27 



the Aeries of four years the average yield of cane without fertilizer is 

 about S tons per acre. It is important, however, to note the seasonal 

 influences. The yield for 1903 is a remarkably poor one both in quan- 

 i it \ of cane and in quality. As these poor seasons, however, regularly 

 recur, it is not probable that the general average was unduly influ- 

 enced by including the results for 1903. The following season, 1904, 

 a remarkably good one as regards both yield and quality. In 

 that season (ield A was a new land and field B an old land. 



KXl'ERIMENTS WITH THE NORMAL-FORMULA FERTILIZER. 



Having studied the yields which can be obtained without the use of 

 fertilizers, the next important problem is the study of the effects of 

 different kinds of fertilizers, different quantities of fertilizers, and 

 different methods of distribution upon the yield and composition of 

 the cane. The so-caUed normal-formula fertilizer used during the 

 experimental work was a mixture of various fertilizing ingredients 

 Containing 9.03 per cent of available phosphoric acid, 5.15 per cent of 

 potash, and 3.90 per cent of nitrogen, reckoned as ammonia. In 1903 

 MX) pounds of this fertilizer were sown broadcast, resulting in an 

 increase over the average for the unfertilized plat A of 2.33 tons per 

 icre, and on field B 0.94 of a ton. Comparing the results with the 

 iverage for 1902 and 1905 only, gains, of 3.55 and 6.15 tons per acre 

 >n fields A and B, respectively, are shown on the fertilized plats. 



The same quantity of normal fertilizer was applied in one, two, and 



hree applications made before planting and at intervals afterwards 



luring the growth of the crop. The data show for the whole series 



)f experiments that 800 pounds of normal-formula fertilizer applied 



u one time, before planting, produced an average yield of 18.07 tons 



m field A, and 17.56 tons on field B, producing canes which contained 



4.o 1 per cent of sucrose on field A and 13.83 per cent on field B, with 



>>7 per cent and 1.01 per cent, respectively, of reducing sugar. Con- 



idering the average for fields A and B for 1902 end 1905, the yields 



>er acre are 16.44 tons and 20.40 tons, respectively, showing an 



n crease on field B over field A of 3.96 tons per acre. This, of course, 



va> due to the superior fertility of field B, as it is almost exactly 



lie same difference as was found on the plats where no fertilizer was 



i>ed. In this case, therefore, it is seen that the 800 pounds of ferti- 



izer made up according to the normal formula did not change the 



elative fertility of the two fields, but only increased the yield. The 



icrease over the unfertilized plats is 8.54 tons per acre on field A for 



he whole number of years and 10.55 tons per acre on field B. 



\\ hen the 800 pounds of this fertilizer was added, partly before plant- 



ig and partly at a later period of growth, as described in the reports, the 



ve rage yield on field A was 18.64 tons per acre and on field B 17.03 tons 



er acre. These data show that there was practically no benefit, taken 



