The size of your equipment does not dictate the depth you have your drill or planter set to.
> When horses pulled ploughs,they didnt cut too deep into the soil
Yes they did. Plowing completely turns over the top soil.
There are other things at play too like row spacing. We used to plant at 36", eventually we went down to 30", some of our neighbors even went down to 20" or so.
You cant deep plough (>50cm) with horses they dont have the strength as this YT vid shows https://www.youtube.com/watch?v=t7F4X3idewA
>Yes they did. Plowing completely turns over the top soil.
Once metal ploughs were introduced they could start to cut deeper into the soil, but the earliest horse drawn ploughs could not cut deep because they were wood as seen in some parts of the world today with oxen pulling wooden ploughs.
https://howardsuer.wordpress.com/2009/11/01/how-the-chinese-... The "mold" of moldboard is old German for soil but it was the Chinese who introduced the modern day moldboard plough most people are familiar with.
However is ploughing even needed today? This practice was started after Brexit, and its reduced fuel costs on the farm because now there is no need for ploughing and the dustbowl situations are extremely unlikely to occur.