Silent Spring: Chapter 5,6
Summary of Chapter 5: Realms of the Soil
Without the soil, plants and animals could not survive. Soil was created over millennia by the interaction of volcanoes, flowing water, ice, and lichens. The soil is not dead but full of living things. Many organisms keep it alive and healthy, and in constant change, in nitrogen-fixing cycles. Bacteria, fungi, and algae are the microscopic plant life and agents of decay, reducing elements to their rich compounds and minerals. Insects play their part in the decay of vegetable matter. The earthworm is of prime importance to soil health, adding over an inch of topsoil in a decade and aerating the earth. Chemicals are carried down into the realms of the soil and affect these communities of life. It is not possible to kill only one kind of insect without killing beneficial organisms as well. The herbicide 2,4-D, for instance interferes with the nitrogen cycle. The metabolic activity of the soil is affected, and insecticides like aldrin and chlordane remain in the soil for years. Repeated sprayings build up residues. There is the problem of both the poisoning of the soil and the plants that grow in the contaminated soil.
Commentary on Chapter 5: Realms of the Soil
This short chapter gives examples of crops in the South that had to be destroyed because they contained too many pesticides. The most alarming news is that some chemicals remained in the soil even fifteen years after being used. The Department of Agriculture first recommended pesticides like heptachlor and then had to withdraw approval. Many growers sued, trying to recover their losses.
Summary of Chapter 6: Earth’s Green Mantle
Plants harness the sun’s energy and manufacture the nutrients for all the earth’s beings. Humans have a narrow idea of plants, thinking of some as immediately useful and others as weeds in the way. Vegetation forms a web of life that we need to approach with humility. Carson give the example of the lands in the West where there is a campaign to destroy the sage and plant grassland in its place. Sage is natural to the area, holds soil and moisture. Many animals like antelope and grouse eat sage. The low shrubs are places for nesting. The sage is evergreen and provides winter grazing for deer. Yet sage has been eradicated by spraying, which will make these animals suffer. Justice William O. Douglas has written a book on the destruction of sagelands in Wyoming by the U. S. Forest Service. Willows were also killed that supported moose and beavers. Trout and waterfowl were once plentiful, but all those animals disappeared when the sage and willows were devastated by spraying.
She gives many examples of land management by blanket spraying being supposedly cheaper than mowing. Tourists notice, however, the wilderness roads that were once beautiful with wildflowers and native shrubs have become barren and ugly with herbicides killing the roadside “weeds.” Hedgerows provide food and shelter for many species, and for wild bees and other pollinators. Selective spraying around highways as a safety factor can be done so that it does not need to be repeated. Herbicides such as 2,4-D are used by people for their lawns but have been shown to disrupt cell respiration and damage to chromosomes.
There is a relationship between the so-called weed and the soil. Some plants considered weeds, such as marigolds, are natural insecticides and kill soil nematodes. Such plants as ragweed, causing allergies, have been blanket sprayed, without the understanding that the ensuing open space allowed them to come back stronger than ever. There are also better ways to control crabgrass than spraying.
Commentary on Chapter 6: Earth’s Green Mantle
One effect of this chapter is to make the chemical sprayers look ignorant. The chemical approach has too often not been well thought out or informed by a knowledge of the target plants. The results have been dangerous, wasteful, and unsuccessful. The anecdotes display human arrogance. She gives examples of successful management through introducing other species of plants, and by introducing plant-eating insects.