• Korean Journal of Organic Agriculture
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• v.9 no.3
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• pp.45-71
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• 2001

The duck-rice forming system is increasingly spread up throughout Korea since 1992. It is discussed the rice field, rice quality, weed and pest management in the duck-rice weeding system compared to conventional farming system. Moreover the optimizing duck population, system management and fertilizer application rate were reported. Energy input and output by duck-rice farming system were carefully compared with those of low input sustainable paddy field and conventional farming paddy field. To find out the environmentally sound function of duck-rice system, the total nitrogen in paddy soil and paddy water, and nitrogen cycle in paddy rice cultivation system were analysed. finally the input and output were calculated, and ecological characteristic were determined in terms of nitrogen balance, labor input, animal input, renewable energy input, turnover of soil organic matter, energy loss, non-renewable indirect and direct energy input. It was concluded duck-rice weeding system could be recommended in terms of net only environmentally sound, but also farmer's income. But there are still some research needs for successful adaption of duck-rice farming to investigate to determine the optimal population of duck in rice paddy field unit, release time of duckling, duck management after release, and strategy for duck marketing and duck processing.

• Korean Journal of Organic Agriculture
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• v.13 no.3
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• pp.291-300
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• 2005

Diseases were surveyed in 5 Rice paddy field areas of Organic paddy field and conventional paddy field. The 3 major diseases, rice leaf blast, bacterial leaf blight and sheath blight in rice were surveyed at duck raising, rice bran and conventional rice paddy field. They were serious in duck raising paddy field, rice bran paddy field more than conventional paddy field. The Ilpum variety were infected seriously more than Chucheong. At the effectivity test of the environment-friendly substance for the rice-seed sterilization, 1000-times diluted brown-rice vinegar showed controlling effect against Bakanae disease, and germination rate also was good. There was no Weeds Control efficacy by cultivating of hairy vetch in rice paddy field. However, extract of hairy vetch Leaf and root repressed the germinating of lettuce seed.

• Korean Journal of Organic Agriculture
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• v.13 no.3
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• pp.301-314
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• 2005

Insect pests were surveyed in 5 Rice paddy field areas of Organic paddy field and conventional paddy field. At the each rice-growth period, the occurrence rate of 'Small brawn plant hopper was high at the case of duck raising and rice bran farming on middle stage of rice paddy field in Gang-Hwa region. The occurrence rate of Rice water weevil was high at the conventional paddy field on the early stage of rice paddy field in Yeo-Ju region. In the Hong-Seong region, the occurrence rate of 'Rice water weevil' and 'Green rice leafhopper' was high at the 'duck raising compare to the conventional farming on the early stage of rice paddy field. According to each period, the occurrence rate of insect was high at late stage of rice paddy field, and there was no difference between each region. It showed high-occurrence tendency at duck pasture farming rice paddy field. The major natural enemies were spiders and parasites. Theridiidae and Linyphiidae were highly occurred on the conventional farming rice paddy field in Hong-Seong. Web builders containing Theridiidae, Linyphiidae and Tetragnathidae was occurred more than wandering spiders containing Lycosidae, Clubionidae and Pisauridae at various regions, and then occurrence of spiders was different at the various regions but was not different at each farming system.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.91.2-92
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• 2003

In order to elucidate influence of nutritional status on rice brown spot caused by Cochliobolus miyabeanus, rice cultivation soils and rice straws were collected from paddy fields where ice brown spot occurred severely, moderately, a little and none respectively. Rice plant materials were analyzed to measure inorganic nutrients in rice straws and rice seeds. Analysis of chemical properties of rice paddy soil showed that EC and contents of available phosphate, cation and silicic acid in soil with severe infections were lower than those in healthy soil. This result suggests that amount and holding capacity of nutrient contents in soils collected from paddy field with infection of C. miyabeanus are relatively low compared to those in soils collected from healthy paddy field. Analysis of inorganic nutrients in rice straws showed that amount of macronutrient elements such as silicic acids, available phosphate and total nitrogen, and micronutrients such as copper, iron and zinc in rice straws from paddy field with infection were lower than those in healthy soil. Especially amount of iron and silicic acid were very low in rice straws from paddy field soils with infection Amount of inorganic nutrients such as iron and zinc in rice seeds was the same trend as those of rice straws. These results showed that one of major factors affecting rice brown spot was amount of nutrient contents in soil and rice straw.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.98-104
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• 2010

Excess nitrogen (N) uptake of rice, which could cause much lodging, disease and reduction of rice quality, could be occurred at the paddy field with previous upland condition at which much soil N could be mineralized by soil-drying effect. N fertilizers of 0, 3, and 6 kg N $10a^{-1}$ were applied to early-maturity rice, cultivar Joanbyeo at the paddy field of first and second year after upland condition, and rice growth and nitrogen uptake were investigated to know the increase of rice N uptake at the paddy field with previous upland condition for one-year. Total dry matter (DM) and N uptake of rice at the paddy field with previous upland condition increased more than continuous paddy field. Total DM and N uptake of rice at the paddy field with previous upland condition increased linearly to N fertilizer 6 kg $10a^{-1}$ at the paddy field owing to vigorous growth compared to continuous paddy field. Rice N uptake was higher at the paddy field of the first year than the second year after upland condition in considering N uptake at the plot of no N fertilizer. Vigorous growth at the paddy field with previous upland condition resulted in higher rice yield which was related with high panicle and spikelet, but much N fertilizer as much as 6 kg $10a^{-1}$ at the paddy field with previous upland condition resulted in higher lodging and protein content of brown and milled rice. Particularly, protein content of brown and milled rice increased more when the same N fertilizer was applied two times splitly at transplanting and panicle initiation stage than when N fertilizer was applied one time at transplanting as basal N. N application with under 3 kg $10a^{-1}$ as only basal N was recommended at the paddy field with previous upland condition to obtain high quality rice without lodging.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.352-352
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• 2017

Recently, the South Korean government encourages the cultivation of upland crops in the paddy field to maintain an adequate level of rice production and then to balance the demand and supply of rice. This is mainly because the rice consumption per capita per year has continued to decline from 135 kg in 1979 to 61.9 kg in 2016, although the rice production was relatively stable. As a result, the rice overproduction became a big social problem. As a part of that, various upland crops such as soybean, maize, minor cereals and forage crops are planted in the paddy field 10 years ago. The cultivation of these crops may settle the problem of short supply and mass import of the crops to some extent. However, a systematic remote observation of upland crops in the paddy field is very scarce. This study investigated the cultivation status of upland crops and any changes of crop harvesting in the paddy field by using an unmanned aerial vehicle (UAV). Also, we analyzed the kind of upland crops and cultivation area in the paddy field by utilizing time series observation images. A fixed wing UAV is used for the investigation. This is because it is easy to use the flight operation and to control flight management software, and it can automatically cope with various emergency states such as a strong wind and battery discharge. The material of UAV is expanded polypropylene, which has an advantage of less equipment damage and risk during takeoff and landing. We acquired observed images in Buljeong-myeon, Goesan-gun, Chungcheongbuk-do, South Korea by using fixed wing UAV in 2015 and 2016. The total investigated area reaches 6,045 ha, and among them the agricultural area was 1,377 ha. For the next step, we created an orthoimage from all images taken using Pix 4D mapper program. According to the results of image analyses in 2015, the paddy field covered total 577 ha (75.9%) with crop plant. The cultivation area of beans, ginseng, maize, tobacco and peach was 256 ha (36.6%), 63 ha (9.2%), 37 ha (5.4%), 31 ha (4.5%) and 27 ha (3.8), respectively. And in 2016, the total covered area was 586 ha (77.1%), and it was comprised of 253 ha (35.5%), 88 ha (12.3%), 29 ha (4.1%), 22 ha (3.1%) and 32 ha (4.5%) in the same order. In this study, we focused on identifying the paddy field which was converted to the cultivation of upland crops by using UAV. And, it has been indicated that the cultivation area of rice decreased from 141 ha in 2015 to 127 ha in 2016, although that of ginseng increased by 25 ha. As a result, it is expected that a lot of paddy field could be replaced by high-income crops such as ginseng and fruit tree (peach) instead of relative low-income rice. More specific and widespread research on the remote sensing in the paddy field needs to be done.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.429-433
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• 2001

This study was carried out to investigate the occurrence and characteristics of off-type rice plant according to agronomic conditions. The occurrence density of the off-type rice plant in farmer's paddy field was greater as the years of self-produced seed use increased, and in the direct sowing paddy field it was twice as much as in the transplanting paddy field. When the long-grain red rice and the short-grain red rice in the cultivated field of cultivar were artificially sown, in the direct sowing on a flooded paddy surface culture rather than in the machine transplanting culture the off-type rice plant occurred much more, the culm length was longer, and the number of productive culm per plant increased. These characteristics were more conspicuous in the long-grain red rice than in the short-grain red rice. In the transplanting farmer's paddy fields, the off-type rice plant that occurred outside of the hills of the cultivar rice ranged 0 to 6%. Whereas in was 70.6 to 91.9% when the long-grain red rice and short-grain red rice were artificially sown. Therefore, it was assumed that most of the off-type rice plants occurred in the farmer's paddy fields was caused by seed contamination.

• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.268-273
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• 2005

This study was conducted to investigate the specificities of four fulcrum types for geo-statistical analysis of elevation within rice paddy field. In Korea, the spaces between inter-rows and between hills for rice transplanting are 30cm and 11cm to 14cm, respectively. So, the size and shape of fulcrum for field elevation measurement should be considered according to the inter-row and the hill spaces. Four kinds of fulcrum were chosen such as round-shape with 2.5cm diameter, circular-shape with 10cm diameter, 10cm (one third of inter-row space) by 24cm (double of hill space) rectangular-shape, and 20cm (two-thirds of inter-row space) by 24cm rectangular-shape. The resulting descriptive statistics couldn't determine the best fulcrum type to measure the rice paddy field elevation. But the results of geo-statistical analysis could determine the best fulcrum type. In the case of 10cm by 24cm rectangular-shape fulcrum, Nugget and range, meaning measurement error and/or noise, and limit of spatial connection, respectively, were minimum; Q value meaning weight of spatial structure and $r^2$ value were minimum, and residual sum of squares was minimum. It means that 10cm by 24 cm rectangular-shape fulcrum could best describe the rice paddy field elevation.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.187-192
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• 2010

In order to monitor the possibility of horizontal gene transfer between transgenic rice and microorganisms in a paddy rice field, the gene flow from a bifunctional fusion (TPSP) rice containing trehalose-6-phosphate synthase and phosphatase to microorganisms in soils was investigated. The soil samples collected from the paddy rice field during June 2004 to March 2006 were investigated by multiplex PCR, Southern hybridization, and amplified fragment length polymorphism (AFLP). The TPSP gene from soil genomic DNAs was not detected by PCR. Soil genomic DNAs did not show homologies on the Southern blotting data, indicating that gene transfer did not occur during the last two years in the paddy rice field. In addition, the AFLP band patterns produced by soil genomic DNAs from both transgenic and non-transgenic rice fields appeared similar to each other when analyzed by the NTSYSpc program. Thus, these data suggest that transgenic rice does not give a significant impact on the communities of soil microorganisms, although long-term observation may be needed.

• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.337-339
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• 2005

In Iksan, Korea, Parnara guttata Brener et Grey spend three generations per year, 1st generation adult emerged mid to late May from pupa developed from overwintered larva in weeds on bank around rice paddy field or on hillside and moved to rice paddy field to lay eggs on leaves of rice. The damage to rice by 2nd generation larva began to increase late July and reached peak from mid to late August. The 3rd generation adults were observed early to mid September and flew away from rice paddy field. There was significant relationship between the transplanting time and the occurrence of P. guttata in rice paddy fields. P. guttata preferred the rice transplanted in late season in paddy field. Insecticide treatment on late July about a week before the peak larval occurrence reduced the damage by P. guttata up to 91.2%, whereas the treatment on early August was a lot less effective reducing only 57.2% of the damage.