CLEVER HYDRANT DELIVERS ON-FARM BENEFITS

Aboev: The Larall Smart Hydrant in action.

INSTALLING A SMART EFFLUENT management system that delivers benefits like maximum nutrient utilisation and compliance with council regulations, and takes minimal labour to operate, has to be the aim for dairy farmers.

The Larall Smart Hydrant (LSH) from Effluent & Irrigation offers those benefits. It utilises 4-6 medium size Rainguns which are controlled intermittently, meaning a very low average application rate of 1.5mm per hour.

It also requires relatively low labour to operate and enables high volumes of effluent to be pumped per session, maximising irrigation opportunity.

This offers dairy farmers smarter effluent management control with deferred irrigation, effective utilisation of nutrients, as well as labour savings.

Failsafe features are also available such as if there is a low or high pressure fault registered, caused by either a leak or blockage, the LSH system will shut down the main effluent pump, giving the farm operator added peace of mind.

The low application intensity reflects a ‘little and often’ concept enabling nutrients to be maintained within the plant root zone. This is critical to gain the maximum value of the nutrients produced in effluent and maximise the return on investment.

This system also allows irrigation to take place when traditional systems may not because of ponding or runoff risks.

When effluent enters the LSH its pressure is activated but only one of the valves is opened at one time. The LSH directs the effluent through the open valve to the raingun for a set duration, for example 15mins. Once the set time has lapsed, the next valve opens as the open valve closes and continues spreading effluent to the next raingun.

Over wetter months, the amount of effluent that goes to each raingun could be based on 10 mins of pumping. Based on a 10-minute period there would be a 50-minute rest between each application. The rest time allows the effluent to be absorbed by the soil which limits ponding and run off and maximises nutrient retention.

If the LSH was irrigating two 3ha paddocks, there would be 6 shifts per gun to complete the area. The total application depth is relevant to pumping time and should be based on soil moisture levels.

For example, to apply 10mm total depth the pumping time would be 7 hours between shifts. The total pumping time to complete the paddocks (after 6 shifts) would therefore be 42 hours.

Pumping approximately 18m³ per hour, this would equal 756m³. When based on a herd size of 500 cows and producing 35m3 per day this is about 21 days of effluent irrigated.

In this situation the system can be used once every three weeks for deferred irrigation. If the total required depth is higher, say 15mm, then the pumping time between shifts would be 10 hours. The total volume pumped would be 1080m³ or 30 days effluent.

Labour savings are a result of setup time, or trips to the paddock, versus the total volume pumped. A common comparison here is with travelling irrigators and the ‘turnaround time’ required for their given output.