Setting Budget Lines

This week we will look at budget lines and how to set them.  Budget lines are the full point and refill point in the soil profile.  The full point is the maximum amount of water we want in the soil.  Depending on the growth stage, we set that at 5% of the field capacity.  The capacity can be found after a rain or irrigation event when the water level spikes and then drains back out.  The point when the draining starts to level off is the field capacity.

In our demo field, the field capacity is 12.6 inches, so we set the full point at 11.97 inches.

We set the refill point at 70% of the field capacity.  Below you can see that as the water level gets below the refill point the graph begins to level out indicating that the plant is struggling to draw water from the soil.  

As the season goes on, these points will change due to crop needs.