Determination of Leaf Area Index - Living Leaf Area Meter

Determination of Leaf Area Index - Living Leaf Area Meter

The leaf area index was determined on the basis of the single leaf area and the leaf area of ​​a single plant, and then calculated based on the number of crop plants per unit land area. The formula for calculating the leaf area index is: leaf area index = total leaf area/footprint. It reflects better dynamic indicators of crop size and has a certain relationship with crop yield. In general, the larger the leaf area index, the higher the crop yield, because the leaf area index is high and the relative leaf area is large, while the large leaf area means high photosynthesis efficiency. Therefore, we often need to know the leaf area index parameter for the study of crop growth status.

Instruments and equipment: meter ruler; leaf area scanner; scissors; covered enamel plate with wet gauze; scale; live leaf area meter; tape measure (50m).

Measurement method: First, the actual number of crops per square meter or several square meters of land area should be investigated. According to the size of the plot and the topography of the plot, three to five representative points are determined by the diagonal five-point fixed point method or the three-point fixed point method. The size of each measuring point varies from crop to crop, such as corn, sorghum and other high-stem crops, preferably 20 - 30 m 2 , rice, wheat, soybeans, etc. to dwarf crops may take 2 - 5 m 2 , each measuring point available Take a square or a rectangle. After the determination of the measuring points, the actual number of plants in each measurement point was determined and the number of plants per square meter was calculated.

After identifying the number of plants, a representative number of plants were selected at each site, such as 3-5 strains (9-25 strains) for maize and sorghum, and 5-10 strains for rice and wheat. 15-50 strains), the leaf area per plant was measured.

In order to determine the leaf area per plant, the area of ​​single leaf should be determined first. In the determination of single leaf area, the leaf area of ​​the individual plants in vitro or in vivo can be determined by the long-width coefficient method or the leaf area analyzer method. From the measured value of the individual leaf area of ​​several strains at each measuring point, the average individual leaf area value at the measuring point was determined. Finally, the following formula calculates the leaf area index

Leaf area index = average individual leaf area (cm 2 ) ÷ 10000 (cm 2 . m -2 ) × number of test points/measured area (m 2 ).