Thursday, 31 March 2022 12:55

Trial shows CSAs prevent soil damage

Written by  Staff Reporters
Leaving critical source areas (CSAs) in winter forage paddocks ungrazed over winter helps prevent soil losses and water contamination. Leaving critical source areas (CSAs) in winter forage paddocks ungrazed over winter helps prevent soil losses and water contamination.

Farmers are being reminded of the importance of leaving critical source areas in winter forage paddocks ungrazed over winter to prevent soil losses and water contamination.

Beef+Lamb New Zealand's Jane Chrystal says the interim results of a Landcare Trust/AgResearch study 'Understanding the impacts of sheep wintering' reinforced the value of leaving critical source areas (CSAs) ungrazed. The CSAs help trap and retain sediment and contaminant run-off resulting from winter grazing.

Under good practice winter grazing management, CSAs - which are low-lying areas within a paddock such as depressions, gullies and swales - should be fenced off and left ungrazed until spring or summer. Ideally, these areas should be left in grass, which acts as an ideal filter and sediment trap.

Chrystal - B+LNZ's principal science advisor, farm systems & environment - says early results from the trial comparing contaminant loss and sediment trapped on similar paddocks, one where the CSAs were grazed while the other was ungrazed, were consistent and significant.

While both paddocks were sown in kale and under a similar management regime of top-down grazing and two breaks of five days, there was a marked difference in the amount of suspended sediment in the water samples collected from each paddock after rainfall events.

Even before analysing the suspended sediment data, the scientists found visually striking evidence of the immediate effectiveness of the CSA on reducing the loss of soils from the paddocks.

The report states that "these visually striking differences provided an immediate indicator that the CSA was having a demonstrable impact on retaining soil and sediments eroded from the uphill portions of the paddock".

Subsequent analysis of the suspended sediments from all rainfall events throughout the winter of 2021 supported these results.

Chrystal explains that the trial, which started in the winter of 2020, is being run on a commercial farm in Waitahuna, West Otago. The goal is understanding the impacts of winter sheep grazing management on several environmental indicators.

"These results highlight the importance of keeping stock away from CSAs during winte and valuing these areas for their ability to prevent soil and contaminant losses."

She encourages all farmers growing winter forage crops to work through the Forage Cropping Management Plan, which is a chapter in B+LNZ's Farm Plan or available as a stand-alone resource.

"This plan will help farmers identify their risks and plan how they will make the best use of their winter feed resources, while protecting their environment and animal welfare."

More like this

B+LNZ bosses head to Europe

For the first time since Covid-19 travel restrictions were implemented, Beef + Lamb New Zealand (B+LNZ) says it will send a contingent of its leaders overseas.

Hogget lambs - keep or quit?

Should twins born to ewe hoggets and grown out to heavy weights be retained as replacements and mated as ewe lambs?

Getting rams ready

Ensuring rams are in peak condition prior to mating will help maximise their performance and their contribution to the genetic improvement of the commercial flock.

HWEN favours farm levy

Industry levy organisations Beef+Lamb NZ (BLNZ) and DairyNZ claim they've got a strong steer from the recently completed farmer consultation for a farm levy for pricing agricutural emissions.


FMD scare puts NZ on watch

A recent outbreak of Foot and Mouth disease (FMD) in Indonesia has the NZ agriculture sector and its officials on…

Public round up on glyphosate

The country's environmental regulator agency has released the public feedback it has received on the glyphosate weed killer - commonly…

New bee Guy!

Former Agriculture Minister Nathan Guy will take over as the independent chair of Apiculture New Zealand (ApiNZ).

Machinery & Products

A new approach to apprenticeships

By taking a new approach to its apprenticeship programme, agricultural equipment supplier Norwood says it is ensuring farmers’ machinery will…

Buck-Rake does the job

With many self-propelled forage harvester manufacturers offering machines hitting 1000hp, the bottleneck in any harvesting system is always likely to…

» The RNG Weather Report

» Latest Print Issues Online

The Hound

Yeah, right!

OPINION: Your old mate reckons recent ‘research’ carried out by consultants PWC – claiming that ‘actively managed carbon forestry’ creates…

All Claas!

OPINION: Your canine crusader - like many in the sector probably would have - raised an eyebrow when he heard…

» Connect with Rural News

» eNewsletter

Subscribe to our weekly newsletter