2018 05 17 11.13.27

Growing high value crops in a dry season

10/09/2018

Fenland farmer David Hoyles is renowned as a grower of high yielding crops, especially wheat for which he is a past record holder. But to maximise margins across the range of crops grown on the 700 ha family enterprise he has become increasingly concerned with quality, timely production and efficiency.

You can read about the steps he has taken to improve yields and quality in September's Anglia Farmer or continue reading below:

Apart from wheat, David's seven-year rotation on three farms between Wisbech and the Wash includes sugarbeet, vining peas, mustard, potatoes and beetroot. Since 2015 his attention has turned to the last two, comprising 110 ha of potatoes and 35 ha of beetroot. Both are grown for the quality end of the market.

The Grade 1, Wisbech series silt is a fine, powdery soil effectively free of stones which holds moisture well. Even so, to avoid scab on potatoes the ridge needs to be moist as the tubers form. Ideally this means they need to have been well watered two to three weeks after emergence.

If there is insufficient rainfall irrigation is required. None of the farms under David’s management had irrigation which meant they were at the mercy of the weather. In poor years this could result in failure to achieve a quality premium for the contracted volume.

First reservoir

In autumn 2015 he built the first reservoir and installed an irrigation system on one farm under the LEADER (Liaison Entre Actions de Développement de l’Économie Rurale)grant scheme. Awarded through South Lincolnshire’s ‘Wash Fens’ programme the grant was paid via the RPA and covered 40% of the equipment, although not the 18 million gallon reservoir. In the first season this was more than enough for his irrigation requirements.

“In 2016 we used very little water; primarily for beetroot emergence and to aid the potato harvest. In 2017 we used much more, partly because even though the rainfall figure for May was average, it came in 24 hours with long dry periods in between. 

The success of the first system, which is based on two Briggs Irrigation hosereels and 64 metre booms, which irrigate to 72m, has led to a second installation on land fronting the River Nene in Cambridgeshire. In this case the Cambridgshire Local Action Group (LAG) scheme has included grant aid for the (lagoon) underground mains.

The systems were designed by Adrian Colwill of Briggs Irrigation for maximum efficiency and ease of use. On the second site a small 5 million-gallon, lined reservoir has been created next to the river. While this is insufficient for a whole season, David aims to top it up at times when water is available and the quality is suitable. As the farm is two metres below sea level salinity is an issue and the abstraction pump is fitted with a conductivity meter to monitor salt content and stop water flow if necessary.

On both systems a 200 mm main has been installed by Philip Millington Water Services to ensure there is adequate water pressure throughout farm. The fields are served by 160 mm spurs and hydrants have been installed every 72 metres – the wetted width of the Briggs R64/2 boom – to avoid long feed pipes to the VR7 hosereel, fitted with 600 metres of 110 mm diameter hose.

With very little pressure loss throughout the system a 55 kW (75 hp) rated electric pump can easily maintain the 7 to 8 bar pressure requirement throughout the network. A relatively small 5.5kW submersible pump in the lagoon maintains positive pressure to the main pump house and the total power requirement is therefore kept to a minimum at around 18-19 kW with 1 machine working and 36kW with 2 machines working; an efficiency objective that fits well with the requirements of the grant scheme.

Comprehensive controls

The pump house, specified and constructed off-site by Powerflow Systems of Usk, includes a comprehensive control system inside the secure, shipping style container. The variable speed control system ensures there are no ‘spikes’ in power consumption on start up and reduces the effect of water hammer at the beginning and end of the irrigation cycle.  A digital water meter allows easy detection of leaks and automatic shut down in the event of low or high flow scenarios.

Attention to detail is equally evident in the application of water. The booms provide far greater accuracy - especially under the windy condition that are common in this part of the fens – than a raingun. David also wants to ensure the ridge is wetted rather than allowing water to run down the sides into the trough. This can be achieved by reducing the instantaneous application rate by using nozzles with a large diameter and an even spread throughout the radius. Brown deflector plates work at a 14 – 15m diameter and deflect the water evenly due to multi trajectory streams. Reduced nozzle sizes during the early part of the year until ‘canopy cover’ are being used to lower the instantaneous application rate. Each 15 mm application can therefore be applied uniformly and gently with an increased wetted area. 

Under ‘normal’, dry conditions water will be applied 10 days after 50% leaf emergence and then throughout the growing season as required. This season the exceptionally dry spell meant continuous irrigation was needed for nine weeks, until the reservoir ran out in mid July. By this time the drain that supplies it was too low for further extraction.

“On these farms I have achieved my objectives of security of water supply under normal conditions, plus the ability to manage water for maximum quality. We have already seen the financial benefits for the beetroot in particular where irrigation helped us bring a good quality crop to the market ahead of the competition. On potatoes I anticipate this year our yields will still be down by 20% where we have irrigated because the temperature was too high for growth. However, our unirrigated yields are likely to be down by 30-40% at the very least; irrigation certainly helped to set the crop up. Looking ahead, if we are to maintain our relationship with the high quality retailers I believe we need to be able to ensure we meet our obligations for quality and volume and that will require effective irrigatin,” David explained.