일년생 잡초인 물달개비 및 올챙이고랭이의 출아와 초기생장을 예측하기 위한 모델 구축을 위하여 온도조건을 달리한 식물생장상에서 포트실험을 수행하였다. 이들 잡초의 출아 및 초기생장과 유효적산온도와의 관계를 비선형회귀로 분석한 결과 온도조건에 상관없이 각각 Gompertz 모델 및 logistic 모델로 설명이 잘 되었다. 물달개비 및 올챙이고랭이의 최대 출아율의 50%에 필요한 유효적산온도는 각각 69.3 및 $94.8^{circ}C$이었으며, 4엽기에 이르는데 필요한 유효 적산온도는 각각 247 및 $234^{circ}C$이었다. 본 연구에서 개발된 모델로 분석한 결과 평균 기온이 $3^{circ}C$ 상승하게 되면 이들 잡초의 50% 출아는 물달개비의 경우 1일, 올챙이고랭이의 경우는 2일 빨라지고, 4엽기에 다 다르는 날짜는 이들 잡초 모두 3일이 빨라질 것으로 예측되었다. 따라서 온도상승조건에서 물달개비 및 올챙이고랭이를 효과적으로 방제하기 위해서는 현재의 처리시기보다 약 2-3일 빨라져야 할 것으로 예상된다.
This experiment was conducted to investigate seedling emergence and early growth of Monochoria vaginalis and Scirpus juncoides in the controlled-environment chamber maintained at different temperatures. Non-linear regression analyses of observed data against effective accumulated temperature (EAT) with the Gompertz and logistic models showed that the Gompertz and logistic models worked well in describing seedling emergence and early growth of both weed species, respectively, regardless of temperature. EATs required for 50% of the maximum seedling emergence and the maximum leaf number of M. vaginalis were estimated to be 69.3 and $131^{circ}C$, respectively, while those of S. juncoides were 94.8 and $137^{circ}C$, respectively. Models developed in this study thus were used to predict seedling emergence and early growth under elevated temperature condition. If rotary tillage with water is made on 27 May under $+3^{circ}C$ elevated temperature condition, dates for 50% of the maximum seedling emergence and 4 leaf stage were predicted to be 1 June and 15 June for M. vaginalis and 3 June and 14 June for S. juncoides, respectively. As compared with current temperature, these dates are 1-2 days earlier for the seedling emergence and 3 days earlier for the early growth, suggesting that earlier application of herbicides is required for effective control of M. vaginalis and S. juncoides under elevated temperature condition in the future.
