Everyone knows that fruits and vegetables are good for us. Most people know we don’t get enough. But fewer people know that the nutritional content of conventionally grown fruits and vegetables has been declining steadily since the introduction of chemical farming (sometimes called industrial agriculture) after World War II.Various studies using government data have documented significant nutrient declines in fruits and vegetables from 1930 to the present—declines up to 99% in one case!—in protein, calcium, phosphorus, iron, potassium, copper, magnesium, riboflavin, vitamin C, and vitamin A, while data on other nutrients like zinc, vitamin B6 and vitamin E weren’t collected until more recently, so no comparisons could be made.Why is nutrient content declining? Partly it’s due to traditional breeding techniques, in which fruits and vegetables are bred for better appearance, sweetness, faster growth, or ease of transport, often at the expense of nutritional quality. But a much larger re…