• 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.

• Food Science and Preservation
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• v.30 no.2
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• pp.272-286
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• 2023

Garlic sprouts can provide data on functional and food processing materials. This study compared the leaves, bulbs, and roots of garlic sprouts grown on smart farms during two growth periods (20 and 25 days). In addition, data for garlic bulbs grown in open fields were presented as reference materials. All garlic sprouts' total free sugar content decreased as the growth period increased. All plant parts' total organic acid content decreased as the growth period progressed, except for the root section. Potassium, phosphorus, and sulfur content increased during growth in all parts of the garlic sprouts. Alliin content decreased in all parts of the plant over time, whereas thiosulfinate content increased in the roots but decreased in the leaves and bulbs. Total polyphenol content increased in all parts of the plant during the growth period, except for the bulb, whereas the flavonoid content did not change significantly over time. The 2,2-diphenyl-1-picrylhydrazy (DPPH) and 2,2'-azinobis (3-ethylben-zothiazoline 6-sulfonate) (ABTS) free radical scavenging activities, as well as the superoxide dismutase (SOD)-like activity of garlic sprouts were 37.45-65.47%, 59.12-89.81%, and 89.52-98.59%, respectively. These activities tend to decrease during the growth period. Here, we showed that garlic sprouts have higher levels of functional substances and physiological activities than general garlic sprouts. It was also determined that a growth period of 20 days was suitable for garlic sprouts. Data for research on functional and food-processing materials can be obtained by analyzing garlic sprouts produced by smart farms.

• Food Science and Preservation
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• v.30 no.5
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• pp.833-846
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• 2023

Onions are essential vegetables for Koreans' diet and have various physiological activities. However, problems arise every year due to the imbalance between production and demand. Therefore, in this study, nutritional and functional components, and antioxidant activity were analyzed for each growth period in order to utilize onions at the disposal period. Whole onions harvested before June showed higher values of general ingredients, inorganic ingredients, organic acids, spiraeoside, quercetin, total chlorophyll, and antioxidant activity than bulbs harvested in June. On the other hand, the free sugar content was higher in the bulb of the harvest season in June than in whole onions. The total thiosulfinate content was similar to that of whole onions and bulbs in the early stages of growth. In addition, as a result of comparing the flavonoid compound and antioxidant activity of each onion variety, whole onions harvested at 25 weeks were higher in content than onion bulbs harvested in June. In conclusion, onions before the harvest season in June had excellent utilization value as food. Harvesting before 21 weeks is desirable for growing onions with excellent nutritional value, while harvesting after 23 weeks is recommended for excellent functional components and antioxidant activity in onions.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.418-428
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• 2007

Physical and chemical properties of the aggregate by-products including sludge and crushed dust samples collected from the 21 private companies throughout the country were analyzed to evaluate possible usage of the by-products as artificial soil materials for plantation. The pH of the materials ranged from 8.0 to 11.0. The organic matter content was $2.85g\;kg^{-1}$, and the total nitrogen content and available phosphate content were low as 0.7 percents and $12.98mg\;kg^{-1}$, respectively. Exchangeable $Ca^{2+}$, $Mg^{2+}$, $K^+$, and $Na^+$ were 2.29, 0.47, 0.02 and $0.05cmol\;kg^{-1}$, respectively. Heavy metal contents were lower than the limits regulated by environmental law of Korea. Textural analysis showed that most of the materials were silt loam with low water holding capacity ranged from 0.67 to 7.41 percents, and with low hydraulic conductivity ranged from 0.4 to $2.8m\;s^{-1}$. Mineralogical analysis showed that the aggregate by product materials were mostly composed of silicate, alumina and ferric oxides except calcium oxide dominant materials derived from limestones. The primary minerals were quartz, feldspars and dolomites derived from granite and granitic gneiss materials. Some samples derived from limestone material showed calcite and graphite together with the above minerals. According to the result, it can be concluded that the materials could be used as the artificial soil material for plantation after proper improvement of the physico-chemical properties and fertility.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.103-134
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• 1977

The physiological and biochemical role of potassium for upland crops according to recent research reports and the nutritional status of potassium in Korea were reviewed. Since physical and chemical characteristics of potassium ion are different from those of sodium, potassium can not completely be replaced by sodium and replacement must be limited to minimum possible functional area. Specific roles of potassium seem to keep fine structure of biological membranes such as thylacoid membrane of chloroplast in the most efficient form and to be allosteric effector and conformation controller of various enzymes principally in carbohydrate and protein metabolism. Potassium is essential to improve the efficiency of phoro- and oxidative- phosphorylation and involve deeply in all energy required metabolisms especially synthesis of organic matter and their translocation. Potassium has many important, physiological functions such as maintenance of osmotic pressure and optimum hydration of cell colloids, consequently uptake and translocation of water resulting in higher water use efficiency and of better subcellular environment for various physiological and biochemical activities. Potassium affects uptake and translocation of mineral nutrients and quality of products. potassium itself in products may become a quality criteria due to potassium essentiality for human beings. Potassium uptake is greatly decreased by low temperature and controlled by unknown feed back mechanism of potassium in plants. Thus the luxury absorption should be reconsidered. Total potassium content of upland soil in Korea is about 3% but the exchangeable one is about 0.3 me/100g soil. All upland crops require much potassium probably due to freezing and cold weather and also due to wet damage and drought caused by uneven rainfall pattern. In barley, potassium should be high at just before freezing and just after thawing and move into grain from heading for higher yield. Use efficiency of potassium was 27% for barley and 58% in old uplands, 46% in newly opened hilly lands for soybean. Soybean plant showed potassium deficiency symptom in various fields especially in newly opened hilly lands. Potassium criteria for normal growth appear 2% $K_2O$ and 1.0 K/(Ca+Mg) (content ratio) at flower bud initiation stage for soybean. Potassium requirement in plant was high in carrot, egg plant, chinese cabbage, red pepper, raddish and tomato. Potassium content in leaves was significantly correlated with yield in chinese cabbage. Sweet potato. greatly absorbed potassium subsequently affected potassium nutrition of the following crop. In the case of potassium deficiency, root showed the greatest difference in potassium content from that of normal indicating that deficiency damages root first. Potatoes and corn showed much higher potassium content in comparison with calcium and magnesium. Forage crops from ranges showed relatively high potassium content which was significantly and positively correlated with nitrogen, phosphorus and calcium content. Percentage of orchards (apple, pear, peach, grape, and orange) insufficient in potassium ranged from 16 to 25. The leaves and soils from the good apple and pear orchards showed higher potassium content than those from the poor ones. Critical ratio of $K_2O/(CaO+MgO)$ in mulberry leaves to escape from winter death of branch tip was 0.95. In the multiple croping system, exchangeable potassium in soils after one crop was affected by the previous crops and potassium uptake seemed to be related with soil organic matter providing soil moisture and aeration. Thus, the long term and quantitative investigation of various forms of potassium including total one are needed in relation to soil, weather and croping system. Potassium uptake and efficiency may be increased by topdressing, deep placement, slow-releasing or granular fertilizer application with the consideration of rainfall pattern. In all researches for nutritional explanation including potassium of crop yield reasonable and practicable nutritional indices will most easily be obtained through multifactor analysis.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.2
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• pp.97-104
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• 1979

According to Soil Taxonomy which has been developed over the past 20 years in the soil conservation service of the U. S. D. A, Soils in Korea are classified. This system is well suited for the classification of the most of soils. But paddy field soils have some difficulties in classification because Soil Taxonomy states no proposals have yet been developed for classifying artificially irrigated soils. This paper discusses some problems in the application of Taxonomy and suggestes the classification of paddy field soils in Korea. Following is the summary of the paper. 1. Anthro aquic, Aquic Udipsamments : The top soils of these soils are saturated with irrigated water at some time of year and have mottles of low chroma(2 or less) more than 50cm of the soil surface. (Ex. Sadu, Geumcheon series) 2. Anthroaquic Udipsamments : These sails are like Anthroaquic, Aquic Udipsamments except for the mottles of low chroma within 50cm of the soil surface. (Ex. Baegsu series) 3. Halic Psammaquents : These soils contain enough salts as distributed in the profile that they interfere with the growth of most crop plants and located on the coastal dunes. The water table fluctuates with the tides. (Ex. Nagcheon series) 4. Anthroaquic, Aquic Udifluvents : They have some mottles that have chroma of 2 or less in more than 50cm of the surface. The upper horizon is saturated with irrigated water at sometime. (Ex. Maryeong series) 5. Anthro aquic Udifluvents : These soils are saturated with irrigated water at some time of year and have mottles of low chroma(2 or less) within 50cm of the surface soils. (Ex. Haenggog series) 6. Fluventic Haplaquepts : These soils have a content of organic carbon that decreases irregularly with depth and do not have an argillic horizon in any part of the pedon. Since ground water occur on the surface or near the surface, they are dominantly gray soils in a thick mineral regolith. (Ex Baeggu, Hagseong series) 7. Fluventic Thapto-Histic Haplaquepts : These soils have a buried organic matter layer and the upper boundary is within 1m of the surface. Other properties are same as Fluventic Haplaquepts. (Ex. Gongdeog, Seotan series) 8. Fluventic Aeric Haplaquepts : These soils have a horizon that has chroma too high for Fluventic Haplaquepts. The higher chroma is thought to indicate either a shorter period of saturation of the whole soils with water or some what deeper ground water than in the Fluventic Haplaquepts. The correlation of color with soil drainage classes is imperfect. (Ex. Mangyeong, Jeonbug series) 9. Fluventic Thapto-Histic Aeric Haplaquepts : These soils are similar to Fluventic Thapto Histic Haplaquepts except for the deeper ground water. (Ex. Bongnam series) 10. Fluventic Aeric Sulfic Haplaquepts : These soils are similar to Fluventic Aeric Haplaquepts except for the yellow mottles and low pH (<4.0) in some part between 50 and 150cm of the surface. (Ex. Deunggu series) 11. Fluventic Sulfaquepts : These soils are extremely acid and toxic to most plant. Their horizons are mostly dark gray and have yellow mottles of iron sulfate with in 50cm of the soil surface. They occur mainly in coastal marshes near the mouth of rivers. (Ex. Bongrim, Haecheog series) 12. Fluventic Aeric Sulfaquepts : They have a horizon that has chroma too high for Fluventic Sulfaquepts. Other properties are same as Fluventic Sulfaquepts. (Ex. Gimhae series) 13. Anthroaquic Fluvaquentic Eutrochrepts : These soils have mottles of low chroma in more than 50cm of the surface due to irrigated water. The base saturation is 60 percent or more in some subhroizon that is between depth of 25 and 75cm below the surface. (Ex. Jangyu, Chilgog series) 14. Anthroaquic Dystric Fluventic Eutrochrepts : These soils are similar to Anthroaquic Fluvaquentic Eutrochrepts except for the low chroma within 50cm of the surface. (Ex. Weolgog, Gyeongsan series) 15. Anthroaquic Fluventic Dystrochrepts : These soils have mottles that have chroma of 2 or less within 50cm of the soil surface due to artificial irrigation. They have lower base saturation (<60 percert) in all subhorizons between depths of 25 and 75cm below the soil surface. (Ex. Gocheon, Bigog series) 16. Anthro aquic Eutrandepts : These soils are similar to Anthroaquic Dystric Fluventic Eutrochrepts except for lower bulk density in the horizon. (Ex. Daejeong series) 17. Anthroaquic Hapludalfs : These soils' have a surface that is saturated with irrigated water at some time and have chroma of 2 or less in the matrix and higher chroma of mottles within 50cm of the surface. (Ex. Hwadong, Yongsu series) 18. Anthro aquic, Aquic Hapludalfs : These soils are similar to Anthro aquic Hapludalfs except for the matrix that has chroma 2 or less and higher chroma of mottles in more than 50cm of the surface. (Ex. Geugrag, Deogpyeong se ries)

• Korean journal of applied entomology
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• v.13 no.3 s.20
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• pp.105-133
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• 1974

The present study is an attempt to solve the basic problems involved in the control of the Sclerotium disease. The biologic stranis of Sclerotium rolfsii Sacc., pathogen of Sclerotium disease of Magnolia kobus, were differentiated, and the effects of vitamins, various nitrogen and carbon sources on its mycelial growth and sclerotial production have been investigated. In addition the relationship between the cultural filtrate of Penicillium sp. and the growth of Sclerotium rolfsii, the tolerance of its mycelia or sclerotia to moist heat or drought and to Benlate (methyl-(butylcarbamoy 1)-2-benzimidazole carbamate), Tachigaren (3-hydroxy-5-methylisoxazole) and other chemicals were also clarified. The results are summarizee as follows: 1. There were two biologic strains, Type-l and Type-2 among isolates. They differed from each other in the mode of growth and colonial appearance on the media, aversion phenomenon and in their pathogenicity. These two types had similar pathogenicity to the Magnolia kobus and Robinia pseudoacasia, but behaved somewhat differently to the soybaen and cucumber, the Type-l being more virulent. 2. Except potassium nitrite, sodium nitrite and glycine, all of the 12 nitrogen sources tested were utilized for the mycelial growth and sclerotial production of this fungus when 10r/l of thiamine hydrochloride was added in the culture solution. Considering the forms of nitrogen, ammonium nitrogen was more available than nitrate nitrogen for the growth of mycelia, but nitrate nitrogen was better for sclerotia formation. Organic nitrogen showed different availabilities according to compounds used. While nitrite nitrogen was unavailable for both mycelial growth and sclerotial formation whether thiamine hydrochlioride was added or not. 3. Seven kinds of carbon sources examined were not effective in general, as long as thiamine hydrochloride was not added. When thiamine hydrochloride was added, glucose and saccharose exhibited mycelial growth, while rnaltose and soluble starch gave lesser, and xylose, lactose, and glycine showed no effect at all,. In the sclerotial production, all the tested carbon sources, except lactose, were effective, and glucose, maltose, saccharose, and soluble starch gave better results. 4. At the same level of nitrogen, the amount of mycelial growth increased as more carbon Sources were applied but decreased with the increase of nitrogen above 0.5g/1. The amount of sclerotial production decreased wi th the increase of carbon sources. 5. Sclerotium rolfsii was thiamine-defficient and required thiamine 20r/l for maximun growth of mycelia. At a higher concentration of more than 20r/l, however, mycelial growth decreased as the concentration increased, and was inhibited at l50r/l to such a degree of thiamine-free. 6. The effect of the nitrogen sources on the mycelial growth under the presence of thiamine were recognized in the decreasing order of $NH_4NO_3,\;(NH_4)_2SO_4,\;asparagine,\;KNO_3$, and their effects on the sclerotial production in the order of $KNO_3,\;NH_4NO_3,\;asparagine,\;(NH_4)_2SO_4$. The optimum concentration of thiamine was about 12r/l in $KNO_3$ and about 16r/l in asparagine for the growth of mycelia; about 8r/l in $KNO_3$ and $NH_4NO_3$, and 16r/l in asparagine for the production of sclerotia. 7. After the fungus started to grow, the pH value of cultural filtrate rapidly dropped to about 3.5. Hereafter, its rate slowed down as the growth amount increased and did not depreciated below pH2.2. 8. The role of thiamine in the growth of the organism was vital. If thiamine was not added, the combination of biotin, pyridoxine, and inositol did not show any effects on the growth of the organism at all. Equivalent or better mycelial growth was recognized in the combination of thiamine+pyridoxine, thiamine+inositol, thiamine+biotin+pyridoxine, and thiamine+biotin+pyridoxine+inositol, as compared with thiamine alone. In the combinations of thiamine+biotin and thiamine+biotin+inositol, mycelial growth was inhibited. Sclerotial production in dry weight increased more in these combinations than in the medium of thiamine alone. 9. The stimulating effects of the Penicillium cultural filtrate on the mycelial growth was noticed. It increased linearly with the increase of filtrate concentration up to 6-15 ml/50ml basal medium solution. 10. $NH_4NO_3$. as a nitrogen source for mycelial growth was more effective than asparasine regardless of the concentration of cultural filtrate. 11. In the series of fractionations of the cultural filtrate, mycelial growth occured in unvolatile, ether insoluble cation-adsorbed or anion-unadsorbed substance fractions among the fractions of volatile, unvolatile acids, ether soluble organic acids, ether insoluble, cation-adsorbed, cation-unadsorbed, anion-adsorbed and anion-unadsorbed. and anion-un-adsorbed substance tested. Sclerotia were produced only in cation-adsorbed fraction. 12. According to the above results, it was assumed that substances for the mycelial growth and sclerotial formation and inhibitor of sclerotial formation were include::! in cultural filtrate and they were quite different from each other. I was further assumed that the former two substances are un volatile, ether insotuble, and adsorbed to cation-exchange resin, but not adsorbed to anion, whereas the latter is unvolatile, ether insoluble, and not adsorbed to cation or anion-exchange resin. 13. Seven amino acids-aspartic acid, cystine, glysine, histidine, Iycine, tyrosine and dinitroaniline-were detected in the fractions adsorbed to cation-exchange resin by applying the paper chromatography improved with DNP-amino acids. 14. Mycelial growth or sclerotial production was not stimulated significantly by separate or combined application of glutamic acid, aspartic acid, cystine, histidine, and glysine. Tyrosine gave the stimulating effect when applied .alone and when combined with other amino acids in some cases. 15. The tolerance of sclerotia to moist heat varied according to their water content, that was, the dried sclerotia are more tolerant than wet ones. The sclerotia harvested directly from the media, both Type-1 and Type-2, lost viability within 5 minutes at $52^{\circ}C$. Sclerotia dried for 155 days at$26^{\circ}C$ had more tolerance: sclerotia of Type-l were killed in 15 mins. at $52^{\circ}C$ and in 5 mins. at $57^{\circ}C$, and sclerotia of Type-2 were killed in 10 mins. both at $52^{\circ}C$ or $57^{\circ}C$. 16. Cultural sclerotia of both strains maintained good germinability for 132 days at$26^{\circ}C$. Natural sclerotia of them stored for 283 days under air dry condition still had good germinability, even for 443 days: type-l and type-2 maintained $20\%$ and $26.9\%$ germinability, respectively. 17. The tolerance to low temperature increased in the order of mycelia, felts and sclerotia. Mycelia completely lost the ability to grow within 1 week at $7-8^{\circ}C$> below zero, while mycelial felts still maintained the viability after .3 weeks at $7-20^{\circ}C$ below zero, and sclerotia were even more tolerant. 18. Sclerotia of type-l and type-2 were killed when dipped into the $0.05\%$ solution of mercury chloride for 180 mins. and 240 mins. respectively: and in the $0.1\%$ solution, Type-l for 60 mins. and Type-2 for 30 mins. In the $0.125\%$ uspulun solution, Type-l sclerotia were killed in 180 mins., and those of Type-2 were killed for 90 mins. in the$0.125\%$solution. Dipping into the $5\%$ copper sulphate solution or $0.2\%$ solution of Ceresan lime or Mercron for 240 mins. failed to kill sclerotia of either Type-l or Type-2. 19. Inhibitory effect on mycelial growth of Benlate or Tachi-garen in the liquid culture increased as the concentration increased. 6 days after application, obvious inhibitory effects were found in all treatments except Benlate 0.5ppm; but after 12 days, distingushed diflerences were shown among the different concentrations. As compared with the control, mycelial growth was inhibited by $66\%$ at 0.5ppm and by $92\%$ at 2.0ppm of Benlate, and by$54\%$ at 1ppm and about $77\%$ at 1.5ppm or 2.0ppm of Tachigaren. The mycelial growth was inhibited completely at 500ppm of both fungicides, and the formation of sclerotia was checked at 1,000ppm of Benlate ant at 500ppm or 1,000ppm of Tachigaren. 20. Consumptions of glucose or ammonium nitrogen in the culture solution usually increased with the increment of mycelial growth, but when Benlate or Tachigaren were applied, consumptions of glucose or ammonium nitrogen were inhibited with the increment of concentration of the fungicides. At the low concentrations of Benlate (0.5ppm or 1ppm), however, ammonium nitrogen consumption was higher than that of the ontrol. 21. The amount of mycelia produced by consuming 1mg of glucose or ammonium nitrogen in the culture solution was lowered markedly by Benlate or Tachigaren. Such effects were the severest on the third day after their treatment in all concentrations, and then gradually recovered with the progress of time. 22. In the sand culture, mycelial growth was not inhibited. It was indirectly estimated by the amount of $CO_2$ evolved at any concentrations, except in the Tachigaren 100mg/g sand in which mycelial growth was inhibited significantly. Sclerotial production was completely depressed in the 10mg/g sand of Benlate or Tachigaren. 23. There was no visible inhibitory effect on the germination of sclerotia when the sclerotia were dipped in the solution 0.1, 1.0, 100, 1.000ppm of Benlate or Tachigaren for 10 minutes or even 20 minutes.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.1
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• pp.41-60
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• 1983

Experiments were conducted to study the effect of stage of maturity at harvest on the quality of silage. Herbage samples taken from the barley plant, rye plant, wheat plant, oat plant, Orchardgrass, Italian ryegrass, a mixed grass sward of Orchardgrass and Italian ryegrass and corn plant at different stages of maturity and ensiled in order to evaluate the effect of maturity on the chemical composition and feeding value as well as digestibility using sheep. Forage material were ensiled in small concrete silo. 1. The dry matter yield per 10a increased with advancing the maturity. Yield of brarley plant was 404, 635 and 900 kg at heading, milk and milk dough stage, respectively. Rye plant yield was 279, 589, 708, 10,000, 1,265, 1,376 and 1,492 kg at booting, before heading, early heading, late heading, early flowering, late flowering and after flowering stage, respectively. Italian ryegrass yield was 355, 613, 844 and 1,109 kg at vegetative, booting, heading and flowering, respectively. Orchardgrass/Italian ryegrass production was 477, 696, 891 and 1,027 kg at before was 458, 1,252, 1,534, 1,986 and 2,053 kg at tassel, early milk, yellow ripe and ripe stage, respectively. 2. Dry matter content increased with advancing maturity, but crude protein declined markedly. The NFE content decreased with advancing maturity of all the herbages except corn plant where NFE content increased, but corn plant increased. The content of crude fiber increased with advancing maturity except corn plant. The content of crude ash decreased with advancing maturity. In the rye plant, the content of neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose increased with advancing maturity. 3. In vitro dry matter digestibilities of the rye plant was 53.6, 54.1, 50.7, 47.1, 44.9, 40.1 and 38.9% booting, before hcading, early heading, late heading, early flowering, late flowering and after flowering stage, respectively. The regression equation was $Y=56.22-0.74X+0.009X^2$ (X=cutting date from the first cut, Y=dry matter digestibilities). 4. In vitro digestible dry matter yield (kg/10a) of rye plant increased with advancing maturity, but declined from the flowering stage. The regression equation was $Y=168.88+26.09X-0.41X^2$ (X=cutting date from the first cut). 5. In vitro digestibility of dry matter in the corn plant was 69.2, 71.5, 69.8 and 69.9% at tassel, early milk, milk and yellow ripe stage, respectively. 6. The digestibility of crude protein and crude fiber of all plants decreased with advancing matuity, but NFE of the barley and corn generally increased. 7. The TDN contents on the dry matter basis decreased, but those of barley and corn silage were not different. TDN content of barley was 57.8, 57.1 and 57.9% at heading, milk and milk dough stage, respectively. That of rye silage was 50.0, 27.2 and 43.7% at early flowering, after flowering and milk stage, respectively. Italian ryegrass silage was 67.9, 63.7, and 54.9% at before heading, early heading and after heading, respectively. In case of Orchardgrass silage the TDN was 54.8, 52.9 and 46.1% at after heading, after flowering and milk, respectively. Corn shows TDN value of 59.5, 62.8 and 61.6% at milk, yellow ripe and ripe, respectively. 8. The pH value increased slightly by advancing maturity. 9. the content of organic acid decreased by advancing maturity and also increasing the DM content.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.2
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• pp.71-97
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• 1974

Many studies on the changes of the materials in the water-logged paddy soil have been reported, but there will be several problems to apply them on the field soil. The main differences between the method of soil packed in beaker or column tube to that of natural field furrow slice are with or without of the rice root and the effect of water percolation. On the other hand, the mechanism of the water percolation on the changes of material in the natural field furrow slice are gradually understood. The purpose of this experiment is to know the effect of the rice cultivation on the chemical and physical changes of material in the water-logged paddy soil. Obtained results are as follows. 1. The physical and chemical changes on the water-logged paddy soil in the non-planted control-plot were nearly the same as the beaker or column tube experiment, while in the planted plot, slightly altered patterns were observed. 2. The relation between the number of tillers and total cation, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, Fe and Mn in the leachate showed very high significance. T hisresult showed that the leaching of those cation was promoted by growing of the rice r- of the rice root. 3. On the other hand, the concentration of the potassium, silica and phosphorus in leachates was gradually decreased and that of $NH_4$-N could not detect after the stage of active tillering. These facts revealed that such components were absorbed by rice plant. 4. The highly significant correlation between the number of tillers and the concentration of the total cation, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, $Fe^{{+}{+}}$, Fe and Mn in the percolated water was observed except that of $Mg^{{+}{+}}$. It was also showed that the rice root promoted the leaching of those cation. 5. The very high significance in the correlation between $HCO_3{^-}$ and the number of tillers indicated that the higher activity of the rice root was, the more $HCO_3{^-}$ concentration in the leachate was increased. 6. The relationship between the $HCO_3{^-}$ and the total cation, $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, $Fe^{{+}{+}}$, Fe and Mn was appeared very highly significant. $HCO_3{^-}$, the metabolite of the rice root, promoted the leaching of $Ca^{{+}{+}}$, $Mg^{{+}{+}}$, $Fe^{{+}{+}}$ and Mn. This fact might be a result that these cations were leached as the form of bicarbonate. 7. The iron in the leachate was the form of $Fe^{{+}{+}}$ and the correlation between $Fe^{{+}{+}}$ and $HCO_3{^-}$ was very highly significant. This result indicated that it seemed to be ferrous bicarbonate when it is leached out. 8. In the rhizosphere, ferrous iron was decreased gradually and the concentration of glucose was as high as 2 to 3 times in comparison with the other parts of the soil. These facts were the same as the previous reports in which rhizosphere was oxidized by the oxigen excreted from the root, and was enriched by the organic matter which was also excreted from the root and accumulated residues of the root. 9. ${\beta}$-Glucosidase and phosphatase activity in the rhizosphere was higher than that of the other parts of the soil. This facts might be attributed to the vigorous activity of microorganism in the rhizosphere where glucose concentration was high. 10. The pH in the leachate of the planted plot was lower than that of control, and the Eh on the planted soil was elevated in the last stage.

• Journal of Korean Society of Forest Science
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• v.75 no.1
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• pp.1-18
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• 1986

This study was initiated to estimate productivity of Quercus variabilis stand. However the practical objective of this study was to provide some information to establish the basis of selecting the suitable site for Quercus variabilis. The productivity measured in terms of DBH, height, basal area and stem volume was hypothesized, respectively, to be a function of a group of factors. This study considered 32 factors, 20 of which were related to the forest environmental factors such as tree age, latitude, percent slope, etc. and the rest of which were related to soil factors such as soil moisture, total nitrogen, available $P_2O_5$, etc. The data on 4 productivity measurements of Quercus variabilis growth and related factors cited were collected from 99 sample plots in Kyeongbook and chungbook provinces. Some factors considered were, in nature, discrete variables and the others continuous variables. Each kind of factor was classified into 3 or 4 categories and total numbers of such categories were eventually amounted to 110. Then each category was treated as an independent variable. This is amounted to saying that individual variable was treated a dummy variable and assigned a value 1 or 0. However the first category of each factor was deleted from the normal equation for statistical consideration. First of all, each of 4 productivity measurements of Quercus variabilis growth was regressed and, at the same time, those 110 categories. Secondly, the partial correlation coefficients were measured between each pair of 4 productivity measurements and 32 individual foctors. Finally, the relative scores were estimated in order to derive the category ranges. The result of these statistical analyses could be summarized as follows: 1) Growth measurement in terms of height seems to be a more significant criterion for estimation of productivity of Quercus variabilis. 2) Productivity of forest on stocked land may better be estimated in terms of forest environmental factors, on the other hand, that of unstocked land may be estimated in terms of physio-chemical factors of soil. 3) The factors that a strongly positive relation to all growth factors of tree are age group, effective soil, soil moisture, etc. This implies that these factors might effectively be used for criteria for selecting the suitable site for Quercus variabilis. 4) Parent rock, latitude, total nitrogen, age group, effective soil depth, soil moisture, organic matter, etc., had more significant category range for tree growth. Therefore, the suitable site for Quercus variabilis may be selected, based on this information. In conclusion, the above results obtained by the multivariable analysis can be not only the important criteria for estimating the growth of Quercus variabilis but also the useful guidance for selecting the suitable sites and performing the rational of Quercus variabilis forest.