Timothy Yield and Nutritive Value by the CATIMO Model: III. Validation for Eastern Canada
Timothy Yield and Nutritive Value by the CATIMO Model: III. Validation for Eastern Canada
复制标题
CATIMO 模型的蒂莫西产量和营养价值：III。
作者：
H. Bonesmo;G. Bélanger
机械模拟模型可以帮助制定优化产量和营养价值的建议，并有助于理解植物生长、营养价值和环境条件之间的复杂相互作用。本文给出了一个综合模型[CATIMO(Canada Timothy Model)]的生长和N浓度模型。初级生长和营养价值。这种生长模型的特点是辐射截获和利用效率、叶和茎的生长、叶片的衰老和基于全株临界氮浓度的氮函数。模型参数被校准为关键的模型属性：叶面积指数(LAI)；饲草氮浓度；以及叶、茎和饲草干物质(DM)产量。每周在一个地点(弗雷德里克顿，北卡罗来纳州，加拿大)对蒂莫西四个不同年份的初级生长进行校准测量。总体而言，该模型与实测值的均方根误差分别为32.8、42.0和65.9gm-2。在初生期末期，模型倾向于低估茎干物质产量，高估非限制氮条件下的饲草氮浓度，低估限制氮条件下的氮浓度。该模型在3/4年中对LAI进行了满意的拟合。校准的汇总统计数据表明，成功地描述了模拟消化率所需的基本植物成分的生长和发育。
Mechanistic simulation models can assist in developing recommendations to optimize yield and nutritive value and in understanding the complex interaction among plant growth, nutritive value, and environmental conditions. In this paper, we present the growth and N concentration modules of an integrated model [CATIMO (Canadian Timothy Model)] of timothy (Phleum pratense L.) primary growth and nutritive value. This growth model features radiation interception and use efficiency, leaf and stem growth, leaf senescence, and a N function based on the critical N concentration of whole plants. Model parameters were calibrated to key model attributes: leaf area index (LAI); forage N concentration; and leaf, stem, and forage dry matter (DM) yields. Calibration measurements were taken weekly on timothy primary growth in four different years at one location (Fredericton, NB, Canada). Overall, the model satisfactorily fitted the measured values with root mean square errors of 32.8, 42.0, and 65.9 g m -2 leaf, stem, and forage DM yield, respectively. The model tended to underestimate stem DM yield at the end of the primary growth cycle, overestimate forage N concentration under nonlimiting N conditions, and underestimate N concentration under limiting N conditions. The model satisfactorily fitted LAI in 3 of 4 yr. Summary statistics of the calibration indicate a successful description of growth and development of the essential plant components required for modeling digestibility.