Method and device for determining leaf area index

Abstract

The invention discloses a method for determining a leaf area index, comprising the following steps that: a laser outputs light to irradiate on overlapped leaves; a photoelectric transmitter detects the light energy transmitting through the leaves, and a voltage signal output by the photoelectric transmitter is acquired by a data acquisition card and sent to a computer; the computer judges the number of the overlapped layers according to the magnitude of the voltage signal, and multiplies the number of the overlapped layers by a receiving area of the photoelectric transmitter to obtain the leaf area of a test point; the laser and the photoelectric transmitter are synchronously in translational motion; the region of the leaf layers is scanned, and the leaf area of each test point is accumulated to get the total leaf area of the leaf layers; and the total leaf area is divided by an occupied area to obtain the leaf area index. The invention further provides a device for determining the leaf area index, which is used for implementing the determination method; and in comparison with the prior art, the method and the device are accurate in determination result, the device is simple and the preparation cost is low.

Description

technical field [0001] The invention relates to the field of ecology, in particular to a method and device for measuring leaf area index. Background technique [0002] Leaf area index LAI (Leaf Area Idex) refers to the ratio of the total area of ​​crop leaves on a field to the area occupied, and is one of the key parameters in ecological research. At present, there are many researches on the indirect optical model measurement method in the LAI detection method, mainly studying the porosity, that is, the probability that the solar radiation in the canopy is not intercepted, and then a series of canopy LAI analysis instruments based on porosity analysis have emerged. [0003] However, due to a large number of overlapping leaves, when the leaf area index value reaches 5-6, the total area of ​​leaves per unit land area is relatively large, resulting in a small void ratio, and the overlapping of leaves cannot be distinguished by ordinary canopy LAI analysis instruments. The meas...

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Problems solved by technology

[0003] However, due to a large number of overlapping leaves, when the leaf area index value reaches 5-6, the total area of ​​leaves per unit land area is relatively large, resulting in a small void ratio, and the overlapping of leaves cannot be distinguished by ordinary canopy LAI analysis instruments. The measured value is much smaller than that measured by direct measurement

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