Yield secrets could be buried in our soils

Ploughing in Heacham. Picture: Ian Burt

Considering its fundamental importance to life on earth, it seems incredible that a resource as crucial as the soil could be taken for granted.

But, as a major report highlighted in December, farmers' greatest asset is not in the best of health.

The United Nations report, published to mark the end of the International Year of Soils, concluded that the majority of the world's soil resources are in 'fair, poor or very poor condition' with the greatest threats being erosion, loss of organic carbon and nutrient imbalance.

But after decades of neglect, the topic of soil health is now the subject of industry-wide discussion at scientific, commercial and governmental levels.

And East Anglia has become the proving ground for a partnership between growers and academics, aiming to give farmers the data to make more informed decisions on how to keep their soils in prime condition.

Farms across the region are contributing valuable soil data to a pioneering 'agri-informatics' system, designed to give growers more accurate intelligence on yield, efficiency and crop performance.

The soil information management system, named Soil for Life (SFL), began as a government-funded Knowledge Transfer Partnership (KTP) between Produce World, one of the UK's largest vegetable growers, and academic partners at Cranfield University.

It aims to generate a central database from the treasure trove of disjointed information held in farm records, spreadsheets and filing cabinets – including nutrient applications, land use and rotation, environmental measures, soil samples, cultivations, fertiliser regimes and irrigation.

The partners hope this information can be combined into 'big data' sets which can be statistically analysed to optimise soil fertility, match crops to soil type, and therefore improve the marketable yield of vegetables and the sustainability of farming businesses.

Guy Thallon, head of research, development and innovation at the Peterborough-based Produce World Group, said: 'We recognised that in businesses such as these, there is a huge amount of data that is captured and put into a filing cabinet. It has never been properly used or analysed to its full capacity, even though it has cost the farm up to £100 per sample. So there is a lot of opportunity there.

'Once we have got that data, we can compare one farm with another and start to look at similarities. That is where things start to get really exciting.

'This is a science that has never been applied to agriculture at a farm scale. We've started to use computational statistics and that is where the experts at Cranfield come in.'

During its three-year KTP phase, a prototype data set was created for 4,000 hectares of brassica crops, spread across five Produce World growers.

'That data set has enabled us to get to a position where we can predict 70pc of the variability on a brassica crop from a yield and quality perspective,' said Mr Thallon. 'That is just a small sample set and we were surprised by the amount of data that came out of it.'

After its initial phase, the partners secured a £250,000 award from the Agritech Catalyst Fund to widen the project for a second three-year period, now working with 10 growers across Produce World's supply chain.

One of them is Taylorgrown, which produces 500 acres of organic vegetables on the Houghton Estate in Norfolk.

Farm manager Joe Rolfe said: 'There are a lot of decisions we make because we think we know the answers. But this is about validating those decisions.

'In the short term, it is about investment in kit, planning where the crop goes in certain fields and in rotations, the amount of nutrients you put on, and the effect on yield. Then the longer term strategy would be to ask is this the best place to farm this crop, or is this the best time of year to achieve that?

'Organic farming is all about taking that long-term view. Because we cannot use insecticides, we learn more about pest life cycles and how they feed and when they come into the crop and how they mate. The more we understand about farming, the more we can do about it.

'We have a certain amount of soil information from our landlord, but it is about measuring right down to the trace elements like magnesium, manganese and boron, not just the key nutrients.

'In 10 years we will have an amazing amount of information. I wish I had this data for 100 years. It is minimising risk through experience.

Back to our roots

The solutions to soil health are a complex conundrum including better use of machinery to reduce compaction and improve drainage, cultivation techniques, crop genetics, rotations, and how best to place nutrients to feed the millions of micro-organisms which help the soil to support healthy plants.

But for one commercial expert, one of the most important factors in this 'Brown Revolution' is improving roots.

Mark Law, managing director of Law Fertilisers, based in Wimblington, near March in Cambridgeshire, said the yield potential of UK crops is being limited by inadequate rooting.

He said recent research from agricultural consultancy ADAS had found there were now 400pc fewer roots in the topsoil compared to the 1970s and 1980s, with the trend towards minimum tillage methods contributing to the problem, as nutrients were not distributed deeply enough for uptake by longer roots.

'In medieval times when farmers first took a plough to a field they doubled their yield overnight,' he said.

'Now with min-till we are going back to the situation where the nutrients are not returned to the roots.

'With the lack of ploughing there has been a concentration of base fertiliser within the top part of the soil. There is evidence to show a reduction at the lower levels of the topsoils, in particular there is a massive reduction in phosphorus, which is the key nutrient for plant growth.

'If you get this concentrated zone in the top soil then you won't get the vigorous root growth you need for record-breaking crops.

'The bigger the root structure the bigger the crop, and the better the nutrient and water uptake will be. If you have got this concentrated layer in the topsoil the roots will be lazy, and they will stay in that zone. We want them to be encouraged to be as deep as possible.'

Mr Law also urged growers and agronomists to consider rooting traits when choosing crop varieties.

He said one of his customers, near Downham Market in west Norfolk, made an extra 10 tonnes per acre, equating to a £1,500 per acre of extra income, by simply changing his potato variety to one with more favourable rooting structures for his soil type.

'People need to understand that roots are the fundamental factors in yield potential,' he said. 'We need to manage crops for better rooting, through a combination of minimising machinery passes, placement of phosphates, careful organic manuring, application of root based trace elements and reduced application of pesticides, some of which may be harmful to soil microorganisms.'