Thursday, 19 September 2019 07:55

Fertiliser use in spring

Written by  Bala Tikkisetty, sustainable agriculture advisor at Waikato Regional Council
Bala Tikkisetty, sustainable agriculture advisor at Waikato Regional Council. Bala Tikkisetty, sustainable agriculture advisor at Waikato Regional Council.

The refreshed National Policy Statement for Freshwater Management increases the pressure on farmers to improve their nutrient management. 

As the soil starts warming over the next few weeks, farmers will be preparing to fertilise their paddocks. Balancing the best bang-for-buck with protecting economic and environmental bottom lines is critical for farmers and requires advice from fertiliser reps and consultants. 

That’s because healthy soils are a balance of biological, physical and chemical properties, and are a dynamic mixture of minerals, organic residues and living micro and macro organisms, all of which support farm production and provide various ecosystem services.

As there are risks when applying fertiliser, and strategies to help you avoid them, it’s recommended all farmers have a nutrient budget and a nutrient management plan for their properties and discuss their situation with their fertiliser rep. 

A range of tools will help practice sustainable nutrient management.

Nutrient budgeting is widely accepted as the appropriate first step in managing nutrient use and it’s also the preferred tool for evaluating the environmental impact of farm management practices.

Overseer, a computer decision support model, is being used to advise on nutrient management and greenhouse gas emissions. It predicts what happens to the nutrients brought onto the farm in the form of fertilisers and supplementary feed in the same way that a financial budget can track money. 

When doing nutrient budgets in Waikato, bear in mind recent soil quality monitoring results that reveal high fertility and compaction remain problems on dairy and some drystock sites.

Another issue to consider is nitrate leaching. Plants need nitrogen (N) for healthy leaf growth. But N is an extremely mobile nutrient. If more nitrogenous fertiliser is applied than plants can take up, most of the unused nitrogen ends up leaching down through the soil into groundwater. Sometimes N will also be lost to waterways as run-off and some is always released back into the air as gas. 

The amount of N leaching from pastures can be reduced by: 

• Timing fertiliser application to avoid periods when plant uptake of N will be low, such as when soils are saturated, during heavy rain, colder periods and times of low soil temperatures

• Applying N fertiliser in split dressings (as many split doses as possible)

• Irrigating farm dairy effluent to a large enough area

• Adjusting fertiliser policy for effluent irrigated areas to account for the nutrient value of effluent

• Using fenced wetlands and well-managed open drains as nutrient traps.

• The nutrient phosphorus behaves very differently from N because it binds with the soil and only dissolves slowly in water over time. This means it doesn’t readily leach to groundwater. But it can damage the health of waterways by soil erosion and surface run-off into water.

Farmers can reduce the amount of phosphorus run-off by keeping Olsen P to optimum agronomic levels.  Other tips include:

• Following the codes of practice for FertMark and SpreadMark

• Applying fertiliser when the grass is actively growing

• Leaving a grassed buffer strip between paddock and waterway. The strip filters the phosphorus before the run-off reaches the water

• Controlling run-off from tracks, races, feed and stand-off pads.

A clear assessment of fertiliser needs will improve economic returns from pasture and help avoid contamination of ground and surface water with nutrients, particularly nitrogen and phosphorus.

In New Zealand, the common nitrogenous fertilisers are urea (46% N), ammonium sulphate (21% N), DAP (18% N) and calcium ammonium nitrate (27% N). The form of nitrogenous fertiliser best used depends on the cost per unit N and the overall efficiency of the fertiliser N. 

• Bala Tikkisetty is a sustainable agriculture advisor at Waikato Regional Council. This email address is being protected from spambots. You need JavaScript enabled to view it.

More like this

Spring up with fertilisers

With spring in the air and soils starting to warm up over the next few weeks, farmers will be preparing to fertilise their paddocks.

State funding for riparian planting

More than 600km of Taranaki river and stream banks will be planted with a million native plants next winter as the region’s farmers take advantage of a $5 million government boost.

$300m to clean up harbour

A $300 million project has been signed to try and prevent sediment loss from land to sea at Kaipara Harbour.

Featured

 

John Deere names new Aust/NZ head

John Deere Australia/New Zealand’s new managing director Luke Chandler says he will prioritise leading the way in technology and investing in strong relationships.

Trade deal delivers new 'rulebook'

A new trade agreement, the Regional Comprehensive Economic Partnership (RCEP), has been described as a new rule book for trade in the Asian region.

National

Miraka picks up awards

Taupo-based Maori dairy company Miraka took the top honours at this year’s Biosecurity Awards.

Wyeth ready for new challenge

The chief executive-elect of Yili-owned Westland Milk Products Richard Wyeth says he’s looking forward to the challenge of running the…

Machinery & Products

Mixer makes feeding easy

Coolbreene Trust near Taupo is a large-scale dairy operation farming 1150ha, including run-off blocks, within a 10km radius of its…

More colour to light range

Originally available with amber lenses only, Narva’s ‘Geomax’ Heavy Duty LED Strobe Beacon light range has been upgraded with the…

State funding for recycling

Having declared in July that all farm plastics sold in New Zealand will have to be recycled or reused, the…

» The RNG Weather Report

» Latest Print Issues Online

Milking It

Avoiding listeria

OPINION: The company that makes dairy products under “The Collective” brand, and which copped a nearly $500,000 fine for failing…

Greenpeace seeing red

OPINION: Still with Greenpeace, the organisation’s push for a price on agricultural greenhouse gas emissions is gaining momentum since the…

» Connect with Dairy News

» eNewsletter

Subscribe to our weekly newsletter