• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.43-60
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• 1968

In order to find the effects of nitrogen type (ammonium sulfate and urea fertilizer) and fertilized depth, (0~10cm, 0cm, 5~10cm, 10~15cm, 15~20cm, and 20cm below) on leaching and absorption of nitrogen in paddy soil, and growth and yields of rice, the pot culture experiment was carried out, using the variety Jaekun, one of the Korean leading variety. Experimental results were Summarized as follows: 1. No variations of the pH of percolating water were induced by the differences of nitrogen types and their fertilized depth (Table. 2). 2. The leaching of nitrogen was less in ammonium sulfate and top soil fertilizing plots than in urea and subsoil fertilizing plot, and the growth of rice in early stage was more promoted in ammonium sulfate and topsoil fertilizing plots (Table. 1, 7 and 8). 3. Leachng of nitrogen through the percolating water almost came to an end at the most numerous tiller stage (Table 1). 4. The absorption of nitrogen of each part of the rice plant in the harvesting stage correlated closely with the yields of each part (Table 5, 6, 9 and 10) and the leaching of nitrogen in the early stage was inversely proportion to the absorption of nitrogen of rice plant in the harvesting time (Table 1, 5, 6, 9 and 10). 5. The number of spikes was more numerous in ammonium sulfate plots than in urea plots on an average, so that the yields were higher in the ammonium sulfate plots than in urea plots although no differences in the grain number per spike were found in above two plots. The number of spikes was more numerous in topsoil fertilizing plots than in subsoil fertilizing plots, but the grain number per spike was less in former than in latter, so that no difference in yields was found. The absorption of nitrogen correlated closely with the yields in complete paddy grains (Table 5, 9, and 10). 6. At the ammonium sulfate fertilizing plots, the number of spikes was more numerous in topsoil fertilizing plots than in subsoil fertilizing plots, (among the each of the topsoil plots, 0~10cm and 5~10cm fertilizing plots kept more spikes than the 0cm fertilizing plots), but the grain number per spike was less in former than in latter (among the each of topsoil plots, no differences were found), so that no significant difference in yields was showed between the topsoil and subsoil fertilizing plots, but the results showed the tendency that the yields were highest in 0~10cm plots and the lowest in 20cm below plots. At the urea fertilizing plots, the number of spikes decreased in proportion to the increasing of fertilized depth, but no variations were found in the grain number per spike, so that the yields decreased in proportion to the increasing of fertilized depth. The absorption of nitrogen correlated closely with the yields in complete paddy grains (Table 5, 6, 9, and 10). 7. When fertilized in topsoil, the number of spikes was more numerous in ammonium sulfate plot than in urea plot, but the grain number per spike variated reversely, so that no differences were found in the yields between the ammonium sulfate and the urea plots, when fertilized in subsoil, both the number of spikes and the grain number per spike were larger in ammonium sulfate than in urea plot, so that the yields were also higher in ammonium sulfate plots (Table 5, 6, 9 and 10). 8. The weight of straw and its nitrogen absorption were higher in ammonium sulfate plot than in urea plot and decreased in proportion to the increasing of fertilized depth. Among the each of topsoil fertilizing plots, the 0~10cm and the 5~10cm fertilizing plots excelled the 0cm plot (Table 5, 6, 9 and 10). 9. No significant variations in the fertilizer treatments were found in the characters of heading date, maturing date, length of culm, length of spike, weight of empty grain, 1,000 grain weight, and one liter weight.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.4
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• pp.315-320
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• 1986

The investigation was conducted to find out amounts and ratios of N, P and K fertilizers applied on rice in 410 farmers' fields. The application ranges of N, P and K fertilizers, respectively, were 15.4-16.3, 7.6-8.0 and 8.2-8.5kg/10a for high yielding varieties, and 13.1-13.8, 7.0-7.1 and 6.4-7.7kg/10a for ordinary varieties. N fertilizer was applied in the ratio of 56% at basal dressing, 34% at tillering, 9% at panicle formation and 1% at heading stage. The amounts of soil amendment application were 179-192kg/10a for silicate, 1,031-1,360kg/10a for compost, 420-540kg/10a for rice straw, and 17.8-25.2 ton/10a for red earth.

• Korean Journal of Environmental Agriculture
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• v.21 no.4
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• pp.248-254
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• 2002

This study was carried out to evaluate the proper application amount of anaerobic digestion waste water and the environmental influence on rice. The waste water collected after methane fermentation process of pig manure was used as a liquid manure. Liquid manure 100%+chemical fertilizer 30%(LM 100%+CF 30) treatment was the most favorable at all growth stages of rice. The LM 100%+CF 30% treatment was applied to 100% amount of liquid manure which was correspond to the same amount of nitrogen for the standard application amount on rice, with adding 30% amount of chemical fertilizer(urea) at tillering stage. The yields of rice in the treatments of 100%(LM 100%) and 150% amount(LM 150%) of liquid manure were similar or a little higher than NPK treatment but LM 100%+CF 30% treatment was less than the NPK treatment due to the increase of straw weight and plant lodging. In periodic changes of the $NH_4-N$ and $NO_3-N$ contents, the LM 70%+CF 30% treatment in paddy soil was the highest in all treatments. The NPK and the LM 100% treatments in irrigation water quality were higher than other treatments. In infiltration water quality, $NH_4-N$ content was leached out much in the LM 150% treatment and $NO_3-N$ content was in the LM 100%+CF 30% treatment. The proper application amount of anaerobic digestion waste water as a liquid manure must be to analyse the nitrogen content of the waste water and to apply the same amount of nitrogen for the standard application amount on rice.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.280-289
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• 2002

This study was conducted to evaluate the effects of annual application of slowle cooled slag silicate fertilizer on rice yield and soil chemical properties. Field experiment was done on the condition of fertilization of silicate fertilizer 1,500 and $2,500kg\;ha^{-1}$ to the clay loam paddy field during 26 years from 1975 to 2000. The results obtained were as follows; Rice yield of NPK+silicate fertilizer $1,500kg\;ha^{-1}$ and $2,500kg\;ha^{-1}$ were increased by 15%, 8% respectively incomparion with NPK control plot in 2000($26^{th}$ year). Changes in average rice yield for 5 years interval were continually showed increase in the treat of silicate fertilizer $1,500kg\;ha^{-1}$ compared to NPK and NPK+silicate fertilizer $2,500kg\;ha^{-1}$ treated plot. The amounts of N, $K_2O$, CaO and MgO in the treat of silicate fertilizer $1,500kg\;ha^{-1}$ were much more than those of silicate fertilizer 2,500kg treated plot, and the treat of silicate fertilizer $1,500kg\;ha^{-1}$ showed higher in nutrients availability and fertilizers use efficiency than other treated plots at harvesting stage. Amount of N, $P_2O_5$, $K_2O$ and MgO in unhulled rice grain, those of CaO, MgO and $K_2O$ in rice straw and those of $K_2O$ and $SiO_2$ in rice root were positively recognized significant relationships with grain yield. According to soil analysis after experiment in 2000, the silicate fertilizer $2,500kg\;ha^{-1}$ annually applied plot were increased especially in soil organic matter, CEC and available phosphate content in comparison with NPK+silicate fertilizer $2,500kg\;ha^{-1}$ applied plot.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.247-253
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• 1985

In order to investigate the effects of water temperature on chemical properties of soil and nutrient uptake of rice plant, four varieties of rice were cultivated in a field where water temperature range was $17.3-23.0^{\circ}C$ and plant samples were taken at three growing stages and were analyzed in detail. The results were summarized as follows: 1. Organic matter content and pH of surface soil were showed no differences while the contents of $P_2O_5$ and $SiO_2$ were increased and potassium was decreased as the water temperature increased. 2. The amounts of nutrient uptake were related to the water temperature and the total nutrient contents of rice plants at harvesting stage were in order of $SiO_2$ > $K_2O$ > T-N > $P_2O_5$ > MgO. The rate of $SiO_2$/N and $K_2O$/N of rice plants grown at water temperature $23.0^{\circ}C$ were over two times to those of the water temperature $17.3^{\circ}C$. 3. Nutrient contents of rice plants showed a increasing tendency as increasing the water temperature. However, nutrient contents such as T-N at whole period, $P_2O_5$ at heading and harvesting stage, and $K_2O$ at heading stage were higher at low water temperature than those of high water temperature. 4. Most of nitrogen was translocated and accumulated in grain, potassium in straw respectively. All nutrients translocated to grain more easily as the water temperature increased.

• Korean Journal of Food Science and Technology
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• v.4 no.4
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• pp.276-284
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• 1972

A strain of Bacillus sp. which has powerful enzymatic activity and sets free a little amount of ammonia nitrogen and large amount of amino nitrogen was separated from Meju, Denzang, Chungkukjang, and paddy straw to make the soy-sauce rapidly and conveniently in the various mixing ratio of steamed soy-bean and wheat parched or steamed. Total nitrogen and amino nitrogen were increased during the maturing. The acidity of soy-sauce was increased to $1.15{\sim}1.98%$ than ordinary soy-sauce. pH were ranged in $4.6{\sim}6.0%$. The fermenting time takes 30 days while it takes at least 4 monthes in ordinary method. The best results were obtained with the mixed ratio of 1 : 1 or 1 : 2 (wheat : soy-bean).

• Applied Biological Chemistry
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• v.22 no.3
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• pp.181-189
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• 1979

In order to establish fertilizing technique for the increase of grain yield and its stability, the total absorbed amount of nutrients and nutritional status of rice plants at different growth stages were studied with respect to the nutrient contents and its relation to grain yield and yield components. This experiment was carried at three different level of nitrogen fertilization; two different seeding and transplanting times, and eight cultivars including both Japonica-and Tongil-type. The results of a part of these experiments are summarized as fallows: 1. The culm length tended to Increase with increasing fertilizer amount, but no significant difference between ordinary and heavy fertilization was observed in Tongil-type cultivars. 2. The panicle length was some what longer in ordinary and heavy fertilization than non-fertilization. 3. As the N-fertilizer level increases, the number of panicles per plant increased with higher response in Japonica-type cultivars than in Tongil-type cultivars. 4. The number of grains per panicle increased significantly in ordinary and heavy fertilization, compared to non-fertilization, but the difference in grain number per panicle among fertilizer treatment was smaller in Japonica-type cultivars than Tongil-type. 5. The 1,000 grains weight showed no significant difference among fertilization levels in ordinary transplanting, but indicated gradual decreasing tendency as the transplanting delayed. 6. In percentage of ripeness, there was no significant difference in ordinary transplanting, but hightly significant in late transplanting among N-fertilization levels and cultivars. 7. In yield, highly significant difference was shown among N-fertilizer levels and cultivars In Tongil-type variety, higher yield was obtained in ordinary fertilization than heavy fertilization. 8. The straw weight showed the tendency to increase in higher nitrogen level, but no significant difference between ordinaly and heavy fertilization was observed in Tonsil-type cultivars.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.2
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• pp.1651-1660
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• 1969

The purpose of this study is to find out the reasonable amount of evapo-transpiration required for the paddy rice plant during the whole growing season. So. On the basis of the experimental data concerning the evapo-transpiration form 1966 to 1968, the author obtained the follow results. 1) The leaf area index in the densely planted plo is generally higher than that in the conventionally planted one during the first half of growing season So, the coefficient of transpiration in the former plot is somewaht higher than in the latter, and the coefficient of water surface evaporation under the plant cover has the inverse relation between both plots. 2) It is unreasonable that coefficient of evapo-transpiration is applied to the calculation of the evapo-transpiration requirements of each growing stage, because a degree of variation in meteorological factors and in the thickness of the plant growth is involved in it. 3) It is most reasonable that the rate of transpiration and of the water surface evapoation is applied to the calculation of the transpirated amount and evaporated one in each growing stage, because it shows almost constant value in spite of any meteorological conditions in so far as the variety of rice, planted density and control of applying fertilizer are sanme and the disease and blight are negligible. 4) The ratio of the amount of transpiration to the weight of the whole air dried yields has the tendency of decreasing as that of the yields increases having almost constant value despite the amount of pan evaporation; and the value is about 210 when the weight of root parts is included to that the yields. 5) Although the required amount of transpiration during the whole growing season can be calculated with the above ratio, Fig. 7 showing the relation between the amount of transpiration and the weight of the yields is more reasonable and will be convinient to find it. And the requirements of water surface evaporation during the same season can also be directly found witht theweight air dried straw refering to Fig. 8.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.23-28
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• 1970

The effect of wollastonite and manganese dioxide on the growth of rice on an acid sulfate soil were investigated in pot experiment. 1. Since aluminum content in the leachate of soil was reduced with increasing the pH and these chemical changes in the leachate were more pronounced by applying wollastonite, aluminum toxicity in flooded paddy rice was overcome by applying wollastonite, or flooding. 2. Poor growth of rice with iron toxicity-like symptoms on the untreated acid sulfate soil may be caused by excess iron and sulfur. Plants applied wollastonite, however, grew normally and did not show any symptoms. Iron and sulfur contents in the plant was reduced by applying wollastonite. 3. Because of the iron content in the both leachate and plant can be lowered by applying wollastonite, iron-toxicity was averted by applying the wollastonite. 4. Application of manganese dioxide in combination with wollastonite did not counteracted iron content in the plant as compared with the wollastonite treatment. 5. The application of wollastonite increased the dry weight of straw and grain yield. Manganese dioxide with wollastonite caused the increase of number of spickelets per panicles and ripened grains as compared with wollastonite. 6. From these results it can be concluded that the major cause of the poor growth of rice on acid sulfate soil is iron toxicity and the Fe-toxicity can be reduced by application of wollastonite.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.3
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• pp.3059-3088
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• 1973

The Object of research was laid on the dry paddy field which had a low level of underground water, rather than on a paddy field with a high level of underground water. In the treatment of the clay paddy field before transplanting we employed 3 kinds of methods; deep plowing, development of cracks by drying the surface of the field under which pipe drain was built. This study was to find which one, among these three methods, is the most effective to let roots extend to deep zone and increase the yield of rice and at the same time, for trafficability of large scale machinery which will be introduced to the harvest, in the light of the earth bearing capacity in relation with underground drainage. In the treatments of plots, 1) the kyong plot was plowed 39 days before transplanting and dried, 2) the kyun plot was plowed again 2days before transplanting after plowing 39 days before transplanting, leveling field surface in the saturation with water and developing the cracks by drying, 3) the kyunam plot was plowed again 2 days before transplanting after setting the drainage pipe and at the same time plowing 39 days before transplanting, leveling field surface in the saturation with water and developing the cracks by drying. Also each plot above had three different levels of soil depth, respectively; that is 15cm, 25cm, 35cm. The kyong plot with 15cm-depth was he control. The results obtained were as follows; 1. The kyunam plot showed a remarkably lager amount of water consumption by better underground drainage than the kyong and the kyun plot, and the kyong plot indicated a greater amount of water consumption than the kyun plot. Therefore the amount of available rainfall was decreased in the order of kyunam>kyong>kyun. The net duty of water decreased in the order of kyunam>kyong>kyun and its showed about 105cm in depth at the kyunam plot, about 70cm in depth at the kyong plot and about 45cm in depth at kyun plot, regardless of soil depth. 2. According to the tendency that the weight of the total root was effected by the maximum depth of the crack, it seemed that the root development was more affected by the depth of the crack than by only the crack itself. The weight of the total roots tended to increase as the depth of the crack got deeper and deeper, and the weight of the total roots was increased in the order of kyun<kyunam<kyong. 3. In the growing of the plant height, the difference did not appear at the beginning of growing(peak period of tillering) of any plot, But for the mid period of growing(ending period of tillering) to the period of young panicle formation, the deeper the depth of plot is, the more the growing goes down. On the contrary at the late period of growing, growth was more vigorous in the plot with deep depth than in the plot with shallow depth. Since the midperiod of growing, in the light of experimental treatment, the kyun plot was not better in growing than the other two plots and no remarkable defference was shown between the kyunam and the kyong plot, but the kyunam plot had the tendency of superiority in growing plant height. 4. As the depth of plot went deeper, the decreasing tendency was shown in the number of tillers through a whole period of growingi. When the above results were observed concering each plot of experimental treatment, the kyun plot was always smaller in the number of tiilers than the kyunam and the kvong plot, and the kyong plot was slightly larger than the kyunam plot in the number of tillers. 5. When each plot of the different experimental treatments was compared with the control plot(15-kyong), yield(weight of grains) was increased by 17% for the 35-kyong plot, by 10% for the 35-kyunam and yields for the other plots were less or nomore than the control plot. On the whole, as the depth of plot went deeper, yields for plots was increased in the order of kyong>kyunam>kyun. 1% of significance between the levels of depths and 5% of significance between the treatments were shown. 6. The depth of consumptive water which was more effective on the weight of grains is that of the last half period. When the depth of consumptive water was increased at the range of less than 2.7cm/day in the 15cm plot, 3.0cm/day in the 25cm plot and 3.3cm/day in the 35cm plot, the weight of grains was increased, and at the same time the weight of grains was increased as the depth of plot went deeper. The deeper plots was of advantage to the productivity at the same depth of consumptive water. 7. The increase in the weight of grains in propertion to the weighte of root showed a tendency to increase depending on the depth of plot at each plot of the same weight of roots. The weight of roots and grains together increasezd in the order of kyun>kyunam>kyong, considering each treatment of experimental plot. The weight of grains was in relation to the minimum water content ratio during the midperiod of surface drainage and the average earth temperature was mainly affected by the minimum water content ratio because it was relatively increased in proportion to the water content ratio(at less than 40%) 8. The weight ratio of straw to grain showed an increasing tendency at the plot of shallow depth and had a relation of an inversely exponental function to the weight of roots. At the same depth of plot except the 15cm plot, the weight ratio of straw to grain was increased in proportion to the depth of consumptive water. The weight of grains was increased as the depth of consumptive water was increased to some extent, but at the same time the weight of ratio of straw to grain was increased. 9. At a certain texture of soils the increase in the amount of the cracks depends on meteorological conditions, especially increase in amounts of pan evaporation. So if it rains during the progressing of field drying the cracks largely decrease. The amount of cracks of clay soil had relation of inversely exponental function to the water content ratio(at more than 25%). The maximum depth of crack kept generally a constant value at less than 30% of water content ratio. 10. The cone index showed the tendency that it was propertional to the amount of cracks within a certain limit but more or less inversely proportional over a certain limit. The water content ratio at the limit may be about 25%. 11. The increase in the cone index with the progressing of time after final surface drainage showed the tendency that it was proportional to the depth of consumptive water at the last half of growing period. Based on the same depth of if the cone index in the kyunam plot was much larger than in the other two plots and that in the kyong plot was much smaller than in the kyun plott, as long as the depth of plot was deeper, especially in the 35-kyong plot. 12. In the light of a situation where water content ratio of soil decreased and the cone index increased after final surface drainage the porogress of the field dryness was much more rapid in the kyunam plot than in the kyong plot and the kyun plot, especially slowest in the kyong plot. In the plot with deeper zone the progress was much slower. The progress requiring the value of the cone index, $2.5kg/cm^2$, that working machinary can move easily on the field changed with the time of final surface drainage and the amount of rainfall, but without nay rain it required, in the kyunam plot, about 44mm in total amount of pan evaporation and more than 50mm in the other two plots. Therefore the drying in the kyunam plot was generally more rapid in the kyunam plot was generally more rapid over 2days than in the kyun plot, and especially may be more rapid over 5days than in the 35-kyong plot.