• Korean Journal of Soil Science and Fertilizer
• /
• v.33 no.6
• /
• pp.493-497
• /
• 2000

An experiment was conducted to evaluate the possibility of using basic oxygen furnace (BOF) slag as soil conditioner in soybean upland field. In 1997, soybean (Glycine max L. cv. Eunha) crop was cultivated under different application rates of BOF slag at an experimental field of Chonnam Rural Development Administration in Nampyung, Najoo city. Five treatments, four application rates of BOF slag (0, 4, 8, $12Mg\;ha^{-1}$) and one application rate of lime ($2Mg\;ha^{-1}$) were tried with three replications. Plant height and shoot dry weight per plant were measured five times during the growth period. Chemical contents of soybean plant tissues and soil were also measured at the same sampling date. Yield were estimated by harvesting $6.6m^2$ per experimental unit and yield components were measured by sampling 10 plants per experimental unit at the harvest date. In upland soil, application of BOF slag rarely affected contents of total nitrogen, organic matter, available phosphate and potassium in soil. Soil pH, and contents of Ca and Fe in soil became higher as BOF slag rate increased. Enhancement of soil pH by application of BOF slag appeared to be closely related with increase in soil Ca content. Application rate of $2Mg\;ha^{-1}$ of lime showed almost the same effect in increase of soil Ca content as application rate of $4{\sim}8Mg\;ha^{-1}$ of BOF slag. Slag treatment hardly affected the contents of total nitrogen, $P_2O_5$, CaO, $K_2O$ and MgO in the shoot of soybean plants. Soybean plants under treatments of BOF salg showed better growth from the earlier growth stage compared with those of control treatment, and at the later growth stage, their growth was even superior to that of lime treatment. BOF slag rate of $8Mg\;ha^{-1}$ showed the highest soybean yield with $1,232kg\;ha^{-1}$. which was $330kg\;ha^{-1}$ or 37% higher than the yield of control with $902kg\;ha^{-1}$, As a result, BOF slag appeared to be useful material as a soil conditioner as well as nurient source for Ca and Fe in upland soybean fields, and its optimal rate for higher yield seemed to be around $8Mg\;ha^{-1}$.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.2
• /
• pp.118-123
• /
• 2017

'Nunkeunheugchal' is a waxy black rice variety that has a large embryo. The quality of black rice depends on the anthocyanin content of the rice seed coat, which is mainly determined by cultivation environment. Factors that affect the anthocyanin content include nitrogen level, planting density, transplanting date and harvesting date. This study was carried out to investigate the optimum black rice cultivation conditions by examining the effects of different nitrogen levels and planting densities. An initial study was conducted to determine the optimum nitrogen level in which four levels of nitrogen were applied to the field (0, 4, 8 and 12 kg/10a). As the nitrogen contents were increased up to 8 kg/10a, there was a concomitant increase in rice yields. However, nitrogen levels greater than 8 kg/10a, the yield was maintained at the same level. Correlation analysis indicated that the optimum nitrogen level for maximum yield was 9.6 kg/10a. In addition, anthocyanin levels showed a trend similar to that of yield, with correlation analysis indicating that the optimum nitrogen level for maximum anthocyanin content is 10.6 kg/10a.On the basis of these results, a second study was conducted to determine the optimum combination of planting density and nitrogen level. The planting densities investigated were $30{\times}12$, $30{\times}14$, $30{\times}16$ and nitrogen levels were 7, 9 and 12 kg/10a. A high planting density ($30{\times}12cm$) was shown to produce higher numbers of tillers and yield. As calculated in the first study, a nitrogen level of 9 kg/10a shown to produce the highest anthocyanin content and yield. Collectively, the results of this study indicate that a planting density of $30{\times}12cm$ and a nitrogen level of 9 kg/10a is the optimal combination in terms of maximizing both rice yield and anthocyanin content.

• Journal of Life Science
• /
• v.17 no.1 s.81
• /
• pp.82-90
• /
• 2007

In an attempt to establish the appropriate ventilation device for the bottle culture of king oyster mushroom (Pleurotus eryngii), we investigated carbon dioxide concentration and fruiting body formation according to the various ventilation systems within the mushroom house. In addition to, the efficiency of air circulation and growth rate as well as the appearance of physiologically abnormal phenotypes during their growth stage were also evaluated. four different ventilation devices, parallel-pressure type, positive-pressure type, negative-pressure type, and positive- and negative-pressure type were applied in this study. The positive-and negative-pressure type showed the highest efficiency of air circulation as $CO_2$ concentration was 800 ppm and the level of air current was relatively low compared to the other types (the $CO_2$ concentration of parallel-pressure type was 1,400 ppm). Moreover, the stipe length, the cap diameter, yield, and general quality grown in positive- and negative type ventilation device were also better than in the other three devices though it took slightly longer period for harvesting (18.4 days) than the others (17.6, 17.9 and 18.3 days). The appearance of physiologically abnormal phenotypes such as fruiting body lump, soft rot, and brown rot were significantly decreased in positive-and negative type compared to other types, while the appearance rates were not much different for other symptoms of bacterial ooze, stipe limb and stipe bumpy. In summary, we propose that the optimal ventilation system for the bottle culture of king oyster mushroom is positive- and negative type, and this device is expected to increase the total quality as well as yield all year around.

• Journal of Sericultural and Entomological Science
• /
• v.53 no.2
• /
• pp.82-86
• /
• 2015

This study was carried out to develop the silkworm rearing technique in unused mulberry leaves after harvesting mulberry fruit. The growth of Gwasang No. 2 and Suhyang was very good compared to control cultivar Chungil in leaves size and new branch growth, but new branch and leaves of Daeshim was similar or small to control cultivar Chungil. The number of leaves of Gwasang No. 2 and Suhyang was lower than Chungil, but weight of leaves per tree was heavyer than Chungil. Mulberry leaf yield was Gwasang No. 2 521 kg/10a, Suhyang 189 kg/10a, Daeshim 73 kg/10a, Chungil 1,095 kg/10a. Content of mineral element of all three mulberry cultivars leaf for mulberry fruit production was higher than Chungil in N, P, K, Ca etc. Feeding quantity of silkworm of Gwasang No. 2 and Suhyang was much more than Chungil. Feeding quantity was highest at Suhyang in 96 kg/box. Growth duration of silkworm larvae was not different in all four mulberry culivars but weight of silkworms (5th instar 3rd day) was heavy at Gwasang No. 2 (2.07 g/head) and Suhyang (2.11 g/head) compared to control cultivar Chungil (1.92 g/head). Mortality of silkworms was 14.6% (Gwasang No. 2), 13.3% (Suhyang), 13.9% (Daesim), 12.6% (Chungil) and than higher at elder instar stage. The production amount of silkworm (5th instar 3rd day) was 35.4 kg/box (Gwasang No. 2), 36.6 kg/box (Suhyang), 35.0 kg/box (Daeshim), 33.6 kg/ box (Chungil). Amount of possible rearing silkworms was estimated 3.4box/10 a (Gwasang No. 2), 1.3box/10a (Suhyang), 0.5box/10a (Daeshim), 8.7box/10a (Chungil).

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.41 no.2
• /
• pp.71-76
• /
• 2021

In order to establish optimal double cropping system for getting the maximum annual productivity, we investigated annual fresh and dry yields of winter forage crops (WFC), Italian ryegrass (IRG) 'Kowinearly', triticale 'Joseong' and summer forage crop (SFC), 'Jonong' and 'Jowoo' as whole crop silage rice in the paddy field of Yeongseo of Gangwon Province. The double cropping of each crops was applied with 2 standard cultivation method of WFC and SFC from 2018 to 2020. For the WFC, the average percentage of dry matter (29.6%) of IRG 'Kowinearly' was lower than that (35.5%) of triticale 'Joseong'. The average fresh matter yield of IR G 'Kowinearly' was 2,662kg/10a that there was no significant difference from the 2,836kg/10a of triticale 'Joseong'. The average dry matter yield (996kg/10a) of triticale 'Joseong' was more than that (696kg/10a) of IRG 'Kowinearly'. For the summer forage crops, the average percentage of dry matter of whole crop silage rice, 'Jonong' was 34.5% that there was no significant difference from the 35.0% of 'Jowoo'. The average fresh matter yield (5,367kg/10a) of 'Jowoo' was more than that (3,966kg/10a) of 'Jonong'. And the average dry matter yield (1,936kg/10a) of 'Jowoo' was more than that (1,433kg/10a) of 'Jonong'. The total maximum dry matter yield was 2,982kg/10a with the combination of the WFC triticale, 'Joseong' and the SFC whole crop silage rice, 'Jowoo'. In conclusion, the combination of crops that can obtain the maximum yield of high quality forage for double cropping is sowing the WFC triticale, 'Joseong' in mid-October, harvesting 'Joseong' around the end of May and then SFC whole crop silage rice, 'Jowoo', to be transplanted in early June.