I can see not using synthetic pesticides or herbicides, but what's wrong with chemical fertilizers - after all nitrogen is nitrogen is nitrogen. Well, yes, nitrogen is nitrogen is nitrogen, but plants shall not live on nitrogen alone. Plants are the same way. Synthetic fertilizers only provide key minerals. However, to be healthy plants need many major nutrients and trace elements to survive.
Organic fertilizers provide many trace elements, major nutrients, as well as organic matter.
Organic fertilizers release nutrients more slowly, so the plant doesn't have a flush of growth when they are applied. Synthetic fertilizers often cause a spurt of unhealthy growth. This makes your plants more susceptible to disease and insects, which leads the synthetic gardener to more pesticides. By using organic fertilizers, you can break this cycle. The organic matter helps hold the nutrients and water the plants need.