168 NINETEENTH HEPOHT. 



apply a formula and find that the peach, for examjjle, in a new region, 

 would come into blossom in tlie majority of years before the average 

 date of the last killing frost in spring, or if there were not sufficient 

 heat between the time of blossoming and the date of the average fall 

 frost, to ripen the fruit, then it could be positively stated that the grow- 

 ing of peaches should not be undertaken in that region. The Weather 

 Bureau records of temperature in tlie United States have been collected 

 from so many points and have covered a sufficient length of time to 

 make it possible to define the thermal conditions of small unit areas 

 throughout the country, witli great accuracy. What is needed is a state- 

 ment of the heat requirements of various crops and a method of evaluating 

 temperature records already established, in terms of tlieir efficiency to 

 meet the plant requirements. It will be necessary to consider eacli crop 

 separately as each has its peculiar characteristics as to minimum, 

 optimum and maximum heat requirements, for its growth and develop- 

 ment, and each is able to overcome unfavorable surroundings by 

 acclimatization. 



Swingle^, wIjo has made an admirable study of the climatic require- 

 ments of the date palm, has this to say in this connection : 



"It is confidently to be expected that in a few years this new branch of 

 l)iological and economic science which concerns itself with the determination of 

 the exact requirements of crop plants as to climate and soil, and with the finding 

 of the limits of their powers to resist unfavorable influences such as cold, excessive 

 lieat, drought, alkali, violent winds, etc., along with a study of the cultural re- 

 (juirements and market conditions of the new industry, will become so well known 

 and its value so well recognized, that it will be a comparatively simple matter 

 to enlist necessary capital and skill in a new culture when once the detailed life 

 history investigations have furnished a sound basis for judgment as to the 

 chances of its proving a financial success in any given region. ****** 

 Millions of dollars have been thrown away in attempts to grow crop plants in 

 regions where a ])ro})erly carried out life history investigation would have shown 

 there was no hope of success. Unfounded inflation of values of agricultural lands, 

 and the rush into new cultures in unsuitable regions, by whole communities at a 

 time, as the result of a 'boom,' could be largely avoided were it possible to furnish 

 the would-be planter with a black-and-white statement of the necessities of the 

 crop plants under discussion, whereby he would be able to question intelligently 

 whether the region were adapted to the proposed cultures. At present it is no 

 exaggeration to state that the life history requirements and the limits of the 

 power to resist unfavorable environmental conditions are far better known for 

 many microscopic lower plants, such as bacteria, fungi and algae, even for species 

 having no economic iinj)ortanee, than for the most inq)ortant crop plants whose 

 culture provides employment for tens of millions of human beings, and whose 

 ])roducts constitute the daily food of hundreds of millions. Such conditions are 

 discreditable alike to !)iologieal and to agricultural science and should no longer 

 continue." 



