I am not sure about that. Mixed farming is a thing, was historically, and nowadays its starting to creep back in as a modern ecologically friendly alternative that can help build soil where intensive farming of monocultures completely drained it.
Examples I have read about talks about improving bacterial composition, increasing the amount of carbon and nitrogen in soil, as well as advantages for no-till farming (which is increasingly being preferred, as it helps preserve the soil bacterial biome).
There are experiments with sheep, cows, and chickens, the latter in a way serves also as a form of pest control, able to devour various insects and even rodents if required.
https://www.csuchico.edu/regenerativeagriculture/ra101-section/integrating-livestock.shtml
First thing first: mixed farming in the past only meant that you raised animals and crops at the same time. Not that they used the same space. If a farm had a coop with chicken but also made wheat, it was mixed farming.
2) Yes, you can put animals on field or fallows. But only for a short time. For example, in medieval time, animals were put on the fallows field maximum a few weeks (heavily dependant on size of field and size of animal pack), the time they eat most of the plants. Doing like that is beneficial. But leaving the animals roam for a few months? That's a bad idea. If you have read your link, it says that you need to often move the animals to avoid overgrazing and over-compaction.
The best example is the chicken. Chicken manure contains a lot of nitrogen, which is good for the soil. But if it keep accumulating, the soil become unbalanced and lose efficiency. In addition, chicken dig a lot to find worms, insect and roots. Leaving chiken a few days on a field is beneficial (removing insects, giving nitrogen, ...) but more than that will start to damage the field. If you want further proof: coop are nearly always barren soil because of that.
Maybe I expressed myself badly: Just placing the animals a short time can be good.
But truly putting them for an extended period on a land destined for crops is a very bad idea.
Before I put my comment in here, I need to state that I am by no means an expert in agriculture nor do I practice any form of agriculture, I'm only repeating what I read on a review article that covers the topic and some of my own opinion. (this is the review article I based my opinion upon: Sekaran, U.
et al. (2021) ‘Role of integrated crop-livestock systems in improving agriculture production and addressing food security – a review’,
Journal of Agriculture and Food Research, 5, p. 100190. doi:10.1016/j.jafr.2021.100190.)
Most of what I wanted to say has already been stated by
@Ovnidemon, in particular the need for proper management and selection of the animals chosen to graze on the fields in the fallow period, animal integration can be a good thing, but you need to choose the specific animals and crops that can vary between climates and soil conditions, as well as proper management of the animals to ensure that the animals do not just stay in one place all the time as well as distribution of the animal manure itself to prevent uneven crop growth. This in itself needs a lot of investment in terms of continuous manpower to manage the fields and animals, as well as the necessary knowledge needed to choose the animal and crop plants.
On another note, monoculture farming (the one most farms do), as the name implies, deals with one type of crop, this can and does lead to higher productivity and efficiency in the short term (in comparison to improper use of mixed farming), as you only need to maintain, process and store one type of crop rather than needing to do so for a variety of crops (that entails various different processes and conditions needed for different crops) that comes with mixed farming.
While mixed farming can lead to better sustainability for farming and thus better economic stability for the farmers themselves, as well as diversification of produce from the farms, but this effect only happens if mixed farming is done properly, and to do mixed farming properly, there is a huge wall of investment needed from the farmers themselves, in terms of manpower and knowledge needed to properly utilize mixed farming.
