Soil varies a lot by region. Some soils are sandy, some are acidic, lighter, more organic matter. Some are heavy packed clay. Some have been intensely farmed or depleted, etc.
Here I think the soil has lots of minerals in it but it's hard clay and alkaline. How do people lower soil pH substantially in soil like this? Mixing in a large amount of organic matter like forest compost comes to mind (as in humic and fulvic acids). Or lowering the irrigation water pH. But I was also wondering if there are any other ways.
You can try any of the following:
1. add organic matter. If you have clay you should do it anyway for better growth. Organic matter only works slowly over time though.
2. add Aluminum Sulfate but some people don't like aluminum as Cannabis is a accumulator and sucks up all impurities in the soil.
3. add Sulfur.
4. add Sulfur coated urea.
I think you are outdoors so fall is a good time for additives to let it mellow in. Your big box store (Home Depot) should have some stuff and you can also get it on Amazon.
I mean, how do you know it's alkaline? Do we have a pH to start from because there's a big difference from 7.3 and 7.2 and the causes therein. Can you give us some more info? Are you actually seeing any issues with this soil/have you used it?
here where i am it's very sandy , ancient sand dunes in fact , and also very alkaline .
i water from a shallow bore which is also alkaline . soil/sand has been tested at 8.5 and the water the same .
i've used scrapings from underneath pine trees and use lots of compost but when its this high then the use of sulphur at 50g per square metre and iron sulphate as well seems to do the trick but it needs to be done regularly .
coming from an area that is acid and to this i know what i prefer . acid is easy to fix !
You should start by adding a few cm thick layer of composted organic matter tilled in to your native soil. Do this for about 5 or 6 seasons on the same patch and then you will never really have to till again unless your OM content falls below about 5%.
While you are adding the COM you should also use a balanced fertilizer so you can take full advantage of the clays CEC.
Do you have a specific sample in mind? If you have current numbers and inputs, we might be able to recommend something suitable for your situation
I can do a pH test on some soil here. Yeah I been gardening this plot and reading the Organic Gardening forums and arguing against agro chem since at least '09 likely before. Cabbage and greens that like calcium do well in it and tomatoes too as long as lots of organic matter is mixed in periodically.
I replied to your question in the anything outdoor thread. It's really not easy. I thought out was your water that was alkaline.
It's easy to fix acidity with lime but the other way around is hard. Peat and composted wood. But you need allot. There are fertilizer amendments that are slightly acidic but it won't do much and it will fluctuate. Easier to fix your water and/or bring in soil.