If you need to condition your soil, and you'd do that only if you couldn't get your hands on enough bulky organic matter, then you could use seaweed meal or pelleted chicken manure. I can't think that putting industrial chemicals found in shampoo would do anything other than harm. If your soil is very clayey, you could use gypsum, which helps to aggregate the clay particles together. I've been organic gardening for forty years or more, and I've found that there is no soil problem can't be cured by the addition of as much bulky manure as you can lay your hands on.