Cultivation (from ’wasteland’) refers to replacement of the natural vegetation by crops and regulate the water (irrigation, drainage). This often happens by controlled burning off plots. The ashes contain many minerals and serve as fertilizer.
You can usually read cultivation as: making economically viable.

LandbouwalaamAfter the fire culture (or burning culture) the production of crops was further improved by irrigation, plowing and fertilizing.

In the first domesticated plants prevailed not to diet but the psychoactive substances. Tobacco was cultivated 8,000 years ago by the Indians in South / Americas.
Aborigines had no agriculture, but tobacco of pituri (Duboisia hopwoodii) was harvested through a complex process and dried, and then also traded.

(Aboriginal: from the Latin ab origo, from the beginning. Every community is aboriginal in his own place.)

Smoking may have been experienced by preserve fire in a shell or sleeve and blow it to ignite again for later used. To find the right plants, as they apparently did, they would have experimented a lot.