18 



cation of the fertilizer on plat No. 11 was less efficacious, while the 

 fertilizers on plats Nos. 12, 13, and 14 were still less remunerative. 

 Plats Nos. 15, 16, and 17, however, gave good results; plats Nos. 18 

 and 19 fair results; plat No. 20 poor results; and plats Nos. 21, 22, 

 and 23 also good. 



Plats Nos. 12, 13, and 14 perhaps are the most instructive in Field 

 A, for they show that a complete fertilizer is absolutely necessary to 

 give the best results. To plat No. 12 no potash was added, to plat No. 

 13 no nitrogen, and to plat No. 14 no acid phosphate. The most 

 striking feature of this part of the experiment is that nitrogen is 

 shown to be the most deficient element in the soil of Field A. since 

 when no nitrogen was added the yield per acre was only a little above 

 1 ton more than when no fertilizer was added. The next most impor- 

 tant plant food to the crop is potash, and the third phosphoric acid. 



Turning to Field B, we find, of course, a different condition of 

 affairs, for in that field a natural fertility of the soil exists. On plats Nos. 

 12, 13, and 14 good crops were grown, showing that no fertilizing ele- 

 ment was altogether absent. Tn the blank plat the yield was about 33 

 per cent higher than in Field A. The fertilizers, as a rule, give larger 

 results on Field B than on Field A. For instance, 1,200 pounds on 

 plats Nos. 1 to 4, inclusive, Field B, produce an average }deld of 27.81 

 tons per acre that is, an increased average yield of 15.81 tons per 

 acre while on plats Nos. 5 to 8, 2,000 pounds of normal fertilizer pro- 

 duce an average yield of 31.87 that is, an increased yield of 19.87 

 tons per acre. In Field B it is also seen that the 800 extra pounds of 

 normal fertilizer applied to plats Nos. 5 to 8, inclusive, produced a 

 yield of nearly 4 tons per acre in excess of the yield of plats Nos. 1 to 4 

 with 1,200 pounds of fertilizer. If we value the cane at $3 per t<m. 

 the 800 pounds of fertilizer produced an increase of crop worth SI:.' 

 per acre. 



In addition to the fertilizers mentioned, barnyard manure is very 

 much prized by cane growers, and it gives much better results than 

 would be expected, judging from its chemical analysis. This is doubt- 

 less due to the mechanical changes which the organic matter produces 

 in the soil and to the, introduction of the organisms causing fermenta- 

 tion {ind decomposition, which quickly form considerable quantities of 

 humus, a constituent in which the sandy soil is particularly deficient. 

 The growth of velvet beans, which are either plowed under or used as 

 a pasture by stock, is also found in many instances to give beneficial 

 effects. The velvet bean being a leguminous crop, it would naturally 

 become a nitrogen gatherer, and when the crop is plowed under in the 

 course of time it also tends to add a considerable quantity of humus 

 to the soil. 



It is evident that in so far as the artificial IV rt Hi/at ion of ordinary 

 sandy soils, of which FiehU A and I> arc types, is concerned, the 



