One subject he covers extensively is the decline of nutrition in our food. He states that American diets lead to a paradox: obesity and nutrient deficiency in the same people.
"USDA figures show a decline in the nutrient content of the forty-three crops it has tracked since the 1950...to put this in more concrete terms, you now have to eat three apples to get the same amount of iron as you would have gotten from a single 1940's apple, and you'd have to eat several more slices of bread to get your recommended daily allowance of zinc than you would have a century ago".
While Pollan blames this decline on many things, especially breeding for quantity over quality, he also points out that industrial fertilizers are to blame for many of the ills.
Industrial fertilizers add three nutrients, nitrogen, phosphorus, and potassium (N-P-K) into the soil. But that's all they add into the soil, and that can be a problem. As noted above, you get many of your minerals and other important compounds from food. If these minerals aren't replaced into soil, then the soil will have none to give to more plants, and the nutritional content of the produce will decline, for this and other reasons.
Now, compost is the decomposing remnants of both food and green waste. It contains the mineral and elemental contents of what was placed into it. That means that it is better for renewing the whole elemental content of the soil, including things which we may not currently know are beneficial for the soil. This is why when I plant my garden, I always enrich the soil with compost, not fertilizer.
When I looked over the Global Buckets design to make my own, I was concerned that they're advocating only enriching their soil with fertilizer. First, the potting mix they use is nutrient-poor, and since we're coming to realize that there's a problem with our industrial form of agriculture, it's best that we don't export the problem to developing countries. Second, if compost can be used as fertilizer, the buckets would be self-sustaining instead of requiring the purchase of fertilizer, saving those using it money.
The inventors of Global Buckets say that compost inhibits their wicking process and therefore isn't practical. But I'm testing this with Fred the Tomato this summer. He might not end up as spectacular as their plants are (since fertilizers cause faster and larger growth at the expense of quality), but if I can make Fred bear fruit, I'll be happy.