What was done for soil fertility prior to crop rotation?

Question

Did fallowing actually work that well? Has it been tested? What was done prior to this? Or did the mesopotamians write about 'two-field system' too? (for lack of a better term for pre-crop rotation) ​ Why in the year 1000 AD (according to Phillip Daileader on Great Courses Plus), did Europeans only receive 2 grain for every 1 planted? Did they not have crop rotation at that point, even though (I thought) they had it in the carolingian era?

Answer 1

What was done for soil fertility prior to crop rotation?

Crop rotation is a relatively new strategy for improving soil fertility. The oldest soil fertility strategy is simple migration: some cultures would simply pick up and move once they'd exhausted the soil or other resources in a given area, essentially fallowing a field but with no intention of returning. Several other fertilization strategies also developed before fallowing: slash-and-burn agriculture predates crop rotation, but functions in a very similar manner: once a field becomes unworkable, some cultures will let nature reclaim it, and then burn the vegetation in a new area for cultivation and use the ashes to fertilize the soil. Some cultures maintain a series of slash-and-burn fields that they rotate in a cycle, much like crop rotation. Collecting and spreading manure on fields is another common strategy to maintain fertility, and ancient Mesopotamians certainly practiced this, as they had domesticated animals. Many cultures today still practice this by simply letting domesticated animals forage through the fields after a crop has been harvested so they'll spread the manure themselves. Another strategy is to farm areas in floodplains near rivers, as practiced most notably by the ancient Egyptians, who took advantage of the Nile's predictable flood cycles. This strategy lets the river do the work of refreshing the fields, and it makes irrigation easier as an added bonus. Fallowing does work and has been extensively tested, but does not perform significantly better than any of the strategies listed above in terms of fertility restoration or crop yields.

The Mesopotamians didn't write about a "two-field system". Most Mesopotamian documents are either receipts, religious documents, or political communiques. The ancient Egyptians sometimes wrote about agricultural strategies, but as previously discussed didn't rely on a fallowing system for agriculture.

I don't know why Phillip Daileader seems to think medieval Europeans only received two grains for every one planted, that sounds like a gross generalization and I don't know how on earth he would have made that calculation. Medieval Europeans planted a wide variety of grains--oats, wheat, barley, buckwheat, spelt--and unless he has access to magically accurate planting and harvesting records for all of medieval Europe there's no way to know that information. Medieval Europeans were absolutely aware of crop rotation as a fertility strategy though, although they may not have deployed it in as calculated as modern farmers do. Intensive single-crop agriculture on a massive scale was not as common during this period, and many small farms deliberately cultivated a wide variety of plants and animals as an insurance policy against famine.