogen of onion by 59-69% than that of CF. N use efficiency in BSF was higher in the order of two time-split application, one time-split application, and three time application. K use efficiency was high 13-17% BSF plots than that in CF($63kg\;ha^{-1}$) plots. The amount of residual N in soils was high by 8-14% in BSF plots compared to that in CF plots, and the loss of N was lowered 26-34% by BSF. Also, the amount of residual K in soils was high by 13-18% and the loss of K was low by 29-31% in BSF plots compared to that in CF plots. The yield of onions increased by 7-13% by BSF due to increased diameter and weight of bulbs. As the results, N fertilization efficiency increased by 22-42% by BSF.

• Korean Journal of Organic Agriculture
• /
• v.20 no.4
• /
• pp.715-725
• /
• 2012

This study was performed to make the method of food waste manufacturing for feeding to earthworm and different ratio of earthworm cast was investigated for applying vegetable plants that cultivated in a family or roof garden. We made conventional treatment of gardening soil and prepared soils with earthworm cast (the only fertilizer) at 30, 50, 70 and 100% for planting vegetable plants and then we studied its growth feature. The treatment was repeated three times with 12 weeks for each time. The cultivation of radish and chinese cabbage were managed at the same cultivation level for RDA standard cultivation method, and each sample of soils and plants was analyzed by appropriate analysis method. The growth investigation was performed 12 week after planting, and as for growth characteristics, height, leaf diameter, leaf number, leaf length, fresh weight and dry weight were investigated. The chemical characteristics, soils and plants, were surveyed. As for the growth characteristics investigated, radish and chinese cabbage showed the biggest growth in 70% and 50% treatment with average growth of all characteristics, height, leaf diameter, leaf number, leaf length, fresh weight and dry weight, respectively. Applying these results, a new equation for vermicast recommendation for radish and Chinese cabbage in summer (June-August) was presented. The earthworm cast 50% level with the gardening soil showed the high production in chinese cabbage. In case of radish, earthworm cast 70% with gardening soil level showed great growth, significantly.

• Journal of Mushroom
• /
• v.17 no.4
• /
• pp.211-217
• /
• 2019

Currently, cultivation of mushrooms using the Information and Communication Technology (ICT)-based smart farming technique is increasing rapidly. The main environmental factors for growth of mushrooms are temperature, humidity, carbon dioxide (CO₂), and light. Among all the mentioned factors, currently, only temperature has been maintained under automatic control. However, humidity and ventilation are controlled using a timer, based on technical experience.Therefore, in this study, a Pleurotus eryngii first-generation smart farm model was set up that can automatically control temperature, humidity, and ventilation. After installing the environmental control system and the monitoring device, the environmental condition of the mushroom cultivation room and the growth of the fruiting bodies were studied. The data thus obtained was compared to that obtained using the conventional cultivation method.In farm A, the temperature during the primordia formation stage was about 17℃, and was maintained at approximately 16℃ during the fruiting stage. The humidity was initially maintained at 95%, and the farm was not humidified after the primordia formation stage. There was no sensor for CO₂ management, and the system was ventilated as required by observing the shape of the pileus and the stipe. It was observed that, the concentration of CO₂ was between 700 and 2,500 ppm during the growth period. The average weight of the mushrooms produced in farm A was 125 g, and the quality was between that of the premium and the first grade.In farm B. The CO₂ sensor was in use for measurement purposes only; the system was ventilated as required by observing the shape of the pileus and the stipe. During the growth period, the CO₂ concentration was observed to be between 640 and 4,500 ppm. The average weight of the mushrooms produced in farm B was 102 g.These results indicate that the quality of the king oyster mushroom is determined by the environmental conditions, especially by the concentration of CO₂. Thus, the data obtained in this study can be used as an optimal smart farm model, where, by improving the environmental control method of farm A, better quality mushrooms were obtained.