A few weeks ago, I published the first post in this series: Towards a Sustainable Diet, Part 1: Sustainable Calorie Sources. Unfortunately, a bit more research led me to believe that I had drawn a picture of sustainability that was somewhat misleading. The yield per acre doesn't take into account one of the most crucial factors in crop growth: water usage. I live in the Puget Sound area, where water is plentiful all year round. In the winter, it rains; in the summer, snow and glaciers melt in the Cascades and provide us with more water than we can use. Global warming may change this someday, but I'm not used to thinking about water shortages as a problem.
This is not the case in, say, Kansas, where the US government pays farmers to pump fossil water out of the Oglala Aquifer to irrigate unsustainable corn monocultures, which are then used for high-fructose corn syrup and animal feed. Don't get me started on farm subsidies; that's a rant for another day. Suffice it to say that relatively low-yield, low-water-need grain crops, such as sorghum, are much more sustainable than corn on the Great Plains. Sorghum has low water needs and can be grown dryland, i.e., without irrigation. (My inner carnivore is urging me to say that cattle ranching is also a good use of dry grassland.) On the other hand, corn is perfectly sustainable when it's grown in Stephan Guyenet's garden, although he says potatoes do better in our climate.
That example just makes it clear that the most sustainable crops depend on the context. The rest of this series will deal specifically with sustainable crops for the Pacific Northwest.
This is not the case in, say, Kansas, where the US government pays farmers to pump fossil water out of the Oglala Aquifer to irrigate unsustainable corn monocultures, which are then used for high-fructose corn syrup and animal feed. Don't get me started on farm subsidies; that's a rant for another day. Suffice it to say that relatively low-yield, low-water-need grain crops, such as sorghum, are much more sustainable than corn on the Great Plains. Sorghum has low water needs and can be grown dryland, i.e., without irrigation. (My inner carnivore is urging me to say that cattle ranching is also a good use of dry grassland.) On the other hand, corn is perfectly sustainable when it's grown in Stephan Guyenet's garden, although he says potatoes do better in our climate.
That example just makes it clear that the most sustainable crops depend on the context. The rest of this series will deal specifically with sustainable crops for the Pacific Northwest.
White potatoes' high yields and tolerance for adverse conditions are well known (see my previous post in this series.) However, potatoes have a undeserved reputation these days as a nutritionally empty, excessively carby food. Potatoes are actually nutritious and contain sufficient amounts of most vitamins and minerals and an abundance of magnesium, potassium, copper, and vitamin C. The limiting factor on a diet based on potatoes is not protein--the human need for protein is actually quite low and can be met with a potato-only diet--but instead certain micronutrients. Other foods in the diet must supply zinc, selenium, heme iron, vitamin B-12, long-chain omega-3, vitamin A, and choline. Many of these nutrients are difficult or impossible to find in sufficient quantity in plant foods that grow efficiently in the Pacific Northwestern climate. On the other hand, these nutrients are rich in animal foods, and with the right choices animal foods need make up only a small part of the diet. Especially good choices include:
The next post in this series will discuss a sustainable meal plan for someone living in the Pacific Northwest.
- Bivalves (i.e., oysters, mussels, scallops, and clams). They are near the bottom of the food chain, making them efficient and sustainable to farm. Because they feed on microorganisms present in the water, they need no supplemental feed. All bivalves are rich in heme iron, selenium, omega-3s, and vitamin B-12; oysters are also extremely rich in zinc. As a benefit, they lack a central nervous system and are therefore acceptable for some vegetarians and vegans.
- Eggs. Rich in selenium, retinol and other fat-soluble vitamins, choline, and omega-3s, eggs are also quite efficient to produce. The birds can be fed table scraps, as well as weeds and worms. The feed-egg conversion ratio is 2:1, which is very good for land animal protein. At the end of the chicken, duck, or goose's life, the bird can be slaughtered and eaten nose-to-tail. Male birds can also be raised for the table.
- Dairy, from cows, sheep, or goats. Providing retinol, fat-soluble vitamins, and calcium, this is a distant third to the more nutrient-dense eggs and bivalves. The feed ratio for cow's milk is 1:1, but dairy has a lower calorie and protein density than other animal products.
The next post in this series will discuss a sustainable meal plan for someone living in the Pacific Northwest.