121 



«very three tons of mill canes will give one ton of tops and leaves. 

 One ton of tops and leaves will remove 35.80 pounds of albuminoids, 

 or 5 . 7 pounds nitrogen, and 68 . 8 pounds ash. Since every ton of cane 

 has about one-third of a ton of tops and leaves, there will be required 

 for the growth of a ton of cane, exclusive of roots, and including tops 

 and leaves, 21.3 pounds of albuminoids, or 3.4 pounds nitrogen, tJud 

 34 pounds ash. When the cane is harvested, the trash (tops and leaves) 

 is left on the ground and usually burnt. In burning, the ash or mineral 

 matter is restored to the soil, but the nitrogen is dissipated into the air. 

 Therefore, to one burning his trash, there is withdrawn from the soil 

 with every ton of cane 3.4 pounds nitrogen, 2. 17 pounds potash, 1 .48 

 pounds phosphoric acid and . 8 pounds of lime. There is a saving of 

 1.9 pounds nitrogen, by buryin^ the trash, to each ton of cane made, 

 «qual to the nitrogen in 27 pounds of cotton seed meal. From the above, 

 it will be seen that the quantities of elements lisually supplied in com- 

 mercial fertilisers are assimilated and utilised by the cane in relatively 

 small quantities when compared with other staple crops. The excessive 

 weight, however, of a crop of cane grown on a given area causes the 

 total absolute quantities of the ingredients referred to, to more nearly 

 approximate those removed from the soil by other plants. 



Forty tons of cane per acre is not unusual. This amount would re- 

 quire 136 pounds of nitrogen if the trash was burnt, or 60 pounds if 

 trash was turned under, 87 pounds potash, and 59 pounds phosphoric 

 acid. 



The above quantities of nitrogen would be represented by 1943 and 

 856 pounds cotton seed meal 



It w(mld require over 700 pounds kainit to supply the potash and 

 nearly 400 pounds of a 15 per cent, acid phosphate to furnish the phos- 

 phoric acid, if none were furnished by the soil. 



Burning of Cane Trash. 



Shall we then burn our trash or shall it be turned over? Chemically 

 there is a loss of nitrogen for each ton of cane harvested, by burning, equi- 

 valent to that contained in 27 pounds of cotton seed meal. On a field aver- 

 aging 30, 20 or 10 tons per acre, there will thus be lost an equivalent of 

 nitrogen contained in 710, 540 and 270 pounds cotton seed meal — a loss 

 which would be serious in any other agricultural industry. Why then 

 do we burn ? The following reasons are given : — The cane borer, which 

 at times becomes so abundant j-s to seriously injure the cane, is practi- 

 cally held in check by burning the tops in the trash, which contain the 

 worms, thus destroying thousands annually. If a cessation of planting 

 cane on the part of every planter in the State could be simultaneously 

 practised for one year, and no cane saved for seed wherein the worms 

 could hibernate, and ail the trash everywhere burned, it is believed the 

 borer would be exterminated in Louisiana. Since it is extremely rare 

 that any are found in the stubble left after cutting down the stalks, and 

 if by chance any should be so found, the cold of our average winters and 

 the heat from the burning trash would destroy them. 



Again, our stubbles are liable to be killed during our winters. It 

 has been clearly demonstrated that this danger is greatly enhanced by 

 excessive moisture, and the latter is frequently produced during our 

 winters, if the trash as permitted to remain on the ground or turned 

 ■under with a plow. Burning trash off the stubble immediately after 



