The leaf area index refers to the sum of the unit area of ​​a single leaf area and is a key parameter that affects global climate change. It is used in many agricultural climates, atmospheric circulation, and biogeochemical models. In order to meet the needs of global climate change, the Global Climate Observing System plans its 0.5-mm accuracy requirement. At present, there are a lot of leaf area meter products for agricultural production. In order to effectively use these various data models, it is first necessary to objectively evaluate the quality of these leaf area meters.
There are differences between various methods of leaf measurement. To understand the differences between different methods of measurement, the area of ​​laurel leaves is measured by different methods and compared. The laurel tree was used as the material for the determination, but the leaf area of ​​each shoot was different. Therefore, when measuring the leaf area with the hand-held leaf area meter, it was necessary to establish the regression equation and the ratio of the area to the length-width product ratio for the leaves of each shoot. .
In the fresh weight method, the total fresh weight WT (g) of 60 leaves is weighed on an electronic balance. The total area S (cm2) of the 60 leaves measured by the photoelectric area method is divided by the WT to obtain the leaves. The area Kf per gram of fresh weight, then the fresh weight W of each leaf is weighed, and W is multiplied by Kf to obtain the leaf area estimated by the fresh weight method.
In the grid method, the outline of the leaves is described on a standard calculation paper, and the number of squares occupied by the leaf outline (the number of cells that meet or exceed the half-lattice, which is less than the half-lattice) is counted by the grid method. The leaf area. The leaf area meter plots the outline of the blade on ordinary drawing paper, and measures the area occupied by the leaf contour with a leaf area meter at a ratio of 1:1. The number of measurements per leaf is not less than twice and the difference is not more than 0.5 cm 2 twice. The average of the results is the area measured by the planimeter method for this leaf.
The leaf area meter is a special instrument developed using photoelectric theory. A variety of leaf area measurements can be any shape, size, thickness, and color of the leaf measurement, and it is a quick and convenient measurement. The leaf area index of different crop areas is determined by studying the leaf area of ​​each plant, and then calculating the number of cotton plants on a certain land. The area can be measured by the leaf area of ​​each plant.
There are differences between various methods of leaf measurement. To understand the differences between different methods of measurement, the area of ​​laurel leaves is measured by different methods and compared. The laurel tree was used as the material for the determination, but the leaf area of ​​each shoot was different. Therefore, when measuring the leaf area with the hand-held leaf area meter, it was necessary to establish the regression equation and the ratio of the area to the length-width product ratio for the leaves of each shoot. .
In the fresh weight method, the total fresh weight WT (g) of 60 leaves is weighed on an electronic balance. The total area S (cm2) of the 60 leaves measured by the photoelectric area method is divided by the WT to obtain the leaves. The area Kf per gram of fresh weight, then the fresh weight W of each leaf is weighed, and W is multiplied by Kf to obtain the leaf area estimated by the fresh weight method.
In the grid method, the outline of the leaves is described on a standard calculation paper, and the number of squares occupied by the leaf outline (the number of cells that meet or exceed the half-lattice, which is less than the half-lattice) is counted by the grid method. The leaf area. The leaf area meter plots the outline of the blade on ordinary drawing paper, and measures the area occupied by the leaf contour with a leaf area meter at a ratio of 1:1. The number of measurements per leaf is not less than twice and the difference is not more than 0.5 cm 2 twice. The average of the results is the area measured by the planimeter method for this leaf.
The leaf area meter is a special instrument developed using photoelectric theory. A variety of leaf area measurements can be any shape, size, thickness, and color of the leaf measurement, and it is a quick and convenient measurement. The leaf area index of different crop areas is determined by studying the leaf area of ​​each plant, and then calculating the number of cotton plants on a certain land. The area can be measured by the leaf area of ​​each plant.
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