Why can remote sensing be used to estimate crop yields? Of course, it is impossible to estimate the yield of crops in a large area. Remote sensing crop yield estimation requires knowing two aspects of information. One is to estimate the planting area of ??crops based on the national agricultural land use database through ground remote sensing technology. The second is to use remote sensing technology to monitor the growth of crops, especially to assess the impact of disasters on crops. After mastering the above data, through a verified prediction model, the unit yield of crops can be estimated, and then the total crop yield in a region or the country can be estimated.
Any substance has spectral reflection or radiation properties, and crops are no exception. As long as the spectrum is subdivided into the three main factors that can reflect the growth of wheat, namely chlorophyll, protein, and moisture, the remote sensing information is collected, and then based on the contribution of the three main factors of chlorophyll, protein, and moisture to the growth of wheat, use Using the linear combination method, the wheat growth function can be calculated. The wheat growth function is graded and evaluated, divided into three, six or nine grades, and finally the wheat growth results can be obtained.
(Excerpted from "China Manned Spaceflight Popular Science Series? Exploring Space")