Most growers i know experience good irrigation as one of the hardest jobs in growing strawberries. A small optimum of the moisture content, a fast reaction on changes in recipes makes it the feeling of a balancing act without rod.
The only way to change this is, to act and check and correct and check and correct and…. Good strawberry growing is really top sport. Performing without loosing attention. Set priorities within your company.
I see it frequently in the values i measure and problems growers face:
– start often quite dry, with low EC’s
– during the season EC’s going up too high, substrates getting dry
– wet substrates, with leaf yellowing
– shelf life issues, or sensitive skins
– tipburn
Below you have some ways to improve irrigation. But before this one main rule: no sudden changes!
Plants adapt to situations, an example: A plant may grow under too dry circumstances, this means roots go down to the moisture, less stomata in order to prevent evaporation, thicker wax layer etc. Sudden changing to more irrigation will lead to oxygen deficiency in the rooting zone of maybe 80% of the roots. This surely will lead to soft strawberries, to leaf yellowing, maybe even root diseases.
In the meantime there are quite some possibilities to get a stable and quite good moisture content. It is just following the rules, but to keep it good, we have to follow them steadily:
1- set irrigation based on radiation. The correlation between evaporation and radiation is very high. If irrigation is based on radiation, irrigation will be more frequent in case of a lot of sun. In case of cloudy weather, it will be less frequent
2- Normal start at about 2 hours after sunrise. Or as i like better: about 25-80 joules (depending on climate) after sunrise.
3- Check what you are doing:
a- if possible follow the following items:
drip: amount, EC, pH
drain: amount, EC, pH
climate: radiation
b- calculation:
% of drain water – goal: depending on weather conditions and LAI: 5-40%
sum EC (total of drip + drain) – goal: 3,0-4,0
irrigation: amount/radsum:
evaporation: drip amount ((ml/m2 ) – drain amount (ml/m2)) / (radsum/cm2)
4- Register this, and act based on this information.
Above 2 pictures. The first one with balance irrigation: roots from top till bottom. The second one of dry growing: roots at the bottom of the container.