I tested alfalfa meal pH with red cabbage juice (pretty accurate pH indicator). This was done against peat moss (pH of 4), baking soda (pH of 9), and MiracleGro potting soil (pH of 6.5). Alfalfa meal is LESS ACIDIC THAN PEATMOSS, but resulted in pinkish solution like MiracleGro potting soil. I'll say its pH is between 6 and 6.5.

However, like leaves, it is acidic INITIALLY but with time it stablizes to neutral. Once fully decomposed, both alfalfa meal and leaves are slightly alkaline. University of Illinois Extension has a good article on the ending alkaline result of leaves. Check it out by googling the fore-mentioned key words.

Most things you put in your compost go to neutral by the time they are done.

Amendments derived from plant products - the alfalfa or cottonseed meal - are typically slightly acidic in nature whereas mineral based amendments can be both acidic or alkaline or neutral, depending on source. Other than the two primary sources to alter pH (lime or sulfur), most other common soil amendments have little to no effect at least no significant long term effect. And it is true that anything organic - that is, plant or animal sourced - will eventually decompose to a pretty much neutral pH.