A Quick Tour of Soil Remineralization
Highly fertile soils are typically described as young’ or unweathered, as they contain primary minerals inherited from the parent material in glacial periods. ‘They generally provide abundant amounts of the essential plant nutrients. Fresh supplies of nutrient elements are continually furnished because weatherable minerals are still present’ (Thompson & Troeh, 1973).
Liberation of soluble salts from unweathered primary rock particles is the prime factor in creating fertile soils. Natural fertility begins to decline when soils are impacted by man’s activities and natural aging processes erosion and leaching. Over time, soils simply wear out.
SR is a straightforward approach to reversing this process. There are several key aspects to the rationale for restoring fertility to worn out soils through remineralization:
1. A well balanced mix of soil minerals is essential for health.
2. Mineral depletion due to man’s activities and natural causes is a growing problem.
3. Over dependence on chemical farming has well documented drawbacks.
4. SR is an environment friendly measure, with both short and long term benefits.
1. Soil Minerals Are Essential For Nutrition: It is universally recognized that plants, animals and human beings all require a steady intake of certain vital minerals, micro nutrients and trace elements to promote healthy growth, general well being and disease resistance. The catalog of essential plant and animal nutrients continues to grow, with advancing knowledge of the mechanisms of these elements in nutrition. A basic list of the most widely recognized essentials would include these 16 elements:
Macro nutrients Micro nutrients
2. Mineral Depletion A Widespread and Increasing Problem: Minerals in the soil are gradually absorbed by all growing plants, in varying quantities sometimes substantial and sometimes minute. When these soil minerals are contained in agricultural crops, they are removed upon harvesting, and over time this process dramatically reduces the mineral balance of the soil. Thus, each successive crop is supported by, and contains when harvested, a steadily diminishing quantity and mix of valuable minerals.
The same phenomenon occurs as animals graze on pastureland, taking soil minerals from grasses and other plants. The minerals are permanently removed from the soil in that location when they are carried away in meat or milk . Natural erosion from wind and water also contributes to the depletion process.
3. Modem Fanning is Not a Panacea: Agricultural science has brought an abundant and varied supply of foods to the developed world, through mechanization, development of hardier varieties, a wide range of pest control materials and techniques, and regular application of the three primary plant food components via NPK fertilizers.
But the ‘miracle’ of modem agriculture is, at best, a mixed blessing: streams and aquifers are polluted by fertilizer and pesticide runoff; insects and diseases develop resistance to chemical attack, requiring ever greater applications; monocultural practices (e.g.: continuous corn) accelerate the depletion of basic minerals in soils. The net result of this short term emphasis is that the very basis of agricultural productivity fertile soil is undermined and degraded.
On forest lands, the process is similar, as growing trees are fed by soil minerals which are exported in timber harvesting. Soil acidity rises through the effects of acid rain; leaching and erosion take a further toll on the soil’s vitality. Growth slows and trees begin to die and decay, releasing carbon dioxide instead of absorbing it, so that parallel degradation of the atmosphere ensues. In worst case circumstances, large areas succumb to these stresses, and the dying forest syndrome rears its ugly head.
4. Restoring the Soil’s Natural Fertility through remineralization is nothing more than a common sense approach which addresses both short term problems of productivity, and the longer term challenges of sustainability.
Basic mechanisms: The addition and incorporation of finely pulverized gravel, moraine or other appropriate rock dust in soils triggers several key reactions:
Microbial activity is stimulated many fold, by the presence of newly availabile mineral nutrients. Just as moss and lichens grow on boulders by extracting their mineral content, bacteria feed on the tiny mineral particles, multiplying rapidly.
Natural ‘weathering’ of the rock particles accompanies this accelerated microbial action. Alteration of the rock particles by microbes, in tun, increases solubility of the mineral nutrients, making them more readily available to plants. Greater microbial action also works on the humus components in the soil, releasing organic matter.
Clay minerals formed in the process of rock alteration are able to store plant available nutrients and retain greater amounts of moisture, which roots can absorb during the whole growing period. Thus, a sustained release mechanism is created.
In moderately acid soils, remineralization alone can often overcome soil acidity, although highly acid soils may require the addition of dolomitic materials to optimize pH. Overall, well executed SR programs have amply demonstrated the ability to restore worn out soils to a ‘young’ condition, returning them to the original fertilitv bestowed by retreating qlaciers.
The Benefits of SR
A wealth of scientific data on SR trials by hundreds of researchers has accumulated over the years. The record includes many detailed studies relating to specific crops and soils, using varying application rates and different mineral sources. Each study reflects the interests, motives and techniques of the particular researcher, but in the aggregate, this body of literature portrays tantalizing opportunities. A few examples:
• The results of long term experiments released in 1986 showed that in a forest where pine seedlings were remineralized, after 24 years the wood volume was four times higher than in the untreated area (Germany).
• In 1977 corn grown on soil mineralized with glacial gravel screenings was tested along with corn from the same seed grown with chemical fertilizer. Mineral corn had 57% more phosphorus, 90% more potassium, 47% more calcium, and 60% more magnesium than chemical corn . . . .no pesticides were used; there was no insect damage. (John Hamaker, Michigan, 1981)
• Urea and potash applications were reduced 80%; dolomite application was halved and at 16 months there was no sign of magnesium deficiency. The banana plants are healthier, with vigorous root systems and 25% heavier yields. There is a 20% increase in growth rate resulting in a faster turnoff of fruit. The sum of these benefits resulted in an incredible 80% increase in production with a substantial decrease in fertilizer cost (Sam Catalano, Queensland, Australia, 1990 91)
• Recent remineralization trials of a dying forest on Mt. Mitchell, showed that 12 weeks after application of rock dust, height growth of red spruce seedlings was increased by 27% over non treated controls, and 19% for Fraser fir. The appearance of the treated trees was that of a very dark green color with good flushing of 1991 tissues, whereas untreated controls appeared to be somewhat yellow and chlorotic. (Dr. Robert Bruck, North Carolina, 1991)
The concept of soil remineralization:
It consists of returning to the soil the vital minerals and trace elements that have been removed over time by erosion, leaching, harvesting and grazing. To overcome this gradual depletion of minerals ‑ wearing‑out of the soil, in effect ‑ it is possible to restore fertility (to fertilize) by direct application of mineral‑rich material, typically a finely ground glacial moraine, feldspar or other rock dust.
SR has been practiced, studied and written about for more than 100 years. The Survival ofCivilization, an early 1980s book by John Hamaker and Donald Weaver, is widely credited as the most important recent factor in raising the world’s awareness of the need for extensive remineralization of the earth’s soils.
The authors note the causes and the implications of an alarming rise in atmospheric carbon dioxide levels in recent years, which they believe will trigger the next Ice Age in a very few years. They go on to examine this deterioration of the atmosphere in terms of its frightening connection to the long‑term degradation of once‑mineral‑rich soils. Hamaker and Weaver then build a strong and comprehensive case for reversing the threat of these destructive developments through a process of massive remineralization of the earth’s soils. Although their forecasts are dismissed by some as unduly alarmist and too immediate, the implications are enormous and global, going well beyond mere nutrition and crop yields ‑ to the preservation of viable atmospheric and climatic conditions for the earth, and indeed, to mankind’s very survival.
Traditional participants in the practice, promotion and investigation of SR have been a polyglot assortment of organic gardening and environmental enthusiasts, a few rock dust suppliers, government agencies and commercial producers of crops and livestock, sustainable agriculture advocates, and a number of professionals in agriculture, forestry and soil science.
Interest in the merits of SR has begun to broaden beyond this small band of devotees in recent years, and there are increasing signs that mainstream agriculture ‘and forestry are belatedly beginning to pay attention. New trials and investigations of the potential benefits of SR are underway or being initiated in a number of countries.
In this era of diminishing resources and growing concern for the long‑term health of our planet, many organizations in agriculture, government and industry are beginning to reexamine ‑and change ‑their traditional methods and practices, for environmental soundness, sustainability, conservation, efficiency and in some cases, a more positive public image.
We believe those environmental pressures, population growth, and the need for more intelligent management of the earth’s productive food and forest resources will be major driving forces in the times ahead. These factors provide a compelling case for the accelerated acceptance and application of SR in mainstream agriculture and forestry over the next several years. Therein lie substantial opportunities.
* Alternative descriptive terms for SR include Agrogeology, Natural Fertilization. Rock Fertilization, Soil Amelioration, Mineral Balance Restoration, Soil Regeneration, Mineral Fertilizing, Stone Flour Fertilization, etc.
The Case for Soil Remineralization
Since the 1800’s, many farmers and gardeners, foresters, geologists, agronomists and others have sought to grow better crops and trees by improving or restoring the inherent fertility of soils. In the process, they have conducted a multitude of studies and field trials, modifying soil conditions through the addition of finely ground mineral matter, and measuring the effects on the quality and quantity of the crops and forest products produced. These researchers have provided a wealth of data, which modern agriculture has largely chosen to ignore, but which may well provide the foundation for the next Green Revolution. Following are a few basic observations on these efforts:
• The incredibly complex and variable nature of the earth’s soils determines the types of plant life that can be supported, and how well or poorly those plants perform under given weather conditions. In remineralization trials, plant responses reflect, among other things, the effects of five key variables: (1) type of rock, (2) fineness of grind, (3) type of soil, (4) type of plants, and (5) the possibility of harmful components. An appreciation of the potential benefits of SR requires a thorough understanding of these variables, and recognition of the shortcomings of current agricultural practices.
• Agricultural and forest soils do indeed undergo steady depletion of the vital minerals bestowed upon them by retreating glaciers from the last Ice Age, to the point where these elements are ultimately unavailable for uptake to trees or crops, animals, and human beings. Mineral deprivation is particularly evident in the low fertility of the tropical laterite soils not endowed by glaciers; but mineral depletion is also becoming a significant factor limiting the quality and quantity of crop and tree production on the better soils of temperate regions.
• As mineral depletion proceeds, growing conditions for plants of all kinds become more stressful. Symptoms of this increased stress are diminished vigor, poorer root development, slower growth, lower resistance to disease, insects, frost and drought, reduced yields, and declining nutritional values. In extreme cases, plant and tree survival rates decline, agricultural failures begin to occur, and dying forests appear.
• Modern agriculture’s use of conventional technology employing large annual applications of NPK fertilizers and a variety of pesticides, crop rotation and cover cropping, and irrigation (sometimes coupled with micro nutrient feeding) may overcome some of these stresses on a year to year basis. But these practices fail to address the fundamental longer term problems of worn out soils. As a result, they are at best, expensive quick fixes, and well known detrimental side effects accompany some of them.
• When a wide range of vital minerals and trace elements is restored to the soil through SR, these stresses are reversed, and plants respond positively, sometimes dramatically. While amateur advocates of SR point to the much better tasting fruits and vegetables grown in remineralized soils, many scientific studies have documented improved mineral content, better root development, hardier foliage, faster growth, and greater resistance to disease, insects, frost and drought.
• The reports of some of these studies also show reduced requirements for conventional NPK fertilizers; a dramatic lowering or elimination of pesticide use; and less need for irrigation, reflecting better moisture retention properties in the remineralized soils.
• This growing body of evidence is based on a host of investigations over more than a century, and is supported by many pieces of anecdotal evidence. It suggests that well executed programs of SR can
offer not only tangible near term benefits to the practitioners, but, just maybe, a healthier and better planet for mankind.
To summarize the impact of remineralization on soils and crops, SR:
|• Causes phenomenal growth of micro organisms in the soil
• Raises the moisture and nutrient storage capacity of the soil
• Makes mineral nutrients readily available, increasing their intake by plants
• Provides sustained release properties
• Counters the effects of soil acidity
• Reduces soil erosion
• Contributes to the building of precious humus complexes
• Improves resistance to insects, disease, fungus, frost, and drought