The development of drip irrigation, the use of driplines underground in the plant root zone offers substantial advantages for permanent crops such as sugarcane, plantation crops, tree crops and certain types of landscaping. To be successful it requires special driplines and system installation and system maintenance and management. PIAL provides products, system design, supply & installation and maintenance & agronomic support for successful SDI installations.

  

Advantages of SDI

• Higher Yields – minimal plant stress and maximum growth promoted by delivering water and nutrients directly to the root zone. Accurate scheduling and quantity can promote desirable growth i.e. fruit rather than vegetative growth.
• Highest Irrigation Efficiency – practically no water loss, so highest production per unit of water used.
• Water-Saving – maximum yield from whatever water is available.
• Reduced Animal, Human and Mechanical Damage – no theft or vandalism, and damage due to frequent in-field operations i.e. tea plucking.
• Efficient Delivery of Fertilizers and Agrochemical – direct delivery to the root zone.
• Labour Saving – once installed only maintenance operations, no shifting of driplines.
• Facilitates Mechanisation – for sugarcane mechanical harvesting will not damage driplines and ratoons are possible without relaying driplines.
• Precision Control of Inputs – fits intensive agronomic production management.
• Soil Surface Kept Dry – harvesting, plucking and intercultivation activities are not hampered.
• Weed Growth Inhibited – minimal water at soil surface restricts weed germination and growth.
• Better Soil Aeration – less saturation of soil pore spaces.

How SDI is Different from Surface Drip

The enemy of controlling water movement in soil is gravity which will always pull water downwards and eventually away from the root zone. The other force is capillary which moves water in all directions but which weakens when soil becomes saturated that is when all pore spaces are full of water. At that point, gravity takes over and moves water downwards. Applying water at the surface means that gravity has to be used to move water into the root zone and some oil will be saturated and deprived of oxygen which is not an ideal state. If water is applied right in the root zone, as in SDI, capillary action can be used to move water throughout the root zone. Irrigation can be stopped before the soil is saturated. Thus SDI works best with frequent but relatively small quantities of water. However, this also requires an accurate delivery system with correct emitter spacing for plant and soil types and each emitter delivering the same amount of water.

Water distribution 10 hours after 1 hour of watering:

 

System Design, Installation and Maintenance

Design of the SDI system will be provided by PIAL after a site inventory and survey which takes into account topography, soil type and strata, water source, quality and quantity, power availability, crop pattern, crop variety, climate, etc. Special to SDI are correct filter selection, air release/vacuum valve placement, dripline drain manifolds and chemical injection facility.

Driplines for some crops – certainly sugarcane, can be mechanically installed using a machine mounted on a tractor.

Maintenance involves regular filter cleaning or backflushing, acid and other chemical injection, regular field inspection and action in case of rodent or insect infestation. Root intrusion has to be controlled by product features and injection of a herbicide.