This article is on irrigation, written by Dr. Pereira and M.S. Pereira
Dr. Pereira is a microbiologist & a coffee farmer and owns the Kirehully Estate in the Western Ghats, in Hassan District, India. Ms. Geeta Pereira, wife of Dr. Anand Pereira is a horticulturist and a coffee farmer.
Irrigation - We call it sprinkler irrigation. It is used to supplement the natural rainfall for the physiological and biochemical growth and blossoming of coffee. Yes we have the most modern irrigation system presently available in the Country. Irrigation is carried out by 100 H.P. Diesel engines coupled with custom made high discharge RKB Kirloskar pumps. The water is sent through a double line of 6inches high density polyethene pipes (HDPE) and is distributed to four inches HDPE lateral lines and fed to Italian rain guns. Each gun can irrigate an area of approximately two acres. (http://www.simie-irrigation.com) Water is discharged under very high pressure (50 to 75 psi) through small orifices or nozzles which uniformly spreads over the land and plant area.
In sprinkler irrigation, time is the essence and the entire operation should be completed in a very specific time. To irrigate one acre of coffee with one acre inch of water 22,750 gallons of water is required.
Irrigation is needed for a number of reasons. The coffee bush is an evergreen plant and requires adequate moisture during the dry months. Coffee cannot tolerate long periods of drought. Long spells of drought limits the production of coffee. Hence in the months of November and December winter irrigation is carried out to retain soil moisture. Winter irrigation also stimulates the physiological activity of the bush by increasing the bearing wood and crop quality. Generally one acre of winter irrigation will suffice. The second type of irrigation is known as blossom irrigation. Hence artificial irrigation is given mainly to insure against failure of good blossom and backing showers. Foremost reason is to artificially induce blossom showers in Robusta coffee. In this variety of coffee, the bud is ready to bloom in the month of February (February 15th to March 15th) and March. The rainfall pattern during these months is simply erratic and secondly if the coffee bush does not receive an adequate shower of one inch of rainfall, then the buds turn pink and fall off. The important point to note is that there is no second chance once the bud drops and the crop for one full year is lost. To overcome this problem, artificial rainfall by way of overhead sprinklers is used to induce healthy blossom. Backing showers of three fourth acre inch of water is a must 20 days after the first blossom showers to ensure fruit retention. Second round of backing showers has to be repeated after 20 days of first backing shower.
The other tangible benefits of irrigation are health and vigor of the plant improves, substantial increase in leaf area, improved nutrient uptake, uniform ripening of berries and retention of foliage.
Yes, sprinkler irrigation involves a back breaking effort and in our case since the entire plantation is Robusta we need to commence irrigation early. Literally, speaking, we pitch our tents inside the plantation for two months, sleep the night inside the tents and wake up every three hours to change the shifts for irrigating different blocks. Irrigation is highly labor oriented and the forest factor (trees) makes it even more difficult. Pipes need to be carried inside the rows and after every shift they need to be brought out and laid afresh.
We have experimented with various technologies, ZM sprinklers, Israel NAAN sprinklers and Italian rain guns. We have devised ways and means on simplifying the entire process and have succeeded in making sprinkler irrigation a pleasure for our work force.