• Korean Journal of Soil Science and Fertilizer
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• v.19 no.2
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• pp.123-131
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• 1986

This study was conducted to evaluate the effect of annual application of silicate fertilizer on rice yield and soil physico-chemical properties. Field experiment was done on the condition of fertilization of silicate fert. 150 and 250kg/10a to the clay loam paddy field for ten years from 1975 to 1984. Data for rice growth and nutrient uptake was analyzed for ten years base. The results obtained are as follows. 1. Average unhulled rice yield for 10 years increased at 16% in the treat of silicate fert. 150kg/10a annually applied in comparison with the N.P.K treated plot, but silicate fert. 250kg/10a treated plot was decreasing tendency somewhat in yield. 2. Amount of potassium uptake of rice straw at the harvesting stage was positively significant recognized with unhulled rice yield and straw yield of rice plant. 3. The amounts of N, $P_2O_5$ and $K_2O$ uptake in the treat of silicate fert. 150kg/10a were much more than those of silicate fert. 250kg/10a treated plot. However the treat of silicate fert. 250kg/10a increased the amounts of CaO, MgO and Silica uptake than other treats markedly. Especially the treat of silicate fert. 150kg/10a was higher in nitrogen recovery rate than other nutrients recovery rate, but the recovery of silica was low. 4. The treat of silicate fert. 250kg/10a annually applied markedly decreased the translocation rate of nitrogen, potassium and silica from straw to the unhulled rice grain. 5. Ten years' average value of soil O.M. content was much more in the treat of silicate fert. 150kg/10a which show higher yield increase than other treats, but in the treat of silicate fert. 250kg/10a, soil O.M. content was lower, however silicate content in soil was the most among other treats.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.443-452
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• 2006

The four rice(Oryza sativa L.) lines, previously demonstrated to have vigorous herbage production at the vegetative growth stage, were investigated for their growth traits, dry matter yield and feed value using the twice-cutting system that 1st-cut is harvested at panicle formation stage and 2nd-cut at the yellow ripen stage. The twice-cutting system is regarded as an effective method in the production of forage rice by escaping lodging and insect damages caused by the overgrowth and typhoon around the heading stage.The feed value of the twice-cut rice plant of there lines were compared with the control of normal, cutting at the yellow ripen stage. The relative feed value(RFV), the total digestible nutrient(TDN) and the crude protein(CP) content of the twice-cut straw were higher the control in every lines. However, the dry matter yield (DMY), represented by the summed forage production of 1st and 2nd cut-rice plant, were lower the control, and the DMY of straws were increase but grains were decrease for twice-cutting system. In addition, TDN yield showed the similar tendency with DMY.Recently, as one of the breeding aims the researches for improving the digestibility of rice straw have been required. In this regard, twice-cutting system is recognized with the fact that it has the effect which raises the digestibility of the straw. Especially, the 2nd cut of IR73111-B-R-15-3-1 line was similar to the control at the TDN yield of straw, and would be used as a breeding material for product the roughage of good quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.47-68
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• 1970

Experiments were conducted by moderate season culture of each of 7 early, medium and late maturing varieties which were considered to be of strong salt tolerance in non-salty, low- and high-salty reclaimed areas (salt content: 0.5% and 1% at the end of April). The results of the experiments revealed that the early maturing varieties were suffered greatly from salt damage in such reclaimed salty area which is the "fall better type" in the year-round changes of soil salt concentration in Korea. Better yielding varieties in the salty area showed generally a high yield ratio in the salty area compared with the non-salty area. This indicates that they are strong salt tolerant varieties. It seemed that the salt tolerance could be measured by the number of delaying days in heading, the growth rate of culm length, number of panicles and number of grains per panicle in the salty area to compare with the non-salty area. The effects or salt damage on the yields of each variety at maturing stage and agronomic characteristics in the salty area were compared and discussed with the non-salty area.alty area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.370-374
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• 1990

A field experiment was conducted to investigate the influence of water weevil damage on growth and grain guality in rice. Plant height was shortened, number of tillers per hill decreased and maximum tillering stage delayed in damaged field by rice water weevil. Heading date was delayed by 1-2days, culm lenght shortened, panicle lengthened, number of panicles decreaced, number of panicles per spikelet increased, ripened grain ratio decreased in damaged field by rice water weevil. Yield per 10a was decreased 4-22% in damaged field compared with that in undamaged field by rice water weevil, yield loss in late transplanting (June 23) was larger than that in early transplanting (May 20). Imperfect kerml rice, especially green kernel rice, was increased in damaged field by rice water weevil.

• Korean journal of applied entomology
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• v.14 no.3 s.24
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• pp.97-109
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• 1975

In an attempt to develop an effective integrated system of controlling blast disease of rice caused by Pyricularia oryzae Cav., the possibility of minimizing the disease incidence by proper application of fertilizers has been investigated. Thus the effect of silicate, nitrogen, phosphorus and potassium fertilizers on the development of blast disease as well as the correlation between the rice varieties an4 strains of P. oryzae were studied. The experiments were made in 1971 and 1973 by artificial inoculation and under natural development of the blast disease on rice plants. The results obtained are summarized as follows. 1. Application of silicate fertilizer resulted in the increase of silicate as well as total sugar and potassium content but decrease of total nitrogen and phosphorus in tile leaf blades of rice plants. 2. The ratios of total C/total N. $ SiO_2/total$ N, and $K_2O/total$ N in leaf blades of rice plants increased by the application of silicate fertilizers. There was high level of negative correlation between the ratios mentioned above and the incidence of rice blast disease. 3. Application of silicate fertilizer reduced the incidence of rice blast disease. 4. The over dressing of nitrogen fertilizer resulted in the increase of total nitrogen and decrease of silicate and total sugar content in leaf blades, thus disposing the rice plants more susceptible to blast disease. 5. Over dressing of phosphorus fertilizer resulted in the increase of both total nitrogen and Phosphorus, and decrease of silicate content in the leaf blades inducing the rice plants to become more susceptible to blast disease. 6. Increased dressing of potash resulted in the increase of silicate content and $K_2O/total$ N ratio but decrease of total nitrogen content in leaf blades. When potassium content is low in the leaf blades of rice plants, the additional dressing of potash to rice plant contributed to the increase of resistance to blast disease. However, there was no significant correlation between additional potassium application and the resistance to blast disease when the potassium content is already high in the leaf blades. 7. When four rice varieties were artificially inoculated with three strains of P. oryzae, the incidence of blast disease was most severe on Pungok, least severe on Jinheung and moderate on Pungkwang and Paltal varieties. 8. Disease incidence was most severe on the second leaf from top and less sever on top and there leaf regardless of the fertilizer application when 5-6 leaf stage rice seedlings of four rice varieties were artificially inoculated with three strains of P. oryzae. 9. The pathogenicity of three strains of P. oryzae was in the order of $P_1,\;P_2,\;and\;P_3$ in their virulence when inoculated to Jinheung, Paltal, Pungkwang varieties but not with Pungok. The interaction between strains of P. oryzae and rice varieties was significant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.11
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• pp.1-9
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• 1972

For a measure against late transplanting, this experiment was conducted to investigate a reasonable seeding rate in nursery bed and a proper nursery size. The treatments applied to this experiment are as follows a) seeding rates: 0.2ι, 0.4ι and 0.6ι per 3.3$m^2$ b) nursery sizes. for 10a-field area: 39.6$m^2$, 49.5$m^2$ and 59.4$m^2$ c) transplanting dates: June 5, June 25 and July 15. The seeding date was April 26 and planting density was determined by the number of sound seedlings based on the combination of seeding rate and nursery size. The results may be summarized as follows: 1. In seedlings both increased nursery period and decreased seeding rate showed a remarkable-increase in plant height, number of leaves, dry matter weight and the ratio of dry weight to plant height. But their number of tillers and live leaves did not show such tendency. 2. Delayed transplanting date shortened culm length and panicle length as well as number of days from transplating to heading and it also delayed heading date. On the other hand the transplanting of 80-day seedlings resulted in premature heading. 3. As a result late transplanting reduced number of spikelets per panicle, maturing rate and 1000-grain weight. In the last analysis it linearly reduced grain yield. The decreasing rate of yield by late transplanting was 15.6% in June 25 plot and 41. 3% in July 15 plot, compared with the yield in June 5 plot. Such a remarkable decrease in yield of the extremely late transplanted plot was mainly due to markedly decreasing number of spikelets per panicle and 1000-grain weight. 4. Both increased seeding rate and nursery size gave a rise in number of tillers per unit area as well as number of transplanting hills but gave a fall in culm length and panicle length. 5. Accordingly, though thick seeded - dense planted plot increased number of panicles per unit area, decrease in number of spikelets per panicle and 1000-grain weight made no differences in yield between thick seeded - dense planted plot and thin seeded - sparse planted one. However, the yield in the thick seeded - dense planted plot transplanted on July 15 was reduced owing to the remarkable decrease in maturing rate and 1000-grain weight. 6. We came to the conclusion that as a measure against the extremely late transplanting the suitable seeding rate was 0.4ι per 3.3$m^2$ and the proper nursery size was 59.4$m^2$ for 10a-field area.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.251-260
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• 2002

The corn (Zea mays L) planting date in a double-cropping system is delayed until mid-May due to delayed rye harvest on May. This experiment was conducted to determine the optimum harvesting time for high yield and the best quality of silage corn at late planting date after harvesting winter rye. Corns were planted on 21 May and harvested at eight different maturity stage at Seoul National University Experimental Livestock Farm, Suwon in 1997. Maturities were B (blister; 16 days after silking), M (milk; 20 days), LM (late milk; 24 days), SD (soft dough; 28 days), ED (early dent; 33 days), FD (full dent; 38 days), LD (late dent; 44 days) and PM (physiological maturity; 53 days) stages. The percentage of whole plant dry matter (DM) showed optimum range for silage making (29.0 to 38.5%) when corn plant was harvested at between ED and LD stages. Maximum whole plant DM (14,831 kg/ha) and total digestible nutrients (TDN) yields (10,675 kg/ha) reached at full dent stage. The percentage of whole plant acid detergent fiber (ADF) was decreased from 35.4 to 22.1%, and that of neutral detergent fiber (NDF) was also decreased from 63.8 to 46.0% as harvest stage progressed. These changes in chemical compositions were associated with changes in plant part composition. A progressive increase in total ear, and the decrease in stover portion in the plant were observed with advance in harvest stage. Calculated on net energy for lactation (NEL) and TDN values based on ADF percentage of stover plant decreased by ED stage and then increased by PM stage. But NEL and TDN values of ear and whole plant increased as harvest stage progressed. While in vitro dry matter digestibility of stover was decreased from 61.1 to 49.7%, whole plant was increased from 58.3 to 65.7% as maturity advanced (P$<$0.05). The results of this study indicate that corn can be harvested for silage at full (1/2 milkline) and late dent (2/3 milkline) stages for maximum yield and optimum quality at late planting. And days after silking at late planting was 38 and 44 days.

• Journal of Bio-Environment Control
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• v.26 no.1
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• pp.7-12
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• 2017

This experiment was conducted to analyze the effect of drainage reuse rate on the growth and fruiting of summer paprika in closed hydroponic cultivation. The experiment was carried out for 25 weeks from March to September 2015 with 0, 20, 30, 50% mixing ratio of waste nutrient solution using non - recycling hydroponic cultivation as a control. As a result, stem diameter of the test was different in the groups 1 and 2, but no difference showed as the group progressed more than 3 groups. L.A.I tended to decrease with increasing drainage mixing ratio. The number of nodes in the 50% reuse test group was 1.4 compared to the control group, but there was no significant difference. The number of harvested nodes was significantly different in the control group (11.1 nodes) and the 50% reuse test group (8.7 nodes), and the harvested nodes tended to decrease as the drainage was reused. The ratio of harvest was also the same as that of the harvesting node, and the control was the highest at 33.2% and the lowest at the 50% reuse test at 27.6%. Relative yields were reduced by 30%, 35% and 45% in the control group in the first group, and this tendency was also observed in the second and fourth groups. However, in the 3 and 5 groups, the production of 50% test group increased by 13% and 5%. The ratio of unmarketable fruit was increased 2%, 4%, 4%, and 7% in 0%, 20%, 30% and 50% reuse test, respectively. In conclusion, if the decrease in yield due to the decline in early growth is carefully managed, even if the imbalance of inorganic ions occurs after the mid-term growth, the growth of the crop will enter into a stable period and the re-use will not be worried about the growth and the yield decrease.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.152-162
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• 1975

Five barley varieties were compared under six 1evels of nitrogen fertilization and two methods of cultural management, conventional and drill seeding. The increase in grain yield and nitrogen content of the leaves showed a significant linear regression from added increaments of nitrogen in Haganemugi and Olbori, particulary under drill seeding. The other varieties resulted in various degrees of lodging and no significant increases in yield. The spike number per square meter was the major component of yield, but when the spike number per square meter was sufficient, 1000 grain weight was equally as important as a component of yield.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.271-278
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• 1993

This experiment was carried out to elucidate the mfluence of honeybees pollinatIOn on yield and YIeld components of soybean at the Kyungbuk Provincial Rural Development Administration from 1990 to 1991. SIX soybean varieties were cultivated in net houses with and without bees. Italian honeybees(Apis melhfem L.) were used. The Vlsiting frequency of bees in net house wIth bees was 58% higher than that of field honeybees, and it was the highest at 10 A.M. during a day. Number of pods per plant and podding ratio of soybean were higher with bees compared with Wlthout bees, especially for the varieties Paldalkong and Dankyongkong. The number of seeds per pod was not significantly different between with bees and without bees, although the percentage of three seeded pod of varieties Danyeobkong and Muhankong and one seeded pod of varieties Hwangkeumkong and Milyangkong 'was increased. The percentage of three seeded pod of Paldalkong and Dankyeongkong, however, was decreased with bees compared with without bees. At the same time no varietal difference was found in two seeded pods between with bees and without bees. Yield of soybeans was increased 0 to 12 % with bees compared with that of without bees. Yield increase was the hIghest in Paldalkong and Dankyongkong. The ratIO of soybean hybrid plant was mcreased with-bees compared with that of without-bees, especially m Paldalkong and Dankyongkong. A negative correlation was found between the ratio of hybrid plant and the duration of flowering in soy¬beans.