임간초지 개발에 관한 연구 V. 차광정도가 주요 초목의 초기생육과 월동에 미치는 영향

Studies on the grassland Development in the Forest V. Effect of sharing degrees on the early growth characteristics and winter survival of main grasses

본(本) 연구(硏究)는 임간초지개량(林間草地改良)과 관리(管理) 및 이용(利用)의 기초자료(基礎資料)를 얻고자 차광정도(遮光程度)를 0%구(區)(自然光狀態), 25%, 50%, 75%차광구(遮光區)를 설치(設置)하고 Orchardgrass, Timothy, Perennial ryegrass를 '84년(年) 8월(月) 25일(日)에 파종(播種)하여 목초(牧草)의 동사(凍死) 및 월동전(越冬前) 초기생육특성(初期生育特性)을 조사(調査)하였던바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 차광정도(遮光程度)에 따른 근장(根長), 분얼수(分蘖數), 발근수(發根數) 및 발근장(發根長)의 생육정도(生育程度)는 자연광상태(自然光狀態)${\geqq}$25%차광구(遮光區)>50% 차광구(遮光區) >75% 차광구순(遮光區順)이었으며(P<0.05), 초장(草長) 및 엽신장(葉身長)의 생육(生育)은 자연광상태(自然光狀態)<25%차광구(遮光區)<50%차광구(遮光區)${\geqq}$75%차광구순(遮光區順)이었다(P<0.05). 2. 차광정도(遮光程度)에 따른 동사율(凍死率)은 자연광상태(自然光狀態)가 4.7%, 25%차광구(遮光區)는 6.2%, 50%차광구(遮光區)는 11.8%, 75%(遮光區)는 22.2%를 보여 차광정도(遮光程度)가 많을수록 동사율(凍死率)은 증가(增加)하였다(P>0.05). 초종별(草種別)로는 Orchardgrass가 10.1%, Timothy가 9.5%, Perennial ryegrass가 14.2%를 나타내었다. 3. 차광정도(遮光程度)에 따른 초종별(草種別) 동사율(凍死率)과 월동전(越冬前) 초기(初期) 생육형질(生育形質)과의 관계(關係)는 분얼수(分蘖數), 발근수(發根數), 발근장(發根長)과는 고도(高度)의 부(負)의 상관관계(相關關係)를 보였으나, 초장(草長) 및 엽신장(葉身長)과는 정(正)의 상관관계(相關關係)를 나타내었다. 4. 차광정도(遮光程度)에 따른 월동전(越冬前) 순동화율(純同化率)은 자연광상태(自然光狀態)가 10.98, 25%차광구(遮光區)가 11.52, 50%차광구(遮光區)가 9.81, 75%차광구(遮光區)가 $6.12g/m^2/day$을 보여 차광(遮光)이 많을수록 감소(減少)하는 경향(傾向)이며, 초종별(草種別)로는 Orchardgrass가 8.58, Timothy가 8.53, Perennial ryegrass가 $11.71g/m^2/day$을 나타내었다. 동사율(凍死率)과 월동전(越冬前) 순동화율(純同化率)과는 부(負)의 상관관계(相關關係)(r=-0.5943*)를 나타내었다.

This field experiment was conducted to determine the effects of shading degrees (0 : full sunlight, 25, 50 and 75%) on the early growth characteristics and winter survival of grasses. For the test different artificial shading houses were established and pasture species used were orchardgrass, timothy and perennial ryegrass. The experiment was performed at Livestock Experiment Station in Suweon, and sowing date was Aug. 25, 1984. The results are summarized as follows : 1. Generally, root length, new root length, number of new root and tillers of grasses were increased at 0% (full sunlight) of shading, followed by 25, 50 and 75% of shading degrees, in that order. Plant length and leaf elongation, however were increased at 50% of shading, followed by 75, 25 and 0%. 2. The percentage of winter killing of grasses was significantly (P<0.05) increased as the shading degrees increased. Also the percentages of winter killing were 10.1% in orchardgrass, 9.5% in timothy and 14.2% in perennial ryegrass, respectively. 3. A significant negative correlations were observed in the relationship between winter killing and tillers, new root length and number of new root of grasses. However, there were positive correlations between winter killing and plant length or leaf elongation under shading conditions. 4. As the shading degrees are increased by 0, 25, 50 and 75%, the NAR of grasses was tended to be decrease to 10.98, 11.52, 9.81 and 6.12 g/$m^2$/day, in that order. Also there was a negative correlation (r=-0.5943*) between winter killing and NAR of grasses, and NAR of orchardgrass, timothy and perennial ryegrass were 8.58, 8.53 and 11.71 g/$m^2$/day, respectively.