22 SHADE IN COFFEE CULTURE. 



few individual trees may show exceptional size and vigor when so situ- 

 ated that they can receive a mulch of leaves and slight shade, which 

 tends to keep the ground from becoming overheated. Thus perhaps 

 the finest plantations in Liberia are to be found in Grand Bassa County 

 on rather loose and open soil, and with the trees planted at such dis- 

 tances that the ground is mostly shaded. It is, accordingly, not at all 

 impossible that, even with Liberian coffee in its original home, the 

 limited use of a carefully selected leguminous shade tree might be 

 found advantageous. There are, of course, many native species, but 

 most of them are either of slow growth or they have a dense, compact 

 habit, so that the importation of desirable leguminous shade trees from 

 other countries may prove to be advisable. 



Whatever may be the facts regarding the ideal requirements of 

 Arabian coffee in the way of sunshine and shade, there seems to be 

 no room for doubt that with the Liberian species shade trees, if used 

 at all, will be emplo} T ed solely for their indirect or secondary effects, 

 namely, to protect the superficial layers of the soil against heat and 

 dryness, to provide for it a mulch of dead leaves, and to increase its 

 fertility b}^ means of root tubercles. Moreover, as there is in this 

 case no possible question as to the ability of the coffee to withstand 

 the sunlight, there is the greater warrant for believing that herbaceous 

 or shrubby plants may be found preferable to trees for shading the 

 soil and assisting in the formation of the mulch so useful in retaining 

 moisture. If a leguminous plant can be found which, like the Florida 

 beggar weed in the orange groves, will keep jiown the grass and add 

 fertility to the soil, the culture of Liberian coffee, at least, will be 

 revolutionized. It is also possible that the danger of fire, which men- 

 aces grass-grown plantations in the diw season would not be so seri- 

 ous in connection with leguminous vegetation. 



PROTECTION AGAINST EEOSION. 



There can be no doubt that where coffee plantations occup} T steep 

 slopes the existence of large trees would, other things being equal, 

 tend to keep the surface soil in place and maintain its fertility. If, in 

 addition, the trees belong to the Leguminosae, and make a direct contri- 

 bution to the nitrogenous content of the soil, the beneficial results 

 sometimes ascribed to shade culture are no longer incomprehensible, 

 even though it be still maintained that the direct effects of the shade 

 itself must in many instances be negative. In Porto Rico the question 

 of keeping the soil in place is a very important one, since many of 

 the plantations occupy slopes of surprising steepness, much greater 

 in fact than could exist with similar soil formations in temperate 

 regions. Without being the least rock} T , Porto Rican hillsides some- 

 times maintain themselves at angles of considerably more than 45 

 degrees from the horizontal. This is possible only because the red 

 clay and underlying hardpan are extremely firm and tenacious, so that 



