• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.370-375
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• 1996

This study was conducted to find out the feasibility in direct seeded rice cultivation on the reclaimed saline soil. Seedling emergence was tested under the different application rates of rice straw and seeding depth, and also under combined treatments soil moisture regimes and seeding depth on saline soils in a greenhouse. The comparison of seedling stand and yield performance of rice in rotary till after broadcast seeding and in non-plow after broadcast seeding were tested on a field that reclaimed saline soil. Seedling emergence ratio in application of rice straw(4 and 6 tons /ha) was higher than that in non-application of rice straw. Seedling emergence and plant height were remarkably increased with the shallow seeding depth in the application of rice straw(4 tons /ha). The seedling emergence under proper soil moisture condition(25%) was higher than that under excess soil moisture condition(35%). Under proper soil moisture condition, the plant height was increased with the shallowed seeding depth. The number of seedling stand per m$^2$ in non-plow after broadcast seeding was larger than that in rotary till after broadcast seeding. Panicle number per m$^2$ in non-plow after broadcast seeding was much larger than that in rotary till after broadcast seeding and the yield showed the same trends as panicle number.

• Journal of Practical Agriculture & Fisheries Research
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• v.12 no.1
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• pp.29-38
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• 2010

This research was conducted to improve a hill seeding technology under puddled wet soil condition for direct seeded rice. There were severe constrains in hill sowing method under puddled wet soil such as a bird damages, dryness of seeds sown due to strong sunlight in May and buoyancy of seeds and young seedlings after raining and irrigation particular under strong wind. Thus, we have adopted a sandy type(<2mm) silicate covering method in Bokto drill seeding technology for a hill seeding method as well. The average silicate amount in order to cover seeds sown was of 840kg/ha which was evaluated to a proper volume for those problem solution and farmer's handling during sowing operation. In this experiment there was an additional problem like a precious hill drop of rice seeds, covering of silicate over hill seeded rice and seed broken during roller operation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.151-159
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• 2012

Direct seeding of rice is a time- and laborsaving method, compared to machine transplanting. However, the area planted to direct-seeded rice is decreasing because of instability of seedling establishment, lodging, occurrence of weedy rice, and deterioration of grain quality. A newly developed wet-hill-seeding of rice, a type of direct seeding method, has shown features of growth similar to machine transplanted rice. This study was carried out to compare tillering pattern, heading characteristics and grain filling traits between transplanting and wet-hill-seeding in rice. Tillering of wet-hill-seeded rice was more vigorous than that of transplanted rice showing maximum tiller number 30~100% higher than transplanted rice. Wet-hill seeded rice showed later heading and shorter heading duration than transplanted rice. To find out the relationship between heading characteristics and grain filling traits, every panicle was tagged for flowering date, and the panicles on each heading date were inspected for grain filling traits. Wet-hill seeded rice and transplanted rice exhibited no significant difference in culm length, panicle length, the percentage of grain filling and perfect brown rice on each heading date during total heading period. Therefore, we conclude that wet-hill-seeding method is not inferior to machine transplanting in terms of seedling establishment, growth, grain filling and head rice yield.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.8-14
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• 1996

Use of phosphate coated urea to decrease ammonia volatilization from directly seeded paddy under dryland condition at early stage was tested. Effect on urea hydrolysis was investigated through laboratory study comparing with use of thiourea, a urease inhibitor, under different water content. A field measurement of volitilized ammonia with phosphate-glycerol ammonia absorber was conducted for surface treated urea, phosphate coated urea, phosphate coated slow-release fertilizer and organic fertilizer. Through laboratory study, hydrolysis rate of phosphate coated urea at three days after treatment was lower than that of urea, however, the rate after one week was same. Thiourea addition retarted urea hydrolysis. By field measurement, ammonia volatilization was effectively reduced by use of phosphate coated urea.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.292-300
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• 1996

This experiment was conducted to investigate the factor of phytotoxicity for herbicides(bensulfuron methyl, pyrazosulfuron-ethyl, dimepiperate, molinate) on flood direct-seeded rice. The phytotoxicity of herbicides was evaluated under controlled environment condition. Bensulfuron methyl and pyrazosulfuron-ethyl reduced more rice growth, especially root growth on low temperature(20/$11^{\circ}C$) than high temperature(30/$22^{\circ}C$) cultivations. The phytotoxicity of bensulfuron methyl and pyrazosulfuron-ethyl were increased relatively by non-nutrient and nutrient solution. cultivation, respectively. The rice applied bensulfuron methyl and pyrazosulfuron-ethyl with pH 3.5, 5.5, 7.5 and 9.5 solution became low growth rate on low pH of pH 3.5 and 5.5 solution cultivation. Bensulfuron methyl application with pH 5.5 and pH 7.5 solution, and pyrazosulfuronethyl application with pH 7.5 and 9.5 solution reduced rice growth inhibition. The root growth of rice seeded in 6cm depth of water solution applied herbicides was suppressed by bensulftuon methyl and pyrazosulfuron-ethyl, the growth of shoot was suppressed heavily by dimepiperate and molinate, in particular dimepiperate suppressed about the growth of 90%. The phytotoxicity of pyrazosulfuron-ethyl became high on light clay soil of non-fertilizer condition and sand loam soil of fertilizer condition, bensulfuron methyl became high on sand loam soil.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.219-224
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• 2016

This study was conducted to investigate the ecology of weed occurrence and to establish an economical paddy field weed control system for direct-seeded rice on water. The main problem weed among annual and perennial weeds was Eleocharis kuroguwai. The control effect of E. kuroguwai was low by the application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice in directly seeded paddy fields, but most annual weeds including Echinochloa crus-galli were controlled. Also, the additional application of pyrazosulfuron-ethyl + thiobencarb GR at 20 days after first treatment or of bentazone SL at 43 days after the first treatment effectively controlled E. kuroguwai. Tuber formation of E. kuroguwai was inhibited by the additional application of pyrazosulfuron-ethyl + thiobencarb by 84%, but the dormancy rate of old tubers of E. kuroguwai under the soil was higher than that of E. kuroguwai tubers following single application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice. Tuber formation was inhibited by the additional application of bentazone by approximately 87%, and the old tuber dormancy rate was low in the bentazone treatment. High amounts of old dormant tubers of E. kuroguwai were found in the weedy plots.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.362-366
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• 2022

This study was conducted to find out the changes in the growth and yield of ginseng and the changes in the soil of direct-seeded ginseng fields after applying different compaction strengths. As a result of surface soil compactions, the topsoil hardness increases as the strength of treatment increases in the first year but topsoil hardness increased only by applying 30 kg weight of compaction in the second year. The germination rate was significantly higher (79.4% and 79.1% at 25 kg and 30 kg, respectively) in 1st year after the application of soil surface compactions. The longest plant was 35.7 cm in 4- years old ginseng in the control and the height was 26.9 cm and 26.5 cm in the soil surface compactions of 25 kg and 30 kg, respectively. In addition, the higher weight of ginseng roots of 31.3 g and 30.3 g were observed after applying 25 kg and 30 kg compaction treatment, and the lowest root weight of 25.6 g was in the control. Therefore, it is shown that after sowing, applying the weight of 25 kg to 30 kg for soil surface compaction is appropriate for better yield in direct seeded cultivation of ginseng at paddy fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.230-235
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• 1999

To study the effects of an urease inhibitor, N-(n-butyl)-thiophosphoric triamide (NBPT), and a nitrification inhibitor, dicyandiamide (DCD), on nitrogen losses and nitrogen use efficiency, urea fertilizer with or without inhibitors and slowrelease fertilizer (synthetic thermoplastic resins coated urea) were applied to direct-seeded flooded rice fields in 1998. In the urea and the urea+DCD treatments, NH$_4$$^{+}$ -N concentrations reached 50 mg N L$^{-1}$ after application. Urea+NBPT and urea+ NBPT+DCD treatments maintained NH$_4$$^{+}$ -N concentrations below 10 mg N L$^{-1}$ in the floodwater, while the slow-release fertilizer application maintained the lowest concentration of NH$_4$$^{+}$ -N in floodwater. The ammonia losses of urea+NBPT and urea+NBPT+DCD treatments were lower than those of urea and urea+DCD treatments during the 30 days after fertilizer application. It was found that N loss due to ammonia volatilization was minimized in the treatments of NBPT with urea and the slow-release fertilizer. The volatile loss of urea+DCD treatment was not significantly different from that of urea surface application. It was found that NBPT delayed urea hydrolysis and then decreased losses due to ammonia volatilization. DCD, a nitrification inhibitor, had no significant effect on ammonia loss under flooded conditions. The slow-release fertilizer application reduced ammonia volatilization loss most effectively. As N0$_3$$^{[-10]}$ -N concentrations in the soil water indicated that leaching losses of N were negligible, DCD was not effective in inhibiting nitrification in the flooded soil. The amount of N in plants was especially low in the slow-release fertilizer treatment during the early growth stage for 15 days after fertilization. The amount of N in the rice plants, however, was higher in the slow-release fertilizer treatment than in other treatments at harvest. Grain yields in the treatments of slow-release fertilizer, urea+NBPT+ DCD and urea+NBPT were significantly higher than those in the treatments of urea and urea+DCD. NBPT treatment with urea and the slow-release fertilizer application were effective in both reducing nitrogen losses and increasing grain yield by improving N use efficiency in direct-seeded flooded rice field.field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.495-501
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• 1994

This experiment was carried out to investigate the proper seeding methed for direct seeding culture of rice in puddled soil at ill-drained paddy field. Mangeumbyeo was seeded on May 11 with drill seeder attached to cultivater, dibbling seeder attached to transplanter and power dust blower. And to determine the proper flooding time after seeding, Mangeumbyeo was seeded on May 7 and June 1 with drill seeder. Emergence ratio wasn't significantly different between drill seeder seeding and dibbling seeder seeding but emergence was very low with power dust blower. Working hour for seeding was shortened in the order of power dust blower, drill seeder and dibbling seeder, and these seeding methods saved the working hour remarkably compared with machine transplanting of infant seedling by omitting the procedures of raising seedling and transplanting. Lodging occurred slightly in all seeding methods. However, yield wasn't significantly different between machine transplanting of infant seeding and direct seeding culture in puddled soil except power dust blower. When field was flooded on seeding date, the emergence period was shortened, emergence ratio was increased and weed occurrence was decreased. Yield was highest when flooding was done on seeding date as the number of panicle per m$^2$ and the number of spikelets per m$^2$ were higher than any other flooding time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.84-88
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• 2001

Two methods of nitrogen application at the 4th leaf stage were evaluated in direct-seeding rice cultivation on dry paddy soil: one was the top dressing of nitrogen on dry paddy condition before irrigation (TNDP) for labor saving, and the other was the top dressing of nitrogen on dry paddy with mechanical rotavation of the inter-row space (TNDPIR) for increasing the efficiency of nitrogen. To evaluate these two application methods, leaf chlorophyll contents, growth characteristics and yields were compared with two conventional methods, basal application (BA) and top dressing on flooded paddy condition at the 4th leaf stage (TNFP). The SPAD value of rice in TNDP was similar with that in TNFP throughout the whole growth stage of rice. Also, there were no differences in rice growth and yield between the two methods. However, in TNDPIR, the SPAD value was the highest during tillering stage among the four application methods, and the tiller number, LAI at heading stage and the panicle number were higher than the two conventional methods.