Due to the recent impact of global warming, heavy rainfall and droughts have been occurring regardless of the season, affecting the growth of Italian ryegrass (IRG), a winter forage crop. Particularly, delayed sowing due to frequent heavy rainfall or autumn droughts leads to poor growth and reduced winter survival rates. Therefore, techniques to improve yield through additional sowing in spring have been implemented. In this study, the growth of IRG sown in Spring and Autumn was compared and analyzed using vegetation indices during the months of April and May. Spectral data was collected using an Unmanned Aerial Vehicle (UAV) equipped with a hyperspectral sensor, and the following vegetation indices were utilized: Normalized Difference Vegetation Index; NDVI, Normalized Difference Red Edge Index; NDRE (I), Chlorophyll Index, Red Green Ratio Index; RGRI, Enhanced Vegetation Index; EVI and Carotenoid Reflectance Index 1; CRI1. Indices related to chlorophyll concentration exhibited similar trends. RGRI of IRG sown in autumn increased during the experimental period, while IRG sown in spring showed a decreasing trend. The results of RGRI in IRG indicated differences in optical characteristics by sowing seasons compared to the other vegetation indices. Our findings showed that the timing of sowing influences the optical growth characteristics of crops by the results of various vegetation indices presented in this study. Further research, including the development of optimal vegetation indices related to IRG growth, is necessary in the future.

Ⅰ. 서론
Ⅱ. 재료 및 방법
    1. 연구지역 및 재배환경 측정
    2. 생육조사
    3. 초분광 무인기 영상 취득
    4. 식생지수 산정 및 통계분석
Ⅲ. 결과 및 고찰
    1. 재배환경 측정
    2. 생육조사
    3. 식생지수 산정
    4. 식생지수 RGRI와 건물수량의 상관분석
Ⅳ. 요약
Ⅴ. 사사

• 양승학(국립축산과학원) Corresponding author
• 정종성(국립축산과학원)
• 최기춘(국립축산과학원)