Gravity drip irrigation system(Part II)
Installation Instructions
1. Land must be completely cleared
2. Ensure that the top of the stand is level in all directions before placing and filling tank
3. Connect ball valve then fill tank
4. Attach screen filter and PVC pipes and fittings
5. Please note that: All threaded male ends should be wrapped with thread tape and all slip connections should be coated with adhesive sealant (Tangit)
6. Connect 25mm PE pipe to PVC pipe using either a 25mm (by three quarter inch) x 25mm Tee or with a 25mm - three quarter male adaptor
7. Lay out 25mm PE main line at the head of the field and punch holes at intervals according to the selected drip line spacing.
8. Attach 12mm drip lines (hydrogol) using 12mm head connectors with barbed end and connect to drip line while the other end should be pushed into the 25mm PE pipe.
9. Flush line for about 10 seconds, close ball valve, and then close end of each line using 12mm end line.
System operation
Scheduling: Irrigation intervals and the amount of water to apply during the critical periods of the crop growth are as follows: Transplanting is approximately 2000-3000 litres (500-800 gallons)
For flowering and/or crop formation, apply approximately 1500-2250 litres (400-600 gallons) twice per week, and during other periods, an average of 2250-3300 litres (600-900 gallons) once per week should suffice.
Fertigation: Combining fertilisation with irrigation has become standard practice for most agricultural crops; in fact it is one of the advantages of this system.
Below is a list of soluble fertilisers available from one local supplier:
Soluble nutrients are Fertrilon Combi 2 - straight micronutrients Foliar Nitrophoska
10-4-7-0.2 (NPK +Mg)
Nitrophoska Sol - different ratios of NPK + Mg and trace elements in a chelated form can be had Ammonium Nitrate (32 per cent straight nitrogen)
Sulphate of Ammonia (21 per cent straight nitrogen)
Note: first dissolve recommended amount in a container, then pour strained solution into tank with water.
Ensure end lines are closed, laterals are properly aligned, extended and anchored, and filter is cleaned before the system is turned on.
Calibrated ball valve - turns on at full bore then checks flow and distribution, adjust accordingly to cut back flow.
Maintenance and care
Dismantle filter as demonstrated at installation and wash after every irrigation.
Flush laterals at beginning of each cropping period with clean water by removing the end lines then opening the ball valve, allowing water to flow freely. Acid -treat system once a year by using 35 per cent HCL acid for 30 minutes to make pH of water or less.
This should be followed by about one hour flushing with clean water.
Safety precautions, such as wearing goggles and plastic gloves, should be taken
Allow two to three days to pass before planting.
CAUTION!
Always add acid to water and never water to acid.
Avoid using sharp implements (cutlass, hoe, etc.) and lighting fires in proximity to the system.
Remember it is made of plastic, hence easily chopped and burnt.
Post-harvest handling: roll lines individually to the top of the field and tie, this will prevent entanglement.
Troubleshooting: Note well that all fittings can easily be replaced:
Cuts to pipe can be repaired by using a line connector
If end line is lost or damaged, it can be replaced or substituted by using cord to tie the lateral.
If water is not dripping from the emitters, check for:
1. Kinks in pipe
2. Blocked emitters
3. Open main lines or laterals
4. Damaged pipes
Acid treatment will clear blocked emitters.
The irrigation system's introduction was made possible through the collaborative effort of RADA's Drought Alleviation Programme and the Ministry of Agriculture and Fisheries Domestic Food Crop Project.
For further information, contact Rural Agricultural Development Authority (RADA) at 1-888-ASK-RADA or by logging on to www.rada.gov.jm. Information for the RADA Diaries is compiled and provided by the RADA Communication and Public Relations Department.
