23 



To make this clear I exhibit, by way of contrast, the drafts made by 

 a relatively good crop of two notoriously soil-impoverishing crops 

 tobacco and corn and, on the other hand, the drafts made by an equiva- 

 lent average cotton crop a product considered to make but light drains 

 upon sources of soil fertility. 



A proportionate tobacco crop of 1,000 kilos per hectare will withdraw 

 from the soil (reduced to the same standard of weights adopted by Mr. 

 Cochran) c 



Pounds. 



Nitrogen 168 



Potash 213 



Phosphoric acid 23 



An equivalent crop of shelled corn, say, of 125 bushels per hectare, will 

 withdraw 



Pounds. 



Nitrogen 200 



Potash 135 



Phosphoric acid 75 



while a relative crop of lint cotton of 237 kilos (700 pounds) per hectare 1 

 will only exhaust, in round numbers 



Pounds. 



Nitrogen 114 



Potash 70 



Phosphoric acid 30 



There is an analogy between these four products that makes them all 

 comparable, in so far as all are largely surface feeders, and, as experience 

 shows that there can be no continuing success with the last three that does 

 not include both cultivation and manuring, we may use the analogy to 

 infer a like indispensable necessity for the successful issue of the first. 



Cultivation as a manurial factor should, therefore, not be overlooked, 

 and all the more strongly does it become emphasized by the very difficul- 

 ties that for some years to come must beset the Philippine planter in the 

 way of procuring direct manures. 



When it comes to the specific application of manures and how to make 

 the most of our resources, we shall have to turn back to the analysis of 

 the nut and note that, relatively to other crops, it makes small demands 

 for nitrogen. At the same time it must not be forgotten that these chem- 

 ical determinations only refer to the fruit and that, with the present in- 

 complete data and lack of investigation of the constituent parts of root, 

 stem, leaf, and branch, we have nothing to guide us but what we may in- 

 fer from the behavior of the plant and its relationship to plants of long- 

 deferred fruition, whose manurial wants are well understood. 



It is now the most approved orchard practice to encourage an early 

 development of leaf and branch by the liberal application of nitrogen, 

 whose stimulant actions upon growth are conceded as the best. 



1 Farmers' Bulletin 114, United States Department of Agriculture. 



