The USDA website gives the following definition of organic produce
But for the uninitiated, a produce can be called organic if no chemicals were used in producing it. Organic farmers prefer biological solutions over chemical solutions. That’s why, sometimes they are called jaivik farmers. In place of synthetic chemicals, plant or animal-based solutions like manure, biogas slurry, neem oil, Jivamreet, etc are used.
Simply, you can think chemicals are replaced with natural sources as mentioned above.
Conventional farming should be called Chemical farming in my view. This is the type of farming that was started during the Green Revolution. Sometimes, conventional farming is also known as industrial farming.
Natural farming is one step above in terms of sustainability compared to organic farming. In natural farming, the continuous use of even natural solutions is avoided. This helps in setting up the ecosystem. The native seeds are used over hybrid seeds.
In the case of natural farming, natural systems are studied, and learning from those systems is incorporated into agricultural practices.
Regenerative farming is one step above then even natural farming. Though many things overlap between the two but regenerative farming also focuses on improving the soil and ecosystem in addition to producing organic crops.
A food forest basically mimics the native forest system but most of the varieties produce food. This system is one of my favorites because not only does this food forest system produce food but also converts a lot of carbon dioxide into soil carbon content.
Generally, organic products are safer than natural products, because they are so strictly regulated by the USDA. This regulation can give you full confidence that an organic product was produced safely and does not contain any ingredients or additives that may be harmful