• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.1
• /
• pp.73-78
• /
• 2017

This study was conducted to elucidate the effects of mulching materials on root growth characteristics and weed occurrence of Platycodon grandiflorum transplants (3 years old) in organic farming. After transplanting, roots were mulched with one of three mulching materials (biodegradable film, sawdust, or rice husks) or a control (no mulching). The average root diameter of all mulching groups was 28.1 mm, which was 5.1 mm thicker than the no-mulching treatment. Roots with the biodegradable film treatment were the thickest at 30.9 mm. Root length was the shortest, 22.0 cm, with rice husk mulching. The number of rootlets was the highest with film mulching (36.0 rootlets/root) and the lowest with no mulching. For root fresh weight, which directly affects yield, the average of treated and untreated roots was 100 and 56 g/root, respectively. The highest fresh weight was in the biodegradable film plot (130 g/root). The mulching treatment groups showed a weed inhibition effect compared with the no-mulching treatment. The dominant weeds with the no-mulching treatment were Setaria viridis and Digitaria ciliaris, and that with the mulching treatment was Setaria viridis. Average annual weed occurrence across all treatments was 72%. Weed occurrence was the highest with the no-mulching treatment ($125weeds/m^2$), and there were no weeds with the biodegradable film treatment.

• Weed & Turfgrass Science
• /
• v.2 no.4
• /
• pp.413-420
• /
• 2013

The climate change affects the growth and development of weeds as well as the outbreak of weeds. Especially, the occurrences of problematic paddy weeds due to climate change might cause the difficulties in weed control. This study therefore, investigated the current dominance and distribution of paddy weeds. As a result of the study on paddy weeds in northern Gyeonggi-do, there were total of 65 taxonomy groups including 23 family, 41 genus, 57 species, 7 subspecies and 1 variety. Among all the plants, 46 species were annual plants and 16 were perennial plants. Echinochloa crus-galli was the highest in importance analysis and the followings were in order of Ludwigia prostrate and Lemna paucicostata. The similarity of different paddy weeds in different regions observed through TWINSPAN analysis was distinguished by Fimbristylis miliacea, Rotala indica and Cyperus flaccidus. Regional differences shown in CCA analysis using weed species and soil environment revealed that Gimpo-si and Namyangju-si has difference soil and weeds, which are features that distinguished them from other regions. In northern Gyeonggi-do the result of paddy weed research showed the interregional difference not in dominant weeds but in distribution species.

• Korean Journal of Weed Science
• /
• v.30 no.3
• /
• pp.258-265
• /
• 2010

The effects of organic-compound fertilizer on weed control and rice growth in the transplanting rice cultivation were researched in this article. The results showed that the growth of transplanted rice was promoted (the increased rate was 10.3~27.2%), but the plant number for Echinochloa crus-galli was controlled (the inhibition rate was 50.3~89.2%), besides, small amount of organic-compound fertilizer in controlling Aneilema keisak was highly effective when the transplanted rice was treated with 125~250 kg $10a^{-1}$ organic-compound fertilizer. Moreover, E. crus-galli, Monochoria vaginalis and A. keisak were inhibited largely by increasing the water depth (1~5 cm), whereas Eleocharis kuroguwai and other sedges weeds were not effected by water depth. Compared with the temperature of $20{\sim}35^{\circ}C$, the plant occurrence of E. crus-galli and M. vaginalis at high temperature was inhibited (the inhibition rate were 75.4~92.2% and 49.5%~81.6%, respectively). When the transplanted rice was treated with the above organic-compound fertilizer after 10day, the inhibition rate of plant occurrence for E. crus-galli and M. vaginalis was 33.7% and 23.3%, respectively. Similarly, in the later period of rice growth, the plant height and the numbers of tiller grew slowly in conventional soil in comparison with the soil treated with organic-compound fertilizer. It has been found that the rice yield in experimental soil was decreased by 4%. This result in the field experiment showed that organic material contents in conventional soil were lower than that in soil which used the organic-compound fertilizer. Weed control in experimental soil showed 60.5% lower effects than that in conventional soil.

• Weed & Turfgrass Science
• /
• v.5 no.2
• /
• pp.82-87
• /
• 2016

Herbicide options for weed control in sorghum is very limited, hence there is a need for exploring potential herbicides. Sorghum herbicide tolerance field trails were conducted at two locations, Yaechoun, Gyeongsangbuk-do, and Miryang, Gyeongsangnam-do, in 2013. Tolerance of sorghum was evaluated following the pre-emergence application of methabenzthiazuron 70% (WP), simazine 50% (WP), oxadiargyl 1.7% (EC), and dimethenamid-P 5% + pendimethalin 20% (EC) at the standard rate 157.5 g, 75 g, 5.1 g, and 75 g a.i. $10a^{-1}$, respectively. As well as double the standard rate. On a phytotoxicity scale of 0 to 9, methabenzthiazuron (WP) induced injury to sorghum up to level 1 at the standard rate and to 3 at double the rate, but did not significantly affect the yield any statistical difference from the untreated. Simazine (WP) induced phytotoxicity up to levels 2 and 4 at single and double rates, respectively. Simazine (WP) did not significantly affect yield: however, the values were numerically lower than those in the methabenzthiazuron (WP) treatment. Oxidiargyl (EC) and dimethenamid + pendimethalin (EC) induced no or slight phytotoxicity; however they failed to provide effective weed control at the standard rate (32 and 68% control, respectively). Out of the tested, methabenzthiazuron (WP) was found to have potential for use in sorghum whereas the other herbicides caused unacceptable levels of injury.

• Korean Journal of Weed Science
• /
• v.31 no.4
• /
• pp.355-359
• /
• 2011

This study was conducted to evaluate the effects of seeding of Vicia tetrasperma and V. hirsuta on the rate of ground cover as well as growth and yield of organic pepper plants in 2008 and 2009. All seeds of both species were gathered from Dangjin, Chungnam in late June of 2006 and stored for two year at room temperature. Capsella bursapastoris, Echinoloa crus-galli, Digitaria ciliaris, and Commelina communiswas were observed as main weeds during the winter and summer, respectively, at the field of V. tetrasperma and V. hirsuta. C. bursapastoris did not affect growth and yield of pepper plants. Seeding of V. tetrasperma and V. hirsuta maintained high percentage of ground cover later in the growing season of pepper plants and reduced significant amounts of weed in 2009. V. tetrasperma and V. hirsuta, therefore, produced more pepper yield compared to that of control but similar yield to the conventional system (polyethylene film).

• Korean Journal of Weed Science
• /
• v.13 no.2
• /
• pp.164-172
• /
• 1993

About 196 weed species composed of 31 annuals, 38 biennials and 127 perennials belonging to 53 families were identified from 90 buryingplaces in Kyungpook province on June and September, 1992. Compositae was the most widely occuring family covering 34 species, followed by 27 species in graminae, 17 species in leguminosae, and 10 species in rosaceae, 8 species in liliaceae ranunculaceae, 7 species in caryophyllaceae cruciferae, 6 species in labiate polygonaceae, 4 species in crassulaceae cyperaceae, and the rest 41 families having 1 to 3 species. The dominant weed species occured in the buryingplaces based on importance value and frequency were Imperata cylindrica, Artemisia princeps, Viola mandchrica, Erigeron annuus, Erigron canadensis, Rubus parvifolius and Prunella vulgaris.

• Korean Journal of Weed Science
• /
• v.31 no.1
• /
• pp.103-111
• /
• 2011

Monochoria vaginalis var. plantaginea (Pontederiaceae) is one of the most problematic weed in the rice field in Korea. Tanysphyrus (Tanysphyroides) major was selected as a potential biological control agent for M. vaginalis. Continuous rearing of T. (T.) major was carried out from 2006 to 2007, and its morphological characteristics and ecological characteristics were investigated. This species has a single generation per year, over-wintering as an adult stage. The emergence of adults starts in later June and last until September. These observations indicate that T. (T.) major takes $22{\pm}0.7$ days to develop from egg to adulthood. Host specificity test showed that finally selected this species was suitable candidates for the biological control of M. vaginalis var. plantaginea since it showed negative host specificity against major 60 test crops.

• Korean Journal of Weed Science
• /
• v.17 no.2
• /
• pp.147-156
• /
• 1997

The survey of weed population in apple orchard was conducted to investigate basic information on weed flora and its ecology at 27 locations in 1996. The weed species observed include 7 species of grasses, 60 species of broadleaves and 2 species of sedges, and the ratio of annual weed vs perennial weed was 64 : 36. Major dominant weed species by frequence were Chenopodium album, Capsella bursa-pastoris, Digitaria sanguinalis, Rorippa islandica, Alopecurus aequalis and Erigeron canadensis. While, on the basis of dry weight, the most dominant weeds were C. album followed by E. canadensis, A. aequalis, R islandica and R indica. The dominant weed species in middle-north Kyeongbuk region were C. bursa-pastoris, C. album, R indica and R islandica, were E. canadensis, Persicaria hydropiper, A. aequalis and Arenaria serpylliforia in Chungbuk region and were A. aequalis, E. canadenris and R islandica in Honam region.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.4 no.1
• /
• pp.62-69
• /
• 1983

This experiment was carried out to find the effect of seeding rates and herbicides on the weed control, yield and crude protein of sorghum-sudangrass hybrid (Sorghum bicolor (L.) Moench). The variety used in the present study was Pioneer 988. Two different seeding rates were 25 kg/ha and 50 kg/ha and five weed control treatments were weedy check, hand weeded check, alachlor, alachlor+simazine, and simazine of preemergence application. The results of this study are summarized as follows: 1. Forage yield was not influenced by seeding rates. There was no significant difference between forage yield from 25 kg/ha and from 50 kg/ha of seeding rates. But weedy plots showed higher yield from the high seeding rate. Alachlor+simazine treatment showed the greatest yield among the weed control treatments. But there was no difference among the hand weeded treatment, simazine treatment, and alachlor+simazine treatment. 2. Seeding rates did not affect weed yield, but weedy plots showed the tendancy toward higher weed yield from the low seeding rate. Alachlor+simazing preemergence application showed the most effective weed control. But there was no significant difference in weed yield among the treatments of the hand weeded, alachlor+simazine and simazine. The weed yield in alachlor treatment was significantly higher than other three treatments. 3. The height of plant was shortest on the weedy plots and the longest height was obtained from the alachlor+simazine application. But in the first harvest the height was reduced by herbicides. Seeding rates did not affect the plant height. But the height was slightly taller under the low seeding rate than under the high seeding rate. 4. The percent crude protein of the forage did not affected by two seeding rates. Simazine treatments increased the percent crude protein and total crude protein yield. Simazine and alachlor+simazine application showed the significantly higher percent crude protein than hand weeded and alachlor treatments. Simazine increased the percent crude protein without reduction of forage yield. 5. Whereas the number of original stand was greater in the high seeding rate, the number of tillers per stand was higher in the low seeding rate. Weed reduced the number of stands and tillers. There was no significant indifference among the weed control treatments. It is concluded from above results that when sorghum-sudangrass hybrids are broadcasted for forage, 25 kg/ha rate of seeding is appropriate and alachlor+simazine treatment is most effective on weed control, maximum forage yield, and high percent crude protein.

• Korean Journal of Weed Science
• /
• v.10 no.2
• /
• pp.83-92
• /
• 1990

Experiment was conducted to establish the weed control system on the paddy fields by investigating species, period and amount of weeds in Gangwon province. Four locations were selected for these experiments : West plain area, Chunchon(74m above the sea level), mid-mountainous area, Hongchon(300 m), high alpine area, Hoengsong(450m), and east sea area, Myungju(14m). Weed emergence was investigated 6 times from 10 days after transplanting to 60 days with 10 days interval. From the experiments stated above, the results were summarized as follows ; The identity of weed species was small in grass family, but broad-leaf family was numerous. Also the dominant weed species was generally the perenial weeds. The weed emergence was initiated from 10 days after translanting. The amounts of weed counted the most in Chunchon. A large number of weeds were emerged between 30-60 days after transplanting in Chunchon and between 40-60 days after transplanting in Hongchon and Hoengsong. Among agronomic characteristics affected by weed emergence during rice development, plant height was decreased by 2~4cm, panicle number by 1.3~2.9, spikelet by 3.7~7.5, ripening rates 3.3~6.5%, and milled yield by 12~17%, respectively.