Decreases in the yield of crops caused by weather are a large reason why we have prayed for our daily bread for the first time in a long time. Thus an article on climate stabilization was recently justified by mentioning food and agriculture thrice in the first paragraph) Although a growing world population has set the stage for our present tragedy, the playwright seems the weather. In 1970 a new pathogen, Helrninthosporiurn maydis, spread through most of the American corn crop in one year because the weather was moist and warm. The cold and drought of 1972 in the U.S.S.R. decreased wheat yields, and Russian buyers sopped up the American wheat surplus. In 1974 a late spring, a dry summer, and early frost defeated the American effort to produce an abundant harvest that would drive down food prices.
Despite the undoubted influence of weather on crops, mankind has not beat a path to the door of the agricultural meteorologists. In fact, we might agree with Mark Twain, who said that everyone talks about the weather, but no-one does anything about it.
Scientists have been studying the reaction of plants to climate at least since Reaumur calculated degree-days in 1740. For about a third of a century we have had Geiger's great book on the climate near the ground, and we have had phytotrons.
Still there has been little use of knowledge of the reaction of plants to weather. The farmer needs a machinery salesman, a fertilizer salesman, a pesticide salesman, a hired man and a banker. Few, however, have ever asked for an ag-meteorologist.
Times are changing, however, under the impact of new forces that are giving new utility to investigating the effect of climate on crops, making it a pre-eminent vista in the ecological view of agricultural systems.
The first force is a growing shortage of (i) land to grow crops upon and (ii) water to keep them turgid. In 1974 the balance in the American land bank approached zero, and in 1973 it was said, "Water is so important that the country can't afford.., to give it away or make it available at less than cost. ''2 Land and water shortages mean that agriculture will move into marginal regions and should know the response of crops to new environments.
The second force is the concern with pollution. Since the need for pesticides and fertilizers often depends upon weather, their conservative i w. W.