Why Maize needs good topsoil to grow well

Maize corn has shallow roots, so it requires healthy topsoil conditions to grow optimally. Poor topsoil conditions like hardening or nutrient loss will impact the harvest and there's a higher chance that your yields will drop significantly and quickly and infact mostly without warning.

I would say the best way to improve the soil condition is to use products like mulch and manure or crop rotation, but I can't say for sure how important crop rotation is to soil health compared to keeping the soil covered and fed. The end result should be the same regardless.

You cannot just plant and hope that your corn is going to grow like you want because it will not forgive if the upper layer of soil is compact, which has happened by foot traffic and heavy rains. Roots cannot spread out and so it will be hard to get good production for the rest of the year.

Sustainable farming and soil preservation is a subject that some farmers like to think doesn't apply to them but it actually just involves respecting the soil you have already. Giving back what's been removed. That makes too much sense to forget, yet some do when they are busy during the planting season. Because of the shallow roots, you must be more mindful of detail versus other types of crops that have deeper root systems that would help to forgive you either for being late with planting or poor management.