The next of our insights into the people and science supported by TMAF features David Purdy. For David, our backing is enabling him to take his observations and questions from years as machinery specialist and soil enthusiast into studying soil health as part of a PhD programme.
“You might wonder why a slightly mature machinery sales representative is interested in a PhD? I often ask myself the same question. But it all comes out of my passion, a passion that goes right through my career, for the importance of healthy soil and the impact of soil-plant relationships. The other thing – and it may sound hypocritical coming from a machinery person – is to find the optimal way of using machinery to reduce any damaging impact they may have on our soils.
When I see soil damage, I want to know the cause. Too much rainfall or not enough infiltration? Over cultivation? Loss of organic matter? Too much field traffic? Too heavy? Or a combination of all of those things? But there must be solutions, to create a more resilient system. For there are some serious economic implications of the impacts we are having on our soils. So, the question I want my research to answer is this: can plants, in particular cover crops, deliver better soil structure? levels and depths of soil disturbance is actually required. In short, the roots versus iron debate.
From the ground up
As a machinery person, for my studies I have had to become a biological and plant-based person as well. I am conducting my research around three topics:
- What is the role of cover crops and companion crops on soil health and crop yields, including their establishment methods?
- Can plant roots systems help alleviate the effect of compaction?
- What do we find in a strategic examination of tillage especially ultra-low disturbance technology?
A site for sore eyes
My extensive trials are at Agrovista’s Project Lamport site in the East Midlands where I have more than 100 plots, 12m x 12m each.
Agrovista Technical Manager Mark Hemmant says that my work is exceptionally complementary to what is already being done at Project Lamport, looking at long term rotational systems to control blackgrass and improve soil health plus investigating the best combination of cover crops and cultivation. He welcomes my research because it is putting the science and numbers behind a lot of what they are trying to do on the same site. See Agrovista’s latest summary of the work underway.
Made to measure
Of the experiments running at Lamport so far, the first, now in its second year, includes different cover crop species along with different establishment practices.
The second experiment, also in its second year, looks at ultra-low soil tillage at two depths and levels of soil compaction produced by tyres at 18psi and 9psi and then biological treatments comparing no cover crops with black oat and phacelia combined.
There are further pot experiments looking at biomass production of cover crops from different timings of establishment
The first phase of experiments has been in two very different autumns: one dry, one wet which has had its challenges. First, the cover crops struggled with lack of moisture and next autumn they struggled with too much!
In addition to the many biological and physical measurements, I have had to develop a way to really assess soil and plant health to help understand the often-complex interactions that exist in an agricultural production system.
Also, being a machinery person, you would expect me to get as much technology as possible which has included telematics to gather as much machine data as I can and normalized difference vegetation index (NDVI – a simple graphical indicator that can be used to analyse remote sensing measurements, often from a space platform, assessing whether or not the target being observed contains live green vegetation) we’re starting to tease out some really, really interesting data out of all this.
Early results
Results from the first couple of years are showing that plant root systems are creating very strong biological and physical responses. Examples are worm numbers are increasing and soil structure improving along with many other interesting changes.
So that’s the kind of production systems approach philosophy really that I’m trying to research and come up with some practical farmer-relevant findings. I still feel I’m no scientist, but I’m really enjoying this and part-time while continuing to work as Territory Manager for John Deere to be researching what I feel very passionate about.
With the help of Professor Karl Ritz, Professor Debbie Sparkes and Professor Sasha Mooney, all from University of Nottingham, and support from Agrovista and TMAF, I’m making some progress already.”
