Hi There- I recently had my raised bed and trees in the yard soil tested - 3 different batches and all of them came back with extremely high salinity levels - referenced as toxic levels of plants. Explaining my burned/yellowing edges etc... I think it is coming from my irrigation water -which is city water so, I wonder if leaching is even possible. Any ideas on what organic matter/compost can be added w/o increasing salt? I wanted to get some European nightcrawlers in to assist with drainage. Thank you for you advice
Clark County Nevada soil
Thanks for your question about your soil problems. It is unlikely that the high salt content is being caused by the city water. It would be salty if there were no humans in sight! Here's a link to a UN Extension article that explains the problem and how to 'cure' it. The information is on page 2 (on the left) and 3 (on the right) under "The Soil." The answer to just about any soil issue is adding organic material, and the answer to your "what can I safely add" is on page 3. Note that adding organic matter will also improve drainage (and supply nutrients to your plants.)
You're probably going to have to solve the salinity problem before you can introduce earthworms and expect them to help the soil. From this U Cal Extension article:
"Although earthworms are considered beneficial to soil productivity, few valid studies have been made to determine whether their presence will significantly improve plant growth. This may seem odd since many of us have learned from childhood that worms are good. It is something like the chicken and the egg analogy. The conditions that are conducive to earthworms are also ideal for plants. Both plants and worms need temperatures between 60 and 100 degrees F for good growth; both need water, but not too much or little; they both require oxygen for respiration; and they do not like soils that are too acid or basic or too salty. By correcting soil conditions that are unfavorable for one will also improve the outlook for the other. The earthworm is a natural component of the soil population. If the soil is properly managed this natural population will thrive. In this sense, the presence or absence or earthworms can be an indicator of the "fertility" of one's soil."
You might want to consider vermicomposting, with a different type of worm, that you can control the environment (contents of compost, temperature and frequency of 'harvesting' the castings for use as great fertilizer in your garden).
Hope this is helpful. Good luck!