Paraskaragrihyasutra 3.1.6

3.1.6

atha yavānāmetamutyaṃ madhunā saṃyutam \ yavaṃ sarasvatyā adhivanāya cakṛṣuḥ indra āsītsīrapatiḥ śatakratuḥ kīnāśā āsanmarutaḥ sudānava iti \6\

For barley, however, (he uses the Mantra), 'This barley, mixed with honey, they have ploughed through Sarasvatî under Manu. Indra was lord of the plough, the hundredfold wise one; ploughers were the Maruts, the exuberant givers.'