David The Good is in a hurry to help his trees in this one and he inspired an interesting comment by Garden Earth Guy that piqued my interest and so I had to research further.
Here’s Garden Earth Guy:
When I used to manage sports fields and large parks- I would place to magnets on the irrigation line. When the water passes through magnets it creates ions, much like how things green up after an electrical storm.
After a bit of digging I found that this could actually work, with a caveat. It depends on the water harness (calcium carbonate > 50 mg/L) and alkalinity (pH >7.2) of the water source. Seems the divalent ions (Calcium and Magnesium) that make water hard, and whether your soils are also high in these and alkaline, determines how effective this is.
In addition to the Ca+Mg, one drip irrigation study with magnetically treated water also showed phosphorus solubility almost doubled inside the water front, and that suggests an effective pH change toward neutral. Interestingly, with the increase in phosphorus at the edge of the water front (where there’s air) there was also almost a doubling of nitrate compared to control. Nitrate was ~4x higher at the edge than close to the dripper.
So by magnetically treating your water, you’re effectively lowering your Ca+Mg in alkaline soil which brings the soil closer to neutral pH and increases phosphorus availability. Simples.
So if your soil or water is alkaline this should work great for you, but if they’re not, it may do little or in fact be negative in the long term. Measure your soil pH to know.
The effects of magnetic treatment on irrigation water have been studied. We showed that the main effects were the increase of the number of crystallization centers and the change of the free gas content. Both effects improve the quality of irrigation water. As an example, changes in natural water due to magnetic treatment in a commercially available apparatus, Magnalawn 2000, have been studied. On the basis of laboratory and field results, the type and the chemical content of natural water for which a magnetic treatment method is the most efficient have been determined. Our analysis shows that the important components for effective magnetic treatment are flow rate through the apparatus and certain chemical parameters of water, namely, carbonate water hardness of more than 50 mg/L and concentration of hydrogenous ions in water at pH > 7.2. Irrigation with magnetically treated water is the most effective for soils with high soda content.