teart
Tending toward scouring (diarrheal illness) in grazing livestock, being high in molybdenum content and neutral to alkaline in pH.
Teart soils contain molybdenum in amounts varying from about 0·002 to 0·010% in the surface horizon and are neutral or alkaline in reaction and often calcareous. The contents of molybdenum increase down the soil profile. Those [soils] which are acid in reaction in the surface horizons are not teart even if their molybdenum content is high. […] How a knowledge of the relation between soil and teartness can be turned to practical advantage is briefly discussed.
Where it comes from
Dialectal form of tart, applied by British farmers to soils since before the era of chemical science and the discovery of molybdenum but retroactively defined by molybdenum concentration and pH level.
Adapted from the Wiktionary entry teart (CC BY-SA 4.0).