Describe the environmental impact of intensive land use during the middle ages

During the Middle Ages farming was the basis of society. Every one of the feudal system - the lord, servants, and retainers - was supported by the income that came from farming. So the exploration of land was extremely important which caused a huge environmental impact.

The problem was that in that time there was no agricultural improvement, they did not know how to enrich the soil or how to do the proper rotation of crops, they used the system that cultivated 2/3 of the land and let the other third to rest. This caused a series of impacts such as climate changes, deforestation, and soil erosion.

which time period is this? or is this story fictional, i'm going to need more info to answer this question