基于生长度日的紫花苜蓿生育期预测模型

Study of simulation model of alfalfa plants development based on growing degree days

利用2014年在吉林省农业科学院草地研究所试验田开展紫花苜蓿（Medicago sativa）种植试验数据,建立基于生理发育时间和生长度日的生育期模型,再利用气象站观测数据资料进行模型验证。结果表明,紫花苜蓿从返青至分枝的发育基点温度为5℃;从分枝至现蕾为16℃;从现蕾至开花为18℃;从开花至结荚为23℃。以此为依据建立紫花苜蓿植株发育的动态模拟模型,以各生育期发育基点温度确定返青期至分枝期、分枝期至现蕾期、现蕾期至开花期、开花期至结荚期所需的生长度日（Growing degree days,GDD）分别为38.18、90.16、76.6、23.96℃·d。参试的5个紫花苜蓿品种的回归估计标准误差（RMSE）在1.1~2.72 d,相对误差（RE）范围在9.48%~17.87%,该模型的实测值与预测值较为吻合,适用于紫花苜蓿生育期的预测模拟。

Based on the experimental data of planting alfalfa at the grass field of Jilin Academy of Agricultural Sciences in 2014,the models of the physiological development period and growing degree days were established and validated by the observational data from local meteorological stations. The results showed that the limit temperature from reviving period to branching period of 5 alfalfa cultivars was 5 ℃,from branching to budding period of 5 alfalfa cultivars was 16 ℃,from buding to flowering period of 5 alfalfa cultivars was 18 ℃,from flowering to poding period of 5 alfalfa cultivars was23 ℃. The parameter of growing degree days in different development stages was quantified and different development stages were predicted systematically by lower limit temperature of alfalfa. The GDD of alfalfa from reviving period to branching period was 38. 18 ℃ ·d,from branching to budding was 90. 16 ℃ · d,from budding to efflorescence was76. 6 ℃ ·d,from efflorescence to poding was 23. 96 ℃ ·d. The root mean square errors（ RMSE） of 5 different alfalfa varieties were 1. 1 ~ 2. 72 d. The relative estimation error（ RE） of 5 different alfalfa varieties were 9. 48% ~ 17. 87%.These results suggested that GDD might be suitable to predict alfalfa development stages.