Wine lovers seem to care a lot about “terroir“, or the patch of land on which the grapes used in making their wine were grown. You could have two wines that use the same grape varietal, same vineyard management techniques and the same production methods, yet one will sell for 10-100 times the price of the other if grown on particular plots of land in Burgundy, France. Similarly, the most valuable Bourbons come from Kentucky and the surrounding area, thanks to the low iron and high limestone content of the water under the ground. Why does this affect price so much? Because of the difference in taste imparted, thanks to the terroir. So then why doesn’t terroir matter for other foods, like turnips?
Ok, maybe it sounds ridiculous to use a fancy term like terroir with such a lowly vegetable as a Turnip. But even if the taste differences aren’t all that apparent, what about nutritional value?
Stephanie Seneff, PhD. recently published an article about sulfur deficiency, in which she hypothesizes that one reason Icelanders have such low rates of depression, heart disease, diabetes and obesity is related to their consumption of cabbage, beets and potatoes that are grown in Iceland’s sulpher-rich soil (which comes from centuries of volcanic activity). Could Americans’ health problems be related to lack of nutrients in our fruits and vegetables? Wouldn’t it also apply to meats, eggs and dairy, since they all come from animals that ordinarily would be consuming nutrient-rich plants on pasture?
I pondered all this on Sunday while admiring a beautiful display at one of the largest stands at the Dupont Circle farmer’s market. This stand offers an impressive variety of leafy greens – all picked and prewashed, for $11/lb. I’ve purchased their baby arugula many times and two things have always struck me about their arugula. First of all, it’s very mild – almost sweet. It lacks that nutty/peppery/zesty “zing” that arugula can sometimes have. Secondly, their arugula lasts a full week in my refrigerator before showing any signs of age. So this weekend I asked the grower about how they tend and fertilize their crop. Our conversation went as follows:
- Grower: [showing a picture of the farm] Here are our greenhouses, the lettuce plants are grown here on these rows. For fertilizer, we typically use 10-10-10.
- Me: That’s a chemical fertilizer that only provides nitrogen, potassium, and phosphorous. How do you replenish all of the other nutrients that are lost when you harvest the plants? Like the minerals, beneficial microorganisms and fungi? Do you rotate animals onto the land in off years or add compost or manure?
- Grower: No, we don’t practice organic farming, but we do turn over what’s left at the end of the year, into “green compost.”
I was stunned. After all these years of buying their premium-priced lettuce, thinking that I’m actually getting the nutrients that the USDA tells me I should be getting from this vegetable, only now do I realize that there’s no way I could be. Because every time they harvest the arugula, they are depleting the soil of calcium, magnesium, iron, etc that the leaves take with it. If we assume that 60% of the plant is harvested then turning over what’s left only puts ~40% of those depleted minerals back into the soil. Do this for 5 years and you’re left with less than 3% of the minerals that were there before you planted your first crop!
Disappointed, I reluctantly walked over to a neighboring vegetable stand and asked the same question. Thankfully, this answer was different. The farmer went on and on about various types of natural mineral amendments, compost and manure they use and how they don’t use any chemical fertilizers. “We’re too small to be able to afford organic certification, but the methods we use are better than you get with most certified organic,” he told me. Same with the next stand I asked. One even told me about a special organic fertilizer that’s made of seafood products! I thought to myself, “Why isn’t this guy advertising this fact?? He should at least have a sign or something!”
Hypothetically speaking, let’s say you’re at the farmers market next weekend and there’s a stand selling turnips. You approach the farmer who tells you the following:
- My farm’s about an hour from here, in [blah-blah city], at the north-facing base of the [blah-blah] mountains, where we have the perfect conditions for growing this variety of turnips. The climate is mild, the soil drains well and is rich in [blah-blah] minerals from years of [blah-blah geological events], which imparts a unique flavor that you only get from our turnips. Sure, you can put them in your vegetable soup, but personally I prefer to eat them raw in a salad, shaved paper thin, tossed only with olive oil and sea salt.”
Then let’s say you tasted one and noticed a difference. Would you be willing to pay triple supermarket turnip price for these special turnips? I know I would!
 I’m sure that my numbers here are inaccurate, as I don’t know exactly what percentage of the nutrients go into the leaves versus staying in the roots. Also, I don’t know what percentage of the total nutrients in the soil a single crop extracts. I suspect it depends on the type of crop, plant spacing, root depth, tilling depth and maturity at harvest. But even if my numbers are off, there’s no doubt that the general trend of year-over-year nutrient depletion still applies.