초지의 관개효과에 관한 연구 1 . 관개와 질소시비수준이 토양수분장력과 목초의 재생 및 수량에 미치는 영향

서성,박문수,한영춘,이종열 ( S . Seo,M . S . Park,Y . C . Han,J . Y . Lee ) 한국축산학회 1986 한국축산학회지 Vol.28 No.2

Pasture irrigation has been much paid attention to for the increase of forage yield and persistence in dry area. This field experiment was conducted to determine the effects of irrigation and nitrogen(N) fertilization on the soil moisture retention, regrowth and yield of orchardgrass/ladino clover mixtures during the dry season. Irrigation point was 0.5bar, irrigation method was sprinkler system, and N levels (subplot) were 140, 280 and 420 ㎏/㏊. The experiment was performed at Livestock Experiment Station in Suweon, 1985. The results are summarized as follows: 1. Considering the meteorological conditions during the experimental period, the temperature was higher by 0-2℃ than that of average year, and the dry season was prolonged from May 20 to June 26. 2. With irrigation the temperature of soil surface and underground was decreased by 4.4℃ and 1.6℃, respectively. 3. The regrowth plant length, leaf area and dry weight of grasses with irrigation were markedly increased during the dry season. Also under the irrigation condition the regrowth speed was significantly increased with increasing level of N, while that of unirrigated pasture was no differences between the plots of N 280 and N 420 ㎏/㏊. 4. With irrigation dry matter yield (5.9 t/㏊) and fresh yield (35.4 t/㏊) during the dry season (at the second and the third cut) were significantly (P$lt;0.05) increased by 36% and 50%, respectively. 5. Yield of irrigated pasture was rapidly (P$lt;0.05) increased with increasing level of N application. However, that of unirrigated pasture was shown no difference between the plots of N 280 and N 420 ㎏/㏊.

고온기 초지의 예취관리에 관한 연구 2 . 고온기 예취방법이 Orchardgrass 초지의 재생 , 목초고사 , 잡초발생 및 수량에 미치는 영향

서성,한영춘,박문수 ( S . Seo,Y . C . Han,M . S . Park ) 한국축산학회 1986 한국축산학회지 Vol.28 No.1

Optimum pasture management during the summer season is an important factor to maintain good regrowth and persistence of pasture. This field experiment was carried out to investigate the effects of the cutting management on the regrowth, dead plants, weed appearance, root activity and D.M. yield of orchardgrass pasture during the mid-summer season. Two different the third cutting times (July 15 and Aug. 3) as the mainplot, and three different cutting heights (3,6 and 9 ㎝) at the third cut as the subplot were treated, and the experiment was done at Livestock Experiment Station, in Suweon, 1985. 1. Temperature of soil surface and underground after the third cut tended to decrease by 1-4℃C as cutting height was high, and soil moisture content also decreased as stubble height was high. 2. Regrowth leaf length, leaf area and root activity of orchardgrass after the third cut increased significantly with the high cutting height (P$lt;0.05). 3. The percentage dead plants and weeds after the third cut were significantly decreased (P$lt;0.05) with the high stubble height during the mid-summer season, and main weeds appeared after the third cut were Digitaria sanguinalis$gt;Portulaca oleracea$gt;Cyperus iria, Rumex cripus, and so on. 4. Regrowth dry matter yield at the fourth and fifth cut were significantly increased (P$lt;0.05) with the high stubble height, regardless of cutting time. 5. From the above results, it is suggested that the 9㎝ cutting height during the mid-summer season is the most effective for good regrowth, weed control and forage yield of orchardgrass pasture.

하고기간중 규산질비료의 시용이 목초의 생육과 수량 및 사료가치에 미치는 영향

서성(S . Seo),이종경(J . K . Lee) 한국축산학회 1991 한국축산학회지 Vol.33 No.1

This experiment was carried out to determine the effects of additional application of silicate fertilizer during summer season on growth, dry matter (DM) yield and nutritive value, and to obtain basic understanding on diminishing of summer depression of grasses. Application date (June 30 and Julv 15) and application amount (0. 150, 300 and 450 kg/ha) in Experiment 1, and application amount (0, 200, 400 and 800 kg ha) of silicate fertilizer m Experiment 2 were treated in existing pasture mixtures dominated by orchardgrass, 1988 and 1989. Grass growth, DM yield, lodging, neutral detergent fiber, acid detergent fiber, hemicellulose, water soluble carbohydrate and DM digestibility were not significantly influenced by application date and application amount of silicate fertilizer. In this experiment. therefore, there was no diminishing effect of summer depression by application of silicate fertilizer. However. performance of continuous research may be desirable in hill pasture with low soil fertility and bad soil conditions.

월동전후 초지관리에 관한 연구 9 . 기존초지에서 이른 봄 화입이 목초의 생육과 수량 및 사료가치에 미치는 영향

서성 ( S . Seo ) 한국축산학회 1991 한국축산학회지 Vol.33 No.9

A field experiment was carried out to determine the effects of dead material length (15 ㎝ and 30 ㎝) and burning time (Feb. 21. Mar. 2. Mar. 11. and Mar. 20) during early spring on grass growth, dry matter yield and nutritive value in pasture mixtures dominated by orchardgrass. A non-burning (control) plot was involved. and the Experimental Site, Grassland Div.. Livestock Expt. Stn., RDA was burned over two years (1989 and 1990). Burning treatments increased the temperature of soil surface and 10 ㎝ depth on an average by 5.5℃ and 2.8℃ respectively. Also a little burning damage was found in late burning time. However. grass growth and yield were not influenced by burning. burning time and length of dead materials. In control plot, sometimes, better production was observed in spring. As the burning time was delayed, crude protein content was increased, and NFE content was decreased. No disease and insects were observed in all treatments. From the above results, grassland burning in early spring could not he recommended in Korea, because burning was not beneficial on forage production and a cause of forest fire.

고온기 초지의 예취관리에 관한 연구 6 . 고온기간중 예취높이와 질소 및 칼리추비가 혼파초지의 식생과 수량 및 목초품질에 미치는 영향

서성(S . Seo),조무환(M . H . Jo),박문수(M . S . Park),이종경(J . K . Lee),한영춘(Y . C . Han) 한국축산학회 1988 한국축산학회지 Vol.30 No.8

A field experiment was carried out to determine the effects of cutting height at the third cut and application of N and K₂O after cutting during mid-summer season on the soil temperature, plant height, grass coverage, percentages of grass and legume, yield and grass quality in orchardgrass dominated pasture. With three cutting heights (3, 6 and 9㎝) and 4 fertilizer levels (0, N 50㎏, K₂O 50㎏, and N 50㎏ + K₂O 50㎏ ㏊^(-1)), present experiment was conducted at Livestock Experiment Station, Suwon in 1987. 1. The soil temperature after the third cut was rapidly elevated, and lower value was observed with 9㎝ of cutting height through the regrowth period. Plant height after cutting was remarkably increased with higher stubble height regardless of fertilizer levels. 2. The grass coverage and percentage of grass were increased as stubble height was high, while the influence of fertilizer on those was very little. Application of N and K₂O with lower stubble height significantly increased the percentage of bareland. 3. The yield at the third cut was decreased with higher height. But the regrowth yield was significantly increased as the cutting height was increased regardless of fertilizer levels. Regrowth yield was great at N 50㎏ + K₂O 50㎏ $gt; 0 $gt; K₂O 50㎏, N 50㎏, in that order. However, there were not significantly different on regrowth yield among fertilizer treatment. 4. The contents of crude protein, crude fat, crude ash, P, K and Ca were decreased as stubble height was high, and that of crude fiber was increased at 9 ㎝ cutting height. Also the influence of N and K₂O fertilizer on grass quality was little.

초지의 관개효과에 관한 연구 6 . 관개와 질소시비수준이 계절별 , 생육시기별 목초의 건물생산과 질산태질소 함량 및 관개효율에 미치는 영향

서성(S . Seo),이종경(J . K . Lee),이성철(S . C . Lee),박문수(M . S . Park) 한국축산학회 1990 한국축산학회지 Vol.32 No.3

For basic understanding on pasture irrigation, an experiment was conducted to determine the effects of irrigation and nitrogen(N) fertilization (200 and 400kg ha^-1 y^-1) on the seasonal grass dry matter (DM) production, nitrate nitrogen(N0₃-N) concentration, and irrigation efficiency in pasture mixtures dominated by orchardgrass, 1988. It was investigated on 7, 14, 21, and 28 days after harvesting in spring(May), summer(July) and autumn (Sept.), respectively. During experimental period, rainfall was controlled artificially, and irrigation point was ca. 1.0 bar. Higher DM production was observed in spring (1967 kg ha^-1), irrigated plot, and higher N fertilization plot, respectively. Also the DM production was increased with advancing maturity of plants. Irrigation efficiency in spring (20kg ha^-1 mm^-1) was significantly higher than summer(9kg), especially in high N fertilization plot. On the other hand, the efficiency in summer season was high in low N plot. NO₃-N concentration in spring was very low (less than 0.1%), however, the N0₃-N was high (more than 0.2%) in summer and autumn. Also the NO₃-N was increased remarkably with increasing of N level, and decreased slightly with advancing of plant growth. Based on the results, it is suggested that higher N in spring, and lower N fertilization in summer and autumn are more effective for grass production and irrigation efficiency. Also enough regrowth period is desirable to decline N0₃-N in summer and autumn.

초지의 관개효과에 관한 연구 8 . 관개기준점에 따른 목초의 생산성과 사료가치 및 관개효율 비교

서성 ( S . Seo ) 한국축산학회 1991 한국축산학회지 Vol.33 No.10

To determine the optimum irrgating point for saving water. this experiment was carried out in a pasture mixture dominated by orchardgrass (Ductylis glomerata L.). The effects of different irrigating points (-.0.2 bar as a control, -0.5, -1.0 and -3.0 bar) including a non-irrigated plot on grass growth, dry matter (DM) yield, nutritive value and irrigation efficiency were investigated. During experimental period, rainfall was controlled artificially. In grass growth and DM yield, there were no significant differences among the plots of -0.2, -0.5 and -1.0 bar. However, yields of -3.0 bar and non-irrigated plot were decreased significantly (P$lt;0.05) by 24% and 57% compared with control plot, respectively. Regrowth yield was similar in all treatments. The irrigation efficiency was the highest in -1.0 bar (16.0 DM ㎏/㏊/㎜). Crude protein, NDF, ADF, digestibility and relative feed value of grasses were not significantly different regardless of irrigating point. The most poor forage quality was observed in non-irrigated plot. The level of nitrate concentration was 0.1, to 0.2% in all plots. Based on the results, the optimum irrigating point for saving water was ca. -1.0 bar in pasture considering grass production, nutritive value and irrigation efficiency.

고온기 초지의 예취관리에 관한 연구 5 . 고온기 예취방법에 따른 목초의 재생과 하고성 분석

서성(S . Seo),박문수(M . S . Park),한영춘(Y . C . Han),이종경(J . K . Lee) 한국축산학회 1988 한국축산학회지 Vol.30 No.3

This field experiment was carried out to determine the effect of the third cutting time (July 15 and Aug. 2) and cutting height (3, 6 and 9㎝) at the third cut on the regrowth and summer depression of grasses during mid-summer season. In this study, the grass growth and summer depression index were analyzed in association with temperature and rainfall, and this experiment was done at Livestock Experiment Station in Suwon during 1984-1986. The results obtained are summarized as follows: 1. Ary matter production during mid-summer season was significantly (P$lt;0.05) increased with higher cutting height at the third cutting, regardless of cutting time. 2. The grass growth and summer depression index mostly depended on temperature after the third cutting, The summer depression index of grasses in 1984, 1985 and 1986 were 1.34, 1.83 and 1,51, respectively. 3. The summer depression index was significantly (P$lt;0.05) decreased with higher cutting height. The index observed were 1.89 (3㎝), 1.50 (6㎝) and 1.19 (9㎝) in the plot of July 15, and 2.54 (3㎝), 1.67 (6㎝) and 1.29 (9㎝) in the plot of Aug. 2, respectively. 4. From the results of regrowth of grasses and summer depression index after the third cut, it is suggested that the 9㎝ of cutting height is the most effective during the mid-summer season, regardless of year and cutting time.

초지의 관개효과에 관한 연구 3 . 봄철 생육시기별 한발 ( 旱魃 ) 이 목초의 생육과 수량 및 품질에 미치는 영향

서성(S . Seo),박문수(M . S . Park),이종경(J . K . Lee),한영춘(Y . C . Han) 한국축산학회 1988 한국축산학회지 Vol.30 No.11

For basic understanding on pasture irrigation, this experiment was carried out to determine the effects of spring drought in relation to growing stage on the growth, dry matter yield and quality of grasses. Duration of non-irrigated treatments were early vegetative stage (Mar. 24-Apr. 5, T₁), vegetative stage (Apr. 6-Apr. 18, T₂), boot stage (Apr. 19-May 1, T₃), and heading stage (May 2-May 14, T₄) and irrigated plot (control, T_5) was involved. During experimental period, rainfall was controlled artificially, irrigation point was 0.5-1.0 bar, and the experiment was conducted at LES in Suwon, 1988. 1. With irrigation, temperature of sod surface and underground was decreased. The highest decreasing effect was observed in T₄, and then T₃, T₂, and T₁, in that order. 2. In grass growth and yield, boot stage (T₃) was the most harmful (DM 3.57 MT ha^-1 ), and there were not significant differences among T₁, T₂, T₄ and T_5. However, regrowth yield was not significantly different among all treatments. 3. DM production per mm of water applied was also the lowest in boot stage (42.0 ㎏), and then in T_5 (46.3 ㎏). That of heading stage (57.4 ㎏ ha^-1 ) was the highest (P $lt;0.05). 4. DM digestibility and nitrate nitrogen concentration of grasses in T_5 were slightly lower than in T₁, T₂, T₃ and T₄, but the differences were not significantly different when compared with T_5. 5. The results indicates that enough water applied during boot stage may be desirable to improve pasture irrigation efficiency, and spring drought stress of short interval on regrowth yield and quality of grasses was very little.

목초의 월별 , 계절별 생산성에 관한 연구 1 . Orchardgrass 우점 혼파초지에서 목초의 생육과 계절생산성

서성(S . Seo),한영춘(Y . C . Han),이종경(J . K . Lee),박문수(M . S . Park) 한국축산학회 1988 한국축산학회지 Vol.30 No.2

Grass growth and seasonal pattern of production from pasture are varied within years and between years, which depend on mostly temperature and rainfall during the growing season. A field experiment was carried out to determine the grass growth and seasonal distribution of production in orchardgrass dominated pasture in Suwon during 1985 and 1986. Regrowth plant height after cutting, LAI, percentage of leaf blade, dry matter (DM) yield, DM distribution and DM production per day were investigated. Also the grass growth and seasonal productivity were analyzed in association with meteorological factors. The results obtained are summarized as follows: 1. During the growing season, about 60% of annual production was produced in spring season, and the highest grass production was achieved in May., which was more than 30% of total production. However, those produced in July and August were very low, and the production in September tended to be recovered slightly from low summer growth. And the final plant height was observed in middle of November. 2. The maximum DM production per day (137.5℃/㏊) was observed in May, followed by June (66.2℃) and September (61.1℃), while DM production during the summer season showed very low (43.2℃ in July and 48.1℃ in August). Significant correlation (r=0.84^(**)) was found between plant height and DM production. 3. In production analysis equation (r2=0.54**) in relation to mean temperature, it was observed grass production began at about 7℃, optimum growth temperature was between 15 and 21℃, maximum production at 18℃, summer depression was shown at over 25-26℃, and summer growth stopped at 28℃. 4. Summer depression index in this study was 1.38, this value does not indicate severe summer depression. But pasture production and regrowth plant height after cutting were very slow during mid-summer season.