Identifying potential threats in areas of the field at different stages of plant growth is crucial to be able to respond in time. This is possible from variations in the NDVI (Normalized Difference Vegetation Index), which can indicate different problems in areas of the field. If the index is extremely low, there may be pests or diseases; if it is abnormally high, weeds may have appeared.
To construct maps for the differential application of fertilizers in the early stages of crops, the MSAVI (Modified Soil Adjusted Vegetation Index) is used. It is a vegetation index that allows determining the presence of vegetation in the early stages of development, when there is a lot of bare soil, minimizing its effect on the visualization of the maps.
Which areas of the farm may have water stress problems? To answer this question, the NDMI (Normalized Difference Moisture Index) is calculated from the ratio between the difference and the sum of the refracted radiation in the near infrared and the SWIR. Up to 2 years of historical images, indices and meteorology can be analyzed.
Areas where the crop has yellow or discolored leaves and thus a possible lack of fertilizer can be detected from monitoring the RECI (red-edge chlorophyll index). It is an index of the photosynthetic activity of the plant canopy sensitive to the chlorophyll content in the leaves and the nitrogen level in the crop.
With NDRE (normalized difference red-edge ) the photosynthetic activity of the plant canopy is monitored in order to estimate nitrogen concentrations in plant leaves in the middle and at the end of a season. Thus, it aids in the decision of when to harvest and, in addition, it allows the detection of aging hidden vegetation and plant diseases.