Leaf Area Index
The Leaf Area Index LAI is a measure for the biomass of the crop. The bigger the leaf area, the better developed the canopy. The LAI is an important parameter which describes the photosynthetically active leaf area and thus is central for the photosynthesis.
Fig. 1: Green Leaf Area Index of several winter wheat fields in mid-June (05.06.2013) at vegetation maximum
The chlorophyll content of a plant is not only a measure for its „greenness“, but also an indicator for the photosynthetic activity of a plant. The chlorophyll content is closely connected with the nitrogen supply. An under-supply with fertilizer can thus be identified.
Fig. 2: Map of chlorophyll content in µg/cm² for several winter wheat fields in mid-June (05.06.2013) at vegetation maximum
Degree of Maturity
The LAI can be differentiated in its green, photosynthetically active and its brown, withered part. The fraction of brown leaves gives an indication as to which canopies are ripe earlier and where to start first with harvesting.
Fig. 3: Degree of maturity of several winter wheat fields, calculated from the fraction of brown leaves
The current plant density is a further parameter that can be derived from remotely sensed data.
Fig. 4: Different development of a wheat canopy depending on normal vs. Broad seeding at the same amount of grains seeded per square meter
Additional parameters which can be derived with remotely sensed data are:
- current biomass
- leaf angle distribution
- plant water content
Each individual acquisition shows just one moment in the development of the canopy but with a series of acquisitions a continuous monitoring can be conducted (crop development).