Modeling light availability for a subordinate crop within a strip–intercropping system
Modeling light availability for a subordinate crop within a strip–intercropping system
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DOI：
10.1016/j.fcr.2013.09.020
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发表时间：
2014
影响因子：
5.8
通讯作者：
Sebastian Munz;S. Graeff‐Hönninger;J. Lizaso;Qing Chen;W. Claupein
中科院分区：
文献类型：
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作者：
Sebastian Munz;S. Graeff‐Hönninger;J. Lizaso;Qing Chen;W. Claupein
华北平原农业劳动力的转移导致了间作的持续减少。带状间作有利于机械化管理，并有可能通过优化间作物种的资源利用而超过单作。因此，我们开发了一个光分区模型，计算在冠层顶部的光合有效辐射（PAR）的可用量为一个较小的，从属作物带内的一个给定的点。该模型进行了描述，评价不同的模拟时间步长和测试的目的，设计带状间作系统。条带状灌木菜豆（Phaseolus vulgarisL.）var.nana）在不同天空条件下连续测量。在优势带，玉米（Zea maysL.）长大了然后，该模型进行了测试，以说明其能力的影响，不同宽度的灌木豆带，带方向和玉米冠层结构（高度，叶面积指数，叶角分布）。每小时平均模拟和观测值的PAR在灌木豆带之间的比较表明，高精度的模拟，在这两个，清晰和多云的条件下。总的来说，对整个豆带PAR每小时值的模拟显示，均方根误差（RMSE）范围在47和87 μmol m−2s− 1之间，百分比偏差（PBIAS）范围在-3.4%至10.0%之间。建议模拟时间步长为20 min，以保持整个条带模型的准确性。该模型合理地捕捉了条带设计（宽度和方向）和玉米冠层结构的影响。结果表明，最大的潜力，以增加PAR在整个灌木豆带是通过降低玉米的高度和叶面积指数，特别是在最阴影的边缘行相邻的玉米带。该模型被证明是一个有用的工具，了解整个地带的从属物种的光可用性的特点，并可以进一步用于检查一些带间作安排之前，劳动力和时间消耗的田间试验。
The shift of rural laborers out of the agricultural sector led to a steady decrease of intercropping in the North China Plain (NCP). Strip intercropping facilitates mechanized management, and has the potential to out yield monocropping by an optimized resource use of the intercropped species. Therefore we developed a light partitioning model, that calculates the available amount of photosynthetically active radiation (PAR) at the top of the canopy for a given point within a strip of a smaller, subordinate crop. The model was described, evaluated on various simulation time steps and tested for the purpose of designing strip–intercropping systems. PAR reaching the top of the canopy of various rows of the strip subordinate bush bean (Phaseolus vulgarisL. var.nana) was measured continuously under different sky conditions. In the dominant strip, maize (Zea maysL.) was grown. Then the model was tested for its ability to account for the influence of different widths of the bush bean strip, strip orientations and maize canopy architecture (height, leaf area index, and leaf angle distributions). Comparison between hourly averaged simulated and observed values of PAR across the bush bean strip showed a high accuracy of the simulations, under both, clear and cloudy conditions. Overall, simulations of hourly values of PAR across the bean strip showed a root mean square error (RMSE) ranging between 47 and 87 μmol m−2s−1and a percent bias (PBIAS) ranging between −3.4 and 10.0%. A simulation time step of 20 min is recommended to preserve the accuracy of the model across the strip. The model captured reasonably the influence of strip design (width and orientation) and maize canopy architecture. Results suggested that the highest potential to increase PAR across the bush bean strip is by reducing height and leaf area index of maize, especially in the most shaded border row adjacent to the maize strip. The model proved to be a helpful tool for understanding the characteristics of light availability across the strip of the subordinate species and can be further used to examine a number of strip intercropping arrangements prior to labor and time consuming field trials.