• Korean Journal of Weed Science
• /
• v.17 no.3
• /
• pp.281-287
• /
• 1997

Growth and anatomical responses of rice and barnyardgrass(Echinochloa crus-galli) to oxyfluorfen were examined under various growing conditions in a greenhouse. With foliar application at 0.08kg ai/ha 7 days after seeding or transplanting, oxyfluorfen completely reduced the shoot and root growth of barnyardgrass under all growing conditions. However, oxyfluorfen reduced the growth of direct seeded and transplanted rice by 0~64% and 0~12%, respectively. Phytotoxic effect on rice growth, with respect to plant height and shoot fresh weight, was more pronounced under water(53~63%) than under dry-condition(16~33%), and in broadcast-seeded(34~62%) than in drill-seeded rice(16~33%). Anatomical changes of epidermal and vascular bundle sheath cells of rice leaves were not induced by oxyfluorfen, but mesophyll cells were partially ruptured and total leaf thickness was reduced. Oxyfluorfen, however, constricted and ruptured mesophyll and vascular bundle sheath cells and severely reduced leaf thickness of barnyardgrass under all growing conditions examined. These anatomical changes were more severe under dry- than under water-seeded condition.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.234-234
• /
• 2017

Recent abnormal weather, especially continued rainfall during sowing season causes difficulty in proper sowing of wheat and delayed sowing after November 15 is concerned about freezing damage during winter, resulting in reduction of wheat yield. To correspond government policy of crop sufficiency improvement and produce and supply raw wheat and barley steadily, expansion of cultivation area is necessary and spring sowing of wheat is required. To obtain basic information on the improvement of spring sown wheat and barley production, comparison and path coefficients analysis was conducted for yield and yield related components from autumn and spring sown wheat and barley. Path analyses were known as very useful in clarifying the effects of yield components on grain yield formation, which were not accurately reflected in simple correlation anaylses. Most cultivated 5 wheat and 9 barley cultivars were sown on October and February at Cheon-ju province according to standard sowing method. For the spring sowing of wheat and barley, the varieties having vernalization degree I~III are seeded in the mid of February and seeding rate is 200~250kg/ha which is increased by 25% than autumn sowing. N-fertilizer of 95 kg/ha and the same amount of P, K dressed in autumn are applied at once as basal fertilizer. The magnitude of direct effect in each yield components on yield was in sequence as follows. In autumn wheat, grain number per $spike{\geq}$ the number of spike per $m^2$>1000-grain weight and in spring wheat, grain number per $ spike{\geq}the$ number of spike per $m^2$> 1000-grain weight. In autumn naked barley, 1000-grain weight> the number of spike per $m^2$, grain number per spike and in spring barely, the number of spike per $m^2$> grain number per spike > 1000-grain weight. In autumn covered barley, grain number per spike>the number of spike per $m^2$ and in spring coverd barley, the number of spike per $m^2$> grain number per spike, 1000-grain weight. In autumn malt barley, the number of spike per $m^2$>1000-grain weight and in spring malt barley, the direct effects of three yield components were similar. According to the path analysis of yield components for spring sown wheat and barley, it was suggested that adequate number of spike per $m^2$ was most important factor for yield increase.

• Korean Journal of Weed Science
• /
• v.7 no.1
• /
• pp.98-106
• /
• 1987

The effect of carbofuran (2, 3-Dihydro-2,2-dimethyl-benzofuran-7-ylmethyl carbamate) on rice growth was evaluated as a direct growth stimulant of rice. For this, several laboratory and field trials conducted from 1981 to 1986 at the Yeongnam Crop Experiment Station. Carbofuran solution affected the germination of rice seed. The growth of seminal roots was adversely affected by the increase of carbofuran concentrations while the length of single root became longer with the concentration increment up to 50 ppm. Carbofuran application (0.18g ai/$m^2$) at the rice nurserybed significantly enhanced the rice growth and recovered from the Low temperature damage. The enhancement effect was more pronounced at the plot that applied carbofuran before rice seeding as soil incorporation than top-dressing. The effect of growth enhancement further extended to transplanted lowland rice. This effect was greater at double cropping area (late of June transplanting) compared to single cropping area (May transplanting). Among important agronomic traits, the increment of panicle number was the most important direct effect for increasing rice grain yield by carbofuran application. Carbofuran application also exhibited the reducing effect against low temperature damage at reductive division stage and at rice heading stage and against submergence damage at booting stage through enhancement of fertile grain ratio, ripening ratio or photosynthetic activity.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.6
• /
• pp.473-477
• /
• 2001

Chinese milkvetch (Astragalus sinicus L.) has been traditionally used as a green manure supplying mineral N and organic matters to soil. In rice-Chinese milkvetch interrelay cropping system, three rice cultivating methods (no-till direct seeding, no-till transplanting, and tillage transplanting) were evaluated for stand reestablishment without reseeding Chinese milkvetch with two cropping times (May 25 and June 4) for two years. Chinese milkvetch incorporated was decomposed rapidly in the first week. Decomposition was fast in topsoil than in subsoil. Natural milkvetch reestablishment (NMR), following harvest of no-till-direct-sown rice was good enough to cover the paddy field in both cropping times, but rice yield of this method was lower than that of transplanted rice on paddy field without milkvetch cultivation. Even though good NMR was secured in no-till rice transplanting, the shoot of milkvetch should be removed before machine-transplanting of rice seedlings. NMR was better in rice cropping at the mid-ripening stage of milkvetch (June 4) than at the late-bloom stage (May 25). Rice yield was higher in tillage transplanting at the mid-ripening stage of milkvetch (June 4) than in the other rice cropping method.

• Korean Journal of Weed Science
• /
• v.18 no.2
• /
• pp.116-121
• /
• 1998

Field experiment were carried out to elucidate the changes of weed occurrence according to the sowing time and to establish the efficient weed control system in dry seeded rice cultivation. E crus-galli and D. sanguinalis are tow major weeds at the earlier sowings, but C. difformis was dominating at the later sowing. In the case of E. crus-galli, there was a tendency of gaining its dominance values as the rice growth stage advances. The later the sowing time was, the more weeds occurred at the early rice growth stages: However, when measured at heading, total dry weight was greater at the earlier sowings. Yield loss due to weeds were also greater at the earlier sowings. Community diversity of weeds was greater at the later sowings, while specific weed was gradually dominating as rice growth stage advances, regardless of sowing time. When herbicides were applied before 15 DAS, weeds were effectively controlled only upto 35 DAS. So systemic herbicide application, one on 0 to 10 DAS and the other on just after flooding, appeared to be recommendable in direct seeded rice cultivation.

• Korean Journal of Weed Science
• /
• v.12 no.2
• /
• pp.183-187
• /
• 1992

This study was conducted to evaluate the effect of systematic herbicide application and polyethylene(PE) film mulching in direct seeded Angelica gigas Nakai. Freshly-collected-seed showed 86% of emergence rate and required 18 days of emergence duration. Cold treatment of seeds increased emergence rate by more than 90% and shortened 2 days of emergence duration. Paraquat) 1,1'-dimethyl-4,4'-bipyridylium dichloride was the most effective when applied just before emergence of A. gigas and provided 96% of emergence rate and 91% of weeding effect when applied 23 days after seeding. Soil applied herbicides used did not cause any phytotoxicity on emergence with application of 2-fold recommended rate and gave more than 90% of weeding effect. Black PE film mulching gave excellent emergence rate and weeding effect, and shortened emergence duration by 8 days.

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

• Journal of Korean Society of Forest Science
• /
• v.13 no.1
• /
• pp.67-78
• /
• 1971

The measures of contour-terracing with sod has been executed as a major measures for hillside erosion control works for a long time in Korea. It is, however, recognized that pair terracings make a new slope-face having the more steeper degree of slope between the upper and the lower terraces on hillsides and it also does not contribute for establishing the natural vegetation-cover by penetration of pioneer seeds on the slope faces or cut-faces of hillsides. The study was therefore conducted in connection with the above problems on the cut-face having slope of $40^{\circ}$ and 1.6 meter in slope length with clay soils. Plot allocation for the experiment consists of 3 kinds of 3 replica plots having each $1.6m^2$ of slope area, i. e., the control plot with direct seeding on slopes only ($T_1$), the covering plot with the straw-mats after seeding on slopes ($T_2$) and the seeding plot after covering with the straw-mats. ($T_3$). The main results obtained may be summarized as follows : 1. Effects of the straw-mat mulchings on surface soil loss control:-The total amount of soil losses from each treatments are measured as 4,651 gr from $T_1$, 163 gr. from $T_2$ and 2,891 gr. from $T_3$ treatment respectively. (Refer to table No. 2, 3 and 4). In short, it is recognized that effect of $T_2$ treatment is compared as 28.5 times than that of $T_1$ treatment and 17.7 times than that of $T_3$ treatment respectively. Effect of $T_3$ treatment compared with $T_1$ treatment is also such recognizable as 1.6 times in control of surface soil losses on a slope face. 2. Effect of the straw-mat mulchings on soil moisture content on slopes; -Average per cent of surface soil moisture content by treatments show as 21.60 at the $T_1$, 23.04 at the $T_2$ and 22.21 at the $T_3$ treatment respectively and that of subsurface soil moisture content by treatment show as 23.81 at the $T_1$, 26.16 at the $T_2$ and 24.81 at the $T_3$ treatment respectively. The variance of soil moisture content by treatments was highly significant (Refer table No. 7, 8 and 9). 3. Effect of the straw-mat mulchings on vegetation establishment;-Average numbers of germination by treatments are counted as 237 Nos. at the $T_1$, 246 Nos. at the $T_2$ and 262 Nos. at the $T_3$ treatment plots and the vegetation coverage on ground was almost same as about 90% of covers in all treatments. This effect is more or less lower than that of surface soil erosion control. 4. Regarding the effect on surface soil erosion control, the straw-mat mulchings would be effective as a new measures for control of soil erosion on erosion susceptible lands such slope-faced bare-lands as cut-fill faces, mass-movement faces and bare hillsides.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.spc1
• /
• pp.52-57
• /
• 2006

This research was carried out to determine the effect of controlling nitrogen application on tiller development, yield, and quality of rice under scanty or excess seedling stands in direct-seeded rice on flooded soil surface. Seedling stand was set to 3 levels: scanty $(60/m^2)$, optimum $(120/m^2)$, and excess $(200/m^2)$. In the scanty plot, additional 4 kg/10a nitrogen was applied at the 3rd leaf stage to promote tiller development. On the other hand, applying 3.3 kg/10a nitrogen at 5th leaf stage in the excess plot was omitted to suppress tillering. Maximum numbers of tillers per plant were 15.2 and 8.6 in scanty and excess plots, respectively, as compared with 9.8 in optimum plot. Productive tiller rate decreased with the increase in number of seedling stands. Regardless of seedling density, the first tiller developed on the 3rd node of rice stem from the bottom. The primary tillers developed at 3, 4, 5, 6, 7 nodes in scanty plot, 3, 4, 5 nodes in optimum plot, and 3, 4 nodes in excess plot. The secondary tillers developed only in some portion of plants in scanty and optimum plots. The order of tiller emergence was negatively correlated to stem length, panicle length, non-productive tiller number, grain number per panicle, and fertility in scanty plot, and to perfect grain ratio in excess plot. In the optimum plot, however, the order of tiller emergence was not correlated to any of the mentioned characteristics. The perfect grain ratio of scanty plot was the highest because green-kerneled rice was a very small portion in the primary tillers as compared with those of optimum and excess plots. Yield indexes of scanty and excess plots were 99%, and 97%, respectively, of the yield (494 kg/10a) in optimum plot. In conclusion, when seedling stands are not at optimum level, rice yield and quality similar to optimum planting density level can be obtained by means of controlling nitrogen application.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.61 no.1
• /
• pp.9-16
• /
• 2016

To investigate the effect of soluble silicate zeolite dressing of the rice against bakanae disease, field trial in reclaimed land and in vitro were carried out. The coated rice seeds (SCS) which were dressed with the mixture of 25% silicic acids (binder), and the zeolite (coating powder). In wet direct seeding, uniform scattering of rice seeds on the soil surface and the better seedling establishment were shown in SCS treatment plots. The incidence of bakanae disease began from the mid tillering stage toward the heading stage. Around heading stage, the ratio of infected tillers reached its highest point by 9.9% in non-SCS treatment plots. While, in SCS treatment plots, the ratio of infected tillers was no more than 0.01%. The vitality of the pathogenic fungi of bakanae disease in the SCS and non-SCS samples were assessed. Samples were incubated for one week keeping proper humidity at $30^{\circ}C$ after inoculated with panicles of infected rice plants from experimental field plots. In non-SCS treatment, pinkish colonies were formed on the grain surface of panicle of infected plants, and mycelium, macro-conidia and micro-conidia were developed actively inside part of infected grain inoculated. While in SCS treatment, micro-conidia and mycelium were not survived and the growth of macro-conidia, mycelia were greatly inhibited and withered. Based on the results, it is concluded that the environmental friendly control of bakanae disease by use of SCS is possible and soluble silicate can be applied as agents for replacement of seed disinfection.