Rebuild from Depression Blog

Soil Fertility?

One argument is that the mineral levels in our soil have been compromised. Many people in small-scale agriculture and in the organic food movement are concerned about nutrient loss in soil and its affect on our health. The argument is that conventional fertilizers used by farmers add only a few nutrients to the soil. Season after season as a spinach plant takes up iron, there is less iron left in the soil for the next spinach plant. Organic farmers avoid this problem by adding compost and other emulsions that are rich in many nutrients.

New Hybrid Crops?

The soil health argument is very difficult to test. And in fact, in the USDA data, there is not evidence that specifically supports the soil fertility argument. In the study of 43 garden crops, researchers point out that many nutrient values have declined, including potassium even though potassium is added to crops with conventional fertilizer. So with potassium values on the decline, the researchers suggest that a more likely suspect is the change in plant varieties themselves.

New hybrid plants are developed to maximize crop yield and to transport and store well. When plants are selectively bred for one characteristic, other beneficial characteristics of the original plant are likely to decline in the new hybrid. A high nutrient content is typically sacrificed when plants are bred to produce more food or to stay fresh in a cold storage. Think about it like this: if you bred people for beauty over twenty generations and each subsequent generation was more beautiful than the prior, how smart would those people be? It's hard to say. Probably not as smart as their ancestors since they were selectively bred for another purpose.

What you can do

As a society, when we buy produce from large grocers, we are, in fact, paying for lesser-quality food from a nutrient stand point. The nutrient content is what is sacrificed for transportation and storage.

What you can do in your own household is shop for produce at a farmer's market and ask for heirloom varieties. Heirloom crops are those created by nature. They may look a little different. They may not travel all that well. But generally I find that they have much more flavor.

If you garden, you can even grow your own. The internet has made it easy for us to collect heirloom seeds. Here's a directory of heirloom seed merchants.

But what if it is a soil fertility problem?

Choosing an heirloom variety will help even if there is a soil fertility problem in this county. First, small market farmers who grow heirloom crops in the first place also tend to use fertilizers such as compost and fish emulsion which have a variety of nutrients. Second, the plant varieties themselves are simply more likely to uptake nutrients because they haven't been bred for other purposes.

Visit a farmer's market today and ask about heirloom varieties of fruit and vegetables.

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Source: Davis, D. R., M. D. Epp, H. D. Riordan. 2004. Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999. Journal of the American College of Nutrition 23: 669-682.