A Determination Method of Correction Coefficient of Potato Leaf Area
一种马铃薯叶面积校正系数的确定方法

Among the nine frequently used determination methods of leaf area, the mechanical leaf area meter, SHY-150 and the plot method of multiplying length by width have the highest accuracy. The coefficient method is the simplest one and is easy to promote for use in large scale. We can get the leaf area correction coefficients of main crops from literature, such as rice, wheat, corn, cotton and sorghum, and researches on some economic crops have already been done. However, due to the amount of potato leaves and their irregular shape, there has been no simple and convenient correction coefficient of leaf area similar to that of wheat yet, resulting in the difficulty in actual measurement of the leaf area and directly affecting the measurement accuracy. In this paper, through experimental study, we performed gap analysis of the accuracy of plot method and figured out the correction coefficient with paper measured values as the standard. At the same time, we tested the applicable range, degree and application effects of the mechanical leaf area meter and SHY-150. At last, we recommended using the plot method of multipling length by width to measure the leaf area of Potato, which can take both usability and accuracy into account. Comparison results of the three methods are as follows: 1) There will be certain error in the actual value when using the mechanical leaf area meter. The measured area is only 92 percent of the actual area, so the measurement value needs to be multiplied by 1.09 to get the real area. Measuring Error is big when leaves are small and small when leaves are large. Besides, during the determination process, the reading is error-prone, the machine is difficult to operate, it wastes time and effort, needs higher labor intensity of staff and is inconvenient to use; 2) SHY-150 has a large error, with the measured area being 71 percent of the actual area, and the measurement value needs to be multiplied by 1.40 to get the real area. Moreover, the meter is very expensive and requires higher professional quality of the operator, thus affecting its widespread use; 3) The correction coefficient of the plot method of multiplying length by width is recognized as 0.76 through a large number of complex measurements. As leaves of different sizes and of various development stages were selected, the test result is more stable and universal. You can get a satisfactory result by selecting more than 11 leaves to measure, so we recommend general agricultural meteorology experiment station and scientific research units to use the plot method of multiplying length by width.