000			03482nab|a22003857a|4500
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003			MX-TxCIM
005			20220103145007.0
008			202104s2021||||sz |||p|op||||00||0|eng|d
022			_a2072-4292 (Online)
024	8		_ahttps://doi.org/10.3390/rs13050987
040			_aMX-TxCIM
041			_aeng
100	0		_aBin Wu _926199
245	1	0	_aMonitoring the vertical distribution of maize canopy chlorophyll content based on multi-angular spectral data
260			_aBasel (Switzerland) : _bMDPI, _c2021.
500			_aPeer review
500			_aOpen Access
520			_aRemote sensing approaches have several advantages over traditional methods in determining information on physical and chemical parameters, including timely data acquisition, low costs, and wide coverage. Thus, remote sensing is widely used in crop growth monitoring. Unlike vertical observations, multi-angular remote sensing technology can obtain the vertical distribution information of the central and lower leaves of a crop. Furthermore, applications of remote sensing on the vertical distribution of maize canopy components is complicated, and related research is limited. In the current paper, we employed multi-angular spectral data, measured by a self-designed multi-angular observation instrument at view zenith angles (VZAs) of 0°, 10°, 20°, 30°, 40°, 50°, and 60°, to explore the monitoring strategy and monitoring precision of the vertical distribution of chlorophyll content in the maize canopy. This was then used to determine the optimal monitoring method for the chlorophyll content (soil and plant analyzer development (SPAD) value) of each layer. The correlation between SPAD value and chlorophyll sensitivity indices at different growth stages was used as the basis for screening indices and VZAs. The correlation between the selected EPI (eucalyptus pigment index) and REIP (red edge inflection point) indices and chlorophyll content indicated view zenith angles (VZAs) of 0°, 30°, and 40° as optimal for the early growth stage monitoring of chlorophyll content in the 1st, 2nd, and 3rd layers, respectively. These values were associated with RMSEs of 4.14, 1.71, and 1.11 for EPI, respectively; and 4.61, 2.31, and 1.00 for REIP, respectively. In addition, a VZA of 50° was selected to monitor the chlorophyll content of the 1st, 2nd, 3rd, and 4th layers at the late growth stage, with RMSE values of 2.97, 3.50, 2.80, and 4.80 for EPI, respectively; and 3.16, 5.02, 4.55, and 7.85 for REIP, respectively. The results demonstrated the ability of canopy multi-angular spectral reflectance to accurately estimate the maize canopy chlorophyll content vertical distribution, with the VZAs of different vertical layers varying between the early and late growth stages.
546			_aText in English
591			_aGonzalez-Perez, L. : Not in IRS Staff list but CIMMYT Affiliation
650		7	_aChlorophylls _2AGROVOC _97635
650		7	_aReflectance _2AGROVOC _95862
650		7	_aCanopy _2AGROVOC _91800
650		7	_aMaize _2AGROVOC _91173
700	0		_aHuichun Ye _918445
700	0		_aWenjiang Huang _918428
700	0		_aHongye Wang _926200
700	0		_aPeilei Luo _926201
700	0		_aYu Ren _926202
700	0		_aWeiping Kong _926203
773	0		_tRemote Sensing _gv. 13, no. 5, art. 987 _dBasel (Switzerland) : MDPI, 2021. _w57403 _x2072-4292
856	4		_yClick here to access online _uhttps://doi.org/10.3390/rs13050987
942			_cJA _n0 _2ddc
999			_c64765 _d64757