FIELD CROPS. 45 



Sugar-cane experiments in the Leeward Islands, 1902-3, F. Watts (Imp. 

 Dept. Agr. West Indies, Rpt. Expts. Antigua and St. Kill's, 1902-3, II, pp. 115; abs. in 

 Imp. Dept. Agr. West Indies, Pamphlet 30, j>/>. 78). — The results of an extensive series 

 of fertilizer experiments are tabulated in detail. The series consisted of 36 tests, and 

 each was repeated 8 times with plant canes and 6 times with ratoon canes. The 

 conclusions and recommendations based on the results are briefly summarized as 

 follows: 



"Plant canes, when the field in which they have been planted has been properly 

 tilled and manured with pen manure, require no artificial manure. "When the soil is 

 in good condition, but it has been found impossible to give the proper dressing of 

 pen manure, then artificial manures may prove remunerative: Under these circum- 

 stances it is suggested that either li to 2 cwt. of sulphate of ammonia, or 2 to 2| 

 cwt. of nitrate of soda be given in one application. A small additional profit will 

 probably follow from the use of f to 1 cwt. of sulphate of potash together with 

 phosphate, either lh to 2 cwt. of basic phosphate, or a similar amount of superphos- 

 phate. All of these manures should be given early. 



" For ratoon canes nitrogen is very necessary, and this may take the form of 2 to 

 3 cwt. of nitrate of soda, or lh to 2h cwt. of sulphate of ammonia. Remunerative 

 results will be obtained without the use of potash or phosphate, but a small additional 

 profit may be expected from their use; f cwt. of sulphate of potash, and Ik to 2 cwt. 

 of either basic phosphate or superphosphate may be employed. It is quite clear, 

 however, that nitrogen, in a rapidly acting form, must be used if good ratoon crops 

 are to be grown." 



Dividing the nitrogen into 2 applications proved detrimental, the effect being more 

 marked where both potash and phosphoric acid were given with the first application 

 of nitrogen, and much more so when potash alone in considerable quantities was 

 applied at that time. 



A comparison between the tonnage of canes and the pounds of sucrose in the 

 juice is reported for plant canes and ratoons, and the conclusion is drawn that "the 

 same inferences for the guidance of the planter would be arrived at by argument 

 derived from the tonnage of cane as from the weight of sucrose." The kind of 

 commercial fertilizers used seemed to have affected the quantity of the sugar in the 

 cane but slightly. Nitrogen mixed with potash and phosphoric acid showed a slight 

 increase of sucrose per ton of cane and when used alone a slight decrease. There 

 was no indication that phosphoric acid increased the sucrose per ton of cane. In the 

 ratoon canes the variation was somewhat greater than in the plant canes. 



The conclusion is drawn "that manures in such quantities as are likely to be used 

 in ordinary practice in the Leeward Islands exert their influence chiefly in altering 

 the weight of cane per acre without profoundly altering the weight of sucrose to the 

 ton of cane." 



Report of the agricultural work for 1901-1903, J. P. d'Albuquekque and 

 J. R. Bovell (Rpt. Agr. Work, Imp. Dept. Agr. West Indies, 1901-3, pp. 121).— The 

 results of fertilizer experiments with sugar cane on different plantations are tabulated 

 in detail and briefly discussed. 



At Dodds the best yields were obtained from a plat fertilized at the rate of 30 tons 

 of barnyard manure, 40 lbs. of nitrogen as dried blood, of>.ti4 lbs. of phosphoric acid 

 as superphosphate of lime, and 60 lbs. of potash as sulphate of potash per acre. This 

 plat produced 34.7 tons of cane per acre, or 10 tons more than the no-nitrogen plat. 

 Basic slag proved more effective than superphosphate of lime. Sixty pounds of pot- 

 ash in the form of the sulphate, applied one-half in January anil one-half in June, 

 gave the highest increase of the potash applications. A plat which had received 50 

 tons of barnyard manure yielded 33 tons of cane per acre, and this result is believed 

 to indicate that this application will maintain the yield without the use of commer- 

 cial fertilizers. 



