10 April 2017 Read: 367
With the recent drought still fresh in the minds of Limpopo’s farmers, optimal irrigation practices were put in the spotlight at the recent Maluma day held on the outskirts of Tzaneen. Michael Esmeraldo, an agronomist at Netafim, explained that drip irrigation has come a long way over the past 20 years with less clogging of dripper-heads, lower delivery rates and better compensation for water pressure on slopes.
‘The biggest problem we had with drip irrigation in the past was the leaching of water and fertilizer past the root zone as it was difficult to irrigate accurately with the high delivery rate drippers,’ said Esmeraldo.
These days the delivery rate of drippers has been brought down to 1.6 to 2.3L/hour and a flow rate of 5 to 14mᵌ/ha/h. The latest generation of drip irrigation technology is an ultra-low flow drip irrigation system using 1L or less water per hour with a flow rate of 2.5 to 3.5mᵌ/ha/h. ‘Ultra low-flow drip irrigation lets farmers save on labour costs as irrigation shifts are longer and irrigation is more accurate than with regular drippers,’ said Esmeraldo. ‘Ultra-low flow drip irrigation allows you to irrigate larger areas at a time and improves the soil-water-air relationship.’
But ultra-low flow drip irrigation is not without its disadvantages. According to Esmeraldo the flow path is much smaller and maintenance becomes more important with ultra-low flow than with regular drip irrigation. Continuous application of Peroxide to the water is a must in order to prevent clogging. The system also requires regular flushing.
Farmers must decide which drip irrigation option suits their needs and circumstances the best, said Esmeraldo. ‘Both will work, it’s just a question of which will work best for you.’
– Alita van der Walt