Test of an extended mathematical approach to calculate maize leaf area index and leaf angle distribution
Test of an extended mathematical approach to calculate maize leaf area index and leaf angle distribution
复制标题
DOI：
10.1016/s0168-1923(01)00219-2
复制
发表时间：
2001-05-02
影响因子：
6.2
通讯作者：
Mesarch, MA
中科院分区：
文献类型：
--
作者：
Antunes, MAH;Walter-Shea, EA;Mesarch, MA
叶面积指数（LAI）和叶角分布（LAD）的准确估计对于估算植被冠层的能量和气体交换具有重要意义。LAI和LAD的直接估计是费力的、耗时的并且常常是破坏性的。斯图尔特和德怀尔[农业。Meteorol，66（1993）247]介绍了一种基于叶宽和叶曲率描述的计算玉米冠层LAI和LAD的数学方法。然而，该方法在其应用中受到限制。本研究的目的是：（1）将该方法扩展到叶尖具有最大曲率高度的叶片（即，直叶，通常出现在玉米冠层顶部的叶），使得该方法提供了对玉米冠层的一般应用，以及（2）测试扩展模型的性能。LAI和LAD模拟使用的数学方法进行了测试，对观察到的LAI和LAD值。从所有叶位测定的平均叶宽系数用于叶面积计算。叶面积模拟总体上在观察到的叶面积值的2%（51 cm（2））内一致。估计的LAD在现场观察到的LAD的5%范围内。该方法提供了一个简单的，可靠的方法来估计LAI和LAD，当适当的系数是已知的，而不需要特殊的仪器或其他条件。该方法还提供了一种检查性能或可靠性的其他方法来表征冠层结构的手段。(C)2001 Elsevier Science B.V.保留所有权利。
Accurate estimates of leaf area index (LAI) and leaf angle distribution (LAD) are important for estimating the exchange of energy and gases in vegetative canopies. Direct estimates of LAI and LAD are laborious, time consuming and often times destructive. Stewart and Dwyer [Agric. For. Meteorol, 66 (1993) 247] introduced a mathematical method to calculate LAI and LAD of maize canopies based on descriptions of leaf width and leaf curvature. However, the method is limited in its application. The objectives of this research are to: (1) extend the method to account for leaves with maximum curvature height at the leaf tip (i.e., straight leaves, which commonly occurs with leaves at the top of maize canopies), so that the method provides a general application to maize canopies, and (2) test the performance of the extended model. LAI and LAD simulated using the mathematical method were tested against observed LAI and LAD values. Average leaf width coefficients, determined from all leaf positions, were used in the leaf area calculation. Leaf area simulations agreed overall within 2% (51 cm(2)) of observed leaf area values. Estimated LAD agreed within 5% of the field observed LAD. The method offers a straightforward, reliable means of estimating LAI and LAD, when the appropriate coefficients are known, without requirements for special instrumentation or other conditions. The method also offers a means of checking the performance or reliability of other methods of characterizing canopy structure. (C) 2001 Elsevier Science B.V. All rights reserved.