• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.261-261
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• 2017

This study was carried out to provide basic data for spreading rice direct seeding by inducing stabilization of seedlings, yield and quality according to sowing times in rice direct seeding cultivation. In 2016, 'Sukwang' was seeded 3 times by 10 days interval on May. 10, 20, 30 and 6kg/10ha of seeding rate respectively in Iksan. In summary, the number of rice seedling establishment was higher than the optimum seedling establishment level at all sowing periods and the seeding rate was better as the sowing period was delayed. Weed development by sowing was the highest at early sowing, May 10, and decreased at late sowing. Heading dates were delayed by 3days for sowing on May 10, 7days for sowing on May 20, and 11 days on sowing on May 30. Rice yield increased with the delay sowing time and compared to the transplanting. It was 84% in sowing on May 10, 94% in sowing on May 20, and 99% in sowing on May 30. In addition, head rice ratio and head rice yield increased according to delayed of seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.159-164
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• 1973

This study was carried out in the central part of Korea for three years from 1970 to 1972. Its aim was to investigate the variations of growth and yield of rice varieties of different cultivating methods (transplanting culture, direct sowing culture on irrigated paddy field, and direct sowing culture on non-irrigated paddy field. The results could be summarized as follows; 1. The number of days from sowing to heading by direct sowing culture on irrigated paddy field was remarkably shorter than transplanting culture. Direct sowing culture on non-irrigated paddy field was longer than transplanting culture. 2. The number of panicles showed direct sowing culture on irrigated paddy field was first, direct sowing culture on non-irrigated paddy field was second, and third transplanting culture. But the number of spikelets per panicle was first on the transplanting culture, second on the direct sowing culture on non-irrigated paddy field and third on the direct sowing culture on irrigated paddy field. 3. The weight of the brown rice showed that direct sowing culture on irrigated paddy field produced the highest yield among the cultivating method in all varieties. The transplanting culture increased more than the direct sowing culture on non-irrigated paddy field. The highly productive varieties were Sadominory, Akibale, Suwon 213-1 when the direct sowing culture on irrigated paddy field was used. 4. The correlation between the brown rice yield and the yield components were as follows; in each cultivating method, it showed highly significant positive correlation between the brown rice yield and the 1, 000 grain weight of hulled rice, and between the brown rice yield and the number of the spiklets per panicle in the transplanting culture, in the direct sowing culture On irrigated paddy field between the brown rice yield and the number of spikelets per panicle and between the brown rice yield and the number of panicles, in direct sowing culture on non-irrigated paddy field between the brown rice yield and number of panicles. 5. It showed highly significant negative correlation between the brown rice yield and the number of days from sowing to heading in the direct sowing culture on irrigated and non-irrigated paddy field, but it was showed very low negative correlation in the transplant culture.

• Journal of Plant Biology
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• v.13 no.1
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• pp.1-12
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• 1970

The Nongkwang variety was sown directly in the field by the three methods of dibbling, drill seeding and broad-casting in non-, low- and high-salty areas, and compared with the growth of transplanted rice in each areas. The yield of rough rice was increased remarkably by direct sowing when compared with that produced by transplanting inboth salty areas, but in non-salty area, the former was decreased significantly. There was no significant difference in the yields of rough rice resulting from three seedling methods of direct sowing in each area. The direct sowing method was predominated in number of panicle, weight of panicle, ratio of matured grains, milling recovery percentage, and straw weight in both salty areas, and dicreased in panicle weight and ratio of matured grain in nonsalty area.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.999-1008
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• 1996

The development and improvement of the originally designed direct rice sowing machine were carried out for the specific purpose of saving labor and increasing the efficiency of field operations in rice cultivation in the northern part of Japan. the prototype super wide spreader has a unique mechanism which propels rice seeds by compressed air and spreads them from the pivoting nozzle while the machine is in motion. The effective field capacity of sowing operation is about 6 ha/h. This spreader can also handle granular chemicals such as fertilizers, herbicides, pesticides and insecticides.

• The Journal of Natural Sciences
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• v.5 no.2
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• pp.49-62
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• 1992

This study was carried out to investigate the emergence, growth and yield components in rice inassoccation with Several cultivation methods direct sowing flooded paddy field(DSF), direct sowing by airplane(DSA), direct sowing in dry paddy field(DSD), 8days seedling planting(8DS), and 35days seedlingplanting(35DS). Also this study was attempeted to know the effects of calcium peroxide on germinationand early growth of rice under different soil conditions, seeding depth, application of organic matter,indirect sowing flooded paddy field.1. Rate of emergence was 73% in DSF, 70% in DSA, 62% in DSD, respectively, under the different cultivation method of rice in reclaimed paddy field.2. Degree of lodging in relation to cultivation was 5 at both DSF and DSA, 3 at DSD, 2 at both 8DS and 35DS respectively.3. Maximum tiller number was 568 per m2 at DSF and 527 at DSA. Heating was delayed for 4 days at DSF, 8 days at DSD and 2 days at 8DS as comparison with that at 35DS.4. Yield was higher 1% to 3% at DSF than that at DSA and DSD while decreased by 12% as compared with that of seedling planting.5. Total dry weight of seedling was decreased by 57% at 8DS, 60% at DSF 63% at DSD, respectively, under 0.3% of salinity. Ratio of decreasing in dry weight was higher with high salinity.6. The amount of O2 released was recorded highest to 2 to 3days after irrigatition, thereafter remaining constant to 10 days after irrigatition.7. The optimum coating amount of calcium peroxide for germination was a half of rice seed weight with 1 cm sowing depth and one-fold with 2-cm sowing depth when rice straw was not applied. With rice straw applied, on the other hand, the amount of peroxide was one-fold with 1-cm sowing depth. It was found that, under the condition of applied 600kg/10a, of 2-cm soil depth with rice straw calcium peroxide coating had no effect on emergence of rice seedling.8. In reclaimed paddy field, lodging degree was 7 with direct sowing by machine and 9 with direct sowing by hand.9. Yield was increased by 5% by applying rice straw with direct sowing by machine.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.221-224
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• 1999

A field experiment was carried out to observe the weed control effects of vetch and to evaluate vetch characteristics on clay loam soil in no-till direct-sown rice-vetch cropping systems. The effects of weed control, forage productivity, and N content of vetch plants were investigated. With the progress of plant growth, density of Chinese milk vetch (Astragalus sinicus L.) gradually decreased, but densities of foxtail and other weeds decreased steeply due to the depression by the over-shaded vetch canopy in a no-till direct-sown rice-vetch cropping paddy field. The vetch density in tillage systems was lower than in notillage cropping systems. Lower vetch density occurred with an increase in foxtail density and other weeds. Weed control effect increased by the progress of vetch growth, which indicated that the vetch canopy over-shaded the weeds. Vetch straw was degraded rapidly submergence after with water at the time of wet sowing of rice. Early harvesting of vetch seed resulted in lower seed germination. To acquire enough seedlings without re-sowing, the harvesting of seed should be delayed at least 28 days after the flowering stage in order to ensure the vetch population is sustainable in a no-till direct-sown rice-vetch cropping system. In order to improve the survival of vetch plants, vetch seeds should germinate from the heading .stage to before the full-ripening stage of rice plants. To enhance the percent of over-wintering survival, vetch seeds should germinate no later than the end of October in southern Korea. The dry weight of vetch plants increased with the progress of vetch growth until the flowering stage but N content decreased for 30 days from before the flowering stage (2.9%) until the ripening stage (1.8%). We concluded that Chinese milk vetch could have an effect on weed control before the flowering stage, sustainability without re-sowing of seed annually, and effective green manure for rice pre-crop in no-till direct-sown rice-vetch relay cropping systems.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.1-11
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• 1998

This experiment was conducted to investigate weed infestation and to determine effective weed control methods in direct-seeded rice. Twenty two weed species occurred in dry- and water-seeded rice, which was mainly composed of annual weeds. Dominant weed species in dry-seeded rice were Cyperus difformis, Echinochloa crus-galli, Aneilema keisak and Digitaria sanguinalis in discending order. Dominant weed species in water-seeded lice were E. crus-galli, C. difformis, Monochoria vaginalis and Scirpus juncoides. E. crus-galli emerged at 7 days after sowing. In water-seeded rice, E. crus-galli emerged at 5 days after sowing, and M vaginalis, S. juncoides and C. difformis at 8~10 days after sowing. Mean days to emerge important weeds was 20 days in dry-seeded rice and 13 days in water-seeded rice. Leaf development of weeds was faster than that of rice in dry-seeded rice. In water-seeded rice, E eras-galli was more vigorous than rice, but leaf development of other weeds were slower than that of rice. Changes in number of weeds and dry weight oil weed species varied depending upon weed species in the direct-seeded rice. Dry weight of weeds were increased greatly from 30 days to 60 days after sowing in dry-seeded rice. Number of weeds tended to increase up to 40 days after sowing drastically, and then trend of the increase was dull thereafter. Dry weight and number of weeds increased up to 20~60 days after sowing in water-seeded rice. Most effective herbicide treatments was foliar application of cyhalofop/bentazon at 20 days after sowing followed by fenoxaprop/bentazon at 45 days after sowing in dry-seeded rice. All herbicide treatments except foliar applications were very effective to control weeds in water-seeded rice. Slight phytotoxicity was observed in foliar applied fenoxaprop/bentazon at 45 days after sowing in water-seeded rice, but it did not affect rice yield.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.97-101
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• 1999

No-till direct seeding cultivation of rice has major advantages such as saving of labor and cost by eliminating tillage, preparation of seed bed and trans-planting procedure compared to the conventional transplanting cultivation. A field experiment was conducted to evaluate the effects of straw treatment and nitrogen levels on the rice growth in no-till direct-seeding cultivation. Rice straw, vetch straw, and the mixture of both of the straws were mulched on the surface of soil before seeding while 4 levels of nitrogen fertilizer, 0, 7, 9, and 11 kkg/10a respectively, were applied at 3 split times, 3-weeks after sowing, 5-weeks after sowing and the panicle initiation stage. Mulching of vetch straw significantly reduced seedling establishment of rice which may be attributed to low oxidation-reduction potential of soil by vetch mulching treatment. Vetch straw increased the concentration of soil ammonium leading to an extension of the greenish leaf to panicle initiation stage. Agronomic nitrogen use efficiency (AD $E_{N}$) in heavy-mixed straw mulching plots was lower than other treatments. Grain yield and AU $E_{N}$ in the vetch treatment were less affected by fertilized N levels. Conclusively, it is suggested that heavy straw mulching was not efficient for rice seedling establishment and nitrogen usage.e.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.189-195
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• 1999

Under the no-till direct-sown rice-vetch cropping systems, where whole chopped rice straw were returned to the paddy surface at combine harvest and whole-plant of Chinese Milk Vetch(Astragalus sinicus L.) was submerged after direct-sowing, three levels of nitrogen top-dressed(0, 2, 4 kg N/10a) without basal N and two levels of sowing rate were applied into the paddy field in expectation of the enhancement of nitrogen efficiency and protection of agricultural environment in reduced N-fertilizer level. A cultivar, Dongjin, was direct-sown on May 30, 1996. Characteristics of rice growth and physicochemical properties of rice plant were observed. Under the system, reduced total N(4 kg N/10a) resulted in high panicle numbers. N-top dressed toward at later growth stages enhanced the ratio of panicle-producing tillers and at spikelet numbers per panicle. As N-level increases, DM yields of leaf and stem at heading were increased. Maximum grain yield was obtained at 4kg N/10a and major attributed factors to grain yield in this case were the number of grains per unit area and the ratio of ripened grain.