• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.41-51
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• 1991

This study was conducted to determine the effect of 20 years long term fertilizations on the physical and chemical properties of paddy soil and the growth, yield, yield components and grain development of rice. Non-fertilized, PK, NK, NP, NPK, NPK + compost, NPK+straw and NPK+lime have been applied since 1968 after surface paddy soil was removed. NPK+compost and NPK+straw applications increased the content of organic matter, available P and CEC, and lime increased soil acidity and SiO$_2$ content. While chemical contents in non-fertilized treatment were low as compared with other treatments. Soil porosity was higher in NPK+straw (51.4%) and NPK+lime(53.1%) than in NPK application (49.8%). Soil hardness was highest in the NPK application and was lowest in the NPK + lime. Continuous application of straw with NPK markedly increased the content of aggregate with over 1mm(19.6%) as compared with NPK application (7.1%). Plant height, tiller number, root number, leaf area index and total dry weight were higher in the applications of compost, straw and lime with NPK than in any other treatments. Brown rice yield in non-fertilized, PK and NP applications was decreased 45, 55, 15 and 5% of that in NPK application, respectively, while application of compost, straw and lime with NPK increased the yield by 11, 14 and 4%, respectively, during 20 years. The number of differentiated rachis branchs in the application of compost, straw and lime was 17 to 21 and that in the other application was 13 to 15, whereas the degenerated rachis branchs was low in the application of compost, straw and lime with NPK. The applications having higher level of perfect rice grain such as non-fertilized, NPK+compost, NPK+straw and NPK+lime had high grain weight and had low level of white core rice, white belly rice. The white core and belly rice was highest in the NP application and notched belly rice kernel was markedly increased in NK and NP applications. The period of grain filling was 30 DAH at NP and NPK applications, 35 DAH at NK and NPK+lime, 40DAH at NPK+compost and NPK+ straw, and 45DAH at non-fertilized, respectively.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.288-294
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• 1997

Field and pot expeiments were carried out to evaluate the interaction between quinclorac and bensulfuron-methyl on growth of the rice plants(Oryza sativa L. cv. Choocheongbyeo) at 20, 45, 65 days-old stages. Quinclorac and bensulfuron-methyl showed antagonistic interaction at both stages, which were detected by the Chisaka's method at isobles of 10% growth inhibition. The antagonism indices were -0.63 and -1.67 at 20 and 65 days-old seedling stages, respectively. Leaf-rolling of rice occurred when quinclorac was applied at 600g ai/ha or more at 20 days-old seedling stage, while it occured at the dose of 900g ai/ha at 65 days-old stage. Bensulfuron-methyl reduced plant height and dry weight as well as tiller production at both stages. Leaf-rolling of rice was reduced when mixture of quinclorac and bensulfuron-methyl was applied due to antagonism of the two herbicides. High temperatures increased the phytotoxicity of bensulfuron-methyl, while the phytotoxicity caused by quinclorac alone was not responsive to temperature. The antagonistic effect between quinclorac and bensulfuron-methyl increased at low temperature as tested by the Colby's method.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.3
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• pp.316-338
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• 1988

To identify the physiological phenomena on the sudden wilting of japonica/indica crossed varieties, Pot experiment was carried out under the heavy N application with various levels of potassium in Japan. The results obtained are as follows. 1. Sudden wilting was occurred in both varieties used, Yushin and Milyang 23. The former showed a higher degree than the latter. 2. Sudden wilting was occurred into two types, one at early ripening stage and the other at late ripening stage. The former type was found in the field with low potassium supply and the latter was seemed to be related to varietal wilting tolerence. 3. By the investigation of concerning the effective tillering rate and the change of dry weight of each organ at the heading stage, it was inferred that the growth status from young panicle formation stage to heading stage were related to sudden wilting tolerence. 4. Manganese content at heading stage, ratio of Fe/Mn and Fe. Fe/Mn in stern at late ripening stage and $K_2$ O/N ratio of stem at harvesting stage were recognized as the specific factors in connection with sudden wilting. Mn content in the sudden wilting rice plant was already in creased remarkably at heading stage. In relation to root age and absoption characteristics of Mn, the senility of root before heading stage was inferred as the cause of increase the value of Fe/Mn or Fe. Fe/Mn. 5. The $K_2$ O/N ratio of culm at harvesting stage was lower in upper node than lower node in relation to sudden wilting. And it was well accordance with the fact that the symptoms of sudden wilting proceeded from upper leaf to lower leaf. These phenomenon was different from the usual one that the effect of potassium deficiency was more remarkable in lower node than upper node. 6. All varieties which have a condition of potassium deficiency have a high degree of nitrogen content of leaves at heading stage and the $K_2$ O/N ratio of each organ was low, Especialy, $K_2$ O/N ratio is much lower in sheath and culm than leaves.

• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.143-149
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• 1996

The study was carried out to find the optimum planting density classified by the different using types in Anthriscus sylvestylis Hoffm. In the different using types, plant height of vegetable type in $30\times20cm$ was 35.2cm, but plant heights of other types were much lower than that of vegetable type. Fresh leaf yield was highest in the vegetable type at the $30\times20cm$ with 3,300kg, in the medicinal type at the $60\times30cm$ with 2,800kg, and in the combination type at the $40\times20cm$, In comparison of underground parts of dry root weight, the highest yield was 3,320kg at $30\times20cm$ of the vegetable type, 2,170kg at $60\times20cm$ of medicinal type, and 2,210kg per ha. at $45\times20cm$ of combination type, respectively. It was showed that the optimum planting densities were $30\times20cm$ in vegetable type, $60\times30cm$ in medicinal type, and $45\times20cm$ in combination type.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.374-383
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• 2010

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. Kim et al. (2009) have measured backscattering coefficients of paddy rice using L-, C-, X-band scatterometer system with full polarization and various angles during the rice growth period and have revealed the necessity of near-continuous automatic measurement to eliminate the difficulties, inaccuracy and sparseness of data acquisitions arising from manual operation of the system. In this study, we constructed an X-band automatic scatterometer system, analyzed scattering characteristics of paddy rice from X-band scatterometer data and estimated rice growth parameter using backscattering coefficients in X-band. The system was installed inside a shelter in an experimental paddy field at the National Academy of Agricultural Science (NAAS) before rice transplanting. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables and personal computer that controls frequency, polarization and data storage. This system using automatically measures fully-polarimetric backscattering coefficients of rice crop every 10 minutes. The backscattering coefficients were calculated from the measured data at a fixed incidence angle of $45^{\circ}$ and with full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh dry weight and Leaf Area Index (LAI) that were collected at the same time of each rice growth parameter. We examined the temporal behaviour of the backscattering coefficients of the rice crop at X-band during rice growth period. The HH-, VV-polarization backscattering coefficients steadily increased toward panicle initiation stage, thereafter decreased and again increased in early-September. We analyzed the relationships between backscattering coefficients in X-band and plant parameters and predicted the rice growth parameters using backscattering coefficients. It was confirmed that X-band is sensitive to grain maturity at near harvesting season.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.75-80
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• 1999

A field experiment was carried out to determine the optimum application level of dicamba herbicide for efficient control of Abutilon avicennae in silage corn field. Five treatments of application levels (0 ; control, $0.75{\ell},\;1.0{\ell},\;1.25{\ell}\;and\;1.5{\ell}$) were arranged at National Livestock Research Institute, RDA, Suwon in 1995 and 1996. The hybrid silage corn was P 3352 and dicamba herbicide was applied at 5~6 leaf stage of corn. The growth of corn was poor in control plot, and the days for tasseling and silking were delayed 2~3 days when compared with the plots of herbicide application. The control efficiency of Abutilon avicennae was excellent as 94.7~98.1% in the plots of dicamba application. A slight injury of herbicide was observed at early stage of corn when applied at $1.0{\ell},\;1.25{\ell}\;and\;1.5{\ell}$ of dicamba per ha. Forage dry matter(DM) yield, length and weight of ear in the plots of dicamba treatments were significantly higher than those of control. The DM yield of control(12,070kg/ha) was only 64.2~66.9% of dicamba treatment plot(18,050~18,795kg/ha). However, there was no yield difference among dicamba application level. The percentage of ear to total DM yield was ranged from 53.4 to 56.8%. The nutritive value(crude protein, ADF, NDF, digestibility and TDN) was very similar among all treatments. From the above results, it is recommended that optimum application level of dicamba herbicide was $0.75{\sim}1.0{\ell}/ha$ for efficient control of Abutilon avicennae and for silage corn production without herbicide injury.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.351-356
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• 2009

Growth, milled rice yield and edible quality of rice in naturally reseeded Chinese milk vetch(CMV)-rice cropping system was compared with those in rice mono cropping on silty loam soil in Milyang from 2006-2008. Practicing natural reseeding technology recorded high CMV reseeding stand ranging from 565-805 plants $m^{-2}$ and resulting in the production of 13.0-17.0 kg N/10a from the CMV plant biomass which is greater than the recommendation rate of 9 kgN/10a. The plant height of rice plant grown in natural reseeding field is shorter at tillering stage but it was similar to the rice mono cropping at later stage. Dry matter production had similar trend to plant height. On the other hand, the leaf color in naturally reseeded CMV-rice cropping system was similar to the rice mono cropping up to panicle heading stage but it was high at mature stage, indicating that the nitrogen was provided by the CMV decomposition until later stage of rice. The yield components such as culm number $m^{-2}$ was greater and 1,000-brown rice weight was heavier than those of rice mono cropping but the ripened grain ratio was lower in naturally reseeded CMV-rice cropping system. Milled rice yield of naturally reseeded CMV-rice cropping system was similar to that of rice mono cropping. However, head rice percentage of milled rice was lower due to low ripened grain ratio. This result indicates that natural CMV reseeding technology can completely replace chemical fertilizer in CMV-rice cropping system.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.189-196
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• 2011

The objective of this study was to investigate the effects of light intensity and electrical conductivity (EC) of nutrient solution during short day treatment in an ebb and flow systems on the growth and nutrient uptake of potted Kalanchoe blossfeldiana 'Rako' and the nutrient accumulation of growing medium. Nutrient concentrations in the growing medium were also analyzed to investigate the accumulation rates of macro-nutrients such as T-N, P, K, Ca, and Mg, respectively. To achieve the objectives, plants were fed with a nutrient solution with 1.2, 1.8, or $2.4dS{\cdot}m^{-1}$ under three daily photosynthetic photon flux (PPF) of 4.26, 5.51, or $9.75mol{\cdot}m^{-2}{\cdot}d^{-1}$. Both light intensity and EC of nutrient solution significantly influenced the crop growth. The elevation of PPFs resulted in the increase of plant growth. For each light condition, plant growth, such as dry and fresh weight and leaf area, was the highest when the electrical conductivity of nutrient solution was controlled to $2.4dS{\cdot}m^{-1}$. However, growth was acceptable in the EC ranges from 1.8 to $2.4dS{\cdot}m^{-1}$. Both light intensity and EC of nutrient solution significantly influenced the uptake of nutrients in the solution tanks and the accumulation of nutrients in the growing medium. As the EC of nutrient solution was elevated, the absorption rates of $NO_3^-$, $PO_4^{-3}$, $K^+$, and $Mg^{2+}$ by crops and accumulation of those in growing medium increased, but the light intensity did not significantly influence the absorption rates. Based on the above results, the regression models were suggested for anticipating the macro-nutrient accumulations in growing medium.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.616-623
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• 2010

Plant samples from 49 sites for Chinese cabbage, 28 sites for radish, 16 sites for cabbage, 8 sites for head lettuce, 20 sites for onion from farmers' and experimental fields in highland of Korea were collected and analyzed to find out the uptake patterns of nitrogen (N), phosphorus (P) and potassium (K) by altitude. Dry weight and uptake of N, P and K were increased at higher altitude in most vegetable crops. Nutrition uptake by Chinese cabbage was 163 ~ 283 kg $ha^{-1}$ for N, 42 ~ 69 kg $ha^{-1}$ for $P_2O_5$ and 146 ~ 270 kg $ha^{-1}$ for $K_2O$ according to altitude. Nutrient uptake by radish according to altitude was 153~159 kg $ha^{-1}$ for N, 38 ~ 46 kg $ha^{-1}$ for $P_2O_5$, and 151 ~ 185 kg $ha^{-1}$ for $K_2O$. In case of cabbage, the plant uptakes of N, P, and K were increased at altitudes of 600 ~ 1,000 m. Nutrient uptake of cabbage was 280 ~ 348 kg $ha^{-1}$ for N, 34 ~ 87 kg $ha^{-1}$ for $P_2O_5$, and 209 ~ 290 kg $ha^{-1}$ for $K_2O$ according to altitude. Uptakes of N-$P_2O_5-K_2O$ by head lettuce at an altitude of 800 ~ 850 m were 93-26-126 kg $ha^{-1}$, respectively. Uptakes of N-$P_2O_5-K_2O$ by onions at an altitude of 600 ~ 800 m were 313-140-234 kg $ha^{-1}$, respectively, but there was no tendency in nutrition uptake patterns by altitude. Small cultivation areas used for leaf vegetable crops do not have fertilizer recommendation standards in alpine regions. It might be preferable to use a correction factor equivalent to the index of available nutrient uptake for the determination of N, P and K fertilizer application rates.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.3
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• pp.41-56
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• 1989

The purpose of this study is to find out the basic data for irrigation plans of garlic and cucumber during the growing period, such as total amount of evapotranspiration, coefficients of evapotranspiration at each growth stage, the peak stage of evapotranspiration and the maximum evapotranspiraton, optimum irrigation point, total readily available moisture, and intervals of irrigation date. The plots of experiment were arranged with split plot design which were composed of two factors, irrigation point for main plot and soil texture for split plot, and three levels ; irrigation points with pP 1.7-2.1, pP 2.2-2.5, pP 2.6-2.8, for garlic and those with pP 1.9, pF 2.3, pP 2.7, for cucumber, soil textures of silty clay, sandy loam and sandy soil for both garlic and cucumber, with two replications. The results obtained are summarized as follows 1.There was the highest significant correlation between the avapotranspiration of garlic and cucumber and the pan evaporation, beyond all other meteorological factors considered, as mentioned in the previous paper. Therefore, the pan evaporation is enough to be used as a meteorological index measuring the quantity of evapotranspiration. 2.1/10 probability values of maximum total pan evaporation during growing period for garlic and cucumber were shown as 495.8mm and 406.8mm, respectively, and those of maximum ten day pan evaporation for garlic and cucumber, 63.8mm and 69.7mm, respectively. 3.The time that annual maximum of ten day pan evaporation can be occurred, exists at any stage between the middle of May and the late of June(harvest period) for garlic, and at any stage of growing period for cucumber. 4.The magnitude of evapotranspiration and of its coefficient for garlic and cucumber was occurred in the order of pF 1.7-2.1>pF 2.2-2.5>pF 2.6-2.8 and of pF 1.9>pF 2.3>pF2.7 respectively in aspect of irrigation point and of sandy loam>silty clay>sandy soil in aspect of soil texture for both garlic and cucumber. 5.The magnitude of leaf area index was shown in the order of pF 2.2-2.5>pF 1.7-2.1>pF 2.6-2.8 for garlic and of pF 1.9>pF 2.3>pF 2.7 for cucumber in aspect of irrigation point, and of sandy loam>sandy soil>silty clay in aspect of soil texture for both garlic and cucumber. 6.1/10 probability value of evapotranspiration and its coefficient during the growing period for garlic were shown as 391.7mm and 0.79 respectively, while those of cucumber, 423.lmm and 1.04 respectively. 7.The time the maximum evapotranspiration of garlic can be occurred is at the date of thirtieth before harvest period and the time for cucumber is presumed to be at the date of sixtieth to seventieth after transplanting, At that time, 1/10 probability value of ten day evapotranspiration and its coefficient for garlic is presumed to be 65.lmm and 1.02 respectively, while those of cucumber, 94.8mm and 1.36 respectively. 8.In aspect of irrigation point, the weight of raw garlic and cucumber were increased in the order of pF 2.2-2.5>pF 1.7-2.1>pF 2.6-2.8 and of pF 1.9>pF 2.3>pF 2.7 respectively. Therefore, optimum irrigation point for garlic and cucumber is presumed to be pF 2.2-2.5 and pF 1.9 respectively, when the significance of yield between the different irrigation treatments is considered. 9.Except the mulching period of garlic that soil moisture extraction patterns were about the same, those of garlic and cucumber have shown that maximum extraction rate exists at 7cm deep layer at the beginning stage after removing mulching for garlic and at the beginning stage of growth for cucumber and that extraction rates of 21cm to 35cm deep layer are increased as getting closer to the late stage of growth. 10.Total readily available moisture of garlic in silty clay, sandy loam, sandy soil become to be 18.71-24.96mm, 19.08-25.43mm, 10.35- 13.80mm respctively on the basis of the optimum irrigation point with pF 2.2-2.5, while that of cucumber, 11.8lmm, 12.03mm, 6.39mm respectively on the basis of the optimum irrigation point with pF 1.9. 11.The intervals of irrigation date of garlic and cucumber at the growth stage of maximum consumptive use become to be about three and a half days and one and a half days respectively, on the basis of each optimum irrgation point.