I just planted some 25 foot Cypress trees in our lousy clay-based soil. They are on a drip irrigation system. I need to know how moist the soil just outside the root ball is, at depths of a few inches up to about 36". My wife has a simplistic probe for indoor potted plants that appears to be two dissimilar metals (Zinc + Steel?) that drives a dc. meter. It is too short for the outside use.
Our problem is that our soil retains water for weeks. We used a backhoe to dig the original 5'x'5x3' holes. They were backfilled with better soil containing mulch and organics. However, the undisturbed dirt around the hole is not at all permeable to water, so the only way a gallon of water poured into the hole can leave is by the tree using it, or by evaporation out of the top layer of dirt. In this scenario, it is very easy to overwater the tree and drown it.
I'm gathering data on how to build a more robust, bigger unit for outside.
Is it better to use a passive system that relies on galvanic action between dissimilar metals, or to use an impedance measurement system that passes ac or dc current between two similar probes?
Our problem is that our soil retains water for weeks. We used a backhoe to dig the original 5'x'5x3' holes. They were backfilled with better soil containing mulch and organics. However, the undisturbed dirt around the hole is not at all permeable to water, so the only way a gallon of water poured into the hole can leave is by the tree using it, or by evaporation out of the top layer of dirt. In this scenario, it is very easy to overwater the tree and drown it.
I'm gathering data on how to build a more robust, bigger unit for outside.
Is it better to use a passive system that relies on galvanic action between dissimilar metals, or to use an impedance measurement system that passes ac or dc current between two similar probes?