Leaf area determination method/leaf area index

Leaf area measurement method overview

At present, there are about the following four methods for the determination of broad-leaved leaf area:

Measurement Method 1 - Measurement Method Based on Digital Camera and Auto CAD Software

A digital camera was used to obtain the digital image of the blade, and the Auto CAD software was used to calculate the leaf area of ​​the garden plant. And compared with the commonly used grid method, paper-cut method and leaf area meter method. The research results show that this method is especially suitable for the determination of the coniferous, lobular garden plants and turfgrass leaf area.

Measurement Method II - Leaf Area Instrument Method

The leaf area meter is a portable instrument that is easy to use and can work in the field. The leaf area and related parameters of the blade can be measured accurately, quickly and without damage, and the area of ​​the harvested plant leaf and other sheet objects can also be measured. Leaf area, average leaf area, leaf length, leaf width, length to width ratio can be measured. Although it is easy to use, the relative cost is relatively high.

Measurement method three-number lattice method

Draw it along the shape of the leaf and draw it on transparent paper. Then count the grid. When calculating the grid, the calculation of the edge of the blade exceeds half a square is 1, and less than half the grid does not count. Generally, when drawing the coordinate paper, the length and width of each square are 1cm, so the area is 1cm2. Therefore, the counted number of children is the area of ​​the blade (in cm2).

Measurement Method Four - Paper Weighting Method

It's a bit like Act 3, which means that the previous steps are basically the same. Draw the leaves on a uniform transparent paper and cut the paper. Due to the uniform paper weight per unit area, the cut paper can be converted into an area after weighing. The specific conversion is as follows: Cut the drawn paper leaf, weigh it on the balance, and record it as W1; cut three 10cm2 pieces of paper on the same paper, calculate the average weight after weighing, and record it as W2. The measured blade area x can be calculated according to the following formula. X(cm2) = W1/W2*100

The above four methods have their own merits. Under specific circumstances, different leaf area measurement methods can be selected. In addition, leaf area measurement methods include: photoelectrometry, paper cutting method, punching measurement method, displacement measurement method, and coefficient measurement method. As for these methods of leaf area determination, I will not specifically introduce it here. Everyone can check for information on their own.

Leaf area determination method is the basis of leaf area index

Leaf area determination is the most important step in determining leaf area index. The leaf area index is the ratio of the total area of ​​the ground crop leaves to the floor space. Namely: leaf area index = total area of ​​green leaves/footprint. The total area of ​​the green leaf is calculated by measuring the area of ​​single leaf and the leaf area of ​​the individual plant, and then calculating the area of ​​the plant based on the unit land area. Therefore, the leaf area index was determined based on the leaf area determination. The size of the leaf area directly affects the absorption of sunlight by the plant, which in turn affects the growth of the plant. Conceptually, the leaf area index is determined by weighing the leaf area of ​​a tree and dividing it by the vertical projected area of ​​the canopy.

Obviously, such an operation method is too time-consuming. Therefore, when determining the LAI of a stand, the leaf biomass (basis data) is usually obtained by multiplying the leaf area to leaf dry mass (SLA).

Of course, now that the technology is so advanced, various agricultural instrument companies have developed many leaf area meters, gps leaf area testers, timed leaf area testers, and so on. Using the leaf area meter to measure the leaf area, convenient and quick results. After measuring the total land area, the leaf area index can be calculated.

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