There are no EU secrets on farming. You can just ask any farmer how they do it. The actual gap in farming efficiency between China and the EU is fairly low for most basic crops, see: https://ourworldindata.org/crop-yields and compare crop yield gaps.

It's very unlikely Jack Ma is trying to exfiltrate "secrets" of agricultural production from poor European farmers. You can just go and ask them. There are not really any secrets.