• Title/Summary/Keyword: h-method

Search Result 21,337, Processing Time 0.056 seconds

Development of the paper bagging machine for grapes (휴대용 포도자동결속기 개발연구)

  • Park, K.H.;Lee, Y.C.;Moon, B.W.
    • Journal of Practical Agriculture & Fisheries Research
    • /
    • v.11 no.1
    • /
    • pp.79-94
    • /
    • 2009
  • The research project was conducted to develop a paper bagging machine for grape. This technology was aimed to highly reduce a labor for paper bagging in grape and bakery. In agriculture labor and farm population has rapidly decreased since 1980 in Korea so there was so limit in labor. In particular there is highly population in women and old age at rural area and thus labor cost is so high. Therefore a labor saving technology in agricultural sector might be needed to be replaced these old age with mechanical and labor saving tool in agriculture. The following was summarized of the research results for development of a paper bagging machine for grape. 1. Development of a new paper bagging machine for grape - This machine was designed by CATIA VI2/AUTO CAD2000 programme. - A paper bagging machine was mechanically binded a paper bag of grape which should be light and small size. This machine would be designed for women and old age with convenience during bagging work at the field site. - This machine was manufactured with total weight of less than 350g. - An overage bagging operation was more than 99% at the actual field process. - A paper bagging machine was designed with cartridge type which would be easily operated between rows and grape branches under field condition. - The type of cartridge pin was designed as a C-ring type with the length of 500mm which was good for bagging both grape and bakery. - In particular this machine was developed to easily operated among vines of the grape trees. 2. Field trials of a paper bagging machine in grape - There was high in grape quality as compared to the untreated control at the application of paper bagging machine. - The efficiency of paper bagging machine was 102% which was alternative tool for the conventional. - The roll pin of paper bagging machine was good with 5.3cm in terms of bagging precision. - There was no in grape quality between the paper bagging machine and the conventional method. - Disease infection and grape break was not in difference both treatments.

Survey on the Regular Maintenance of Agricultural Machinery (농업기계 정기점검정비 실태조사)

  • Kang, J.W;Lee, W.Y.;Lee, S.B.;Lee, J.H.
    • Journal of Practical Agriculture & Fisheries Research
    • /
    • v.3 no.1
    • /
    • pp.142-157
    • /
    • 2001
  • This study was conducted to get the basic information for promoting farm machinery productivity by surveying the regular maintenance and repair status of major farm machinery such as power tiller, farm tractor, rice transplanter and combine harvester. The survey was carried out through 9 provinces including Cheju province by direct visiting farmers with prepared questionnaire. The results of this study can be summarized as follows : 1. The average farming carrier of the surveyed farmers was 25.3 years, and 21-30 years of farming carrier showed the highest portion as 40.7%. The average carrier of using farm machinery was 9.4 years, and that was 14.9 years for power tiller, 8.3 years for farm tractor, 9.0 years for rice transplanter, 7.9 years for combine harvester, 7.5 years for mini tiller, 9.7 years for power sprayer, and 8.2 years for binder etc. 2. The regular maintenance for farm machinery was conducted mainly at repair shop (49.5%) or dealer agency (12.0%) as 61.5%, and 34.9% of farmers conducted the regular maintenance by themselves at their house. 3. The reasons for not-fully recognizing operation manual and insufficient before-, during-, after-maintenance of farm machinery were insufficient time for them (45.8%), troublesome (22.9%), unknown maintenance method (16.3%), unknown the necessity for maintenance (12.4%), and others (2.6%) in order. 4. For the annual exchange of engine oil, 3.2 times is necessary but actually 1.7 times was exchanged for power tiller, 4.3 times is necessary but actually 1.9 times was exchanged for farm tractor, 2.7 times is necessary but actually 1.7 times was exchanged for rice transplanter, 2.2 times is necessary but actually 2.3 times was exchanged combine harvester. 5. For the annual cleanness or exchange of fuel filter, 3.2 times is necessary but actually 1.1 times was done for power tiller, 4.3 times is necessary but actually 1.6 times was done for farm tractor, 2.7 times is necessary but actually 1.7 times was done for rice transplanter, 1.9 times is necessary but actually 0.8 times was done for combine harvester. 6. For the annual cleanness or exchange of air filter, 3.2 times is necessary but actually 1.4 times was done for power tiller, 4.2 times is necessary but actually 2.4 times was done for farm tractor, 2.6 times is necessary but actually 1.6 times was done for rice transplanter, 3.9 times is necessary but actually 7.0 times was done for combine harvester. 7. For the experience of breakdown related to maintenance, 5.3% of farmers experienced breakdown due to the insufficient exchange of engine oil, 7.7% of farmers experienced breakdown due to the insufficient cleanness or exchange of fuel filter, and 2.9% of farmers experienced breakdown due to the insufficient cleanness or exchange of air filter. 8. Most farmers (76.1%) recognized the necessity for agricultural machinery training or education, and most farmers preferred about one week for the training period, simple or ease maintenance for the training level, agricultural technical center or agricultural machinery manufacturer for the training agency. 9. Complete recognition of operation manual and sufficient before-, during-, and after-maintenance for farm machinery can minimize the breakdown as well as conduct suitable period farming, enlarge the endurance, prevent the safety accidents, and promote productivity of farm machinery. Therefore, these can be accomplished by the thorough training or education for agricultural machinery.

Comparison of Rice Growth and Yield in Different Direct Seeding Methods Following by Italian Ryegrass Harvest (사료작물 후작 벼 직파 방법별 생육 및 수량 비교)

  • Park, K.H.;Park, S.T.
    • Journal of Practical Agriculture & Fisheries Research
    • /
    • v.21 no.1
    • /
    • pp.49-59
    • /
    • 2019
  • The field trial was performed to evaluate the rice growth and yield in different direct seeding methods after Italian Ryegrass Harvest The required time for seed emergence was for 7 ~ 8days in the tested direct seeding methods and there was high in seedling establishment in order of wet hill-seeding with iron-coated seeds > water seeding with iron-coated seeds > wet hill-seeding with soil coverage with pregerminated seeds. The rice plant height was shorter in the tested direct seeding methods than that of machine transplanting until 45day after seeding but there was not significant difference in terms of statistical analysis at 63day after seeding. The growth of tiller number in the rice plant was high in water seeding with iron-coated seeds and wet hill-seeding with soil coverage and low in wet hill-seeding with iron-coated seeds compared to machine transplanting. The yield component in the tested direct seeding methods was not significant difference in terms of statistical analysis. The milled rice yield in the tested direct seeding methods was higher 2 ~ 8% being with 4.94 ~ 5.24t/ha than that of machine transplanting but there was not significant difference in terms of statistical analysis. The percentage of head rice was low in the tested direct seeding methods compared to machine transplanting. The weedy rice was not occurred in the tested rice cultivation methods. In conclusion the direct seeding method would be recommended to be a suitable to in following by Italian ryegrass harvesting in southern area of Korea in terms of reduction in production cost and high income basis for rice growing farmers.

Growth and Yield in Direct Seeded Rice Cultivation with Iron Coated-Seeds (철분코팅 볍씨를 이용한 벼 직파재배의 생육 특성 및 수량)

  • Park, K.H.;Park, S.T.
    • Journal of Practical Agriculture & Fisheries Research
    • /
    • v.20 no.1
    • /
    • pp.5-18
    • /
    • 2018
  • The field trial was performed to evaluate the rice growth and yield in direct seeding cultivation with iron-coated rice seeds. The required time for seed emergence was for 9~11days in the tested direct seeding methods. That was 1~2days earlier in direct seeding with pregerminated seeds than that of direct seeding with iron-coated seeds. The seedling establishment was highest in water seeding with iron-coated seeds but there was not significant difference in terms of statistical analysis. The rice plant height was taller in water seeding with broadcasting method than that of wet hill-seeding methods and in direct seeding with iron-coated seeds than that of direct seeding with pregerminated seeds. The tiller number in the rice plant was the highest in machine transplanting at 30days after direct seeding(June 17) and in water seeding with iron-coated seeds at 45days after seeding(DAS) and 60DAS. The tiller number of 75 and 90DAS in the tested rice cultivation methods being with 352~405/m2 was not significantly different in terms of statistical analysis. The heading time was not different in rice direct seeding methods but 2 day earlier in direct seeding with iron-coated seeds than that of direct seeding with pregerminated seeds. The culm length was the highest in water seeding with iron-coated seeds and the panicle length was the longest in wet hill-seeding with pregerminated seeds. The panicle number per m2 was highest in water seeding with iron-coated seeds but not significant difference among the tested rice cultivation methods. The water seeding with iron-coated seeds resulted in the highest spikelet number per m2 and the heaviest grain weight of brown rice. Percentage of ripened kernel was the highest in wet hill-seeding with iron-coated seeds. But there were not significant among the tested rice cultivation methods. The milled rice yield in direct seeding methods was 3~21% higher than that in machine transplanting. Water seeding with iron-coated seeds recorded the highest milled rice yield being with 6.86t/ha.The occurrence of sheath blight was high according to machine transplanting>wet hill-seeding>water seeding. Weed occurrence was the highest in water seeding with pregerminated seeds. Weedy rice occurred not in machine transplanting but occured 0.6~0.7% in direct seeding methods with pregerminated seeds and 0.1% in direct seeding with iron-coated seeds.

Development of High-Resolution Fog Detection Algorithm for Daytime by Fusing GK2A/AMI and GK2B/GOCI-II Data (GK2A/AMI와 GK2B/GOCI-II 자료를 융합 활용한 주간 고해상도 안개 탐지 알고리즘 개발)

  • Ha-Yeong Yu;Myoung-Seok Suh
    • Korean Journal of Remote Sensing
    • /
    • v.39 no.6_3
    • /
    • pp.1779-1790
    • /
    • 2023
  • Satellite-based fog detection algorithms are being developed to detect fog in real-time over a wide area, with a focus on the Korean Peninsula (KorPen). The GEO-KOMPSAT-2A/Advanced Meteorological Imager (GK2A/AMI, GK2A) satellite offers an excellent temporal resolution (10 min) and a spatial resolution (500 m), while GEO-KOMPSAT-2B/Geostationary Ocean Color Imager-II (GK2B/GOCI-II, GK2B) provides an excellent spatial resolution (250 m) but poor temporal resolution (1 h) with only visible channels. To enhance the fog detection level (10 min, 250 m), we developed a fused GK2AB fog detection algorithm (FDA) of GK2A and GK2B. The GK2AB FDA comprises three main steps. First, the Korea Meteorological Satellite Center's GK2A daytime fog detection algorithm is utilized to detect fog, considering various optical and physical characteristics. In the second step, GK2B data is extrapolated to 10-min intervals by matching GK2A pixels based on the closest time and location when GK2B observes the KorPen. For reflectance, GK2B normalized visible (NVIS) is corrected using GK2A NVIS of the same time, considering the difference in wavelength range and observation geometry. GK2B NVIS is extrapolated at 10-min intervals using the 10-min changes in GK2A NVIS. In the final step, the extrapolated GK2B NVIS, solar zenith angle, and outputs of GK2A FDA are utilized as input data for machine learning (decision tree) to develop the GK2AB FDA, which detects fog at a resolution of 250 m and a 10-min interval based on geographical locations. Six and four cases were used for the training and validation of GK2AB FDA, respectively. Quantitative verification of GK2AB FDA utilized ground observation data on visibility, wind speed, and relative humidity. Compared to GK2A FDA, GK2AB FDA exhibited a fourfold increase in spatial resolution, resulting in more detailed discrimination between fog and non-fog pixels. In general, irrespective of the validation method, the probability of detection (POD) and the Hanssen-Kuiper Skill score (KSS) are high or similar, indicating that it better detects previously undetected fog pixels. However, GK2AB FDA, compared to GK2A FDA, tends to over-detect fog with a higher false alarm ratio and bias.

Acute toxicity of ethyl formate to nontarget organisms and reduction effect of sodium silicate on ethyl formate-induced phytotoxicity (에틸포메이트의 비표적생물에 대한 급성독성 및 sodium silicate의 약해저감 효과)

  • Kyeongnam Kim;Yubin Lee;Yurim Kim;Donghyeon Kim;Chaeeun Kim;Yerin Cho;Junyeong Park;Yongha You;Byung-Ho Lee ;Sung-Eun Lee
    • Korean Journal of Environmental Biology
    • /
    • v.41 no.3
    • /
    • pp.193-203
    • /
    • 2023
  • Ethyl formate (EF) is a naturally occurring insecticidal compound and is used to control pests introduced from abroad, in quarantine, by a fumigation method. In particular, it is mainly used as a substitute for methyl bromide and is less toxic to humans and less harmful to plants. This study aimed to investigate the possible acute toxicity of EF to useful organisms, and how to reduce phytotoxicity in watermelon, zucchini, and oriental melon. After fumigation with EF for 2 h, the LC50 values for earthworms, honey bees, and silkworms were 39.9, 7.09, and 17.9g m-3, respectively. The degree of susceptibility to EF was in the order of earthworms, silkworms, and honey bees based on the LC50 value, and EF fumigation induced stronger acute toxicity to honey bees. Phytotoxicity was observed in watermelon leaves treated with a concentration of 7.5 g m-3 EF, and when treated with a concentration of 10.0g m-3, it was confirmed that the edges of watermelon leaves were charred and seemed to be damaged by acids. Zucchini and melon, and other cucurbits, showed strong damage to the leaves when treated with a concentration of 10 g m-3, and sodium silicate, at concentrations of 10% and 20%, was used to reduce phytotoxicity. Therefore, acute toxicity towards nontarget organisms and phytotoxicity during the fumigation of EF should be reduced for efficient agricultural pest control.

Operation of dry distillation process on the production of radionuclide 131I at Puspiptek area Serpong Indonesia, 2021 to 2022

  • Chaidir Pratama;Daya Agung Sarwono;Ahid Nurmanjaya;Abidin Abidin;Triyatna Fani;Moch Subechi;Endang Sarmini;Enny Lestari;Yanto Yanto;Kukuh Eka Prasetya;Maskur Maskur;Fernanto Rindiyantono;Indra Saptiama;Anung Pujiyanto;Herlan Setiawan;Tita Puspitasari;Marlina Marlina;Hasnel Sofyan;Budi Setiawan;Miftakul Munir;Heny Suseno
    • Nuclear Engineering and Technology
    • /
    • v.56 no.4
    • /
    • pp.1526-1531
    • /
    • 2024
  • 131I is a fission product produced in a nuclear reactor by irradiating tellurium dioxide, with a half-life of 8.02 day. The most important and widely used method for making 131I is irradiation using a nuclear reactor and post-irradiation followed by dry distillation. The advantage of the dry distillation process is that the process and the equipment are relatively simple, namely TeO2 (m.p. 750 ℃), which can withstand heating during reactor irradiation. Based on TeO2 irradiation by neutron following the technique of dry distillation was explained for production of 131I on a large scale. A dry distillation followed the radioisotope production operation using the 30 MW GA Siwabessy nuclear reactor to meet national demand. TeO2 targets are 25 and 50 g irradiated for 87-100 h. The resulting 131I activity is 20.29339-368.50335GBq. According to the requirements imposed on the radionuclide purity of the preparation, the contribution of 131I training in the resulting preparation was not less than 99.9 %

Clinical Application of Serum CEA, SCC, Cyfra21-1, and TPA in Lung Cancer (폐암환자에서 혈청 CEA, SCC, Cyfra21-1, TPA-M 측정의 의의)

  • Lee, Jun-Ho;Kim, Kyung-Chan;Lee, Sang-Jun;Lee, Jong-Kook;Jo, Sung-Jae;Kwon, Kun-Young;Han, Sung-Beom;Jeon, Young-June
    • Tuberculosis and Respiratory Diseases
    • /
    • v.44 no.4
    • /
    • pp.785-795
    • /
    • 1997
  • Background : Tumor markers have been used in diagnosis, predicting the extent of disease, monitoring recurrence after therapy and prediction of prognosis. But the utility of markers in lung cancer has been limited by low sensitivity and specificity. TPA-M is recently developed marker using combined monoclonal antibody of Cytokeratin 8, 18, and 19. This study was conducted to evaluate the efficacy of new tumor marker, TPA-M by comparing the estabilished markers SCC, CEA, Cyfra21-1 in lung cancer. Method : An immunoradiometric assay of serum CEA, sec, Cyfra21-1, and TPA-M was performed in 49 pathologically confirmed lung cancer patients who visited Keimyung University Hospital from April 1996 to August 1996, and 29 benign lung diseases. Commercially available kits, Ab bead CEA (Eiken) to CEA, SCC RIA BEAD (DAINABOT) to SCC, CA2H (TFB) to Cyfra2H. and TPA-M (DAIICHI) to TPA-M were used for this study. Results : The mean serum values of lung cancer group and control group were $10.05{\pm}38.39{\mu}/L$, $1.59{\pm}0.94{\mu}/L$ in CEA, $3.04{\pm}5.79{\mu}/L$, $1.58{\pm}2.85{\mu}/L$ in SCC, $8.27{\pm}11.96{\mu}/L$, $1.77{\pm}2.72{\mu}/L$ in Cyfra21-1, and $132.02{\pm}209.35\;U/L$, $45.86{\pm}75.86\;U/L$ in TPA-M respectively. Serum values of Cyfra21-1 and TPA-M in lung cancer group were higher than control group (p<0.05). Using cutoff value recommended by the manufactures, that is $2.5{\mu}/L$ in CEA, $3.0{\mu}/L$ in Cyfra21-1, 70.0 U/L in TPA-M, and $2.0{\mu}/L$ in SCC, sensitivity and specificity of lung cancer were 33.3%, 78.6% in CEA, 50.0%, 89.7% in Cyfra21-1, 52.3%, 89.7% in TPA-M, 23.8%, 89.3% in SCC. Sensitivity and specificity of nonsmall cell lung cancer were 36.1%, 78.1% in CEA, 50.1%, 89.7% in Cyfra21-1, 53.1%, 89.7% in TPA-M, 33.8%, 89.3% in SCC. Sensitivity and specificity of small cell lung cancer were 25.0%, 78.5% in CEA, 50.0%, 89.6% in Cyfra21-1, 50.0%, 89.6% in TPA-M, 0%, 89.2% in SCC. Cutoff value according to ROC(Receiver operating characteristics) curve was $1.25{\mu}/L$ in CEA, $1.5{\mu}/L$ in Cyfra2-1, 35 U/L in TPA-M, $0.6{\mu}/L$ in SCC. With this cutoff value, sensitivity, specificity, accuracy and kappa index of Cyfra21-1 and TPA-M were better than CEA and SCC. SCC only was related with statistic significance to TNM stages, dividing to operable stages(TNM stage I to IIIA) and inoperable stages (IIIB and IV) (p<0.05). But no tumor markers showed any correlation with significance with tumor size(p>0.05). Conclusion : Serum TPA-M and Cyfra21-1 shows higher sensitivity and specificity than CEA and SCC in overall lung cancer and nonsmall cell lung cancer those were confirmed pathologically. SCC has higher specificity in nonsmall cell lung cancer. And the level of serum sec are signiticantly related with TNM staging.

  • PDF

Studies on the Mechanical Properties of Weathered Granitic Soil -On the Elements of Shear Strength and Hardness- (화강암질풍화토(花崗岩質風化土)의 역학적(力學的) 성질(性質)에 관(關)한 연구(硏究) -전단강도(剪斷强度)의 영향요소(影響要素)와 견밀도(堅密度)에 대(對)하여-)

  • Cho, Hi Doo
    • Journal of Korean Society of Forest Science
    • /
    • v.66 no.1
    • /
    • pp.16-36
    • /
    • 1984
  • It is very important in forestry to study the shear strength of weathered granitic soil, because the soil covers 66% of our country, and because the majority of land slides have been occured in the soil. In general, the causes of land slide can be classified both the external and internal factors. The external factors are known as vegetations, geography and climate, but internal factors are known as engineering properties originated from parent rocks and weathering. Soil engineering properties are controlled by the skeleton structure, texture, consistency, cohesion, permeability, water content, mineral components, porosity and density etc. of soils. And the effects of these internal factors on sliding down summarize as resistance, shear strength, against silding of soil mass. Shear strength basically depends upon effective stress, kinds of soils, density (void ratio), water content, the structure and arrangement of soil particles, among the properties. But these elements of shear strength work not all alone, but together. The purpose of this thesis is to clarify the characteristics of shear strength and the related elements, such as water content ($w_o$), void ratio($e_o$), dry density (${\gamma}_d$) and specific gravity ($G_s$), and the interrelationship among related elements in order to decide the dominant element chiefly influencing on shear strength in natural/undisturbed state of weathered granitic soil, in addition to the characteristics of soil hardness of weathered granitic soil and root distribution of Pinus rigida Mill and Pinus rigida ${\times}$ taeda planted in erosion-controlled lands. For the characteristics of shear strength of weathered granitic soil and the related elements of shear strength, three sites were selected from Kwangju district. The outlines of sampling sites in the district were: average specific gravity, 2.63 ~ 2.79; average natural water content, 24.3 ~ 28.3%; average dry density, $1.31{\sim}1.43g/cm^3$, average void ratio, 0.93 ~ 1.001 ; cohesion, $ 0.2{\sim}0.75kg/cm^2$ ; angle of internal friction, $29^{\circ}{\sim}45^{\circ}$ ; soil texture, SL. The shear strength of the soil in different sites was measured by a direct shear apparatus (type B; shear box size, $62.5{\times}20mm$; ${\sigma}$, $1.434kg/cm^2$; speed, 1/100mm/min.). For the related element analyses, water content was moderated through a series of drainage experiments with 4 levels of drainage period, specific gravity was measured by KS F 308, analysis of particle size distribution, by KS F 2302 and soil samples were dried at $110{\pm}5^{\circ}C$ for more than 12 hours in dry oven. Soil hardness represents physical properties, such as particle size distribution, porosity, bulk density and water content of soil, and test of the hardness by soil hardness tester is the simplest approach and totally indicative method to grasp the mechanical properties of soil. It is important to understand the mechanical properties of soil as well as the chemical in order to realize the fundamental phenomena in the growth and the distribution of tree roots. The writer intended to study the correlation between the soil hardness and the distribution of tree roots of Pinus rigida Mill. planted in 1966 and Pinus rigida ${\times}$ taeda in 199 to 1960 in the denuded forest lands with and after several erosion control works. The soil texture of the sites investigated was SL originated from weathered granitic soil. The former is situated at Py$\ddot{o}$ngchangri, Ky$\ddot{o}$m-my$\ddot{o}$n, Kogs$\ddot{o}$ng-gun, Ch$\ddot{o}$llanam-do (3.63 ha; slope, $17^{\circ}{\sim}41^{\circ}$ soil depth, thin or medium; humidity, dry or optimum; height, 5.66/3.73 ~ 7.63 m; D.B.H., 9.7/8.00 ~ 12.00 cm) and the Latter at changun-long Kwangju-shi (3.50 ha; slope, $12^{\circ}{\sim}23^{\circ}$; soil depth, thin; humidity, dry; height, 10.47/7.3 ~ 12.79 m; D.B.H., 16.94/14.3 ~ 19.4 cm).The sampling areas were 24quadrats ($10m{\times}10m$) in the former area and 12 in the latter expanding from summit to foot. Each sampling trees for hardness test and investigation of root distribution were selected by purposive selection and soil profiles of these trees were made at the downward distance of 50 cm from the trees, at each quadrat. Soil layers of the profile were separated by the distance of 10 cm from the surface (layer I, II, ... ...). Soil hardness was measured with Yamanaka soil hardness tester and indicated as indicated soil hardness at the different soil layers. The distribution of tree root number per unit area in different soil depth was investigated, and the relationship between the soil hardness and the number of tree roots was discussed. The results obtained from the experiments are summarized as follows. 1. Analyses of simple relationship between shear strength and elements of shear strength, water content ($w_o$), void ratio ($e_o$), dry density (${\gamma}_d$) and specific gravity ($G_s$). 1) Negative correlation coefficients were recognized between shear strength and water content. and shear strength and void ratio. 2) Positive correlation coefficients were recognized between shear strength and dry density. 3) The correlation coefficients between shear strength and specific gravity were not significant. 2. Analyses of partial and multiple correlation coefficients between shear strength and the related elements: 1) From the analyses of the partial correlation coefficients among water content ($x_1$), void ratio ($x_2$), and dry density ($x_3$), the direct effect of the water content on shear strength was the highest, and effect on shear strength was in order of void ratio and dry density. Similar trend was recognized from the results of multiple correlation coefficient analyses. 2) Multiple linear regression equations derived from two independent variables, water content ($x_1$ and dry density ($x_2$) were found to be ineffective in estimating shear strength ($\hat{Y}$). However, the simple linear regression equations with an independent variable, water content (x) were highly efficient to estimate shear strength ($\hat{Y}$) with relatively high fitness. 3. A relationship between soil hardness and the distribution of root number: 1) The soil hardness increased proportionally to the soil depth. Negative correlation coefficients were recognized between indicated soil hardness and the number of tree roots in both plantations. 2) The majority of tree roots of Pinus rigida Mill and Pinus rigida ${\times}$ taeda planted in erosion-controlled lands distributed at 20 cm deep from the surface. 3) Simple linear regression equations were derived from indicated hardness (x) and the number of tree roots (Y) to estimate root numbers in both plantations.

  • PDF

Studies on the Effects of Rice Plant on the Changes of Materials in Submerged Paddy Soils (수도재배(水稻栽培)가 답상태토양(畓狀態土壤)의 물질변화(物質變化)에 미치는 영향(影響)에 관(關)한 연구(硏究))

  • Kim, Kwang Sik
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.7 no.2
    • /
    • pp.71-97
    • /
    • 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.

  • PDF