27 



IRRIGATION. 



As an auxiliary mammal agent of definite, well-proven value in this 

 Archipelago, I will briefly recite some of the benefits that may be expected 

 to follow occasional irrigation during the dry season. 



It strongly accelerates growth and early maturity. A few irrigated 

 trees, reputed to be under five years from seed and already bearing fruit, 

 were shown the writer on the Island of Jolo. The growth was remarkably 

 strong and vigorous, notwithstanding that the water of irrigation had 

 been applied in such a way that the tree could only hope to derive a mini- 

 mum of benefit from its application. It had merely been turned on from 

 a convenient ditch whenever the soil seemed baked and dry, at intervals 

 of one to three weeks, as circumstances seemed to require. 



Irrigation, but always in connection with subsequent cultivation, may 

 be considered equal to a crop guaranty that is not afforded so effectually 

 by any purely cultural system. 



Earely has a better opportunity occurred to demonstrate the unques- 

 tioned benefits that have inured to these few Jolo trees from the use of 

 irrigating waters than the present season of 1902-3. From many sources 

 reports come to this Bureau of trees failing, or dying outright, from 

 lack of moisture. While it is true that the present dry season has had 

 no parallel since 1885-86, and that the rainfall during the dry season 

 has been less than half the normal, yet it should not be forgotten that, 

 during the eight months from October to May, inclusive, the average pre- 

 cipitation on the west coast, at the latitude of Manila, is only about 

 460 mm. and that, when the amount falls below this, the cocoanut is 

 bound to suffer. 



Though it is true that the evil effects of drought may be modified, if 

 not altogether controlled, by cultivation, the assistance of irrigation places 

 the cultivator in an impregnable position. If evidence in support of 

 this statement were called for, it might be found to-day in the deplorable 

 condition of those groves that have been permitted to run to pasture, as 

 compared with those in which some attempts have been made to bolo out 

 the encroaching weeds and grasses. 



It is probably true that, except on very sandy soils, continued surface 

 irrigation would aggravate the superficial root-developing tendency of 

 the tree; and to what extent, if any, occasional laceration by deep shovel 

 tooth cultivation would injure the tree remains to be seen. There are, 

 however, few economic plants that so quickly repair root damage as the 

 Palmse, and, unless the seat of injury extends over a very large area, it is 

 probable that the resulting injury would be of no consequence, as com- 

 pared with the geneal benefits that would result from irrigation. 



