• Journal of Applied Biological Chemistry
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• v.50 no.1
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• pp.22-28
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• 2007

Most of the uplands in alpine regions during off-season are left as bare soil and thus vulnerable to severe erosion due to the inherent topographical conditions. Appropriate management strategy to cope with this problem is urgently needed, yet few researches have been reported on the effects of winter cover crop and management on soil erosion. We assessed effects of ryegrass (Lolium multiflorum) as cover crop, green manure or mulching residue on soil erosion and quality through field and segment plot lysimeter experiments in alpine uplands. Ryegrass successfully adopted to winter in alpine region based on biomass, nutrient contents, and vigors of top and root systems. Incorporation of ryegrass into soil maintained soil fertility, nutrient uptake, and yield of cabbage exerting potential use as green manure. Cultivation of ryegrass suppressed occurrence of Chinese cabbage pests. Surface coverage by ryegrass as cover crop and mulching residue significantly reduced soil loss up to 96%, when combined with soil conservation management practices. Results revealed maintaining cover crop over winter was beneficial in reducing soil erosion, and sustaining soil quality and Chinese cabbage productivity. This study suggested winter cover crop, followed by green manure and mulching, and conservation tillage system could be one of the best management practices in alpine sloping uplands cultivating Chinese cabbage.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.510-518
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• 2013

Corn was mainly cultivated in slope land during summer season when heavy rain falls so that soil loss occurs severely. Especially, soil disturbance and exposure of topsoil by conventional tillage intensifies soil loss by heavy rain. The aim of this study was to develop surface covering and tillage methods for reducing soil loss in corn cultivation. The experiment was conducted in 17% sloped lysimeter with 8 treatments including strip tillage after surface covering with rye residue, strip tillage after residue covering of several crops and sod culture, black polyethylene film covering after conventional tillage and control. Amount of runoff water and eroded soil, and corn growth were investigated. Amounts of runoff water in all plots except black polyethylene plot ranged from 152 to 375 $m^3\;ha^{-1}$, accounting for 13~32% of 1,158 $m^3\;ha^{-1}$ in control. Amount of eroded soil decreased by 94 to 99% (3 to 89 kg $ha^{-1}$) in plots of strip tillage after covering with crop residues compared to control with 1,739 kg $ha^{-1}$. Corn yields in plots of strip tillage after covering with crop residues ranged from 6.0 to 6.9 Mg $ha^{-1}$, while that of control was 6.5 Mg $ha^{-1}$. The results suggest that strip tillage methods after surface covering with crop residues are very effective on soil conservation of slope land in corn cultivation.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.255-263
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• 1993

The demand of safety assessment for pesticide residues in foods is growing in Korea. In order to assess the actual dietary exposure toward pesticide residues, the problems in utilization of pesticide residue data were reviewed and optimization of food factors applicable to Korean population was conducted. The problems and current status in setting pesticide residue tolerance-domestic and foreign-in foods were also argued. The conclusion is summarized as follows: (1) Anticipated residue estimates(ARE) calculated from field trial residue data, the percentage of crop treated, and the effects of cooking or processing should be utilized for dietary exposure assessment in a real sense. (2) Average daily intake of total foods per person in Korea was 1,104g in 1970's and 1,240g in 1980's. Much variation was observed between the two decades by food commodities. (3) Pesticide residue tolerances in Korea have been established at relatively lower levels in comparison with FAO/WHO or western countries. More extensive studies and data accumulation as related to tolerance setting are called for in future for the sake of health protection and smooth interstate trade.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.345-353
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• 2018

Background: Some phenolics detected in the soil may inhibit the seed germination and seedling growth of ginseng (Panax ginseng). This study investigated the effect of irrigation and ginseng root residue addition on the soil microbial community and root rot disease in 2-year-old ginseng. Methods and Results: Each $20{\ell}$ pot was filled with soil infected with ginseng root rot pathogens, and irrigated daily with $2{\ell}$ of water for one month. After the irrigation treatment, ginseng fine root powder was mixed with the irrigated soil at a rate of 20 g per pot. In descending order, ${NO_3}^-$, electric conductivity (EC), exchangeable Na (Ex. Na) and K (Ex. K) decreased due to irrigation. In descending order, ${NO_3}^-$, EC, Ex. K, and available $P_2O_5$ increased with the additon of ginseng powder to the soil. The abundance of Trichoderma crassum decreased with irrigation, but increased again with the incorporation of ginseng powder. The abundance of Haematonectria haematococca increased with irrigation, but decreased with the incorporation of ginseng powder. The abundance of Cylindrocarpon spp. and Fusarium spp., which cause ginseng root rot, increased with the incorporation of ginseng powder. The abundance of Arthrobacter oryzae and Streptomyces lavendulae increased with irrigation. The abundance of Streptomyces lavendulae decreased, and that of Arthrobacter spp. increased, with the incorporation of ginseng powder. Aerial growth of ginseng was promoted by irrigation, and ginseng root rot increased with the incorporation of ginseng powder. Conclusions: Ginseng root residues in the soil affected soil nutrients and microorganisms, and promoted ginseng root rot, but did not affect the aerial growth of ginseng.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.7-11
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• 2004

Alfalfa (Medicago sativa L.) plants have been reported to be autotoxic as well as allelopathic. Laboratory and greenhouse experiments through petri-dish and pot test were conducted to determine autotoxic effects of alfalfa leaf and soil extracts on the germination or early seedling growth of alfalfa, and to evaluate allelopathic effects of alfalfa leaf residues on alfalfa, barnyard grass, com, eclipta and soybean. Alfalfa seed germination was delayed depending on aqueous extract concentration, with no difference in final germination after 48 hours. Alfalfa root length was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Root growth of alfalfa was significantly inhibited at extract concentration of more than 1 g dry tissue/L (g $\textrm{L}^{-1}$). Hypocotyl growth, however, was not affected by all the concentrations of leaf extracts. Soil extracts from 4-yr-old alfalfa stand significantly reduced alfalfa root length by 66%, while soil extracts from 0,1, and 3yr-old stand stimulated root length up to 14-32% over the control. Residue incorporation with dry matters of alfalfa leaf at 100 g $\textrm{kg}^{-1}$ reduced seedling length of several crop and weed species, ranging from 53 to 87% inhibition. Addition of nutrient solution into alfalfa leaf extracts alleviated alfalfa autotoxic effect. This result indicates alfalfa leaf and soil extracts or residues could exert autotoxic as well as allelopathic substances into soil environments during and after establishment.

• International Journal of Industrial Entomology and Biomaterials
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• v.38 no.2
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• pp.31-37
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• 2019

Silkworm larval mortality specifically during spinning stage leading to non-spinning with specific morphological symptoms was frequently complained by sericulturists in Karnataka, India during 2015. Survey was conducted and information collected through questionnaire from the identified farmers who faced the problem of non-spinning in both traditional and non-traditional areas of Karnataka. Survey results indicate that the problem is specific to the silkworm crop of those farmers' who shifted from other crops of agriculture/ horticulture/olericulture/ floriculture to Sericulture. Silkworm rearing performance of the batches fed with these leaves confirmed that the pesticide sprayed to the crops previous to mulberry, remain in the soil and when mulberry plantation is taken up in these gardens, the pesticide is absorbed by the roots of mulberry plants and transported to the leaves. Silkworms that feed on these mulberry leaves, grow and ripen normally but during spinning stage, larvae die with external symptoms like regurgitation, body shrinkage, rectal protrusion later become hook shaped leading to non-spinning or partial metamorphosis into pupa and death or spin flimsy cocoons. Larval mortality ranged from a minimum of twenty five percent to a maximum of hundred percent. The problem was noticed from the first harvest of leaves and lasted for a maximum period of 36 months. Cocoon crop loss depends on the concentration, duration and type of pesticides used previously for other crops.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.120-126
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• 2014

An accurate analysis of nutrient balance in different cropping systems is necessary for improving soil fertilities, causing higher crop yields and quality. This study was carried out to investigate the nutrient balance, changes in soil properties, and their effects on crop yield in long-term field cultivation under mono- and rotation-cropping systems (MCS and RCS, respectively). The analytical results of the soil properties showed that the application of mineral fertilizers alone in the MCS leads the reduction of soil CEC, exchangeable Ca, and microbial biomass C and N. Compared with the MCS of soybean, the RCS of soybean and barley significantly improved the soil properties, which increased crop yield. It might be due to the barley residue added to the RCS soil. Mean nutrient balances for 4 years were -55.9 kg N, +34.7 kg $P_2O_5$, and -0.3 kg $K_2O$ $ha^{-1}$ for the MCS and +19.7 kg N, +107.4 kg $P_2O_5$, and -48.6 kg $K_2O$ $ha^{-1}$ for the RCS, respectively. These nutrient imbalances mean that conventional fertilizer recommendations were inadequate for maintaining soil nutrient balance. From these results, we can conclude that the crop rotation may change comprehensive physical, chemical, and biological soil properties. These changes could affect the nutrient balance and then the crop yield.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.553-557
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• 2014

The steady increase in livestock industry has greatly required the stable production of food and forage crops. As an alternative, rice-forage cropping system has been attempted in several southern areas. The present study was performed to understand whether an application of cattle-manure compost affects soil chemical properties and crop productivity in rice-forage cropping system, rice ${\rightarrow}$ summer oat ${\rightarrow}$ rye, in Jangheong county, south Jeolla province from 2013 to 2014. Treatments was composed of control (no compost), CM1 (compost application before rice transplanting), and CM2 (two-times compost application, before rice transplanting and after rice harvest), and inorganic fertilizers (N, P, and K) were equally dressed in all plots. Yields of rice were not significantly different between treatments, however, oat production was 1.25-fold higher in CM1 and CM2. Nutrient uptake amounts of rye were higher in CM2 than CM1 and control. Total nitrogen in soil was maintained stable level during crop cultivation. And soil organic matter contents in all treatments were increased by crop residue. Available P_2O_5$ and exchangeable K were increased by cattle manure application. Therefore, it suggested that the amount of nutrient by forage crop residue should be considered in rice-forage multiple cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.450-455
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• 1996

In this study isolation and identification of squalene from amaranth and antineoplastic activity of its residue extract except squalene were determined to examine the utilization of grain amaranth in Korea. The content of squalene in amaranth grain was about 0.43%. The isolated squalene showed 99% pureness containing the identical molecular weight and structure provisionally in comparison with that of animal squalene from Sigma Co. by means of GC /Mass spectrum. Antineoplastic activity against human gastric and colon carcinoma cell line was measured in extract (except squalene) from Amaranth using MTT method. Extract from remaining plant good showed significant cytotoxic effect at the concentration of less than 230$\mu\textrm{g}$/ml.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.195-203
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• 2015

Quintozene, pentachloronitrobenzene (PCNB) is a contact fungicide for control of soilborne phytopathogenic fungi during cultivation of diverse crops. It was introduced to agricultural use around 1930's as a substitute for mercurial disinfectants. Although quintozene had been first registered in Korea on 1969. However, now it was banned to use due to its high residue levels in selected harvest products. Also, high possibility is expected that the residue may be contained in imported agricultural commodities as it is still used widely over the world. Therefore, this study was conducted to establish a determination method for quintozene residue in crops using GC/ECD/MS. Quintozene residue was extracted with acetonitrile from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and n-hexane partition was followed to recover quintozene from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The quintozene was quantitated by GLC with ECD, using a DB-1 capillary column. The crops were fortified with quintozene at 3 levels per crop. Mean recoveries ranged from 79.9% to 102.7% in five representative agricultural commodities. The coefficients of variation were less than 4.3%. Quantitative limit of quintozene was 0.004 mg/kg in representative five crop samples. A GC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of quintozene in agricultural commodities.