Wednesday, 5 November 2014

PhD students contributing to PGP success


Benefits are already flowing from Ravensdown's Primary Growth Partnership (PGP) programme focused on transforming hill country farms through the precision application of fertiliser.

​Two students at Massey University are completing their PhD's with part of the research associated with the programme and a further two PhD students are to be appointed. A third student completing a Masters of Philosophy (Science) is associated with a research project funded by Ravensdown.

The Pioneering to Precision PGP programme is a partnership between Ravensdown and the Ministry for Primary Industries (MPI) with research carried out by Massey University and AgResearch. It is a seven-year programme that aims to improve hill country sheep and beef farming productivity, while protecting the environment through more efficient application of fertiliser.

The globally-recognised Precision Agriculture Group at Massey University is helping define the science which will allow the aerial scanning of farms to flow through to improved accuracy in applying fertiliser.

Among the students working on the project is born-and-raised Kiwi, Pip McVeagh, who is completing her PhD research topic on site specific pasture production in New Zealand hill country.

Her aim is to develop a detailed understanding of pasture production and pasture ecology, and how a range of spatial factors can determine nutrient needs and impact on pasture production in a hill country farming system.

“Fertiliser is a big financial investment for hill country farmers, and many sheep and beef farmers are struggling to sustain a reasonable profit – hill country farming is typically low profit,” she said.

“The research we are doing will help to improve grazing and stock management strategies of hill country farmers because this research will provide them with a more in-depth understanding of the spatial variation in pasture production over the landscape.”

McVeagh has been working on the PGP programme for the past five months and is part of the fieldwork team who collect site-specific data and develop ways to use Geographical Information Systems (GIS) to store, analyse and display that data.

The information collected includes sensed data, pasture and soil samples which will be used to evaluate how remote sensing technology can be used to direct fertiliser applications.

Irishman Tommy Cushnahan is completing his PhD on the initial phase of the PGP programme which involves developing hyperspectral remote sensing and imaging technology. The new technology will be used to categorise hill country pasture in a way that is meaningful for the farmer.

Aircraft-borne hyperspectral sensors will be used to take instrument measurements of the pasture and soil. Cushnahan will then develop a method to calculate the mix of plant species in any given site and its nutrient content. This information will help categorise the productivity and usefulness of current pasture or terrain and allow hill country farmers to make informed decisions about how to get the best returns from each area in the future.

The hyperspectral sensors collect reflected light in much the same way a normal camera does. However, the real difference is that these sensors collect light from well outside the range of what the human eye can see. As the images contain a lot of information there is a need to develop ways to isolate and examine the relevant data to help understand what is happening at the pasture and plant level.

Cushnahan relocated to New Zealand with his wife, a Kiwi, in 2008. He was attracted to the PGP programme because it had practical applications for farmers in New Zealand and the rest of the world.

“Our population is increasing worldwide and we need to start utilising land more effectively,” Cushnahan said.

Massey University student Sue Chok is also completing her Masters of Philosophy (Science) as part of the research in support of the PGP programme. She is helping to develop the automated fertiliser delivery control system that will be applied to a standard aerial topdressing aircraft.

Chok has a bachelor in environmental engineering but developed an interest in agriculture while working as an intern for Massey University and the Fertiliser Quality Control Council in the summer of 2013/2014.

Her main goal is to validate a particle ballistics model which predicts where a fertiliser particle will land once it is released via an automatic hopper door.

“Being able to predict this information will allow us to take into consideration various weather patterns such as the effects of wind when topdressing,” she said.

Today’s aerial spreading techniques of broadcast application or blanket coverage are not always as accurate as they need to be – leading to lower levels of production and potential impacts on the environment. Fertiliser is currently dropped via a manual hopper door that is controlled by a pilot but new variable rate technology (VRAT) will allow the fertiliser to be dropped via a fully automated process that is linked to an aircraft’s Global Positioning System (GPS). This will provide more accurate fertiliser application, at an optimum rate for hill country farmland.

“From the PGP programme, we will be able to understand the nutrient information of hill country farmland. Once this is known variable rate application can better target where the fertiliser is going and avoid other areas such as neighbouring river systems,” Chok said.

“The end goal is to increase productivity and profitability for farmers while lowering the impact of fertiliser application on the natural environment.”

Ravensdown Innovation and Strategy General Manager Mike Manning, who was at the forefront of the programme’s initiation, says it is very satisfying to see keen Kiwis undertaking their high level studies as part of this PGP programme.

“The country needs these people investing their talents to the benefit of hill country farmers and New Zealand. We can all be rightfully proud that we are leading the the world with the application of this technology."