18 



of fertilizer to produce the best results. This point will need to be 

 studied in Peru when the guano supply gives out and high grade fer- 

 tilizers must be resorted to. Experiments will help to determine it. On 

 these soils, from 1000 to 1500 Ibs of guano carrying 8/ nitrogen have 

 been used per acre; where large quantities are used, the aim has been 

 the upbuilding of the soil. 



Applying fertilizers. The ideal way of feeding cane would be to give 

 in only a little fertilizer at a time but give it often. This, however, 

 is hardly feasible for most estates, and in fertilization as in all other 

 departments of the work, the financial and practical must have preced- 

 ence over the theoretical. 



Putting on fertilizer twice or three times might pay; two applica- 

 tions are, prehaps, best. One application should be made as soon as 

 possible after the cane sprouts; and the second, six or eight months la- 

 ter. If fertilizers are put in with the seed cane when it is planted, 

 they should be those that are not easily soluble in water, as 

 there would be no advantage in applying those easily soluble in water. 

 If fertilizer is cheap, spreading it broadcast over the field would be a 

 good practice; but as commercial fertilizers are usually expensive a 

 ton containing more or less 150 Ibs of nitrogen at 12 cts (gold) per Ib, 

 and a fair crop of cane removing about 130 Ibs of nitrogen per acre 

 the planter must economize in its use so he needs to place it where the 

 roots can get at it easily. If the fertilizer is placed along side the grow- 

 ing cane some inches below the surface of the ground^ it will be 

 within easy reach of the roots which do not grow very deep. Fertil- 

 izer should be covered up with a layer of dirt to prevent the escape 

 of ammonia, if it is in the fertilizer, and to prevent the removal of 

 the fertilizer by the irrigating waters and its consequent uneven dis- 

 tribution over the field. 



Guano left on the surface is subject to a number of disadvantages; 

 one is the leaching by irrigation, another is the encouragement of 

 shallow root growth, and another is the loss of ammonia by exposure 

 to the air. Analysis shows the loss of ammonia by exposure to be 

 1.6%. While the loss in the field would be less than this, it 

 would be enough to warrant covering with earth. The percent of ni- 

 trogen in the guano before drying was 9.3; after drying, 8. 



An important reason for not placing the guano on the surface of 

 the soil is because an upward instead of a downward root growth 

 would be encouraged since it is the nature of roots to follow the food 

 supply.; the plant would, therefore, be less firm in the ground and 



