I don't think petite is a height so much as a body shape. I have seen tall women shopping in the petite section because they have a short waist or shorter arms or wanted a skirt that fits them better than the regular ones, and I have seen smaller women shopping in the junior/misses/womens section for similar reasons.
Sweet clover needs a high pH, 6.0 or higher, for proper nodulation to occur, and it has a higher calcium requirement as well. Sweet clover is able to obtain phosphorus from relatively unavailable soil phosphates and will grow on soils where alfalfa, red clover or ladino will fail.
Acidic soil means that the pH level of your soil is below 7. Alkaline soil would have a pH level of 7 and above. Generally garden plants thrive at pH levels between 6.5 and 7. However, some plants require higher or lower levels in order to really do well.