Soil pH Soil pH Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions ( or, more precisely, ) in a solution. In soils, it is measured in a slurry of soil mixed with water (or a salt solution, such as 0.01 M ), and normally falls between 3 and 10, with 7 being neutral. Acid soils have a pH below 7 and alkaline soils have a pH above 7. Ultra-acidic soils (pH < 3.5) and very strongly alkaline soils (pH > 9)
Bohemic acid under neutral or slightly basic pH conditions, and the fats and oils are removed by washing with petroleum ether. Chromatographical separation, in addition to the antibiotics pyrromycin and cinerubin A and B, reveals several individual components of bohemic acid, including alcindoromycin, bohemamine, collinemycin, marcellomycin, mimimycin, musettamycin, rudolphomycin and schaunardimycin. Their names originate from the characters Alcindoro, Colline, Marcello, Mimì, Musetta, Rodolfo (Rudolph) and Schaunard of the Puccini opera "La Bohème", and the acid itself and the bohemamine component carry the name of the opera. The suffix "-mycin" is conventionally added to indicate antibiotics derived from actinobacteria or fungi. The individual