Putting Nutrients Back into the Soil

DO YOU live in a food-growing area? If so, desert and famine conditions may seem like hundreds, even thousands, of miles distant. But that is not true.

Really, food shortage is no more than inches away from any place on earth.

It is only as far removed as the depth of the soil. Should a few vital inches of topsoil be removed from the earth, all life on it would eventually end.

Actual soil erosion is stealing much precious topsoil earth wide. For instance, African nations admit that soil erosion is a major problem. Says the Ethiopian Herald: “Tons after tons of earth are washed away every day from our highlands to neighboring countries so that our fields are gradually becoming sterile. With low fertility they can provide only low yields.”

But soil effectiveness can be crippled in another way: Nutrients can be taken from it and not be replaced, thereby greatly diminishing its ability to grow crops. To understand how this can happen requires that we first of all understand the makeup of soil.

What Is Soil?

Soil is, according to one simple definition, where food is grown. Experts know that not all soils are the same; each has its own history and unique value.

Ordinarily, geologists assert that soil comes from rock that has been ground down through millenniums of time, producing in the process vital minerals for the soil. No human, of course, was around to witness this assumed lengthy process. It is said that rock slowly crumbles under the influence of water and weather and other conditions. Obviously such things do have an effect on even the most stubborn rock. But are the vast periods of time that geologists talk about really necessary to have produced soil?

Not all geologists seem to think so. Thus in 1963, when the island of Surtsey was born in the Atlantic Ocean, National Geographic magazine reports: “Surging surf ground jagged lava into rounded boulders with a speed that astonished geologists attending Surtsey’s birth.” A few years at most, not countless aeons of time, was all that was involved. Also, volcanic ash accounts for much of the fertile soil of Indonesia and other lands, and it, too, is deposited quickly.

Most importantly, the Bible indicates that earth’s soil was formed rather quickly. It speaks of the dry land and vegetation as all appearing within one creative “day”​—a period that the Bible indicates was seven thousand years in length. (Gen. 1:9-13) Appropriately, The Encyclopedia Americana asks: “How long does it take to produce an inch of soil​—an inch of fine rock material that supports plants? One may say a few minutes or a few million years. It all depends upon the exact spot and what stage in the cycle we reckon from.”

Of course, there is much more to soil than just ground-up rock. Otherwise it would be like sand, unable to maintain plant life of any size. To grow plants soil must have humus; humus is produced as plants and animals die and their remains decay. Valuable nutrients that will nourish later plants and animals result from this process of death and decay. Animal droppings also supply nutrients.

How Nutrients Are Produced

All together, it appears that at least sixteen elements are needed for plant life to be sustained. Three of these sixteen are taken from the air: carbon, hydrogen and oxygen.

But the other thirteen come from the soil: phosphorus, potassium, nitrogen, calcium, magnesium, iron, sulphur and traces of boron, manganese, copper, zinc, chlorine and molybdenum. The first three of these thirteen are considered “primary elements.” Where appreciable amounts of these thirteen elements are taken from the soil, they need to be replaced so that other healthy plants can appear in the future.

How does soil naturally act on dead organic material to make it usable by plants? Living organisms convert it into forms that can be employed by plants.

A thimbleful of soil contains billions of living organisms, each of which contributes to the vitality or fertility of the soil. In the top layer of soil is where most of these organisms thrive.

Among the larger ones are earthworms, considered the most valuable of all soil invertebrates. They not only break down much of the debris on the earth’s surface, but a]so turn the soil over and aerate it.

Highly productive soils a]so generally have an abundance of microorganisms, bacteria, fungi, actinomycetes, algae and Protozoans. When a plant or an animal dies, its sugars, starches, cellulose and similar compounds are consumed by certain of these organisms. They, in turn, produce carbon dioxide in the soil and also reduce the dead matter to a form that plants can use. When carbon dioxide combines with moisture, carbonic acid is formed; it, in turn, does some of the work of dissolving minerals in the soil.

Nitrogen is vital to the life of plants. It has been estimated by Harry A. Curtis of the Tennessee Valley Authority that there are about 34,500 tons of atmospheric nitrogen over every acre of land area; that makes up about four fifths of the atmosphere. However, plants cannot directly use this nitrogen in its free gaseous state.

Rather, it must be combined with other elements or “fixed.” One of the ways that nitrogen is fixed for use by vegetation is by means of microscopic plants living on the roots of certain plants such as legumes.

However, when men grow a large acreage of crops, a tremendous amount of nutrients is extracted from the soil. One experiment at a Maine agricultural station found that in an acre of potatoes there are about 143 pounds of nitrogen, 26 pounds of phosphoric acid, 232 pounds of potash, 56 pounds of calcium oxide, 30 pounds of magnesium oxide and 11 pounds of sulphur.

Obviously, to restore these nutrients more is necessary than just allowing matters to take care of themselves “naturally.” Otherwise the soil grows weak and, in time, actually becomes infertile. Expert care of soil will not only keep it fertile but result in maximum yields. How can nutrients be restored to farmland?

Restoring Nutrients to Farmland

The first thing that a soil expert will ask is: ‘What is the soil’s pH?’ But just what does “pH” mean?

Well, soils are put into two basic categories: acid or alkaline. On a scale of 0-14 those soils falling into the 0 through 6 category are acid, while those above 7 and through 14 are considered alkaline. Soils that are 7 are considered neutral, neither acid nor alkaline.

Some crops prefer soils that are somewhat more acid, and others, more alkaline. Lime, when added to the soil, makes it more alkaline, that is, raises its pH.

Even if all the thirteen nutrients needed by plants are in the soil, a proper acid/​alkaline balance is still necessary. Only in this way will plants be able to benefit fully from the nutrients that are in the soil.

Lime added to the soil does at least three things. It supplies needed calcium oxide. Secondly, it keeps some elements in check so that these will not poison the crop. Thus as the pH of acid soil is increased by adding lime, such elements as aluminum, iron, manganese, copper and zinc become less soluble. In more acidic soil the excessive presence of these elements will be harmful to crops, but as the pH of the soil is increased they become more inert. Thirdly, lime releases other elements that the plants can use to good advantage, while encouraging the growth of vital bacteria in the soil.

Since each soil is different, it is vital to consider what each one needs in the way of added nutrients. The primary ones, nitrogen (N), phosphorus (P) and potassium (K), are the substances represented by the three sets of figures on a bag of commercial fertilizer. For instance, 10-12-8 stands for the percentage of nitrogen (10%), phosphorus (12%) and potassium (8%) in the bag.

Where do these fertilizers come from?

Today many farmers and gardeners say that they prefer to use only “natural” organic fertilizers such as manure, sewerage, sludge and compost to provide needed soil nourishment. The use of these products has long been recognized as a fundamental way of returning nutrients to the soil while at the same time adding humus. It is still a very common way of fertilizing soil in Asia, Africa and Latin America.

But much fertilizing done in the Western world today is on a very large scale. It is not possible to provide enough organic fertilizer for these gigantic operations. Fertilizing just one acre of land can require fifteen tons of animal manure. Obtaining such amounts is virtually out of the question for most farming operations today. So what is the alternative? “Chemical fertilizers.”

Some persons claim that chemical fertilizers are harmful if used to promote growth of food for humans. But a report by the U.S. House of Representatives notes: “No reliable evidence was presented that the use of chemical fertilizers has had a harmful or detrimental effect on the health of man or animals.” Nor has it definitely been proved that such chemicals, if used properly, harm soil life. Even “organic” gardeners use some rock powder, including rock phosphate, potash rock and crushed limestone, to build up the soils.

One farmer who has relied on chemical fertilizers for many years reasons: “The plants do not care where the nutrients come from, just as long as they get them.” Similarly, honest “organic” gardeners know too that a balanced view toward plant nutrition must be maintained. Says Organic Gardening and Farming: “There’s little agreement among soils experts on the comparative merits of natural fertilizers (nor on chemical fertilizers either, if the truth be known). Natural fertilizer makers call university agronomists lackeys of the petro-chemical industry . . . University scientists retaliate by labeling soil-conditioning salesmen as hucksters selling bags full of magic and hot air. There is no doubt some truth in both criticisms . . . Honest men stand on both sides of the fence.”

But how do men produce the “primary elements,” nitrogen, potassium and phosphorus, in chemical fertilizers?

Their main source of nitrogen is synthetic ammonia. This comes as a result of combining nitrogen and hydrogen. Pure gaseous nitrogen can be obtained with relative ease by removing from the air oxygen and other gases. Hydrogen is a byproduct of petroleum. Synthesizing the two results in the needed ammonia. Some ammonia is put directly into the soil as a watery solution. However, most is converted into a solid and used by farmers and gardeners in that form. Most phosphates and potassium come from mineral deposits that are ground to the proper consistency.

Future of the Soil

Men have made and continue to make some very foolish mistakes in the way they deal with the earth. But, if properly cared for, the soil can produce crops indefinitely, even as noted in a Farm Journal editorial: “Soil that is properly fertilized and managed is not being used up. It is a renewable resource, as proved by the lands in Europe and Asia which have been cultivated continuously for thousands of years.”

Yes, this valuable “resource”​—a few inches of soil—​must be kept healthy to grant its greatest yield.