Manasara 3.13

3.13

plakṣadrumayutaṃ pūrvaṃ pravaṇamamlarasānvitam
varṇajānāṃ mahī proktā sarvasidhikaraṃ śubham

associated with the plakṣa tree, sloping toward the east, and endowed with an acid taste, / such an earth is declared for the [Vaiśya] class, bringing all success and auspiciousness.