Timely event on improving water management

The topics for Agri-Tech East’s Pollinator Events are set some time in advance, so it seemed to be prescient that Director Dr Belinda Clarke had chosen improving water management through innovation as the topic for the meeting immediately following one of the driest summers on record.

Opening the event at Easton & Otley College’s Easton Campus near Norwich, chairman Paul Hammett, the NFU’s National Specialist on Water Resources, said that while this summer has been extremely challenging, “having the experience fresh in our minds gives us the opportunity to ask good questions, such as: What lessons have we learnt for next time?”

In order to understand what we can learn from this year, it is necessary to know exactly how bad it has been, with Professor Jerry Knox of the Cranfield Water Science Institute (CWSI) at Cranfield University describing it as, “one of the Biblical droughts of the last 30 years.” Using data from Buxton in Norfolk, he showed that 2018 has produced the highest potential soil moisture deficit (and therefore the highest irrigation demand) since 1981, and that the pattern of moisture deficit very closely followed that seen in 1976, although the deficit began earlier that year (early March as opposed to May) as the winter of 1975/76 was also very dry.

He also pointed out that 1920, and not 1976, was the worst drought on record. “Demand for irrigation is always a function of evapotranspiration and rainfall,” explained Jerry. “In 2018 evapotranspiration rates have been broadly similar to the average, but rainfall has been negligible for several months.”

He also warned that recent rainfall did not mean that the drought was over, and that the ongoing effects could be felt well into next season, even if we do experience a ‘normal’ winter. “What if the dry summer carries on?” he asked. “It will take much longer to return fields to field capacity, and also create problems for both cultivation and groundwater recharge. Meteorologically 2018 has been more like 1976 and we know that historically droughts come in pairs.”

He also pointed out that the winter will be critical, with an average or dry winter seriously impacting on the ability to refill reservoirs and challenging the 2019 planting season. “What are we going to do next year as a consequence of this year?” he asked.

Strategic planning

While there might not be any easy answers to such questions, there may be small comfort from the fact that some strategic planning is already in place looking at how to cope with increased demands and less availability across the whole water sector, not just agriculture. “We see things getting worse in the future and collaboration is the only way to deal with that,” stressed Steve Moncaster, Anglian Water’s Supply Demand Strategy Manager. He outlined the planning process and scenarios behind the Water Resources East (WRE) project; a multi-sector resource planning tool for long term water resilience which aims to develop a supply and demand strategy for the 2060s.

“We want [the strategy] to be resilient and sustainable, but it’s also got to be affordable,” stressed Steve. When planning we have to come up with stuff that works in as many scenarios as possible.” In fact, the model used by WRE looks at almost 300 different scenarios, including different combinations of climate change effects, economic growth and people’s behaviour.

“This process forces people to get quantitative and to think very hard,” he added. “We have looked at vulnerabilities in the existing systems and found that we could see a supply deficit of 750 megalitres a day, which is equivalent to three-quarters of our current daily supply.” This is due, not only to increased demand, but issues such as climate change and reduced abstraction from groundwater sources.

Some of the measures selected by the WRE process include the importation of water from other regions, new reservoir capacity to capture high winter flows, desalination and water re-use at key locations on the east coast, and a number of strategic transfers across the region. Demand management across all sectors, including domestic users, power generation and agriculture will also be required.

Furthermore, having completed this first phase of planning, new communications from Defra, the Environment Agency and Ofwat, as well as recent reports from the National Infrastructure Commission and the Environment Agency means that further work is required as part of ‘Phase II’. “Although this is long term work, we need to get into it pretty quickly,” warned Steve. “It’s about collaboration and it can be done. This is the future and we need to make it work.”

Developing solutions

Another area of work undertaken as part of the WRE project has been developing solutions at a catchment level, some of which can then be scaled up or copied elsewhere. Therefore the Water Sensitive Farming catchment based approach described by Ed Bramham-Jones of the Norfolk Rivers Trust could lead to major changes in practical farming techniques to conserve water and prevent both direct and diffuse pollution of water courses.

The catchments covered by Ed include the Broadland, Cam and Ely Ouse, North Norfolk and West Norfolk, with a focus on soil and water management and funding from sponsors including WWF and Coca Cola Freshwater’s Partnership. Acknowledging that farming is just one of a number of pressures which mean that 85 per cent of rivers are failing to meet ‘Good Status’ as defined under the Water Framework Directive, he also pointed out that in East Anglia, over 80 per cent of the land use is agricultural.

As with Anglian Water, a partnership approach is the key to success and best practice needs to be adapted to work in each individual situation. Ed described a range of methods to reduce run off from cover crops and buffer strips, to tree planting, reduced tillage and traffic control.

Reducing run-off

He also presented results from a project at the Elveden SPot Farm East looking at reducing runoff from wheelings in crops of potatoes irrigated by booms and rain guns. These showed that all of the tried methods significantly reduced runoff, with the best results coming from Bye Engineering’s Wonder Wheel machine. A tied ridge, which produced small dams across the wheelings, was also effective, but caused issues for tractor drivers throughout the season.

Constructed wetlands are also becoming popular, not only as a way of creating wildlife habitats, but also of intercepting nutrients such as phosphates and nitrates and preventing them from entering local water courses. Early data from a newly created wetland at Frogshall in Norfolk suggests that up to 90 per cent of phosphates are removed from water draining from, and running off fields, and has led to another project, this time with Anglian Water, at Ingoldisthorpe.

Another way to reduce loses of nitrogen and phosphate is to change the chemistry of the appropriate ions in the fertiliser and/or the soil. Verdesian Life Sciences is a US-based company that is now introducing its polymer-based fertiliser coating technology to the European market. Its Nutrisphere-N product stabilises both urea and urea ammonium nitrate (UAN) fertilisers in liquid and granular forms, reducing losses from volatilisation, leaching and denitrification, while AVAIL prevents phosphate losses, but leaves it available to the crop.

Although the company says it has treated over 27 million hectares around the world, UK farmers and growers will be particularly interested in the results of a number of UK trials which are just beginning, including one being conducted with NIAB at Salle Farms in Norfolk.

Drip irrigation

Drip irrigation is another important method of reducing both the amount of water applied through irrigation, but also associated runoff, and Andrew Howesman, Managing Director of Howesman Agriculture Ltd urged researchers to do more to include it in trials and demonstrations, such as those at Elveden SPot Farm.

Over the years a number of growers, particularly those growing field scale vegetables and potatoes, have tried different forms of drip irrigation with limited results. This, and the fact that it is often perceived as being more expensive, means that there can be a reluctance to try the technique.

However, Andrew points out that,” a lot of people don’t know what their current irrigation costs are,” adding; “previously drip irrigation was often sold for specific uses, and growers are often reluctant to change what they are doing.” His solution is to offer a fully managed irrigation solution for 15-20 acres, including planning, setting up and recovery, with a system that can be hired or purchased. This allows growers to see the benefits for themselves before committing to a large system, and with 1,000 acres of drip irrigation commissioned this year, the scheme is going from strength to strength.

However, it is important that growers realise that the days of being able to use drip irrigation without a licence are now over. Paul Hammett explained that the two-year application window to apply for drip irrigation licences opened at the start of this year and closes on 31 December 2019. Based on current usage, the Environment Agency expects to receive around 5,000 applications for drip irrigation licences, but to date has received just 100. “We have an enormous communications job,” he added. “It is vital that growers apply for what they need.”