• Title/Summary/Keyword: land

Search Result 13,801, Processing Time 0.052 seconds

A Suvey on Satisfaction Measurement of Automatic Milking System in Domestic Dairy Farm (자동착유시스템 설치농가의 설치 후 만족도에 관한 실태조사)

  • Ki, Kwang-Seok;Kim, Jong-Hyeong;Jeong, Young-Hun;Kim, Yun-Ho;Park, Sung-Jai;Kim, Sang-Bum;Lee, Wang-Shik;Lee, Hyun-June;Cho, Won-Mo;Baek, Kwang-Soo;Kim, Hyeon-Shup;Kwon, Eung-Gi;Kim, Wan-Young;Jeo, Joon-Mo
    • Journal of Animal Environmental Science
    • /
    • v.17 no.1
    • /
    • pp.39-48
    • /
    • 2011
  • The present survey was conducted to provide basic information on automatic milking system (AMS) in relation to purchase motive, milk yield and quality, customer satisfaction, difficulties of operation and customer suggestions, etc. Purchase motives of AMS were insufficient labor (44%), planning of dairy experience farm (25%), better performance of high yield cows (19%) and others (6%), respectively. Average cow performance after using AMS was 30.9l/d for milk yield, 3.9% for milk fat, 9,100/ml for bacterial counts. Sixty-eight percentage of respondents were very positive in response to AMS use for their successors but 18% were negative. The AMS operators were owner (44%), successor (44%), wife (6%) and company worker (6%), respectively. The most difficulty (31%) in using AMS was operating the system and complicated program manual. The rate of response to system error and breakdown was 25%. The reasons for culling cow after using AMS were mastitis (28%), reproduction failure (19%), incorrect teat placement (12%), metabolic disease (7%) and others (14%), respectively. Fifty-six percentages of the respondents made AMS maintenance contract and 44% did not. Average annual cost of the maintenance contract was 6,580,000 won. Average score for AMS satisfaction measurement (1 to 5 range) was 3.2 with decrease of labor cost 3.7, company A/S 3.6, increase of milk yield 3.2 and decrease of somatic cell count 2.8, respectively. Suggestions for the higher efficiency in using AMS were selecting cows with correct udder shape and teat placement, proper environment, capital and land, and attitude for continuous observation. Systematic consulting was highly required for AMS companies followed by low cost for AMS setup and systematization of A/S.

Biogas Production from Anaerobic Co-digestion Using the Swine Manure and Organic Byproduct (돈분과 유기성 부산물을 혼합한 혐기소화에서 바이오가스 생산)

  • Kim, W.G.;Oh, I.H.;Yang, S.Y.;Lee, K.M.;Lee, S.I.
    • Journal of Animal Environmental Science
    • /
    • v.17 no.1
    • /
    • pp.49-54
    • /
    • 2011
  • Animal manure is produced annually 43.7 million tonnes in Korea. Among them, about 85.6 % are used as compost or liquid fertilizer to the agricultural land. The animal manure can be effectively utilized by mixing with organic byproducts that result in generation of biogas from anaerobic co-digestion process. This study aimed to optimize the content of total solid materials (TS) and determine the effect of organic byproduct on the co-digestion process. Prior to the byproduct treatments, determination of proper content of TS was conducted by controlling at 5 or 10 %. For the byproduct treatments, swine manure without adding the byproduct was used for control treatment, and swine manure mixed with either corn silage or kitchen waste was used for other treatments. Volume of biomethane ($CH_4$) generated from digested materials was quantified before and after byproduct treatments. In result, a 1.4-fold higher biomethane, about 0.556 L/$L{\cdot}d$, was produced when the content of TS was controlled at 10 %, compared at 5 %, about 0.389 L/$L{\cdot}d$. When the swine manure was mixed with the corn silage or kitchen waste, a two-fold higher biomethane was produced, about 1.theand 1.0heL/$L{\cdot}d$, respectively, compared to the control treatment. Biogas production from organic dry matter (odm) was a3, 362eand 2h6 L/kg odm${\cdot}$d for control, corn silage, and kitchen waste treatment, respectively. The lower biogas production in the treatment of kitchen waste than that of corn silage is associated with its relatively high odm contents. The methane concentration during the whole process ranged from 40 at the beginning to 70 % at the end of process for both the control and kitchen waste treatments, and ranged from 52 to 70 % for the corn silage treatment. Hydrogen sulfide ($H_2S$) concentration ranged between 350 and 500 ppm. All the integrated results indicate that addition of organic byproduct into animal manure can double the generation of biogas from anaerobic fermentation process.

Effects of Green Manure Crop and Cattle Slurry as Fertilizer Sources on Productivity and Nutritive Value of Sorghum X Sudangrass hybrid, and Soil Properties in Kimje, Chunlabukdo (김제지역에서 비료원으로써 녹비작물과 액상우분이 수수 X 수단그라스 교잡종의 생산성, 사료가치 및 토양성질에 미치는 영향)

  • Choi, Ki-Choon;Na, Sang-Pil;Jo, Nam-Chul;Jung, Min-Woong;Kim, Jong-Geun;Park, Hyung-Soo;Yoon, Chang;Lim, Young-Chul;Yook, Wan-Bang
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.29 no.4
    • /
    • pp.337-344
    • /
    • 2009
  • This study was conducted to investigate the effects of various cropping system applied with cattle slurry on productivity of sorghum $\times$ sudangrass hybrid (SSH) and environmental pollution in paddy land. cropping systems used in this study were consisted of two designs, such as double-cropping sorghum $\times$ sudangrass hybrid followed by whole crop barley applied with cattle slurry (DSSCS) and mono-cropping sorghum $\times$ sudangrass hybrid followed by hairy vetch used as green manure (MSSGM). The field experiments were conducted on the clay loam at Backsanmyun, Kimje, Chunlabukdo province in Korea for three years (May 2006 to Apr. 2009). This study was arranged in completely randomized design with three replicates. The yield of dry matter (DM) of SSH in DSSCS increased significantly as compared with that of MSSGM (P<0.05). The contents of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and total digestible nutrients (TDN) of SSH were not influenced by cattle slurry and green manure. The pH, and contents of OM, T-N and $P_2O_5$ in soil samples collected from DSSCS after the end of experiment were higher than those of MSSGM. The pH, and contents of OM in DSSCS treatment were remarkably higher than those at the beginning of the experiment (p<0.05). However, The pH, and contents of OM in MSSGM treatment were hardly influenced, as compared with those at the beginning of the experiment. The contents of T-N in soil samples collected both from DSSCS snd MSSGM treatments were remarkably higher than those at the beginning of the experiment (p<0.05). In addition, the concentrations of CEC in soil samples collected at the end of the experiment were remarkably higher than those at the beginning of the experiment (p<0.05). The concentrations of $NO_3$-N, $NH_3$-N and $PO_4$-P in leaching water were hardly influenced by the cropping system and application of cattle slurry.

Effect of Nitrogen Fertilization on the Forage Growth, Yield and Quality of Native Reed (Phragmites communis) (갈대 생육지에서 질소 시비가 사초의 생육과 수량 및 사료가치에 미치는 영향)

  • Seo, Sung;Park, Jin Gil;Kim, Won Ho;Kim, Meing Jooung;Lee, Sang Hak;Jung, Jong Sung;Park, Hyung Soo;Sung, Ha Guyn;Lee, Joung Kyong
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.33 no.2
    • /
    • pp.105-110
    • /
    • 2013
  • This study was carried out to investigate the effect of nitrogen (N) fertilization on the forage growth, production and quality of native reed (Phragmites communis) grasses. Field experiments were conducted in Cheonan and in Ansan, 2012. Treatments were control (no N fertilization), 50 kg/ha and 100 kg/ha in Cheonan plots (fertilization on April $30^{th}$, and harvest on June $21^{st}$). Treatments in Ansan plots were control (no N fertilization) and 60 kg/ha (fertilization on May first, and harvest on August first). Forage growth and leaf colors were improved in N fertilized plots. However, the drymatter (DM) percentage was slightly decreased with N fertilization. Forage yields, in terms of DM, crude protein (CP) and digestible DM (DDM), were significantly increased with N fertilization in both sites. In Cheonan, DM, CP and DDM yields per ha were 4,026 kg, 235 kg and 1,850 kg, respectively, in the control plot, and were 4,658 kg, 306 kg and 2,388 kg, respectively, in the N 50 kg plot, and 5,622 kg, 446 kg and 3,143 kg, respectively, in the N 100 kg plot. In Ansan, DM, CP and DDM yields per ha were 2,802 kg, 177 kg and 1,288 kg, respectively, in the control plot, and were 3,876 kg, 294 kg and 1,853 kg, respectively, in the N 60 kg plot. Forage quality in terms of CP content, in vitro DM digestibility (IVDMD) and relative feed value (RFV) were also increased with N fertilization in both sites. In Cheonan, the CP content, IVDMD and RFV were 5.85%, 45.96% and 64.5 (grade 5), respectively, in the control plot, 6.58%, 51.27% and 72.3 (grade 5), respectively, in the N 50 kg plot, and 7.94%, 55.91% and 72.7 (grade 5), respectively, in the N 100 kg plot. In Ansan, the CP content, IVDMD and RFV were 6.30%, 45.98% and 70.2 (grade 5), respectively, in the control plot, and 7.59%, 47.80% and 78.3 (grade 4), respectively, in the N 60 kg plot. In conclusion, N fertilization of 60~100 kg/ha was desirable for greater forage production, with a higher quality of native Phragmites communis achievable. This should only be applied if the fertilization area is not located at a riverside/streamside or in riparian land where there is a high risk of water pollution by fertilization.

Optimal Extraction Condition of Anthocyanins in Soybean (Glycine max) with Black Seed Coats (검정콩 종피 함유 안토시아닌의 최적 추출조건)

  • Choung, Myoung-Gun;Hwang, Young-Sun;Lee, Hyeon-Jin;Choi, Su-San-Na;Lim, Jung-Dae;Kang, Sung-Taeg;Han, Won-Young;Baek, In-Youl;Kim, Hyeun-Kyeung
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.53 no.1
    • /
    • pp.110-117
    • /
    • 2008
  • Soybeans (Glycine max) with a black seed coat have been widely utilized as food source and as a medicinal herbs in Korea. The pigmentation in the seed coat of black soybean is due to accumulate anthocyanins in the epidermis palisade layer. The anthocyanin content and composition of the black soybean seed coat are considered as a standard. of quality evaluation of black soybean. The main objective of this study was to investigate the optimal condition for an extraction method of anthocyanins and compare anthocyanin quantity and composition within black soybean varieties and germplasms. In the test of extraction solvent, absorbance at 530 nm and Hunter's a value were increased as increasing the concentration of MeOH, but Hunter's Land b values were the exact opposite of absorbance and Hunter's a values. There was no significant difference for anthocyanin contents from 1% HCl - $H_2O$ to 1% HCl - 80% MeOH. In the aspects of anthocyanin contents and HPLC peak resolution, 1% HCl - 20% MeOH extraction solution was the most suitable solvent. Among the 5 kinds of extraction method using 1% HCl - 20% MeOH solution, the anthocyanin contents of room temperature extraction at 72 h was the highest among the methods. High extraction temperature, sonication and reflux method influenced on the decrease of anthocyanin contents because of breakdown of anthocyanins. There was no significant difference for extraction time between 12 h and 24 h. However, the optimal extraction condition were at room temperature for 12 h. The anthocyanin contents in seed coats of black soybean were determined on the basis of HPLC peak area at 530 nm. Ten black soybean varieties and germplasms were tested with optimal conditions founded in this study. On the basis of antocyanin component, these can be classified into three groups; C3G, C3G + D3G and C3G + D3G + Pt3G. The total anthocyanin content in seed coats ranged from 1.58 to 10.62 mg/g of seed. The total anthocyanin content of the variety "Geomjeongol" was about 7 times higher than that of variety "Heugchong". Information for extraction method and diversity in antocyanin of soybean seed coats can be used for future research for germplasm evaluation and development of high quality black soybean varieties.

Characteristics of Emergence and Growth of Sorghum at Various Soil Salinities and Seeding Methods in Reclaimed Soil (간척지 수수 재배에서 토양염농도와 파종방법에 따른 입모 및 생육특성)

  • Kim, Sun;Ryu, Jin-Hee;Paik, Chae-Hoon;Lee, Su-Hwan;Oh, Yang-Yeol;Lee, Jeong-Tae
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.62 no.3
    • /
    • pp.233-240
    • /
    • 2017
  • This experiment was conducted to establish a cultivation system for sorghum in reclaimed soils. Pot experiments were used to test the effects on seedling establishment of sowing depth, soil water content, and soil salinity using seeds of Nampungchal-susu and Hwanggeumchal-susu in reclaimed soil. Field experiments were also conducted to examine differences in growth characteristics and yield production, by sowing time, and planting distance. The result of the pot experiment, examining seedling establishment at various sowing depths revealed that, it was the highest 76.7% when the seeds were sown at a depth of 3 cm. Seedling establishment did not differ with soil water content between 10~30 kpa and at 51~70 kpa. No effects of seed moisture absorption before sowing were observed. Seedling establishment showed no differences with soil salinity below $3.2\;dS\;m^{-1}$, but decreased with Salinity above $4.8\;dS\;m^{-1}$. In field experiments to assess the effects on seedling establishment ratio of sowing time, Nampungchal-susu was revealed to have a high seedling establishment ratio following sowing on June 15. Hwanggeumchal-susu did not exhibits effects of sowing time, on seedling establishment ratio but exhibited higher seedling establishment when in low soil salinity conditions than when sown in high soil salinity conditions. With respect to yield, the yield of the seeds sown on June 15 was higher by 13% for Nampungchal-susu and by 29% for the Hwanggeumchal-susu than that those sown on June 25. With respect to soil salinity, the yield at a soil salinity of $3.2dS\;m^{-1}$ was lower by 23% than that at $1.6dS\;m^{-1}$ or lower for Nampungchal-susu, and was lower by 30% Hwanggeumchal-susu. With respect to planting density, both breeds showed the highest yield at $60{\times}10cm$. These results suggest that a sowing time of June 15 and a seeding distance of $60{\times}10cm$ are appropriate for sorghum in reclaimed land.

Errors in Net Ecosystem Exchanges of CO2, Water Vapor, and Heat Caused by Storage Fluxes Calculated by Single-level Scalar Measurements Over a Rice Paddy (단일 높이에서 관측된 저장 플럭스를 사용할 때 발생하는 논의 이산화탄소, 수증기, 현열의 순생태계교환량 오차)

  • Moon, Minkyu;Kang, Minseok;Thakuri, Bindu Malla;Lee, Jung-Hoon
    • Korean Journal of Agricultural and Forest Meteorology
    • /
    • v.17 no.3
    • /
    • pp.227-235
    • /
    • 2015
  • Using eddy covariance method, net ecosystem exchange (NEE) of $CO_2$ ($F_{CO_2}$), $H_2O$ (LE), and sensible heat (H) can be approximated as the sum of eddy flux ($F_c$) and storage flux term ($F_s$). Depending on strength and distribution of sink/source of scalars and magnitude of vertical turbulence mixing, the rates of changes in scalars are different with height. In order to calculate $F_s$ accurately, the differences should be considered using scalar profile measurement. However, most of flux sites for agricultural lands in Asia do not operate profile system and estimate $F_s$ using single-level scalars from eddy covariance system under the assumption that the rates of changes in scalars are constant regardless of the height. In this study, we measured $F_c$ and $F_s$ of $CO_2$, $H_2O$, and air temperature ($T_a$) using eddy covariance and profile system (i.e., the multi-level measurement system in scalars from eddy covariance measurement height to the land surface) at the Chengmicheon farmland site in Korea (CFK) in order to quantify the differences between $F_s$ calculated by single-level measurements ($F_s_{-single}$ i.e., $F_s$ from scalars measured by profile system only at eddy covariance system measurement height) and $F_s$ calculated by profile measurements and verify the errors of NEE caused by $F_s_{-single}$. The rate of change in $CO_2$, $H_2O$, and Ta were varied with height depending on the magnitudes and distribution of sink and source and the stability in the atmospheric boundary layer. Thus, $F_s_{-single}$ underestimated or overestimated $F_s$ (especially 21% underestimation in $F_s$ of $CO_2$ around sunrise and sunset (0430-0800 h and 1630-2000 h)). For $F_{CO_2}$, the errors in $F_s_{-single}$ generated 3% and 2% underestimation of $F_{CO_2}$ during nighttime (2030-0400 h) and around sunrise and sunset, respectively. In the process of nighttime correction and partitioning of $F_{CO_2}$, these differences would cause an underestimation in carbon balance at the rice paddy. In contrast, there were little differences at the errors in LE and H caused by the error in $F_s_{-single}$, irrespective of time.

Application of Hyperspectral Imagery to Decision Tree Classifier for Assessment of Spring Potato (Solanum tuberosum) Damage by Salinity and Drought (초분광 영상을 이용한 의사결정 트리 기반 봄감자(Solanum tuberosum)의 염해 판별)

  • Kang, Kyeong-Suk;Ryu, Chan-Seok;Jang, Si-Hyeong;Kang, Ye-Seong;Jun, Sae-Rom;Park, Jun-Woo;Song, Hye-Young;Lee, Su Hwan
    • Korean Journal of Agricultural and Forest Meteorology
    • /
    • v.21 no.4
    • /
    • pp.317-326
    • /
    • 2019
  • Salinity which is often detected on reclaimed land is a major detrimental factor to crop growth. It would be advantageous to develop an approach for assessment of salinity and drought damages using a non-destructive method in a large landfills area. The objective of this study was to examine applicability of the decision tree classifier using imagery for classifying for spring potatoes (Solanum tuberosum) damaged by salinity or drought at vegetation growth stages. We focused on comparing the accuracies of OA (Overall accuracy) and KC (Kappa coefficient) between the simple reflectance and the band ratios minimizing the effect on the light unevenness. Spectral merging based on the commercial band width with full width at half maximum (FWHM) such as 10 nm, 25 nm, and 50 nm was also considered to invent the multispectral image sensor. In the case of the classification based on original simple reflectance with 5 nm of FWHM, the selected bands ranged from 3-13 bands with the accuracy of less than 66.7% of OA and 40.8% of KC in all FWHMs. The maximum values of OA and KC values were 78.7% and 57.7%, respectively, with 10 nm of FWHM to classify salinity and drought damages of spring potato. When the classifier was built based on the band ratios, the accuracy was more than 95% of OA and KC regardless of growth stages and FWHMs. If the multispectral image sensor is made with the six bands (the ratios of three bands) with 10 nm of FWHM, it is possible to classify the damaged spring potato by salinity or drought using the reflectance of images with 91.3% of OA and 85.0% of KC.

Study on the Establishment of Barley Cultivation System using the Power Tiller (동력경운기를 중심으로한 맥류재배의 기계화 -관작업체계 확립에 관한 연구)

  • 이영렬;최규홍
    • Journal of Biosystems Engineering
    • /
    • v.3 no.2
    • /
    • pp.22-33
    • /
    • 1978
  • To maintain the self-sufficiency of food production , it is required to improved the productivity and increase the effective utilization of land in the double cropping areas using improved cultivation technology. The following reasons encourage this cours of action because the overlapping rice harvest and barely seeding seasons complete for labour, the lower price of barley makes it financially less attractive to grow and these two facts together are responsible for a decrease in barley being planted in certain more seasonably marginal double cropping areas. Fro these reasons, it is desirable to carry out tests to improve the current cultivation techniques . In this interest , the following studies were carried out in the experimental field located at Banweol-myeon, Whasung-jkun, Gyeonggi-do from October 1977 to July 1978 in order to establish the mechanical method of barley cultivation using the power tiller. The summarized results are as follows. 1. The work performance in the seeding operation using the rotary barley seeder was 68 minutes per 10 ares which compares favourably with 408 min/10a using the conventional method. This is only one sixth of the time required by th conventional method. The operating costs using the rotary barley seeder was 1, 463 won per 10 areas as against 3, 486 Won per 10 ares for the conventional method, showing a saving of about 50% in comparison with the conventional method. 2. In the manure spreading operation, the work performance was 25 min/10a for the manure spreading machine , compared to 1089 min/10a for the manual operations. This is about one fourth of the time required by the conventional method, The operating costs were 810 Won/10a for the machine and 857 Won/10a for the manual labour. This cost shows little advantage by the machine over the manual labor costs. The conventional method of manure spreading will continue pending decision which will develope and improve the machine.3. Work performance in the rolling operation using the barley rolIer was 30 min/lOa which compares favourably with 135 min/10a using conventional method. This was one fourth of the time required by the conventional method. The operating costs were 514 Won/103. for the machine and 1, 003 Won/lOa for manual labour. In the weed control operation, the work performance and operating costs were 45min/lOa, 1, 399won/10a for the herbcide application using the power sprayer, 1, 149min/10a 8, 541won/lOa for the conventional method respectively. This is 26 times higher efficiency in comparison to the conventional method. 4. In the harvesting operation using the reaper binder and tiller attachment, the work performance was 60min/lOa and represents a cost of 2, 039won/10a. The con\ulcornerventional method took 640min/10a at a cost of 4, 757won/lOa. The reaper binder showns a saving of one tenth over the conventional method. The automatic thresher is already recommended for the current situations, and is now being used. 5. From a comparison of the results of the above trials, the serial cultivation system using the attachment for the power tiller such as the rotary barley seeder is now to be recommended for the current barley cultivation system. It is also recommend from these results that the mechanized technology now available must be used to improve and maintain the increase in barley production. It is seen th1t this is the only course now avaihble to solve the peak seasonal requirements of labour needed for l11rvesting and seeding between rice and barley cultivation.

  • PDF

Improvement of Rotary Tine for Barley Seeder Attached to Rotary Tiller (로우터리 맥류파종기 경운날의 개량시험)

  • 김성래;김문규;김기대;허윤근
    • Journal of Biosystems Engineering
    • /
    • v.4 no.1
    • /
    • pp.1-23
    • /
    • 1979
  • The use of barley seeder attached to rotary tiller in the rural area has a significant meaning not only for the solution of labor peak season, but also for the increase of land utilization efficiency. The facts that presently being used barley seeders are all based on the mechanical principles of the reverse rotation, center drive and are all using forward rotating tine, which is used to be easily and heavily worn out when it rotates reversely, raise problem of recommending them to rural area in Korea. Therefore, the main objective of the study was to develop new type of rotary tine attachable to barley seeders. To attain the objective the following approaches were applied. (1) The kinematic analysis of reverse rotating barley seeders. (2) The studies on the soil bin and artificial soil. (3) The comparative experiment on the power requirement of prototype tine. The results obtained from the studies are summarized as follow: 1. The kinematic analysis of barley seeder attached to rotary tiller: The following results were obtained from the kinematic analysis for deriving general formulae of the motion and velocity characterizing the rotary tine of barley seeders presently being used by farmers. a) The position vector (P) of edge point (P) in the rotary tine of reverse rotating, center drive was obtained by the following formula. $$P=(vt+Rcos wt)i+Rsin wt j+ \{ Rcos \theta r sin \alpha cos (wt- \beta +\theta r) +Rsin \theta r sin \alpha sin (wt-\beta + \theta r) \} lk $$ b) The velocity of edge point $(P^')$ of reverse rotating, center drive rotary tine was obtained by the following formula. $$(P^')=(V-wR sin wt)i+(w\cdot Rcoswt)j + \{ -w\cdot Rcos \theta r\cdot sin \alpha \cdot sin (wt-\beta +\theta r) + w\cdot Rsin \theta r\cdot sin \alpha \cdot cos (wt- \beta + \theta r \} k $$ c) In order to reduce the power requirement of rotary tine, the angle between holder and edge point was desired to be reduced. d) In order to reduce the power requirement, the edge point of rotary tine should be moved from the angle at the begining of cutting to center line of machine, and the additional cutting width should be also reduced. 2. The studies on the soil bin and artificial soil: In order to measure the power requirement of various cutting tines under the same physical condition of soil, the indoor experiments Viere conducted by filling soil bin with artificially made soil similar to the common paddy soil and the results were as follows: a) When the rolling frequencies$(x)$ of the artificial soil were increased, the densIty$(Y)$ was also increased as follows: $$y=1.073200 +0.070780x - 0.002263x^2 (g/cm^3)$$ b) The absolute hardness $(Y)$ of soil had following relationship with the rolling frequencies$(x)$ and were increased as the rolling frequencies were increased. $$Y=37.74 - \frac {0.64 + 0.17x-0. 0054x^2} {(3.36-0.17x + 0.0054x^2)^3} (kg/cm^3)$$ c) The density of soil had significant effect on the cohesion and angle of internal friction of soil. For instance, the soil with density of 1.6 to 1.75 had equivalent density of sandy loam soil with 29.5% of natural soil moisture content. d) The coefficient of kinetiic friction of iron plate on artificial soil was 0.31 to 0.41 and was comparable with that of the natural soil. e) When the pulling speed of soil bin was the 2nd forward speed of power tiller, the rpm of driving shaft of rotary was similar to that of power tiller, soil bin apparatus is indicating the good indoor tester. 3. The comparative experiment on the power requirement of prototype tine of reverse rotating rotary: According to the preliminary test of rotary tine developed with various degrees of angle between holder and edge pcint due to the kinematic analysis, comparative test between prototype rotary tine with $30 ^\circ $ and $10 ^\circ$ of it and presently being used rotary tine was carried out 2nd the results were as follows: a) The total cutting torque was low when the angle between holder and edge point was reduced. b) $\theta r$ (angle between holder and edge point) of rotary tine seemed to be one: of the factors maximizing the increase of torque. c) As the angle between holder and edge point ($\theta r$) of rotary tine was $30 ^\circ $ rather than $45 ^\circ $, the angle of rotation during cutting soil was reduced and the total cutting torque was accordingly reduced about 10%, and the reduction efficiency of total cutting torque was low when the angle between holder and edge point ($\theta r$) of rotary tine was $10 ^\circ $, which indicates that the proper angle between holder and edge point of rotary tine should be larger than $10 ^\circ $ and smaller than $30 ^\circ $ . From above results, it could be concluded that the use of the prototype rotary tine which reduced the angle between holder and edge point to $30 ^\circ $, insted of $45 ^\circ $, is disirable not only decreasing the power requirements, but also increasing the durabie hour of it. Also forward researches are needed, WIlich determine the optimum tilted angle of rotary brocket, and rearrangement of the rotary tine on the rotary boss.

  • PDF