Today we are at a grower's site 
in Altlandsberg, Germany.
The company BB-Obst is one of the major fruit 
producers in the Federal State of Brandenburg.
This orchard serves as a good example 
for finding spatial variability in tree sizes.
Smaller trees with a low total leaf area can bear less fruit 
with a desired fruit quality than bigger trees.
This variability should be considered 
in crop load management.
The intensity of flower and fruit thinning
should be adapted for every individual tree...
... according to its fruit bearing capacity.
In the operational group Primefruit 
we develop a new method...
... for quantifying spatial variability in the fruit bearing 
capacity within commercial orchards.
So we will be able to determine the optimum number 
of fruit for every individual tree.
Six commercial apple growers 
work together in the operational group.
We examine the spatial variability in the fruit bearing 
capacity in the orchards.
We use a porometer to measure the photosynthetic 
performance of leaves every three weeks
 from bloom to harvest.
Additionally, we measure fruit growth
and respiration.
Utilizing a LiDAR laser scanner, the leaf area is estimated
for each tree in the entire orchard.
We have fixed a leaf into the porometer
and now we measure 
the  photosynthetic performance.
We measure how much carbon dioxide is absorbed 
per second per unit leaf area…
…and how much water is transpired 
within the same time.
Scaled up to the whole tree level, 
we can estimate each tree’s fruit bearing capacity.
Here in the orchard the fruit bearing capacity 
ranges from 80 to 170 apples per tree.
For which purpose do we
use the plant sensor data?
We have recorded the total leaf area 
per tree with a laser scanner.
We have also measured fruit respiration rates 
and the photosynthetic performance.
We use the data to estimate 
the tree’s carbon balance.
We can calculate how many fruit 
each individual tree can bear.
This enables precise orchard management practices 
such as fruit thinning or irrigation.
The long term goal is to sustainably intensify the fruit production and to optimize the fruit quality.
