Climate and Food Nutrition
Over geologic time spans, water passing through soil leaches or removes plant nutrients. In climates where there is barely enough rain to grow cereal crops, soils retain their minerals and the food produced there tends to be highly nutritious. In verdant, rainy climates the soil is leached of plant nutrients and the food grown there is much less nutritious. That's why the great healthy herds of animals were found on scrubby, semi-arid grasslands like the American prairies; in comparison, lush forests carry far lower quantities of animal biomass.
Some plant nutrients are much more easily leached out than others. The first valuable mineral to go is calcium. Semi-arid soils usually still retain large quantities of calcium. The nutrient most resistant to leaching is potassium. Leached out forest soils usually still retain relatively large amounts of potassium. William Albrecht observed this data and connected with it a number of fairly obvious and vital changes in plant nutritional qualities that are caused by these differences in soil fertility. However obvious they may be, Albrecht's work was not considered politically correct by his peers or the interest groups that supported agricultural research during the mid-twentieth century and his contributions have been largely ignored. Worse, his ideas did not quite fit with the ideological preconceptions of J.l. Rodale, so organic gardeners and farmers are also ignorant of Albrecht's wisdom.
Albrecht would probably have approved of the following chart that expresses the essential qualities of dryland and humid soils.
Soil Mineral Content by Climate Area
|Plant Nutrient||Dryland Prairie Soil||Humid Forest Soil|
Dryland soils contain far higher levels of all minerals than leached soils. But Albrecht speculated that the key difference between these soils is the _ratio _of calcium to potassium. In dryland soils there is much more calcium in the soil than there is potassium while in wetter soils there is as much or more potassium than calcium. To test his theory he grew some soybeans in pots. One pot had soil with a high amount of calcium relative to the amount of potassium, imitating dryland prairie soil. The other pot had just as much calcium but had more potassium, giving it a ratio similar to a high quality farm soil in the eastern United States. Both soils grew good-looking samples of soybean plants, but when they were analyzed for nutritional content they proved to be quite different.
|Soil||Yield||Calories Protein Calcium Phosphorus Potassium|
The potassium-fortified soil gave a 25 percent higher bulk yield but the soybeans contained 25 percent less protein. The consumer of those plants would have to burn off approximately 30 percent more carbohydrates to obtain the same amount of vital amino acids essential to all bodily functions. Wet-soil plants also contain only one-third as much calcium, an essential nutrient, whose lack over several generations causes gradual reduction of skeletal size and dental deterioration. They also contain only half as much phosphorus, another essential nutrient. Their oversupply of potassium is not needed; humans eating balanced diets usually excrete large quantities of unnecessary potassium in their urine.
Albrecht then analyzed dozens of samples of vegetation that came from both dryland soils and humid soils and noticed differences in them similar to the soybeans grown under controlled conditions. The next chart, showing the average composition of plant vegetation from the two different regions, is taken directly from Albrecht's research. The figures are averages of large numbers of plant samples, including many different food crops from each climate.
Average Nutritional Content by Climate
|Nutrient||Dryland Soil||Humid Soil|
|Total mineral nutrition||5.14%||1.97%|
|Ratio of Potassium to Calciuim||1.20/1||4.50/1|
Analyzed as a whole, these data tell us a great deal about how we should manage our soil to produce the most nutritious food and about the judicious use of compost in the garden as well. I ask you to refer back to these three small charts as I point out a number of conclusions that can be drawn from them.
The basic nutritional problem that all animals have is not about finding energy food, but how to intake enough vitamins, minerals and usable proteins. What limits our ability to intake nutrients is the amount of bulk we can process, or the number of calories in the food. With cows, for example, bulk is the limiter. The cow will completely fill her digestive tract at all times and will process all the vegetation she can digest every day of her life. Her health depends on the amount of nutrition in that bulk. With humans, our modern lifestyle limits most of us to consuming 1,500 to 1,800 calories a day. Our health depends on the amount of nutrients coming along with those calories.
So I write the fundamental equation for human health as follows:
HEALTH = NUTRITION IN FOOD DIVIDED BY CALORIES IN THAT FOOD
If the food that we eat contains all of the nutrients that food could possibly contain, and in the right ratios, then we will get sufficient nutrition while consuming the calories we need to supply energy. However, to the degree that our diet contains denatured food supplying too much energy, we will be lacking nutrition and our bodies will suffer gradual degeneration. This is why foods such as sugar and fat are less healthful because they are concentrated sources of energy that contain little or no nutrition. Nutritionless food also contributes to "hidden hungers" since the organism craves something that is missing. The body overeats, and becomes fat and unhealthy.
Albrecht's charts show us that food from dry climates tends to be high in proteins and essential minerals while simultaneously lower in calories. Food from wet climates tends to be higher in calories while much lower in protein and essential mineral nutrients. Albrecht's writings, as well as those of Weston Price, and Sir Robert McCarrison listed in the bibliography, are full of examples showing how human health and longevity are directly associated with these same variations in climate, soil, and food nutrition.
Albrecht pointed out a clear example of soil fertility causing health or sickness. In 1940, when America was preparing for World War II, all eligible men were called in for a physical examination to determine fitness for military service. At that time, Americans did not eat the same way we do now. Food was produced and distributed locally. Bread was milled from local flour. Meat and milk came from local farmers. Vegetables and potatoes did not all come from California. Regional differences in soil fertility could be seen reflected in the health of people.
Albrecht's state, Missouri, is divided into a number of distinct rainfall regions. The northwestern part is grassy prairie and receives much less moisture than the humid, forested southeastern section. If soil tests were compared across a diagonal line drawn from the northwest to the southeast, they would exactly mimic the climate-caused mineral profile differences Albrecht had identified. Not unexpectedly, 200 young men per 1,000 draftees were medically unfit for military service from the northwest part of Missouri while 400 per 1,000 were unfit from the southeastern part. And 300 per 1,000 were unfit from the center of the state.
Another interesting, and rather frightening, conclusion can be drawn from the second chart. Please notice that by increasing the amount of potassium in the potting soil, Albrecht increased the overall yield by 25 percent while simultaneously lowering all of the other significant nutritional aspects. Most of this increase of yield was in the form of carbohydrates, that in a food crops equates to calories. Agronomists also know that adding potassium fertilizer greatly and inexpensively increases yield. So American farm soils are routinely dosed with potassium fertilizer, increasing bulk yield and profits without consideration for nutrition, or for the ultimate costs in public health. Organic farmers often do not understand this aspect of plant nutrition either and may use "organic" forms of potassium to increase their yields and profits. Buying organically grown food is no guarantee that it contains the ultimate in nutrition.
So, if health comes from paying attention to the ratio of nutrition to calories in our food, then as gardeners who are in charge of creating a significant amount of our own fodder, we can take that equation a step further:
HEALTH = Nutrition/Calories = Calcium/Potassium
When we decide how to manage our gardens we can take steps to imitate dryland soils by keeping potassium levels lower while maintaining higher levels of calcium.
Now take another close look at the third chart. Average vegetation from dryland soils contains slightly more potassium than calcium (1.2:1) while average vegetation from wetland soils contains many more times more potassium than calcium (4.5:1). When we import manure or vegetation into our garden or farm soils we are adding large quantities of potassium. Those of us living in rainy climates that were naturally forested have it much worse in this respect than those of us gardening on the prairies or growing irrigated gardens in desert climates because the very vegetation and manure we use to "build up" our gardens contains much more potassium while most of our soils already contain all we need and then some.
It should be clear to you now why some organic gardeners receive the soil tests like the man at my lecture. Even the soil tester, although scientifically trained and university educated, did not appreciate the actual source of the potassium overdose. The tester concluded it must have been wood ashes when actually the potassium came from organic matter itself.
I conclude that organic matter is somewhat dangerous stuff whose use should be limited to the amount needed to maintain basic soil tilth and a healthy, complex soil ecology.Back to Composting
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