THE IRRIGATION OF THE CANE. 



grms. of water-free material, consisting of 31-8 grams roots, 53'9 grms. stems, 

 and 483*2 grms. leaves, or 147*8 Ibs. water per pound of water- free plant 

 material. The amount of water transpired in each month of growth was 

 found to be as in the annexed table. 



Experiments due to Kammerling 8 in Java showed that on an average one 

 stick of cane by its leaves transpired over its whole period of growth 250 c.c. 

 per day; this he estimates as equal to 3,500,000 litres per bouw over the 

 whole vegetative period, or equal to about 1800 tons per acre. 



During the first month of drought in Java, Kammerling estimates the 

 transpiration per stick as 500 c.c. per day, and using this as a basis he reckons 

 that the replacing of the soil water thus transpired in a month requires 720,000 

 litres per bouw, or about 370 tons per acre. 



Kammerling also observed that the transpiration of the Manila, Cheribon 

 and Muntok canes was as 5 : 4 : 3 ; i.e., the latter will remain in vegetative 

 vigour on the soil water longer than the former, and will be drought resisting. 



Methods of Irrigation, Hilgard 9 distinguishes the following 

 methods: 



1. Surface sprinkling. 



2. Flooding. 



(a.) By lateral overflow from furrows and ditches. 

 (J.) By the check system. 



3. Furrow irrigation. 



4. Lateral seepage from ditches. 



5. Basin irrigation. 



6. Irrigation from underground pipes. 



The first method can be seen in practice in Demerara, where in seasons of 

 drought the ' creole gang ' (the colony-born children of the imported Asiatic 

 labourer) are employed laboriously carrying water in buckets to the ' stumps ' 

 or stools of canes transported from an abandoned field to fill blanks in one still 

 under cultivation ; this method can only be used where labour is of the 

 cheapest. 



The second method is extravagant in the use of water, and is illustrated 

 in the methods described below as in use in Peru. 



The fourth method is exemplified in the so called flooding of the 'English' 

 fields in Demerara mentioned above. 



The fifth and sixth methods do not find application in cane planting. 



97 



