• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.124-132
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• 2019

BACKGROUND: Silver grass (Miscanthus sinensis) No. 1 was developed for production of bio-ethanol, and for the purpose the silver grass growing sector was established in Geumgang basin, Iksan, Jeonbuk, in 2011. However, the other application potentials except for using as the bio-energy resources should be considered because of the drop in international oil prices. Therefore, there is the necessity of a scientific basis to use the silver grass instead of rice straw as the organic matter source that is used for improvement of soil quality in the plastic film house. METHODS AND RESULTS: The silver grass was applied at 5, 10, 15 and 20 Mg/ha and tilled before the watermelon was planted in the plastic film-house. The control plot was treated with 10 Mg/ha with rice straw, and watermelons have been cultivated for 3 years(2017~2019). Soil aggregation, soil chemistry, and the growth characteristics were investigated, when the watermelon was harvested every year. Soil aggregation levels at the 2nd and 3rd year of watermelon harvest were similar from the plot applied with the silver grass at 5 Mg/ha and the control plot, and increased in the silver grass treated plots with more than 10 Mg/ha. However, there was no statistically significant difference between the plots. The nitrogen mineralization of silver grass in the control plot tended to be similar to the 5 Mg/ha plot, but the silver grass treated plots with over 10 Mg/ha showed low nitrogen mineralization. Soil EC on harvest stage was proportional to the applied mass of the silver grass, but pH was in inverse with the applied mass. Soil organic matter content, available phosphate, and exchangeable cations increased with the continued use of silver grass. Watermelon weight found to be the best on more than 15 Mg/ha of silver grass, and the sugar content was highest when 10 Mg/ha was treated. CONCLUSION: The use of the silver grass at 10 Mg/ha annually as the organic source was effective in replacing rice straw while growing fruits and vegetables on the plastic film house.

• Korean Journal of Organic Agriculture
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• v.21 no.2
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• pp.271-282
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• 2013

This experiments was conducted to investigate the influence on organic rice cultivation by continuous use of cow manure in the central region of Korea and investigated productivity of organic rice and feed value, stock carrying capacity of organic rice straw. In the results, application of chemical fertilizer showed higher one of 1st and 2nd year in fresh matter yield (15.77, 30.30ton/ha), dry matter yield (9.90, 13.89 ton/ha), dry matter yield of rice straw (4.88, 7.15ton/ha), dry matter weight of kernel per plant (29.81, 39.99g) and number of kernel per plant (1212.58, 1701units), but there were not significantly differences with each experimental plots in 3rd year. And harvest index showed higher one in application of chemical fertilizer (0.52, 0.48, 0.43) until 3 years. But their quantitative difference between application of chemical fertilizer and cow manure was gradually decreased each year. And the average value of $K_{CP}$ and $K_{TDN}$ showed higher one in application of chemical fertilizer (2.01, 2.94, 1.95 head/ha/yr) until 3 years. However, quantitative difference between chemical fertilizer and cow manure was gradually decreased each year. Especially, application of cow manure showed higher value of 3rd year in $K_{ME}$, but there was not significantly difference with each experimental plots. According to the results, continuous use of cow manure will be reduced their quantitative differences between chemical fertilizer as the year progress in the central region of Korea in terms of productivity of organic rice and feed value, stock carrying capacity of organic rice straw.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.280-283
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• 2005

The growth and yield of ever-bearing strawberry $(Fragaria{\times}ananassa\; Duch.)$ 'Pechika' were compared after transplant treatment in the raised hydroponic culture on highlands in summer season. The transplant production methods compared were whole plant refrigerated, outdoor over-wintered, pot-refrigerated, and 1 -year-old transplants. Growth increment at planting was the highest in pot-refrigerated transplants. C/N ratio of the pot-refrigerated transplants was 39.2 which was higher than 19.5 of 1-year-old transplants. However, the growth increment up to the first harvest were not different among the treatments. The first harvesting date of 1-year-old transplants was August 14, which was 5-9 days late than in the other treatments. The average fruit weight was highest in the 1-year-old transplants with 12.6 g. Marketable yield was the highest in the pot-refrigerated transplants, followed 1-year-old, plant refrigerated, and outdoor over-wintered transplants. Therefore, the pot-refrigerated transplants are recommended for marketable yield increase in ever-bearing strawberry cultured on highlands.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.176-182
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• 1995

Field and pot experiments were carried to find out the effects of direct application of phosphate rock powder on soybean plant in upland soils with different available P content. In newly reclaimed upland soil with extremely low available P, phosphate rock powder was superior to single superphosphate at the application rate of 400kg-600kg/ha, in the first year particularly. In the second year, however, the reverse was the case excepting at the rate of 200kg/ha. In upland soil with low avialble $P_2O_5$($52mg\;kg^{-1}$), the application of phosphate rock powder at the high appliaction rate(400-600kg/ha) increased the yield of soybean remarkably in the first year and there was residual effect in the second year. The application of phosphate rock at high rate, increased the P and Ca contenl of plant and soil. The concentration of all fractions of P in the soil at the harvest was higher in phosphate rock treatments than in single superphosphate and fused magnesium phosphate treatments. In this soil with low avaiable P the occurrence of different fractions of P was in the order of Org-P>Fe-P>Ca-P>Al-P, in the first year and there was no change in the second year.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.711-719
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• 2010

We investigated physiological responses and phytoextraction ability of Pinus thunbergii in cadmium contaminated soil as part of our efforts in identifying plant materials for the restoration and revegetation of forest soil contaminated by heavy metals. Thirty seedlings (ten per treatment) were assigned to three treatments (control, 0.3 and 0.6 mM $CdSO_4$ solution) at first year experiment. At second year, ten seedlings per treatment treated with Cd during the first year experiment were divided by two groups (no Cd-treated and consecutive Cd-treated group). At first experiment, photosynthetic pigment content, and superoxide dismutase (SOD) and glutathione reductase (GR) activities have significantly reduced by Cd application, and the reduction rate was increased much higher as the rate of Cd application increased. On the other hand, thiol and malondialdehyde (MDA) content were significantly increased at the application of 0.6 mM of Cd. At the second year experiment, a general increase in chlorophyll and carotenoid content was observed with Cd treatment while SOD and GR activities showed a relative reduction compared to the control. Similar to the first year measurement, thiol and MDA contents also increased considerably due to Cd treatment. At harvest, dry matter was significantly reduced by Cd treatment especially at the rate of 0.6 mM Cd, but dry yield of P. thunbergii treated with 0.3 mM Cd was less affected and it was comparable with the control seedling. Cadmium concentration in seedling tissues increased with increasing Cd application rate while Cd uptake was higher in seedlings supplied with 0.3 mM Cd, which could be ascribed to their high dry matter. Overall, our study has demonstrated the unique physiological response of P. thunbergii to Cd-prolonged exposure by showing that the changes in photosynthetic pigment content and antioxidative enzyme activities were dependent on the concentration and duration of treatment. In addition, our results have demonstrated the potential of P. thunbergii to withstand up to 0.3 mM Cd (equivalent to cumulative Cd concentration of 134.4 to 268 mg $kg^{-1}$) without showing growth reduction, hence it might be used for phytoremediation of Cd contaminated areas.

• Korean Journal of Medicinal Crop Science
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• v.6 no.2
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• pp.96-101
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• 1998

This experiment was carried out to investigate the effect of fertilizers on yield and paeonol content of Paeonia moutan Sims according to cultivation years. Tested variety was a local cultivar and fertilizer treatments used were compost (3, 000kg/10a), N-P-K (10-10-10kg/10a) fertilizer, fowl dropping manure (100kg/10a), organic fertilizer (200kg/10a) and non-fertilizer. Root yield increased by 12% in N-P-K fertilizer, 18% in compost, 22% in fowl dropping manure and 26% in organic fertilizer treatment compared with non-fertilizer. Increment rate of root yield according to cultivation years from 3 to 6 year cultivation was highest in 5 year cultivation. Paeonol content was highest of 3.08% at October harvest and 3.63% in the fowl dropping manure treatment. Paeonol content was higher at longer cultivation year, but increment rate of paeonol content per year was low from 3 year cultivation. Partial paeonol content of root increased in the order of lower part (3.07%), middle part (2.77%), and upper part (2.38%).

• The Korean Journal of Malacology
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• v.26 no.4
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• pp.291-296
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• 2010

Samples of Turbo (Batillus) cornutus Lightfoot, 1786 in Jeju Island were collected from September 2009 to May 2010. Population ecological parameters and stock assessment of the turban shell were determined, based on the length and age composition data from 2000 to 2009 and ecological parameters. Instantaneous coefficient of total mortality (Z) of turban shell was estimated to be 2.2062/year. The estimated instantaneous coefficient of natural mortality (M) was 0.874/year. The age of turban shell at its first capture ($t_c$) was 2.636 year. Yield-per-recruit were estimated under harvest strategies that based on $F_{max}$, $F_{0.1}$, $F_{35%}$, and $F_{40%}$ was 10.44 g, 1.87 g, 6.53 g and 7.46 g.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.1026-1032
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• 2004

In this study, we assess the recent changes in the amount of excretion by the livestock industry, and discuss the effects of increasing the ratio of cultivated land on the reduction of surplus nitrogen from a cost-performance perspective. Nitrogen has contributed to acidification of ecosystems and nitrate concentrations in groundwater, especially in Europe. Therefore, we assessed the level of nitrogen waste from the domestic Japanese livestock industry, including cattle, swine and poultry during the period 1987-2001. This assessment assumed that 40% of the nitrogen from the domestic livestock industry was emitted as gas into the air and that 60% of the nitrogen was contained in manure used on domestic cultivated land. Nitrogen excreted from livestock, excluding gas emission, decreased by 11% from 0.504 million tons to 0.447 million tons during 1993-2001. Thus, the peak period of nitrogen excretion from livestock is already past in Japan. However, the area of cultivated land under management also decreased during 1990-2000. In addition, the area of paddy and upland fields left unplanted for a year increased during 1990-2000. Therefore, if all manure from the domestic livestock industry had been utilized on the fields as organic fertilizer, but not on arable land left uncultivated for the past year, the nitrogen per net area of cultivated land would have increased by 5%, from 125 to 131 N kg/ha, during 1990-2000. To reduce the nitrogen ratio on cultivated land through the planting of feed grain to utilize the nitrogen, a comparison of the cost performance of feed grains indicated that barley would be more suitable than wheat, rice or soybean. Had barley been planted in 100% of the land left fallow for the past year in 2000, 4% (20,000 tons) of the nitrogen from livestock waste would have been used in the harvest, and the nitrogen per land unit would have not increased but decreased from 125 to 121 N kg/ha during the same decade. Furthermore, when converted into Total Digestible Nutrients, 7% of imported feed corn could have been replaced with the harvested barley in 2000. Planting barley on this fallow land had three benefits; reducing the risk of manure overload on the land, slowing down the decrease in cultivated land, and raising the feed self-sufficiency ratio. Thus, it would be beneficial to plant feed grain such as barley in land left fallow for the past year through utilization of manure.

• The Korean Journal of Pesticide Science
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• v.16 no.2
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• pp.131-136
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• 2012

This study was carried out to elucidate residual characteristics of azoxystrobin and difenoconazole in fresh ginseng. Test pesticides were sprayed onto ginseng both in 2009 for 3-year-old ginseng and in 2010 for 4-year-old ginseng according to their pre-harvest intervals (PHIs). Limit of quantitation (LOQ) of both azoxystrobin and difenoconazole was 0.003 mg/kg. Analytical methods set up for the test pesticides were considered to be suitable for the analysis of their residues in fresh ginseng, considering that their recoveries ranged from 87.58 to 112.79%. Concentration of azoxystrobin in 3-year-old ginseng ranged from 0.004 to 0.011 mg/kg and that in 4-year-old ginseng ranged from 0.007 to 0.016 mg/kg. Amounts of difenoconazole in 3- and 4-year-old ginsengs were from 0.003 to 0.007 and from 0.007 to 0.01 mg/kg, respectively, representing no accumulation effect observed in residue amount between them.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.4
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• pp.300-304
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• 1993

This experiment was carried out to increase the utility and productivity of forage crop as to investigate the rotation system which is suitable to cultivat at the alpine area. The treatments were 9 crops combinations including corn - rye treatment. The results obtained were as follows: 1. Rye can be cultivated satisfactorily at cold and high altitude areas such as Tae Kwan Ryong. 2. Corn, to be raised as a second crop after rye in the same year, does not have to be early (short) or medium maturity varieties in the high alpine area. 3. It is possible to increase the harvest by 30% in terms of dry melter or green crop yield through raising two crops, rye and corn, in the same year. 4. Maturity period or growth conditions of corn. as a tropical crop and the best forage crop, can improve or worsen acording to the external circumstance, such as low temperature resulting from high atitude.