An adequate irrigation system supplies the necessary amount of water at the right time, wetting the soil to the depth required by the crop. Excessive irrigation can be detrimental to the crop as it facilitates the attack of fungi and diseases and a loss of water resources for the farm.

If humidity is too low, plant growth will be compromised, since crops in the absence of water or food reduce their growth, and to avoid water loss by evapotranspiration, the first response to the lack of irrigation is the loss of leaves.

Through multispectral analysis, thanks to satellite images or from drones, we can calculate certain indices that indicate the humidity in the crop.
The crop moisture index (NDMI) uses the near infrared (NIR) and shortwave infrared (SWIR) bands to provide information about the water content of vegetation.

The formula is:

More specifically:

-NDMI (Sentinel 2) =  (B8-B11) / (B8+B11)

-NDMI (Landsat 8)= (B5-B6) / (B5+B6)

The interpretation of the NDMI makes it possible to differentiate zones with water stress problems on the farm. NDWI values vary between -1 and 1. It is not possible to establish specific values for the interpretation of this index because for each type of soil and crop, these values may vary. But in general terms we can establish:

-Values near the lower limit (-1) represent bare soil.
-Average values (0) represent a medium canopy cover with high water stress.o.
-Values close to the upper limit (1) represent high canopy cover with water stress (high moisture content).

 

One of the many products that Mapsens® Agro incorporates, is the zoning of the farm according to humidity. With these classes we could adjust the irrigation system, applying less irrigation in areas with high humidity and more irrigation in areas with humidity deficit.