The plant physiological apparatus includes a crop nutrition diagnostic apparatus, a leaf area meter, a chlorophyll content meter, a blade thickness meter, and a photosynthesis meter. German company WALZ has strong technical advantages in the development and production of modulated chlorophyll fluorometers. In addition, British Han-satech, American PP Systems, CID, LI-Cor, Decagon and Canada REGENT are all plant physics. A well-known company in the field of ecological instrument research. The SPAD chlorophyll meter manufactured by Minolta Corporation of Japan is a hand-held measuring instrument that can nondestructively detect the chlorophyll content in crop leaves and understand the nutritional status of crop growth. Guo Jianhua and others used the handheld active remote sensing spectrometer Greenseeker developed in the United States and the chlorophyll meter SPAD from Japan's Minolta Company to test the normalized vegetation index (NDVI) values ​​and leaf SPAD values ​​at different growth stages of maize under different nitrogen levels. This shows that the integrated application of these two instruments can diagnose corn's nitrogen status. Sun et al. studied a solar-induced chlorophyll fluorescence instrument based on the Fraunhofer-Feifei line principle. The data measured by the instrument and the data correlation coefficient measured by the ASD spectrometer were greater than 0.9. It can replace the traditional laser pulse modulation fluorescence. Measuring method, and has the advantages of low cost and real-time measurement. The Crop Canopy Pigment Ratio Diagnostic Instrument developed by the National Agricultural Information Engineering Technology Research Center can rapidly measure the spectral inversion ratio spectral index and normalized vegetation index of plants and is widely used in various plants such as corn, wheat, rice and cotton. Rapid and accurate determination of canopy pigment ratio. The NDVI instrument developed by Zhao Chunjiang et al. uses daylight as the light source, and adopts four photodetectors with special spectral response characteristics to reflect the near-infrared reflectance platform and the red chlorophyll absorption valley in the vegetation. In the band, the reflected light of the incident light and vegetation was detected respectively, and compared with the NDVI data measured with the ASD fieldSpec portable spectrometer. The results showed that the data was very reliable, demonstrating the application of the NDVI instrument in crop growth and nutrition diagnosis. prospect. Zhang Xijie and others have developed an optical fiber-based portable greenhouse crop growth diagnostic instrument, which collects reflected light from crop canopy and other parts through light guide fiber. According to different crops, the measurement wavelength can be easily changed and multiple wavelengths can be performed simultaneously. The purpose of the measurement is to obtain real-time statistics of the parameters such as nitrogen content and chlorophyll content of crops that reflect the growing situation of crops. Li Xiuhua and others designed a non-destructive crop canopy analyzer based on the principle of spectroscopy. The wireless data communication method between the sensor and the controller, and the low-power design of the signal amplifier and the wireless transmission module ensure that the instrument can be used for more than 20 hours. . Ceiling Box Fan,Ceiling Exhaust Fan,60 By 60 Ceiling Fan,Ceiling Fan Remote Control Foshan Windfeel Electrical Appliances CO., LTD , https://www.windfeel.cn