• Korean Journal of Microbiology
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• v.50 no.4
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• pp.368-371
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• 2014

A variety of abiotic stresses limit plant growth and crop productivity. Among the abiotic stress, salinity is one of the major harmful stresses to plants. Plant growth-promoting bacterium was isolated from reclaimed land soil of Kyehwa-do and identified as Pseudomonas. Pseudomonas sp. strain G19 produced $7.5{\mu}g/ml$ of indole acetic acid and solubilized 25% of insoluble phosphate after 36 h cultivation. Also, G19 was able to produce a protein that was structurally homologous to 1-aminocyclopropane-1-carboxylate deaminase of Pseudomonas fluorescens KACC10070 playing a role in reduction of ethylene in plant. The strain G19 increased the biomass of Chinese cabbage seedlings grown in the presence of 150 mM NaCl. The results indicated that the strain G19 promoted the growth of Chinese cabbage seedling under salinity stress through microbe-plant interactions.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.11-20
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• 2020

We estimated the spatio-temporally distributed soil moisture using Sentinel-1A/B SAR (Synthetic Aperture Radar) sensor images and soil moisture data assimilation technique in South Korea. Soil moisture data assimilation technique can extract the hydraulic parameters of soils using observed soil moisture and GA (Genetic Algorithm). The SWAP (Soil Water Atmosphere Plant) model associated with a soil moisture assimilation technique simulates the soil moisture using the soil hydraulic parameters and meteorological data as input data. The soil moisture based on Sentinel-1A/B was validated and evaluated using the pearson correlation and RMSE (Root Mean Square Error) analysis between estimated soil moisture and TDR soil moisture. The soil moisture data assimilation technique derived the soil hydraulic parameters using Sentinel-1A/B based soil moisture images, ASOS (Automated Synoptic Observing System) weather data and TRMM (Tropical Rainfall Measuring Mission)/GPM (Global Precipitation Measurement) rainfall data. The derived soil hydrological parameters as the input data to SWAP were used to simulate the daily soil moisture values at the spatial domain from 2001 to 2018 using the TRMM/GPM satellite rainfall data. Overall, the simulated soil moisture estimates matched well with the TDR measurements and Sentinel-1A/B based soil moisture under various land surface conditions (bare soil, crop, forest, and urban).

• Journal of Radiation Industry
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• v.4 no.4
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• pp.307-312
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• 2010

Plants have evolved physiological, biochemical and metabolic mechanisms to increase their survival under the adverse conditions. This present study has been performed to select salt-tolerant rice mutant lines through in vivo and in vitro mutagenesis with gamma-rays. For the selection of the salt-tolerant rice mutants, we conducted three times of selection procedure using 1,500 gamma ray mutant lines resulted from an embryo culture of the original rice cv. Dongan (wild-type, WT): first, selection in the a nutrient solution with 171 mM NaCl; second, selection under in vitro condition with 171 mM NaCl; and third, selection in a reclaimed saline land. Based on a growth comparison of the entries, out of the mutant lines, two putative 2 salt tolerant (ST) rice mutant lines, ST-87 and ST-301, were finally selected. The survival rate of the WT, ST-87 and ST-301 were 36.6%, 60% and 66.3% after 7 days in 171 mM NaCl treatment, respectively. The WT and two salt tolerant mutant lines were used to analyze their genetic variations. A total of 21 EcoRI and Msel primer combinations were used to analyze the genetic relationship of among the two salt-tolerant lines and the WT using the ABI3130 capillary electrophoresis system. In the AFLP analysis, a total of 1469 bands were produced by the 21 primer combinations, and 700 (47.6%) of them were identified as having polymorphism. The genetic similarity coefficients were ranged from 0.52 between the ST-87 and WT to 0.24 between the ST-301 and the WT. These rice mutant lines will be used as a control plot for physiological analysis and genetic research on salt tolerance.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.194-194
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• 2016

Gansu, located in the northwestern region, is a typical agricultural province of arid, semiarid in China. The shortage of water resources is the biggest obstacle of Gansu Province's development, and the dry farming water-saving is the eternal theme of Gansu agricultural sustainable development. In recent years, intensify reform in Gansu, has walked out a successful way in the agricultural water-saving. Using the integrated river basin governance as opportunity, the total water-using quantity was regarded as rigidity to retrain, distributed to counties (districts), irrigated areas, towns, associations, groups step by step. Agricultural water price was substantially increased, with the surface water price from about $0.1RMB/m^3$ to more than $0.2 RMB/m^3$, and the ground water from zero to more than $0.1RMB/m^3$. Simultaneously, the difference water prices and over-quota water progression price markup were carried out. The transaction of water rights was encouraged to impel the peasant to establish the consciousness of saving-water. The regulatory documents were formulated to standardize the scope, condition, mode, program etc. of agriculture water-rights transaction, to guarantees the transaction of water rights is carries out in order. The pattern of farming was optimized and adjusted, reducing the high water-consumption crop, increasing economic crops with high benefit and low water-consumption, developing industrialized agricultures such as green house. The relative engineering and measuring facility were comprehensively improved, with the anti-seepage of canal system and the enforcement of dynamo-electric well, developing high-efficient water-saving irrigation and overall metering facilities. The water fine-grained management has realized, and obvious water-saving effect has obtained: water-using rate in the irrigation area by river water has brought up to 0.57 from 0.52, and by well water up to 0.84 from 0.76. Although the water price has increased, the proportion that the water rate expenditure accounted for the cost lasts decline, and the farmers' income has gone up. The peasants express, the used water is few, and it is few to till land, but the income is many, and life is better.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.262-270
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• 2015

The scientific information between microbial community and chemical properties of reclaimed tidal soil is not enough to understand the land reclamation process. This study was conducted to investigate the relation between chemical properties and microbial activities of soils from reclaimed tidal lands located at south-western coastal area (42 samples from Goheuong, Samsan, Bojun, Kunnae, Hwaong and Yeongsangang sites). Most of the reclaimed soils showed chemical characteristics as salinity soil based on EC. Only $Na^+$ in exchangeable cation was dependent on EC of reclaimed soil, whereas other cations such as $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were independent on EC. The mesophilic bacteria decreased with an increase in EC of soil. Microbial population increased with soil organic content in the range of $0{\sim}10g\;kg^{-1}$ and dehydrogenase activity less than $100{\mu}g-TPF\;g^{-1}h^{-1}$. Microbial population of soils from reclaimed tidal lands was closely related to the microbial community containing hydrolytic enzyme activities of cellulase, amylase, protease, and lipase.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.773-778
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• 2011

Long-term continuous application of livestock by-products to agricultural land may adversely affect the soil characteristics and the crop yield. Five year term study from 2007 was carried out to assess the effects of repeated application of low-concentration swine slurry on soil chemical properties including phosphate and heavy metal contents and yield of tomato (Lycopersicon esculentum) and cucumber (Cucumis sativus L.) in a greenhouse. Treatments were conventional chemical fertilizers and three application rates of low-concentration swine slurry (Slurry composting and biofiltration, SCB): 50%, 100%, and 200% of recommended nitrogen fertilization. For swine slurry treatment of 50% nitrogen, deficient nitrogen was supplemented with urea fertilizer. The soil phosphorus and heavy metal contents after five year continuous application of swine slurry were not significantly higher than those of chemical fertilizer use. Repeated application of the swine slurry alone for five years resulted in relatively high soil exchangeable potassium and sodium compared with chemical fertilizer treatment. Contents of heavy metals in leaves of tomato and cucumber did not show significant difference among treatments. Yields of the crops for the swine slurry were not significantly different from that of chemical fertilizer. The results imply that continuous application of the swine slurry may not influence levels of soil phosphate and trace elements in greenhouse soils but could accumulate potassium and sodium in the soil.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1286-1294
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• 2011

This paper reviews the future directions and perspectives on the soil environmental researches in the 21 century. Previously, the principal emphasis of soil environmental researches had put on the enhancement of food and fiber productions. Beside the basic function of soil, however, the societal needs on soil resources in the 21st century have demands for several environmental and social challenges, occurring regionally or globally. Typical global issues with which soil science should deal include food security with increasing agronomic production to meet the exploding world population growth, adaptation and mitigation of climate change, increase of the carbon sequestration, supply of the biomass and bioenergy, securing the water resource and quality, protection of environmental pollution, enhancing the biodiversity and ecosystem health, and developing the sustainable farming/cropping system that improve the use efficiency of water and agricultural resources. These challenges can be solved through the sustainable crop production intensification (SCPI) or plant welfare concept in which soil plays a key role in solving the abovementioned global issues. Through implementation of either concept, soil science can fulfill the goal of the modern agriculture which is the sustainable production of crops while maintaining or enhancing the ecosystem function, quality and health. Therefore, directions of the future soil environmental researches should lie on valuing soil as an ecosystem services, translating research across both temporal and spatial scales, sharing and using data already available for other purposes, incorporating existing and new technologies from other disciplines, collaborating across discipline, and translating soil research into information for stakeholders and end users. Through the outcomes of these approaches, soil can enhance the productivity from the same confined land, increase profitability, conserve natural resource, reduce the negative impact on environment, enhance human nutrition and health, and enhance natural capital and the flow of ecosystem services. Soil is the central dogma, final frontier and new engine for the era of sustainability development in the $21^{st}$ century and thus soil environmental researches should be carried according to this main theme.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.3
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• pp.210-216
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• 2021

Pollution of agricultural soil by alkaline salts, such as Na₂CO₃, is a critical and long-lasting problem in cultivable land. The aim of the study was to examine the putative role of citric acid (CA) in alleviating Na₂CO₃-stress in alfalfa. In this study, Na₂CO₃ significantly induced leaf chlorosis, inhibited plant growth and photosynthesis related parameters, increased hydrogen peroxide (H₂O₂) and reduced major antioxidant enzymes (SOD, CAD, APX) in alfalfa. However, the presence of CA these negative effects of Na₂CO₃-stress largely recovered. Interestingly, expression of antioxidant and ion transporter genes (Fe-SOD, CAT, APX, DHAR and NHX1) involved in Reactive oxygen species (ROS) homeostasis and oxidative stress tolerance in alfalfa. These findings suggest that CA-mediated Na₂CO₃ stress alleviation is an ecofriendly approach that would be useful to local farmer for alfalfa and other forage crop cultivation in alkaline soils.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.3
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• pp.1-14
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• 2019

North Korea has frequently suffered from extreme agricultural crop droughts, which have led to food shortages, according to the Food and Agriculture Organization (FAO). The increasing frequency of extreme droughts, due to global warming and climate change, has increased the importance of enhancing the national capacity for drought management. Historically, a meteorological drought index based on data collected from weather stations has been widely used. But it has limitations in terms of the distribution of weather stations and the spatial pattern of drought impacts. Satellite-based data can be obtained with the same accuracy and at regular intervals, and is useful for long-term change analysis and environmental monitoring and wide area access in time and space. The Evaporative Stress Index (ESI), a satellite-based drought index using the ratio of potential and actual evaporation, is being used to detect drought response as a index of the droughts occurring rapidly over short periods of time. It is more accurate and provides faster analysis of drought conditions compared to the Standardized Precipitation Index (SPI), and the Palmer Drought Severity Index (PDSI). In this study, we analyze drought events during 2015-2017 in North Korea using the ESI satellite-based drought index to determine drought response by comparing with it with the SPI and SPEI drought indices.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.49-59
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• 2021

The effects of green manure crops, hairy vetch and sesban, supplemented with HS (humic substance) on biological soil health indicators was studied in a pot containing two kinds of reclaimed soil previously contaminated with petroleum hydrocarbons; a soil remediated by land-farming (DDC) and another soil by low-temperature thermal desorption (YJ). Treatments include no plant (C), plants only (H), and plants+2% HS (PH), which were evaluated in a pot containing respective soil. Biological indicators include microbial community analysis as well as soil enzyme activities of dehydrogenase, 𝛽-glucosidase, N-acetyl-𝛽-D-glucosaminidase (NAG), acid/alkaline phosphatase, arylsulfatase, and urease. Results showed an increase of enzyme activities in pot soils with plants and even greater in soils with plants+HS. The enzyme activities of DDC soil with plants (DDC_P) and with plants+HS (DDC_PH) increased 1.6 and 3.9 times on average, respectively than those in the control. The enzyme activities YJ soil with plants (YJ_P) and with plant+HS (YJ_PH) increased 1.8 and 3.8 times on average, respectively than those in the control. According to microbial community analysis, the relative abundance of nitrogen-fixing bacteria in DDC and YJ soil was increased from 1.5% to 7% and from 0 to 5%, respectively, after planting hairy vetch and sesban. This study showed that mixed planting of green manure crops with a supplement of humic substance is highly effective for the restoration of biological health indicators of reclaimed soils.