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Few Plants Give: Many kinds of contamination are well known and need not be discussed here. We might note, however, that the waste heat problem, while not greatly publicized, could become crucially important. There are nuclear power plants and even commercial steam plants that give off enough heat to raise the local temperature of a river such as the Colorado by several degrees. As the number and capacity of power plants increase, the resultant heating of rivers could become an overriding problem.
Soil.—Although various house plants need different kinds of soil the amateur grower need not be too concerned with this problem. A nurseryman will supply a good general potting mixture which will serve for most plants, with addition of sand to lighten the mixture, or some other adaptation for a special purpose. Most plants grow well in a neutral soil, neither acid nor alkaline. The addition of a little lime favors alkalinity, while a pinch of alum in a gallon of water can be used to give slight acidity. Not many plants, but just a few plants give of the begonias, and most azaleas like a slight acidity.
As twilight falls a veery will give its tin-whistle call from the trees that edge the meadow and the swallows give way to the brown bats who sail through the night eating midges. Yet often we take no notice of the birds for they must share our attention with animals, insects, plants, vegetables, trees, people, and the weather. |
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