• Journal of Agricultural Extension & Community Development
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• v.21 no.1
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• pp.219-244
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• 2014

Agricultural extension service in Ethiopia was started in early 1950s with mandate of transferring local research outputs and technologies to farmers, and importing technologies and improved practices from abroad. Extension service provided in this early time was limited to areas surrounding the experiment stations. Since then, Ethiopian Agricultural extension service has passed through at least five stages: the land grant extension system, the Comprehensive Package Programs, the Minimum Package Projects, the Peasant Agricultural Development Program, and the Participatory Demonstration and Training Extension System (PADETS). The comprehensive package extension program was initially implemented in selected pilot areas and eventually to be scaled up to cover about 90% of the farming community within 15-20 years time. The program used demonstration plots managed by development agents and used to train farmers organized through various field days. However, since all of these programs were operational in only small areas, the vast majority of the country was out of their reach. Through Participatory Demonstration and Training Extension System, the extension service in Ethiopia has come under the spotlight and government debates and external reviews are putting additional scrutiny on the system. Despite this long history, the system is still in its infancy in terms of coverage, communication and institutional pluralism. Currently in Ethiopia the Agricultural extension is provided primarily by the public sector, operating in a decentralized manner through which extension is implemented at the district level. Therefore, the main focus of this paper is to scrutinize the past, the present and the future Agricultural extension system in Ethiopia.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.649-658
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• 2003

Early introducing the ducks into the paddy field involves a variety of environmental changes such as new surroundings and contact with water, so that some free-ranged ducks show behavioral and physiological changes indicative of stress or die from not adapted for new circumstances. Moreover, the free-ranged ducks was tread on the rice plant, and required a great deal of labor and time for captured the ducks after finishing the introducing. The aim of the present study was to examine the effect of accustoming and imprinting of duckling on behavior patterns, body weight gain and yield of the rice plant in paddy fields. Three paddy plots were used as control (no imprinting and no contact with people), taming (imprinting and regular handling) and roughness (handling roughly and strike terror to ducks) plots. Right after introducing the ducks into the paddy field, eating and moving behaviour of taming plot ducks tended to be longer time spend than that of other treatments. However, eating and moving time tended to be longer in the control than that of other two treatments on the 2 weeks after. Flighting distance was not showed in the free-ranging period taming plot, but the control plot was significantly (P<0.05) longer than the roughness plot. The captured time of free-ranged ducks tended to be shorter in the order of taming, control and roughness plots. Body weight gains was not significant. The number of rice plants damaged by free-ranging ducks in the taming plot were significantly (P<0.05) less than that in the control plot, but the yield and yield components of the rice plant were not differ among 3 treatments. These results indicated that the imprinting or regular handling and related treatments of duckling was reducing badly damage of rice plants, captured time and labor of free-ranged ducks in paddy field, although the working behavior of ducks and yield ability of the rice plants were not affected.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.279-286
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• 2009

This study carried out to find out feed value of barley plus pea mixture with different ratio and cutting date to got basic information when introduced the mixture as new cropping system in middle part of Korean peninsular. Dry matter (DM) yield increased as barley seeding rate was higher and showed the highest yield in the plots with barley 85% plus 15% ratio when harvested on May 16. There was no different in crude protein, available protein and digestible protein cutting on April 25 in every mixture, but the content increased with higher pea mixture rate after May 2. The content of acid detergent fiber (ADF) and neutral detergent fiber (NDF) increase coincided with higher barley rate and late cutting dates. But relative feed value (RFV) resulted in opposite trend. Higher pea ratio influenced increased content of total digestible nuterients (TDN), but decreased before May 9 cutting and increased after the next cutting regime. There was no statistical difference in P and Mg between sowing rate, but Ca increased at higher pea ratio and P, Ca, K decreased in all plots as harvests were delayed. The content of estimated net energy (ENE), net energy maintenance (NEM) and net energy gain (NEG) significantly increased with higher pea rate and earlier cutting. But net energy lactation (NEL) was no significant differences between seeding rates and cutting dates. In conclusion, mineral yield such as P, Ca, K and Mg showed the highest yield at barley plus pea ratio of 75 : 25 and energy yield of ENE, NEL, NEM, NEG and TDN was the highest at 85 to 15 mixture plots and DM yield, TDN yield, mineral yield such as P, Ca, K and Mg and energy yield of ENE, NEL, NEM, NEG were the highest on each treatment cutting on May 16.

• Journal of Animal Science and Technology
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• v.53 no.1
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• pp.51-57
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• 2011

The performance of grass filter strips (GFS) in abating $NO_3$-N concentrations from the forage cropland was tested in an experiment on the 10% slope in Grassland and Forages Division, National Institute of Animal Science, Rural Development Administration (RDA) from October 2007 to September 2009. Forage croplands with rye-corn double cropping system applied with chemical fertilizer and livestock manure (LM) were compared in a natural condition. The plots were hydrologically isolated in a randomized block layout of 3 treatments $\times$ 2 factors $\times$ 3 replicates. Main plots consisted of the length of GFS, such as 0 m, 5 m, 10m and 15m. Sub plots consisted of the type of LM, such as chemical fertilizer (CF), cattle manure (CM) and swine manure (SM). Dry matter yields of rye and corn increased significantly in order of CF > CM > SM (p<0.05). Concentrations of $NO_3$-N in surface runoff water were reduced as the length of GFS increased. Especially, GFS with 10 m and 15m reduced $NO_3$-N concentrations significantly compared to that with 0 m and 5 m (p<0.05). The results from this study suggest that GFS improved the removal and trapping of manure nutrients from forage croplands.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.4
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• pp.309-316
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• 2010

The performance of grass filter strips (GFS) in reducing $PO_4$-P concentrations and soil loss from the forage cropland was tested in an experiment on the 10% slope in Grassland and Forages Division, National Institute of Animal Science, Rural Development Administration (RDA) from October 2007 to September 2009. Forage cropland with rye-corn double cropping system receiving inorganic fertilizer or livestock manure (LM) were compared in a natural condition. The plots were hydrologically isolated in a randomized block layout of 3 treatments $\times$ 2 factors $\times$ 3 replicates. Main plots consisted of the length of GFS, such as $25\;m^2$ ($5{\times}5\;m$), $50m^2$ ($5{\times}10\;m$), $75m^2$ ($5{\times}15\;m$). Sub plots consisted of the type of LM, such as chemical fertilizer (CF), cattle manure (CM) and swine manure (SM). Concentrations of $PO_4$-P in surface runoff water were reduced as the length of GFS increased. Especially, GFS with 10 m and 15 m reduced $PO_4$-P concentrations significantly compared to that with 0 m (p<0.05). However, there was not significant different between $PO_4$-P concentrations of GFS with 10m and that of GFS with 15 m. Moreover, Soil loss in surface runoff water were reduced as the length of GFS increased. GFS with 15 m reduced soil loss significantly compared to that with 5 m and 10 m (p<0.05). The results from this study suggest GFS improve the removal and trapping $PO_4$-P and soil loss from forage cropland.

• Korean Journal of Organic Agriculture
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• v.22 no.3
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• pp.503-519
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• 2014

This study was conducted to investigate ginger growth and its nutrient uptake depending on changes of soil properties as affected by applications of green manure crop and/or charcoal in continuous cropping system. The green manure crops applied were barley and hairy vetch, and charcoal was additionally treated in selected plots as a soil conditioner. Experimental plots were prepared as Plot 1 (control), Plot 2 (barley of 8kg $10a^{-1}$), Plot 3 (hairy vetch of 12kg $10a^{-1}$), Plot 4 (charcoal of 1,000kg $10a^{-1}$ and barley 8kg $10a^{-1}$), and Plot 5 (charcoal of 1,000kg $10a^{-1}$ and hairy vetch of 12kg $10a^{-1}$) with two different soil conditions (high clay content, HCC and low clay content, LCC). When comparing selected chemical properties of soils before and after cultivating ginger plant, soil pH decreased from 6.9~8.1 to 6.8~7.6, and electrical conductivity (EC) also declined from $0.45{\sim}1.25dSm^{-1}$ to $0.30{\sim}0.61dSm^{-1}$. However, the content of soil organic matter (SOM) and total nitrogen (T-N) increased. Thus, the soil chemical properties were improved with the applications of green manures and charcoal. Also, macro- and micro-nutrient contents of ginger plants in the different plots were various between normal and diseased plants grown in soils with HCC and LCC. In particular, the concentration of manganese (Mn) was 3~4 folds higher in the diseased plant than in the normal plants. Ginger growth status and yield was relatively improved with the applications of green manures and charcoal as comparing with control plot. Especially in the Plot 4 with LCC, the ginger plant was not infected by root-rot disease.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.15-22
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• 2001

A soil temperature was known as extremely important factor in terms of measuring the values of the growth and yield of vegetable in the greenhouse. A low temperature water irrigation was had much trouble in its growth. This study was performed to analyze the effect of the heating water irrigation on the soil temperature and the growth of a cucumber within a greenhouse environment. Soil temperature was 5-7$^{\circ}C$ below to 10cm in depth and 2-3$^{\circ}C$ to 20cm when the irrigation water temperature was 13$^{\circ}C$ (non-warme water irrigation). Soil temperature was similar to irrigation water temperature at 5cm in depth and was 1.5-2$^{\circ}C$ below at 10cm when the irrigation water temperatures were 2$0^{\circ}C$, $25^{\circ}C$. The early growth rates of heating water irrigation were 109-110% in plant height, 107-108% in leaf number, 103% in node number compared with those of unheated water irrigation for 30 days after planting it. The rates of total yield were 115% in 2$0^{\circ}C$ water irrigation plots and 121% in $25^{\circ}C$ water irrigation plots while those of unheated water irrigation plots were.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.515-521
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• 2013

The objective of this study was to estimate the changes of stand structure before and after applying the three different silvicultural treatments such as selection cutting system, two-storied system, and shelterwood system. This study has been conducted in the natural deciduous forests in Pyeongchang of Gangwon Province, Korea. Nine permanent sampling plots of 0.09 ha were established in the forests and each of the three silvicultural treatments was applied to three sampling points. Some tree variables were measured in each stand before and after the silvicultural treatments were applied. With these data, stand attributes were estimated in each stand before and after applying the silvicultural treatments. In this study, a competition index was used to analyze the differences among structures of stands managed by three different silvicultural treatments. Hegyi's distance-dependent competition index was estimated and compared to analyze the differences of stand structures among the stands before and after silvicultural treatments. A method using a height angle $50^{\circ}$ from the base of the subject tree was adopted as the selection method of competitor trees. Duncan's multiple range test and t-test were then employed to statistically analyze the difference of stand structure among the stands. The results revealed that competition status among trees in the stand seems to be improved after applying the silvicultural treatments. There are significant differences in the competition index between before and after silvicultural treatments for each stand. According to the evaluation of competition index, it was confirmed that spatial structure of the stands was improved by applying the silvicultural treatments.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.297-304
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• 2012

The objective of this study was to estimate the changes of stand structure before and after applying the three different silvicultural treatments such as selection cutting system, two-storied system, and shelterwood system. This study has been conducted in the natural deciduous forests in Pyungchang of Gangwon Province, Korea. Three permanent sampling plots of 0.09 ha were established in the forests and the three silvicultural treatments were applied in 2008. For this study, some tree variables were measured in each stand before and after the silvicultural treatments were applied. With these data, stand attributes were estimated in each stand before and after the silvicultural treatments. In this study, four stand structure indices were used to analyze the differences among structures of stands managed by three different silvicultural treatments. Contagion index, DBH-difference index, height-difference index, and mingling index were estimated and compared to analyze the differences of stand structures among the stands before and after silvicultural treatments. Duncan's multiple range test and t-test were then employed to statistically analyze the difference of stand structure among the stands. The results revealed that all of the stand structure indices seem to be increased after applying the silvicultural treatments. There are significant differences in the stand structure indices between before and after silvicultural treatments for each stand. According to the evaluation of stand structure indices, it was confirmed that spatial structure of the stands was improved by applying the silvicultural treatments. For attaining the specific goal of each stand types acquired by different silvicultural treatments, the frequencies and amounts of additional practices should be decided based on the changes of stand structure as time passed.

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.235-244
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• 2012

This paper presents a design and simulation of bi-directional DC/DC boost converter for a fuel cell system. In this paper, we analyze the equivalent model of both a boost converter and a buck converter. Also we propose the controller of bi-directional DC-DC converter, which has buck mode of charging a capacitor and boost mode of discharging a capacitor. In order to design a controller, we draw bode plots of the control-to-output transfer function using specific parameters and incorporate proper compensator in a closed loop. As a result, it has increased PM(Phase Margin) for better dynamic performance. The proposed bi-directional DC-DC converter's 3pole-2zero compensation method has been verified with computer simulation and simulation results obtained demonstrates the validity of the proposed control scheme.