Novel technique for non-destructive LAI estimation by continuous measurement of NIR and PAR in rice canopy
Novel technique for non-destructive LAI estimation by continuous measurement of NIR and PAR in rice canopy
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DOI：
10.1016/j.fcr.2021.108070
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发表时间：
2021-01-29
影响因子：
5.8
通讯作者：
Sugiura, Daisuke
中科院分区：
文献类型：
--
作者：
Fukuda, Shota;Koba, Kentaro;Sugiura, Daisuke
叶面积指数(LAI)是衡量作物生长发育的有用指标，但用破坏性抽样方法估算叶面积指数既费时又费力。在本研究中，我们开发了一种新的技术，可以无损地、准确地测定水稻整个生育期的叶面积指数。利用光学传感器每隔1min测量水稻冠层内外的近红外辐射(NIR)和光合作用有效辐射(PAR)。测定了不同生育期的简单比(SR)和NIR/PAR比(N/P)，确定了准确反映叶面积指数的有效SR和N/P的提取标准。在阴天条件下获得的SR和N/P能较准确地反映叶面积指数(R2=0.91)，并成功地绘制了两个水稻品种在两个试验田的冠层生长曲线的季节动态。数学分析表明，不是累积PAR，而是累积温度可以触发冠层指数增长。本技术可作为评估、模拟和表型不同水稻品种以及其他作物作物生长特性的有力工具。
Although leaf area index (LAI) is a useful index of crop growth, evaluating LAI by destructive sampling is laborious and time-consuming. In the present study, we developed a novel technique to determine rice LAI nondestructively and accurately throughout growth period in paddy field. Near-infrared radiation (NIR) and photosynthetically active radiation (PAR) were measured by a pair of optical sensors inside and outside rice canopy at 1-min intervals. Simple ratio (SR) and NIR to PAR ratio (N/P) were measured depending on growth stage, and the criteria to extract valid SR and N/P that represent LAI accurately were determined. SR and N/P obtained under cloudy conditions were found to represent LAI with high accuracy (R2 = 0.91), and seasonal dynamics of canopy growth curves were successfully drawn for two rice cultivars at two experimental fields. Mathematical analysis revealed that not cumulative PAR but cumulative temperature could trigger exponential canopy growth. The present technique can be used as a powerful tool for evaluating, modelling, and phenotyping crop growth characteristics in various rice cultivars as well as other crops.