Video transcript: Big questions in agriculture need bigger experiments

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September 2012

Professor Philip Murray, Head of Site, North Wyke
The North Wyke Farm Platform is an exciting new facility that is being built by BBSRC and hosted here at North Wyke, part of Rothamsted Research, as a national capability for researchers to come and better understand aspects of grassland farming and farming sustainability. The Farm Platform consists of about 80 hectares of land. Here we've split it into three different farmlets, each of about 20 hectares, all comprising different waste to manage, beef and sheep farming.

Video shows a series of drains and flumes used to measure chemical characteristics of water running off the farm.

Bruce Griffith, Sustainable Soils & Grassland Systems, North Wyke
The reason we can capture all the water in one place on the Farm Platform is down to our soils and the slopes we have here. We have clay soils starting about 30cm deep so any water landing on the land will percolate down through the soil, either run off the top, or hit that clay there and then run sideways down the slopes. And to intercept that, we put in French drains. The drains are 80cm deep. They have a perforated pipe at the bottom of them and then they're back filled to the top with stone.

Video show water in the H flume.

All of the water coming off the 12.5 hectares of land behind us is being channelled down to this H flume. Because we know the geometry of the front of this H flume, and where the water is being channelled through, we simply need to calculate the level inside that, the water level inside that, to be able to turn that into a flow rate. So coming through here at the moment on a drizzly day in the middle of the summer, we've got approximately 1/2 - 3/4 of a litre per second, but during a heavy rainfall event we can expect up to 100 litres per second coming through this flume.

Video shows Bruce Griffith inside the research station.

In here we have a range of sensors that measure the water quality parameters, so the water that is coming off the fields. The first one we have here is a dissolved organic carbon sensor. We'll take that off to have a look at.

Video shows Bruce Griffith showing the dissolved organic carbon sensor.

So this is a UV absorption sensor. The wavelength of light is passed through the water and it measures what is absorbed. So that's measuring dissolved organic carbon. And at present we can see that in the last 15 minutes the carbon's DOC content was 22.5mg per litre.

Video shows Bruce Griffith showing the multi-parameter sonde sensor.

Another sensor we have, this is a multi-parameter sonde measuring a range of sensors, a range of parameters. This one is measuring pH, conductivity and temperature, turbidity, chloride, ammonium, and dissolved oxygen.

Professor Philip Murray
The three systems that we're comparing on the Farm Platform are increase in the use of nitrogen on the existing permanent grassland, to reduce the amount of nitrogen that we use and increasingly use biologically fixed nitrogen from legumes, and thirdly in a rotational system to include new varieties of grasses and legumes.

Bruce Griffith
So all this data is pumped into the boxes, the computers, so we've got a present 2.9mg per litre of nitrate and nitrite N coming in off the fields. The carbon sensors are reading 21.4mg per litre of dissolved organic carbon. This device is the bubble meter, so this is a device measuring flow inside the flumes. So at present we've got 25.2mm of water level inside the flume, which equates to 0.6 litres per second. So all that data is transferred to a radio telemetry unit inside this box and that's beamed up to site using a UHF radio every 15 minutes.

Professor Philip Murray
We're comparing the different farms through a number of means. We're looking at all aspects from production through to looking at the environmental impacts, for example water quality, air quality, and grassland quality. But on top of that we're also looking at the economic aspects of that in terms of how much fertiliser we're using, how much diesel we're using, how many man hours and tractor hours that are going into managing each of the three systems.

Video shows a 3D landscape of the Farm Platform.

Dr Anita Shepherd, Sustainable Soils & Grassland Systems, North Wyke
We're looking at a 3D landscape of the Farm Platform. This is created from a 3D geographical information system using an aerial photograph, over layered on radar, and also digitised information. We can see, in red, the dots are the 25 metre sampling grid and the blue lines are the drainage from the hydrologically isolated fields.

Professor Philip Murray
One of the big challenges in the food security area is about feeding more people globally. At North Wyke here we're setup now to understand how we can do that on a grassland system.



This video may be reproduced in its entirety with due credit to BBSRC.

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Image and video credits:

  • 3D Spatial Modeling System animations created by Anita Shepherd and Bruce Griffith
  • Sound from cinephonix.com