168 



TBINIDAU AND TUB AGO BULLETIN. [XVIIL 



FOOD CROPS. 



EXPERIMENTS ON YAM CQLTIVATION 1918-19. 



r._v Joseph de Verteuil, F.I.C, F.C.S. 



Superintendent of Field Experiments 



and L. A. Brunton, 



Assistant Superintendent of Field Experiments. 



During the season of 1918-19, the previous year's experiments on 

 yam cultivation at St. Augustine Experiment Station were repeated 

 and two additional experiments added viz :— (a) staking the vine 

 versus non-staking and (6) different size of plants. The results obtained 

 were as follows. 



Trenches and holes were dug eighteen inches deep and half the 

 width of the distances apart. For example trenches four and three feet 

 apart were dug two feet and eighteen inches wide respectively; holes 

 four feet by three feet and four feet by two feet were dug two feet by 

 eighteen inches and two feet by one foot wide. The weight of the 

 " plants " was approximately a quarter of a pound, unless otherwise 

 specified. The plants were put into the ground between June 10 and 

 14, 1918, and reaped between February 17 and March 20, 1919, i.e., 

 eight to nine months later. All the experiments were made with the 

 Barbados Lisbon varietv and the results given are the average of 

 duplicate plots. 



V.AUIETIES. 

 Three varieties, tlie 1 Barbados Lisbon, Horn and Red yams were 

 tried on duplicate plots. The following results were obtained : — 



The yield of tlic Horn yam is disappointing and practically ten tons 

 less per acre than that of the previous year, whereas the yield from the 

 Lisbon and Red yams was three and two and a half tons less respec- 

 tivelv. The Lisbon has again proved tlie most prolific yielder, having 

 given 5-8S tons per acre more than the Red yam. 



SELECTION OF PLA^NTS. 



The experiment to ascertain whether it \\as preferable to use the 

 top, centre or bottom portions of the tub-rs for planting purposes was 

 .again carried out. 



