All about the gravity drip irrigation system - Part I
The gravity drip system is an on-farm drip irrigation technique that relies on gravity to supply energy/power needed to operate it, i.e. no pump is used.
Target Areas:
Farms and potential farms situated in areas that have no natural water source, or are not connected to a public irrigation scheme.
In areas of limited water resources, drip irrigation is the most efficient and economical method of water application to crops.
Lands must be flat or gently sloping, as drippers do not work well on steep slopes.
Benefits:
The gravity drip system may or may not be able to satisfy the optimum crop water requirement, but it is able to assist in the critical periods of a plant's life.
It not only increases yield, but also improves the quality of the produce.
It offers the following advantages:
- Highly efficient water use
- The allowance of a simple fertiliser application to be administered through the system
- High resistance to clogging
- Increased crop yield and quality through precise water and fertiliser application
- Durable, long-life drip line easy installation, operation and maintenance
- Uniform distribution of water
- Planting pattern and orientation
Recommended planting distance is usually the pattern followed for spacing drip lines between rows.
There are two proven patterns that can be used:
Single-row planting, one drip line to each row of crop, or
Multiple-row planting, one drip line to two or more rows of crop.
Spacing will be different from that of single-row planting, usually with a tandem or staggered orientation of the crop.
Technical data of system main features:
Large surface inlet screen
High clogging resistance
Available in spacing of 10 to 250 centimetres between emitters
Materials:
1. Dripline: Hard plastic (polyethylene)
2. Dripper: Hard plastic (polyethylene)
- Specifications Hydrogol drip hose drip line nominal diameter: 12, 16, 20mm
- Constant internal diameter: 10.4, 13.8, 17.6mm
Recommended working pressure: up to 1.4 bar (20 psi) Discharge rate/emitter: 0.37 litre per hour (0.1 gallon per hour)
Tank for a 0.1 ha (a quarter acre) field, a tank with a capacity of 3,330 litres (880 gallons) or more is recommended.
For a 0.1 ha (a quarter acre) field, a tank with a capacity of 3,330 litres (880 gallons) or more is recommended.
A typical 0.1 ha (1/4 acre) plot with drip lines spaced 1.5 m (5 ft) apart and drippers every -254 m ( 10 inches) has 2400 emitters, and with a discharge rate of 0.37L/hr/emitter, then the overall discharge is 880L/hr (2400 X 0.37).
Hence, with a tank capacity of 3,330 litres, a tank will give approximately 3 hours and 45 minutes of water before it is empty.
Stand for Tank: reinforced concrete should be used in stand construction... cast top to ensure a smooth and level finish, allowing tank to sit firmly
Height of stand: 1.09 m (3.6ft) or more
Width/breadth 1.8 m (6ft by 6ft).
Note: Other types of materials such as iron pipes, in addition to wet packing of stones, can be used for stand construction.
CAUTION: When filled with water, a 3,330-litre tank weighs approximately four tonnes.
Further information can be had from the Rural Agricultural Development Authority (RADA) by calling 1-888-ASK-RADA or by logging on to www.rada.gov.jm.
