Development and experiment of portable NDVI instrument for estimating growth condition of winter wheat

A portable NDVI instrument was designed and tested in winter wheat field. It can display NDVI values of winter wheat in field. The crop growth can be assessed based on their NDVI values. This will be very important for crop management. It uses sunlight for its light source. There are four special different photoelectrical detectors with red and near infrared wavelengths, which are used for detecting incidence and reflex. The computer calculates the NDVI value based on the A/D value. The value can be displayed on its LCD. The portotype was tested in winter field at different hours and directions. The optimum test method was provided.