Trickle Irrigation

Press, Volume CIX, Issue 32233, 27 February 1970, Page 8

Trickle Irrigation

Trickle irrigation, which originated in Israel to utilise a limited waler supply for irrigation, was seen in action on the vegetable research area at Lincoln College last week when the horticulture department at the college held a field afternoon. Mr 3. S. Dunn, senior research officer in the New Zealand Agricultural Engineering Institute, said it made it possible to irrigate quite an area with a very small amount of water. Under the system that was seen on the field afternoon, Mr Dunn said less than three gallons of water was being used a minute under a pressure of 31b to 41b to the square inch. From a 2in polythene header pipe four lin polythene lateral pipes were running down the field following the rows. These laterals are inserted into the header pipe after making holes 1-lfiin less in diameter than the external measurement of the jin pipe and these joints will stand pressures of up to 301 b to the square inch. In the laterals, at 2ft intervals, were tiny microtubes or “whiskers” which have an internal diameter of about a millimetre. These “Whiskers” are placed in the jin polythene pipe by making a bole with a punch and expanding it and into this is quickly placed the microtube before the polythene expands again and locks the tiny tube in position. This will stand a pressure of 601 b to the square inch. It is important to use clean water in the system. Mr Dunn said that the system was more applicable for use with bush fruits or in apple orchards,

but it had enabled vege- , tables to be grown where none would have been grown otherwise. On this area he said that i the cost of the system would be about $3OO an acre, but in an orchard of 100 trees to the acre the cost would be only about : 850 an acre. Mr Dunn said he had . seen the system ip use in

Australia last year on soils with impeded drainage and in this situation very good lateral movement of the water was being obtained. The Lincoln experiments are aimed at determining the role of the system. The accompanying photograph shows the header pipe, the lateral pipe and the mierotube er “whisker.”