• Korean Journal of Weed Science
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• v.31 no.1
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• pp.34-40
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• 2011

Cover crop can be used to suppress weeds by competition for light and nutrient. Objective of this study was to evaluate the effectiveness of legume cover crops on change of weed community in no-till corn cultivation. Two legume cover crops, hairy vetch and crimson clover were grown in the field, and succeeding corn was sown on 4 May, 2010. The distribution of weed was surveyed at 15 April, 1 June, and 20 August. At 15 April, the weed biomass in hairy vetch field was higher than in crimson clover field. The dominant weeds were Capsella bursa-pastoris L. and Stellaria aquatica L. in hairy vetch and crimson clover fields, respectively. At vegetative stage of corn, occurred weeds in hairy vetch and crimson clover fields were four and six species, respectively, while the weed was occurred with nine species in conventional. Also the dry weight of weed was decreased by 82 and 75% in hairy vetch and crimson clover fields compared to conventional. On the other hand, after harvest of corn, occurred weed in hairy vetch, crimson clover and conventional was five, four and five species, respectively. Dry weight percentage of occurred weed in conventional was 23.5%, and the value was higher than 13.8 and 14.7% in hairy vetch and crimson clover fields, respectively. Stellaria aquatica L. as winter annual weed only occurred in cover crop field during corn growing season. It is these possibilities that low soil temperature and light interception by soil cover of legume cover crop.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.3
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• pp.259-263
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• 2007

Sowing time of barley after cultivation of rice has frequently been delayed because of rainfall or some other reasons by rice cultivation. Partial tillage direct grain seeder with eight row, which had been developed for rice sowing and showed many advantages in wet field, were tested for barley sowing. After flooding during $2{\sim}3days$, plots were designed to make wet condition. Three sowing methods were tested; high ridged broadcasting, plat drill seeding and partial tillage direct grain seeding. It were impossible to sow properly even in 27% of soil water content by high ridged broadcasting, plat drill seeding but could be possible to sow normally by partial tillage direct grain seeder in 42% of soil water content as good as in 27% of soil water content. Initial growth condition after sowing in plots of partial tillage direct grain seeder were normal even in plots sown in more than 50% of soil water content. No. of spike, which was $508/m^2$, in plot of partial tillage direct grain seeder sowed at 30% soil water content was better than plat drill seeding, $404/m^2$. Yield and yield components of plot of partial tillage direct grain seeder, were higher than plot sowed by plat drill seeder in same soil water content. Partial tillage direct grain seeding can be a good sowing way for barley especially in wet condition. However, parts of seeder have to be improved for barley sowing; 1) ridged width of partial tillage direct grain seeder should be $10{\sim}20cm$ wider than 10 cm, which is necessary for drainage during barley growing season in wet paddy field. 2) sowing width of partial tillage direct grain seeder was not same with one of drill seeder which was the best width for light interception and should be shorter than 30cm.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.279-288
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• 2021

Low-density transplanting is a cultivation technology that reduces labor and production costs. In this study, the growth and yield of several varieties with different tillering characteristics were analyzed in order to establish an appropriate planting density for low-density transplanting. Varieties with Low-Tillering (LT), Medium-Tillering (MT), and High-Tillering (HT) were planted at a density of 37-80 hills/3.3 m². As the planting density decreased, the number of tillers per hill increased, but the number of tillers per square meter of hill decreased, especially for the LT variety. Decreasing density extended the tillering stage, which was longest in the LT variety. As the planting density decreased, SPAD(Soil plant analysis development, chlorophyll meter) values just before heading increased while canopy light interception decreased. Such changes were much greater in the LT variety than in the MT and HT varieties. The heading date tended to be delayed by 0-2 days as the planting density decreased, and there was no difference in the length of the period from first heading to full heading. As the number of spikelets per panicle increased, the number of spikelets per square meter did not differ according to the planting density. Decreasing planting density did not affect the grain weight; nevertheless, the yield ultimately decreased because of the decreasing ripening rate. The optimal planting density for stable low-density transplanting cultivation was determined to be over 50 hills/3.3 m2. In addition, these results suggest that LT varieties should be avoided, since these showed large decreases in growth and yield with decreasing planting density.