Friday, July 1, 2022

Putting water on the map

New resource tool helps farmers mitigate water contamination risks.
Different flow pathways dominate in different parts of the landscape.

Losing nutrients before they can be utilised on-farm is costly to a business and can have an adverse impact on water quality.

But to reduce losses, we need to understand how they are transported from the land and identify the areas that are more susceptible to losses. A new web platform has been designed to give farmers insight into what happens on their land and what considerations could minimise water contaminant risks.

“A lot of these contaminants that we’re losing, including nitrogen, phosphorus and sediment are all things we want to keep on our land,” Land and Water Science lead earth and environmental scientist Dr Lisa Pearson says.

“We pay for nutrients through fertiliser and supplementary feed inputs and sediment is our soil.

“These are all things that are necessary for a productive farm system so if you can’t utilise them and they are lost, that’s a financial loss to the farming system as well.”

The web platform, Landscape DNA, is a freely available resource for farmers and their advisors to support decision making on-farm. Pearson explains when farms are more efficient at using their nutrients and have lower losses they are more productive, which is reflected in profits too.

“By using the website farmers can identify areas on their property that are more susceptible to contaminant losses, understand how contaminants travel across the land and which contaminants are largely carried by that pathway,” she says.

This information helps farmers predict which contaminants are likely to be an issue and by matching their knowledge of the landscape and activities, then they can start looking at mitigation strategies to help reduce contaminant loss.

An example could be in an area that is susceptible to overland flow, which is when runoff occurs, farmers could consider mitigations to prevent those contaminants from reaching waterways. Interception could be by a detainment bund or sediment trap, as well as looking at activities that will lower the risk of runoff from the landscape.

The project was funded by the Sustainable Food and Fibre Futures programme from the Ministry for Primary Industries (MPI), with co-funding from Our Land and Water National Science Challenge, the Foundation of Arable Research, Deer Industry, Living Water, Balance and Ravensdown.

“We wanted to understand how and why water quality varies across New Zealand,” she says.

“Nutrients, such as nitrogen and phosphorus, along with sediment and disease-causing microbes, are the main contaminants that degrade water quality and are readily connected to agriculture.

“But we know land-use isn’t the only thing that causes variation in water quality, you do need intensive land-uses to have poor water quality outcomes but in some areas where there is intensive land-use, there isn’t the expected outcome.

“And that’s because processes occurring in the landscape can remove or reduce the contaminant load.”

The platform is geared with robust science and supported with informative videos, but the gold is in the interactive maps. The team behind the project have integrated water quality data with existing map layers, such as soil, geology, topography and land cover and built a landscape classification that models the processes that control the variability of water quality.

Pearson studied at Waikato University and has a Masters and PhD in Geochemistry. She enjoys applying science to bring research to life to benefit farmers. And she and the team are looking at further developments for Landscape DNA.

“In the future, we want to offer packaged information for a specific area. So if someone added a farm boundary, it would create a summary of information that is relevant to the property and match recommended actions specific to the location,” she says.

“We want to help people make better decisions on-farm that are grounded in the landscape, so the landscape becomes front and centre of decision-making.”

Ultimately, they want to support better water quality across NZ and the interest in the platform has been encouraging so far.

“It’s about connecting people to land and water, both rural and urban because we all have an effect on the health of our water bodies,” she says.

“The top of catchments don’t tend to see the issues that accumulate all the way down the catchment.

“But it’s the little things that add up and put stress on the water further down the system and conversely, if we’re all doing little things to improve the quality of the water, it has a cumulative effect and there are better outcomes overall.

“We all need to take responsibility even though we don’t all see the negative effects and those little improvements will help the farm directly too by maintaining nutrients within the farm system.”

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This article first appeared in the May 2022 issue of Dairy Farmer.

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