LII REPORT OF THE SECRETARY OF AGRICULTURE. 



of the specialization of agriculture and a principal cause of the local 

 importance of certain districts for special crops, such as truck, tobacco, 

 and fruit, as well as for the distribution of such farm crops as corn, 

 wheat, and grass. The recognition of this fact is largely the basis of 

 the soil survey and for the highest prosperity of agricultural commu- 

 nities. Furthermore, it is a well-known fact that the degree and char- 

 acter of cultivation has a marked effect upon the moisture supply of 

 the soil, and thus controls in no little degree the climatic conditions 

 under which the crop is grown. 



In certain sections of the countr} r and on certain soils, notably in 

 California and the Northwestern States, the condition of the soil for 

 various crops and the probable yield can be fairly estimated from the 

 water supply in the soil some weeks, or even months, before the 

 harvest. 



In former reports attention was called to the progress made in the 

 perfection of instruments for recording the moisture contents of soils 

 in the field and for determining the tendency to evaporation or loss of 

 water from plants for which an adequate moisture supply must be 

 maintained. Stations were established in different parts of the coun- 

 try and on important soil types for these moisture records. From these 

 records it was possible to show the normal variations which could 

 occur in any soil between the conditions of excessive wet and drought, 

 and the possibilities were pointed out of determining a numerical rela- 

 tion between the soil moisture and the sunshine, temperature, humidity, 

 and wind velocity which would enable the climatic condition to be 

 expressed by some figure representing the relative condition of plant 

 growth at any place in terms of the most favorable conditions. This 

 is in no way covered by the work of the Weather Bureau, which is 

 concerned largety with dynamic meteorology, or the laws and predic- 

 tion of storms, and will involve an entirely different equipment and 

 an independent set of observations, taken in the fields and soils of 

 growing crops rather than in cities and towns. 



The value of such observations, taken by a corps of experts trained 

 to observe and understand plants as florists understand greenhouse 

 plants, can not be estimated. Reports based upon such observations 

 in a period of drought, such as the Middle West has just experienced, 

 would show the actual conditions existing far more accurately than is 

 now possible. Furthermore, as the drought limit is approached in any 

 soil suggestions can be made for preventive measures in cultivation 

 or cropping which may save many bushels of grain on any farm, which 

 in the aggregate for all the farmers who would heed the warnings sent 

 out from Washington would save an immense sum of money to the 

 agriculturists. 



The time has come when this work should be again taken up on a 



