• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.31 no.2
• /
• pp.204-213
• /
• 1986

The objective of this paper was to examine the response of rice seedling emergence and early growth under the different temperature (day/night, 29/21$^{\circ}C$, 17/17$^{\circ}C$, 12/12$^{\circ}C$) and the different seeding depth (1 cm, 2 cm, 3 cm). The trial was carried out in the phytotron and field in the Crop Experiment Station, Suwon, Korea in 1985. Calcium peroxide-coated seeds were very effctive in promoting seedling emergence, seedling establishment and eary growth of rice. Coated seeds were more effective in low temperature condition (17/17$^{\circ}C$, 12/12$^{\circ}C$) than in high temperature (29/21$^{\circ}C$) at the phytotron trial. The deeper the seeding depth, the less the emergence and seedling establishment, and the available seeding depth was I cm in the direct seeding under the flooded soil. In the field trial (seeding date, May 1) the results for the emergence and seedling establishment were similar to those in the phytotron trial. Available cultivars for the direct seeding cultivation under the flooded soil were Cheonmabyeo, Namyangbyeo, Kihobyeo, Akibare, Nakdongbyeo and Dongjinbyeo in Japonica type, and Taebaegbyeo, Samgangbyeo and Gayabyeo in Indica x Jponica type. Coefficients of variation to the emergence and seedling establishment between rice cultivars were very high. Therefore, in the direct seeding cultivation under the submerged paddy, choice of rice cultivars and improved technique for direct seeding will be more necessary.

• Korean Journal of Weed Science
• /
• v.14 no.4
• /
• pp.245-251
• /
• 1994

The initial growth and herbicidal responses of Scirpus planiculmis were examined under both laboratory and greenhouse condition. Initial growth of S. planiculmis at two different soils(soil A and B), was compared with the growth at normal paddy soil, and growth rates at two soils were 32% and 86% as compared to the growth rates at normal paddy soil. Two different soils were soil A(rice-uncultivable) and soil B(rice-cultivable). Transplanted(2.5 leaf stage) and direct seeded rice(Dongjinbyeo) could not grow at soil A. The growth of transplanted rice at soil B was almost same as the growth at normal paddy soil, but the growth of direct seeded rice was 50% of the growth at normal paddy soil. S. planiculmis among the perennial weeds was most tolerant to NaCl, and Cyperus serotinus, Eleocharis kuroguwai, Sagittaria pygmaea, Sagittaria trifolia, Potamogeton distinctus were followed. The intial growth rate of S. planiculmis was more rapid than C. serotinus. Cutting types and times of corm reduced 20-40% of the initial growth of S. planiculmis. During the initial growth of S. planiculmis, the growth of S. planiculmis was severly inhibited by the earlier removal of corm from seedlings, and it represents that the corm plays an important role in the initial growth of this species. Bentazone among 14 commercialized herbicides showed the best safety on direct seeded rice and the highest control effect agaist S. planiculmis.

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

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.4
• /
• pp.209-213
• /
• 2006

This study was carried out to investigate the changes in soil chemical properties and yields of crops by rice-soybean rotation cropping system at silt loam soil. There were 4 rotation cropping systems; continuous rice cultivation, annual, biennial and triennial rotation of soybean and rice. There were little change in pH, organic matter, $Ca^{2+}$ and $K^+$ contents with decrease in available phosphate content in the continuous rice cropping. The cropping system of soybean-rice caused to increase in available $P_2O_5$, $K^+$ and $Ca^{2+}$ in the soil after harvest. Content of $NH_4-N$ in the soil also increased after the rotation of soybean than the continuous rice cropping in the soil during the rice growth period. These chemical change in the soil caused to increase rice growth in number of the panicles and the spikelet per square meter. The yield of rice was increased by the rotation with soybean, and was gradually increased in the triennial rotation of soybean and rice. But the yield of soybean was decreased in continuous cultivation for two or three years in the paddy field. It was recommended for annual rotation to prevent the yield of soybean from decrease.

• Korean Journal of Weed Science
• /
• v.11 no.1
• /
• pp.3-10
• /
• 1991

Several rice herbicides were evaluated to determine the herbicidal efficacy on dry seeded paddy rice. The time of herbicide application was within 1 day after seeding(DAS), 18 DAS, and 40 DAS. Under the upland conditions 30 DAS(before permanent flooding) dominant weed species were Echinochloa sp., Digitaria sp., Leptochla sp., weedy rice and other several annual broadleaved weeds belonging to Cruciferae, but after flooding Echinochloa sp., Aeschynomene sp., Eleocharis kuroguwai, Cyperus sorotinus, Ludwigia prostrata, Aneilema japonica were dominat. Early application (1 DAS) of thiobencarb, pyrazolate/butachlor, or chlomethoxyfen/butachlor resulted in very good herbicidal efficacy only during the first 30 days, but not thereafter. Application of propanil+butachlor on 18 DAS did not control the late occurring weeds effectively. Application of bentazone/quinchlorac on 40 DAS successfully suppressed weed growth throughout the remaining rice growing season and showed similar grain yield as hand weeded plot. Weed growth reduced the plant height, panicle number, 1000-grain weight, percent ripened grains, and grain yield of rice by 7, 82, 19, 55 and 87% respectively. There was a positive linear relationship between weed weight and lodging index of rice.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.32 no.2
• /
• pp.93-100
• /
• 2012

We examined the contents of amino acids to provide the basic data for the utilization of white panicled rice (Oryza sativa L., WPR) cultured in reclaimed paddy field of Bigumdo of Korea in 2011. WPR used in this study were collected in 1000 ha of reclaimed paddy field of Bigumdo. Crude protein contents of whole rice have the highest in leaf blade, followed by whole grain, leaf sheath and stem. The contents of total amino acids showed the highest trend in region received the most severe damage, but the lowest trend in region of normal growth. The content of glutamic acid was the highest among amino acids in leaf blade, whole grain, leaf sheath and stem collected in all regions, but the content of methionine was the lowest. Therefore, the contents of amino acids showed a similar level between the region occurred WPR and the region of normal growth. Further research on the nutritional aspects of forage must be performed because nutritive values of WPR were influenced by the degree of damage of WPR.

• Korean journal of applied entomology
• /
• v.49 no.4
• /
• pp.343-349
• /
• 2010

The golden apple snail was introduced to the Korea from Japan as a potential food for people in 1983. It is one of the pests of direct-seeded rice in korea. This study was conducted to investigate rice(Oriza sativa) consumption and the extent of damage by the golden apple snail(Pomacea canaliculata) in direct-sown paddy fields. Food consumption of the golden apple snail was highest at $30^{\circ}C$. When the emergence of the 1st, 3rd, and 5th leave of rice supplied food, the consumption of young(shell height 15mm) and adult golden apple snail(over shell height 30mm) at $30^{\circ}C$ were 19.0/79.8, 11.0/54.5, 5.5/18.5, and 0.0/2.0 individuals, respectively. Young rice seedings(before 5th leaves of rice) are very susceptible to golden apple snail damage because the young, tender leaves and stems favor the snail's feeding habits. The field experiment with four treatments (0, 2, 5 and 10 individuals respectively per 10 $m^2$) was carried out. The most serious yield loss was 16% from the plot with 10 adults released at emergency stage of rice.

• Korean Journal of Weed Science
• /
• v.5 no.1
• /
• pp.24-34
• /
• 1985

To estimate the fundamental situation of weed emergence and it's competition to paddy rice (critical competition period and threshold level) in the southern paddy area in Korea, two rice cultivars (Pungsanbyo and Tongjinbyo) under two cropping periods (Mono- and After-barley-cropping) were experimented. As a result, the dominant weed species (Monochoria vaginalis and Scirpus juncoides Roxb.) and the better emerging conditions (rather at the monocropping and cv. Punsanbyo) were identified. Also, the main components of yield decrease (25-55% of the weed-free check) of both cultivars as affected by weed competition were the number of spikelets, panicle and ripening rate in monocropping, and the ripening rate and grain weight in after-barley-cropping, respectively. Under the situation of combinated dominance with Monochoria v. and Scirpus j. among others, the duration of critical competition periods was enlarged.

• Korean Journal of Weed Science
• /
• v.31 no.2
• /
• pp.134-145
• /
• 2011

The objectives of this study were to investigate fitness difference in growth and rice yield in herbicide-transgenic rice overexpressing Myxococcus xanthus and Arabidopsis thaliana protoporphyrinogen oxidase (Protox) genes and non-transgenic rice. We also aimed to determine whether these fitness differences are related to ALA synthesizing capacity, accumulation of terapyrroles, reactive oxygen species, lipid peroxidation, and antioxidative enzymes at different growth stages of rice. Plant height of the transgenic rice overexpressing M. xanthus (MX) and A. thaliana (AP37) Protox genes at 43, 50, and 65 days after transplanting (DAT) was significantly lower than that of WT. Number of tiller of PX as well as MX and AP37 at 50 and 65 DAT was significantly lower than that of WT. At harvest time, culm length and yield of MX, PX and AP37 and rice straw weight of MX and AP37 were significantly low compared with WT. The reduction of yield in MX, PX, and AP37 was caused by spikelets per panicle and 1000 grain weight, ripened grain, spikelets per panicle, 1000 grain weight, and ripened grain, respectively. On the other hand, 135 the reduction of yield in MX, PX, and AP37 was also observed in another yearly variation experiment. The reduction of rice growth in MX, PX, and AP37 was observed in seedling stage as well as growth duration in field. There were no differences in tetrapyrrole intermediate Proto IX, Mg-Proto IX and Mg-Proto IX monomethyl ester, reactive oxygen species ($H_2O_2$ and ${O_2}^-$), MDA, antioxidative enzymes (SOD, CAT, POX, APX, and GR) and chlorophyll between transgenic lines and wild type, indicating that accumulated tetrapyrrole intermediate and other parameters were not related to growth reduction in transgenic rice. However, ALA synthesizing capacity in MX, PX, and AP37 at one day after exposure to light and 52 DAT was significantly lower than that of WT. Further study is required to elucidate the mechanisms underlying the growth and yield difference between transgenic and WT lines.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.5 no.3
• /
• pp.185-190
• /
• 2003

This study was conducted to examine rice growth duration by analyzing agricultural climatic conditions at different latitudes in unified Korea. The climatic conditions of nine sites from Wunggi (latitude 42N) to Jeju (latitude 31N) were examined in this study. The rice growth duration of various cropping patterns was determined by analyzing consecutive days when effective daily mean air temperature was suitable for rice growth from the first seeding date to the last maturing date. The rice growth duration in Wunggi located in North Korea was available 138 days for machine transplanting, 115 days for direct seeding on dry paddy cultivation, and 97 days for direct seeding on a flooded surface with cultivation after seeding. On the other hand, the rice growth duration in Kwangju (latitude 35N) located in South Korea was 195 days for machine transplanting, 180 days for direct seeding on dry paddy cultivation, and 170 days for direct seeding on a flooded surface cultivation after seeding.