28 SHADE IN COFFEE CULTURE. 



to the planter's interest not to bare the land entirely, but rather by careful selection 

 to retain and make use of the forest trees already in possession. The finest shade, 

 with the least exhaustion to the soil, is provided by deep-rooted umbrageous tr^es 

 growing at 60, 80, and even 100 feet apart. Specimens of this description are suffi- 

 ciently abundant in the virgin forest, and planters should always utilize them when 

 making new clearings. It is under shade of this sort, with perhaps a little secondary 

 planting here and there to fill up gaps, where one sees the finest coffee. 



It is true that most saplings will soon establish their leading roots in the subsoil at 

 depths far beyond the reach of the coffee bush, and as they increase in size this 

 tendencv to draw nourishment from the substratum increases until in many fully 

 developed forest trees surface rooting is reduced to a minimum. All other condi- 

 tions being favorable, it is deep-rooting trees of this class that should be preferred to 

 shade coffee. The only exceptions would be in the case of fig trees, which (proba- 

 bly from their quasi-parasitic nature) do not appear to exhaust the soil to the same 

 extent as other shaders, and leguminous trees, which assist nitrification in the sur- 

 face soil. 



Of course it is hardly to be supposed that the shade of leguminous 

 trees is more " nitrifying " than the shadows cast by any other objects; 

 but that the positive contribution of the leguminous trees to the fer- 

 tility of the soil was not appreciated, is evidenced by the fact that the 

 author's investigations resulted in the approval of the current method 

 of mixed shade, over twenty trees being listed as in use. But as eight 

 of these, including those most commonly used, are leguminous it is 

 evident that the facts will bear a different interpretation, and that in 

 the East Indies theory and practice are still a stage behind Venezuela 

 and Colombia, where only leguminous trees are recommended for shade. 



But whatever be the cultural possibilities of "nitrification" either 

 by genuine soil organisms or by those symbiotic with leguminous 

 plants, it seems probable that such agencies are to be considered merely 

 as the most effective means of maintaining the fertility of the soil, 

 coffee not being necessarily dependent on organic products or remains. 

 Like many other plants, coffee makes extremely vigorous growth on 

 soil from which the humus has been burned away hy the method of 

 clearing b} T fire usual in heavily forested tropical countries. The 

 fertility of such soil for the first two or three } 7 ears is commonly 

 ascribed to the ashes, but it seems not unlikely that larger quantities 

 of plant foods may have been liberated and rendered soluble in the soil 

 calcined by the fierce heat developed in the combustion of the large 

 masses of dry vegetation. The belief is general among the natives of 

 West Africa that the success of the subsequent agricultural operations 

 depends upon the size and thoroughness of the conflagration. Thus 

 they open new farms each year in the dense forest, and submit to the 

 hard labor of cutting the large timber rather than avail themselves of 

 areas which could be much more easily cleared, and state, as an 

 explanation of this preference, that the former will "burn better." 



Crops planted immediately after the burning shoot up at once into 

 vigorous growth, presumably long before soil organisms would have 



