YAM CULTURE IN PORTO RICO. 
CONTENTS. 
Page. 
The yam as a food crop in Porto Rico_ 3 
General practices in yam growing- 4 
Treatment of seed roots 6 
Distance apart to plant — r 7 
Tests with fertilizers 8 
Page. 
Tests of vine pruning 10 
Harvesting 11 
Varieties and cultural treatments 
recommended 11 
Conclusions 21 
THE YAM AS A FOOD CROP IN PORTO RICO. 
The yam is one of the important foods of Porto Rico, and among 
the root crops is second in this respect only to the yautia. The quan- 
tity consumed is far greater than of either the Irish potato or the 
sweet potato. It is found in nearly ever}' family garden in Porto Rico, 
because it is well adapted to most soils of the island and is almost en- 
tirely free from destructive insect pests and plant diseases. Notwith- 
standing its importance and wide local distribution, very little has 
been written regarding its culture, at least so far as this has a bear- 
ing on the agricultural conditions of Porto Rico. Planters are so 
sure of obtaining a fair yield that they have developed to a large 
degree a tendency to be content with a moderate crop from a mod- 
erate outlay. Practically the entire production is for home con- 
sumption. 
With the great increase in price of all food products, the yam, 
which is still among the least expensive of the food crops, is more 
in demand than formerly. Yet, despite the fact that high prices for 
foods have prevailed and the local consumption of the yam has been 
stimulated, its use in other countries has increased but little. If 
properly handled, however, it might be shipped to other markets 
with little fear of loss by deterioration. In the continental United 
States the yam is rarely purchased by any other than people from 
the Tropics, and it is still practically unknown. In the Southern 
States the name " yam " is commonly applied to a certain type of 
sweet potato, which, however, is a different plant. The high food 
value of the yam, due mainly to its very large starch content, the 
many ways in which it can be prepared for the table, and its low 
cost should serve greatly to stimulate extension of its use. 
