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Background The number of banana plants is closely related to banana yield. The diameter and height of the pseudo-stem are important morphological parameters of banana plants, which can reflect the growth status and vitality. To address the problems of high labor intensity and subjectivity in traditional measurement methods, a fast measurement method for banana plant count, pseudo-stem diameter, and height based on terrestrial laser scanning (TLS) was proposed. Results First, during the nutritional growth period of banana, three-dimensional (3D) point cloud data of two measured fields were obtained by TLS. Second, the point cloud data was preprocessed. And the single plant segmentation of the canopy closed banana plant point cloud was realized furtherly. Finally, the number of banana plants was obtained by counting the number of pseudo-stems, and the diameter of pseudo-stems was measured using a cylindrical segmentation algorithm. A sliding window recognition method was proposed to determine the junction position between leaves and pseudo-stems, and the height of the pseudo-stems was measured. Compared with the measured value of artificial point cloud, when counting the number of banana plants, the precision,recall and percentage error of field 1 were 93.51%, 94.02%, and 0.54% respectively; the precision,recall and percentage error of field 2 were 96.34%, 92.00%, and 4.5% respectively; In the measurement of pseudo-stem diameter and height of banana, the root mean square error (RMSE) of pseudo-stem diameter and height of banana plant in field 1 were 0.38 cm and 0.2014 m respectively, and the mean absolute percentage error (MAPE) were 1.30% and 5.11% respectively; the RMSE of pseudo-stem diameter and height of banana plant in field 2 were 0.39 cm and 0.2788 m respectively, and the MAPE were 1.04% and 9.40% respectively. Conclusion The results show that the method proposed in this paper is suitable for the field measurement of banana count, pseudo-stem diameter, and height and can provide a fast field measurement method for banana plantation management.

Given the lack of technical conditions and research methods, instruments that can measure the canopy apparent photosynthetic rate have low precision and are rarely studied. Comparative studies on canopy apparent photosynthetic rate and single leaf photosynthetic rate are also relatively few. This study aims to measure and predict the canopy apparent photosynthetic rate of tomato. A canopy apparent photosynthetic rate measuring system, which was comprised of a wireless sensor network (WSN), an assimilation chamber, and a LI-6400XT photosynthetic rate instrument was established. The system was used to determine the greenhouse environmental parameters and CO 2 absorptive capacity of the whole growth stage of tomato. A semi-closed assimilation chamber was designed as a side opening to conveniently measure the canopy apparent photosynthetic rate. WSN nodes were placed in the chamber to monitor environmental parameters, including air temperature, air humidity, and assimilation chamber temperature. A grid and pixel conversion method was used to measure the whole plant leaf areas of tomato. As a semi-closed measurement system, the assimilation chamber was used to calculate the canopy apparent photosynthetic rate. To conduct a comparative research on the canopy apparent photosynthetic rate and the single leaf photosynthetic rate, the LI-6400XT portable photosynthesis system was used to measure the single leaf photosynthetic rate, and the support vector machine was used to establish the prediction model of canopy apparent photosynthetic rate. The experimental results indicated that the correlation coefficients of the photosynthesis prediction model in the seeding and flowering stages were 0.9420 and 0.9226, respectively, showing the high accuracy of the SVM model.

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