402 BOAKD OF AGRICULTURE. [Pub. Doc. 



the period of time in which the crop makes its growth. 

 These figures, of course, only represent averages. In very 

 moist times evaporation would be checked, and in dry times 

 it would be increased. In other words, at times when the 

 plant uses water most rapidly there is the least available 

 amount from the rainfall. 



Professor King of Wisconsin has shown that the amount 

 of water transpired through the foliage and evaporated from 

 the soil by some of our common crops is as follows, when 

 estimated on the basis of dry matter in the crop and one 

 acre in area : — 



Dent corn, per ton of dry matter,. . . 2.64 inches. 



Flint corn, per ton of dry matter, . . 2. 14 inches. 



Red clover, per ton of dry matter, . . 4.03 inches. 



Oats, per ton of dry matter, . . . 4.76 inches. 



Potatoes, per ton of dry matter, . . . 4.73 inches. 



If we assume a fair yield of red clover to be 10 tons per 

 acre (green), with 25 per cent of dry matter (equal to 2^ 

 tons per acre) , the clover crop would use about 10 inches 

 of water in its growth. An acre of dent corn yielding 15 

 tons green, with 25 per cent dry matter (equal to 3% 

 tons), would use during its period of growth 10.6 inches 

 of water. As shown in the table of rainfall previously 

 given, the average rainfall for the past fourteen years from 

 about twenty localities in Connecticut for the months of 

 June, July and August is only 11.3 inches, and no account 

 is made here of water lost by leaching. 



The one important lesson that these results do point out 

 is the large amount of water used in the growth of plants, 

 and the need of conserving the stores in the soil or of add- 

 ing an artificial supply when the rainfall is below the 

 average. We know of no extensive experiments showing 

 the amount of water used by small fruits, but all crops 

 which produce a heavy growth of foliage transpire moisture 

 rapidly. A crop like strawberries, which makes a heavy 

 growth of both foliage and fruit in about two months, 

 must use immense quantities of water. 



The discussion of the large amounts of water used by 

 plants naturally leads to the consideration of the third point, 



