b SHA.DE in coffee culture. 



increase of nitrogen among the incidental advantages possible under 

 the shade system, this simple interpretation of the general problem 

 seems never to have been made, and the practice of growing coffee 

 under shade is still defended on grounds at once illogical and insufficient. 



Without denying that shade may be a necessity in a few instances 

 when coffee is grown in arid regions like parts of Arabia and Mexico, 

 it is evident that the persistent and increasing use of shade in the moist 

 tropics is irrational and unjustifiable on the basis of an} T existing 

 theories. If the increased fertility of soil through leguminous trees 

 be left out of account the adverse opinions of Dafert and other scien- 

 tific investigators must be admitted as justified, and shade must be 

 condemned as a cultural error of huge practical dimensions. If, on 

 the other hand, the nitrogen fixed in the soil by the bacteria of the 

 root tubercles of the leguminous shade trees be held as a factor of 

 prime importance, to which other alleged advantages of shade are 

 negative or merely incidental, estimates of the relative wisdom of 

 existing systems of culture are entirely changed. New lessons from 

 the past and new experiments for the future suggest themselves, and 

 it becomes apparent that scientific coffee culture holds possibilities as 

 unsuspected as they are unrealized. 



The question of shade in coffee culture is fundamental, in the sense 

 that from the clearing away of the forest to the harvesting of the 

 crop the operations of the plantation are largely influenced or deter- 

 mined b}^ the presence or absence of shade trees. The selection of 

 suitable sites for plantations, whether the forest shall be completely 

 destroyed or merely thinned out, which trees to leave for shade, or 

 which to plant in advance of the coffee, how to lay out the plantation, 

 the spacing of the trees, the drainage, cultivation, catch crops, soiling 

 crops, weeding, fertilizers, and irrigation — none of these details can 

 be intelligently dealt with until a decision has been reached in the 

 matter of shade. Not that a general decision for or against shade 

 is to be expected; shade is a cultural question which each planter must 

 decide from the study of his local conditions. There are soils and 

 climates where shade trees are unnecessary, or even harmful; there are 

 others where leguminous shrubs or herbs can be utilized to much bet- 

 ter advantage than trees, but in the broken and mountainous regions, 

 where a large proportion of the world's coffee crop is grown, and in arid 

 regions, where a great extension of the industry is possible, legumin- 

 ous trees have, and will doubtless continue to have, enormous agricul- 

 tural importance. To determine the true extent of the utility' of shade 

 trees and of the different kinds of trees adapted to this purpose is a 

 scientific problem which should receive early experimental attention. 



In many coffee-growing regions, such as Porto Rico, steep slopes 

 and heavy rainfall forbid agricultural methods similar to those gener- 

 ally employed in temperate regions. The soil can not be stirred lest 





