Years ago I went to Kenya and Tanzania to asses some fields for trials of new cultivars my group was developing. There were a lot of issues with people seeing a yearly decrease in crop yield. But the major issue was actually the lack of crop rotation causing a buildup of disease in the soil which was weakening the plants each year.
I don't know this guy or his field. And, not carefully fertilizing fields can cause root burn for sure. But poor agricultural yield in Africa is definitely impacted by poor crop rotation.
I think its a way to argue that sports developed by certain groups shouldn't be allowed in the Olympics because then those who didn't traditionally develop said sport might compete in them. It results in exclusion, which is worse than the risk of cultural appropriation IMO.