Steve Jenkins, age 14, of Dallas, North Carolina, for his question:
How does fertilizer make plants grow?
As we grow aware of pollution, we are led to take a new look at our basic attitudes toward the earth and its systems of ecology. In this department, nothing is more basic than the soil that supports the plant world which in turn supports itself and the entire animal world. Reliable researchers already suspect that our present methods of fertilizing and tending the soil are not what they should be.
The Green Revolution, of course, is rooted in the rich earth, and progress depends upon how well we understand the soil and what it needs to grow healthy plants. Our crops need air and moisture and sunlight, all of which nature provides in abundance. They also need a balanced diet of mineral plant foods. These they absorb from the soil and build them into their cells. When we harvest the crops, the soil is left with fewer nutrients for next year's crops. So we renew it by adding fertilizers that contain the lost ingredients. Or so we hope.
Nature restores the soil with a continuous recycling system. The lost ingredients are remodeled in subtle ways, first by the plants which absorb them and later by animals who eat plants and each other. Eventually these remodeled ingredients become what we call waste materials. Nature, however, treasures these so called wastes. In the good earth, teeming bacteria and other organisms wait to attack them. As they rot and decay, they are broken down again into those original basic plant foods.
In bygone days, farmers fertilized their fields with manures and such to help hasten nature's recycling process. In modern times, experts invented shortcuts. They listed nine or so ingredients absorbed by all plants, reduced them to basic chemicals, called them fertilizers and dumped them on the soil. For a while at least they got bumper crops. But old timers claimed the food had less flavor and recent researchers suspect it is less nourishing. Perhaps those experts forgot a few things.
Certainly these crude chemical fertilizers fall far short of the subtly balanced diet needed by each plant species. They include no crumbly materials to make the soil porous for healthy roots. And some of the strong chemicals destroy decay bacteria, worms and other useful organisms in the soil. Nature, apparently, abhors crash programs of this sort. But she patiently waits for us to help improve her time tested recycling program.
It is time now to let nature teach us about fertilizing and rebuilding our soils. It is time to stop wasting our so called wastes and calling them pollutants. For example, we can return our sludge, fallen leaves and treated sewage to the fields. There nature will gladly recycle them into fertilizers that really enrich the soil to grow our crops.
Some people call this ancient and modern system organic farming. Organic gardeners recycle their wastes in a marvelous, self operating thing called a compost pile. There the kitchen garbage, old leaves and other precious wastes, good old dirt and a few worms are left to remodel themselves into a pile of super enriched soil. The Green Revolution needs compost piles.