Which practice produces farmland with poor soil ?
a. slash and burn
b. crop rotation
c. thinning
d. shelterwood harvest

A. Slash and burn

Explanation:

The slash and burn method is a very harmful method for the soil, as well as for the whole environment. This method is consisted in total removal and burning of the vegetation in certain area in order to free up space for farmlands. The slash and burn method is mostly used in forested areas, the majority of which are tropical rainforests. The soil in this areas is relatively good, but its top part is very loose, so once the natural protection of the vegetation is removed, it is heavily affected by erosion. This leads to a situation where the soil can only be used fro few years before it becomes almost unusable, so the people continue to slash and burn other areas, living behind barren land with very poor soil.