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.
The soil pH is best when slightly acidic, between 5.0 and 7.0 pH, which is also the right pH level for the nitrogen conversion occurring within the soil to feed the plant. Arid regions tend to see soil conditions higher in alkaline and salts, and tap water tends to be more on the alkaline side.