484 



pounds ])er acre, in ISSS, and 100 j^ounds, in 1889, were applied on all 

 the plats. The same v^ariety of corn was raised on all the plats in the 

 three successive years. The results for each year were as follows : 



In 1887, the year in which the phosphates were applied, eqnal money valuos >f 

 (lissolvecl bone-black, Grand Cay man's phosi^hate, and Thomas slag had approximately 

 equal effects on the yield of the corn crop. An eqnal money value of gronnd Soul li 

 Carolina rock prodnced less than half as much increase of sonnd ears as the other 

 phosphates .and no increase at all of stover. * * * 



In 1H8S no phosphates were applied. The effects of Grand Cayman's phosphate 

 and Thom.as slag, however, were .as pronounced as they were the year before, making 

 as large or a larger jiercentage increase over the plats which had received no phos- 

 phate in 1887. South Carolina rock made a considerably larger percentage increase 

 than the year before, showing that it was slowly becoming available in the soil. But 

 while Grand Cayman's phosphate and Thomas slag produced nearly 40 per cent more 

 of sound ears and 25 per cent more of total crop than the no-phosphate plats, dis- 

 solved bone-bl.ack yielded only 11 per cent more of sound ears and G per cent more of 

 total crop than the uo-phosph.ate plats * * * 



The yield of corn in 1889 was very small, as was anticipated. The stover was so 

 damaged by continuous wet weather and blight that it was not thought worth while 

 to weigh it. We have, therefore, only the weights of the ears for comparison. From 

 these it appears that the plat which h.ad received dissolved bone-black in 1887 pro- 

 duced no more ears than the plats which received no phosphate then or since. This 

 fertilizer had entirely spent itself in the two previous years. Grand C.aym.an's phos- 

 phate and Thomas slag, however, produced 4.5 and 56 per cent more corn than the 

 no-phosphate plats, and South Carolina rock 29 per cent, a larger percentage increase, 

 indeed, than cither Last year or the year before. 



Thar is, to carry out the illustration the investments made in Thomas slag, Grand 

 Cayman's phosphate, and South Carolina rock in 1887 were still paying considerable 

 dividends in 1889, while the investment in dissolved bone-black had ceased to yield 

 any returns whatever. 



On this ])articnlar piece of land and in these three seasons Thomas slag and Grand 

 Cayman's phosphate have been more profitable than dissolved bone-black. 



The other experiment which was commenced in 1888 was on sixteenth- 

 acre i)lats. Dissolved bone-black 16 and 32 pounds, Grand Cayman's 

 })hosphate 23 pounds, Thouias slag 27.5 pounds. South Carolina rock 

 34.5 pounds, and Bolivian guano 27.5 pounds, were each applied in 1888 

 on one plat, and two plats received no phosphate, l^o phosphates were 

 applied in 1880. Ou all the plats muriate of potash at the rate of 320 

 l)Ounds per acre, and sulphate of ammonia 200 pounds per acre, were 

 applied each year. Corn was raised bath years. The results were as 

 follows : 



In 1888 dissolved bonel)lack gave a much heavier yield than an e(iual money 

 value of any other phosphate. This year [188;)J it has yielded much less, both of 

 cars and stover, than any other iihosphate. * * " The double ([uantity of dis- 

 solved bone-black applied last ye.arhas produced about as large a relative gain this 

 year as last. * * * 



The most striking thing in the experiment of 1889 is the very large increase pro- 

 duced on the Bolivian-guano plat over the yield of the no-phosphate plats, whidi 

 is particularly noticeable in the ears. Whetber this is due to the rapid disintegra- 

 tion and solution of the phosphate by .a single season's exposure, or to an elfect. on 

 the soil pi'oduced by the large (luantity of carbonate of lime contained in it, must 

 be left undecided for the present. 



