The Water Problem in Agriculture

Abstract

THE increasing use of artificial manures and of improved tillage implements has rendered possible an increase in the amount of produce obtained from a given area of land, and attention has during the past few years been directed to another factor, the water supply, which at present limits crop production in a number of cases. The amount of water actually transpired through the crop depends on too many circumstances to be stated with precision, but it may be roughly estimated at 300 Ib. or more for every pound of dry matter produced, so that if two tons of dry matter is produced per acre, at least 600 tons of water, equal to 6 inches of rain, will be used in transpiration, quite apart from what is lost by evaporation, percolation, &c. A crop of this size is by no means excessive; indeed, in some types of intense cultivation three times as much produce would be aimed at. Even in England the problem is often serious; it is far more so in countries where the rainfall is deficient during the whole or part of the growing season.