May, 1910.1 



430 



Miscellaneous. 



leading, but the large number of liter- 

 ary and other societies which exist in 

 this country would seem to indicate 

 that there is an abundant supply of 

 disinterested service if only it can be 

 tapped. If, however, rewards are re- 

 quired we know of few forms of public 

 work which are more deserving of en- 

 couragement than efforts to lift the 

 peasantry of India out of the morass 

 of debt. 



IRRIGATION METHODS. 

 By A. S, Kenyon. 



(BVom the Philippine Agricxiltural 

 Review, Vol. I., No. 10, October, 1908.) 



A correspondent writes asking for 

 some notes on the amount of water 

 necessary for the growth of different 

 crops, the best means of applying the 

 water, the number of applications, and 

 the periods of the year for watering. 

 This makes too much of a demand upon 

 the limited space available for " Answers 

 to Correspondents," so that the reply 

 is given here in the ordinary pages of 

 the Journal as being of general interest. 



In the first place, the volumes of water 

 required for the full growth of various 

 crops will vary very much. Water is 

 directly required by plants for transpi- 

 ration or evaporation through the sur- 

 faces of their leaves, consequently the 

 amount of foliage is an important factor, 

 and for the formation of their actual 

 bulk, of which water is a large consti- 

 tuent; running, in some cases, over 90 

 per cent.; but its greatest service is in 

 dissolving and thus rendering available 

 the plant foods contained in the soil. 

 In many parts of the State winter crops 

 get sufficient moisture from the heavens 

 for all their requirements, at any rate 

 with proper cultivation, while the same 

 may be- said to a less degree of summer 

 crops. The latter may be successfully 

 grown, without artificial aid in watering, 

 over large areas where they are at 

 present either whole or partial failures, 

 by the adoption of improved methods 

 which are, in general, sowing in drills 

 sufficiently wide apart to permit of culti- 

 vation and, especially after rains, the 

 frequent use of the horse-hoe or scuffler, 

 between them. But in other localities — 

 over the greatest part of our northern 

 districts - winter crops require additional 

 moisture in many, nay, most years, and 

 the summer crops always. The supply 

 of these requirements is met by irri- 

 gation which may be derived from pub- 

 lic works under the State rivers and 

 water supply commision or from private 

 sources, such as pumping plants or by 



the construction of dams. It is well to 

 bear in mind thht the Water Act 1905, 

 the water in all rivers, creeks, lakes, 

 laeoons or marshes even if wholly on 

 private land, is the property of the 

 Crown and can only be used lawfully 

 for irrigation under the authority of the 

 Commission. True, riparian owners are 

 entitled to the tree irrigation of 3 acres ; 

 but only in direct connection with a 

 homestead or for its service, so that the 

 exception is only trifling. Licenses to 

 divert water from any source may be 

 obtained on reasonable terms and give a 

 much-desired security of tenure. 



Having obtained the water, care must 

 be taken in applying it to the ground 

 so as to make a thorough job of it. 

 Mere soaking of the top few inches only 

 means early loss by evaporation with 

 but little water reachiug the subsoil to 

 be there stored for future use. Sur- 

 face roots are encouraged and a brief 

 stimulus given the plant, too soon to 

 be lost. As water cannot be forced into 

 the ground, sufficient time must be 

 allowed for it to soak in and penetrate 

 to a reasonable depth. The time neces- 

 sary may be as little as fourteen hours, 

 but will generally amount to twenty- 

 four or over. The volume of water 

 necessary will depend upon the charac- 

 ter of the soil, and upon the method of 

 distributing adopted the rooting charac- 

 ter of the plant will also be a factor, 

 tomatoes and lucerne, for instance, re- 

 quiring very different volumes. The 

 volume may vary from 3 inches or under 

 to as much as 20 inches in depth over 

 the whole surface. The most usual 

 depth is found to be about 7 inches. 

 One inch in depth over a surface of 

 one acre is equivalent to 23,000 gallons or 

 3,630 cubic feet. 



The best means of distributing the 

 water so as to reach the plant's roots, is 

 undoubtedly underground perforated 

 pipes ; but this is a very costly method 

 and one not likely to Be brought into 

 use here for some time to come. The 

 next best is by distributing furrows. 

 The furrows are ploughed out by the 

 ordinary garden or orchard plough and 

 generally along the line of fall, the 

 plants being sown in drills to suit. The 

 distance apart of the f urrows depends 

 upon the nature of the soil ; but 6 to 8 

 feet may be taken as the furthest and 

 3 feet as the most general. For fruit 

 trees, only two furrows are used for the 

 first two years, one on each side of the 

 row. Later, as the root system increases, 

 four or five furrows in each, depending 

 upon the distance apart of the trees, are 

 adopted. The water is let into the 

 furrows from a head ditch or distribu- 



