602 EXPERIMENT STATION RECORD. 



sunshine on plant development, this knowledge will be utilized in 

 making the daily, weekly, and monthly bulletins of greater value. 



But in addition to these efforts in the application of meteorology 

 to the needs and interests of agi"iculture, more intimate and system- 

 atic studies are now to be inaugurated upon the relation of the 

 environmental factors embraced in climate to the growth of plants 

 and the production of crops. These studies will relate not only to 

 the limiting factors of the season as affecting the application of 

 special crops or varieties to a region, but to the effect of weather and 

 climate upon the factors of plant growth. The latter studies will 

 for the present take the form especially of investigation of the criti- 

 cal periods in the development of plant life. 



It is planned to conduct these studies by two general methods: In 

 the first method the crop yields will be correlated with the weather 

 conditions that have prevailed during a long period of years, by 

 means of charts and correlation tables. The other method contem- 

 plates a systematic record of the temperature, rainfall, sunshine, and 

 evaporation, taken in connection with observations upon the develop- 

 ment of certain agricultural plants, the time at which definite stages 

 of growth are reached, etc. In other words, the attempt will be 

 made to determine by direct experiments the critical periods of 

 growth and the effect upon them of varying meteorological factors, 

 as well as the susceptibility or response of the plants at these dif- 

 ferent periods. 



This type of studies is especially planned to be carried on in close 

 cooperation with the agricultural experiment stations. To that end 

 the "Weather Bureau is soliciting the cooperation of the stations, in- 

 viting suggestions as to the plan as a whole, special methods to be 

 followed, kind of data to be taken, etc. It is aimed to make the 

 cooperation a real one in every sense, pertaining to the development 

 of the plan and methods as well as to the field observations and the 

 handling of the results. 



This is a matter in which the experiment stations are in position to 

 render verj^ material assistance. They have fields for experiment 

 with agricultural crops, and can provide the proper conditions for 

 experiment and for the accurate recording of data. The field of in- 

 quiry is one which naturally interests them, and there will be marked 

 advantage from the provision of a central agency to give unity and 

 continuity to such studies distributed over the country. It is to be 

 hoped, therefore, in the interest of the new undertaking, that there 

 will be quite general response to the proposal for cooperation. 



Other branches of this Department, notably the Bureau of Plant 

 Industry, have been for some time conducting studies relative to the 

 water requirement of crops, drought resistance, and the effect of 

 various environmental factors on plant growth. These have a ditect 



