Growers of outdoor crops face numerous challenges when it comes to irrigation that their indoor counterparts do not have to contend with. In particular, the way they manage water use over large areas, predict weather patterns and deal with climatic anomalies is crucial to the overall success of the crop.
There are numerous projects currently looking at outdoor irrigation, one of which is Hort Link’s HL0165 - ‘precision irrigation and nutrient uptake’ (PINT).
According to Howard Hilton of the University of Warwick, the project has demonstrated that field vegetables can be grown to a commercial standard with reduced fertiliser and irrigation through careful soil moisture monitoring and fertigation. Though PINT is soon set to come to an end, researchers hope to continue the work through other sources of funding, where they will attempt to provide evidence encouraging growers to reduce ‘inadvertently wasted water’ using the novel irrigation system developed in PINT. Further work hopes to incorporate meteorological forecasting data, with the premise being that by using probabilities of rainfall events, it should be possible to evaluate whether irrigation one day will be wasteful because it will rain the next, and so on.
Hilton believes that the level of interest by growers and producers in irrigation research projects is a reflection of their keenness to address the problem of water scarcity. “I think the pressure for growers to justify their water use will result in a greater take-up of efficient ways of both applying and monitoring irrigation,” Hilton explains.
On the subject of drip irrigation on a field basis, Hilton had this to say: “I understand drip irrigation has not been taken up a massive amount in the UK by growers, but I think this is likely to change in the future, particularly on high value longer-length field grown crops. In addition to local authority pressure, there is likely to be public and media attention to water use so a grower being seen to use rain guns on their crop may not be viewed as favourably as one using drip or sprinklers. This is irrespective of their efficiency because managed correctly, a rain gun has proven to be as effective as other methods of irrigation.”
Other projects on the go, Hilton explains, include one on climate change, which is collating opinions and current practices to climate change (including water use). Also outside of Warwick HRI subjects under the microscope include looking at such things as partial root drying.
The key thread passing through much of the research being done is the drive for efficient water use. Andrew Thompson’s Defra water use project aims to develop tools and information for breeders to help with the production of crops with improved water efficiency. This is measured at the leaf level using carbon and oxygen isotope discrimination and at the field level by simple biomass calculations, Hilton explains, while regions of chromosomes are identified from populations of plants available from the Warwick HRI gene bank.
HRI also has projects looking at rooting traits of Solanum mapping populations with a goal of relating these traits to water use efficiency, as well as further molecular ABA relations work.
The technique of drip irrigation, which has been developed in Israel, the United States and elsewhere, has proven highly effective in providing effective water management across a number of field crops including potatoes, carrots, leaks and also soft fruit, among others.
Leading irrigators Field (GB) recently announced a tie-up with Israeli firm Plastro Irrigation Company to market their range of drip irrigation equipment and specialised sprinklers in the UK.
Plastro has 13 international subsidiaries as well as manufacturing facilities located around the world. To the firm’s range Field is also promoting its own range of control equipment, its range of pumping, filtration and UV treatment equipment, as well as fertigation equipment to make use of efficient drip systems.
Peter Youngs of the UK Irrigation Association’s executive council, said that the industry was always looking at new developments in field irrigation, whether it be in terms of weather forecasting, on-farm storage or trickle irrigation, the latter which he feels however is ‘not really a viable option’ for field scale use.
Youngs feels that climate change will have a significant effect on the way growers farm outdoors, with more flash rainfall and less of a steady flow. He believes that while there are places where dirty water could be collected and used, these are likely to be limited with drainage water a better option. He says that it is important for growers to be seen as being efficient in terms of water, particularly with the danger that the Environment Agency can restrict abstraction when it perceives there to be a drought.
UK firm Plantsystems believes that a range of approaches can be taken to ensuring that every drop of water used is made to count. This can range from detailed irrigation scheduling and monitoring, to weather data reporting, soil moisture sensing and reservoir level sensing.
The company is one of several talking up the benefits of accurate weather forecasting and data reporting, looking at information such as rainfall, temperature, wind speed, wind direction, relative humidity and solar radiation. Its service is said to generate daily values of local potential evapotranspiration from which crop water use can be calculated. Local rainfall is calculated as it arrives allowing effective daily fieldwork planning.
The company is a leading supplier of weather stations to the UK agriculture industry, and has supplied and operated Adcon weather stations in this country since 1996. Its equipment delivers real-time data from farms to Plantsystems data servers every 15 minutes, while in intensive areas networked VHF radio telemetry is used to link all devices.
Data is primarily used for disease modelling and prediction, according to the company, but also for irrigation scheduling as daily E10 values are automatically generated by the system software. Contractors are also able to use the wind data to gauge suitable spraying conditions.
Plantsystems also offers an irrigation sensing service to help managers measure the quantity of applied water and see its effect on the soil water reserve in a few hours. They are then able to adjust the frequency and quantity of applied irrigation to achieve the desired result and avoid over and under irrigation.
Wroot Water meanwhile says that retrieving drip tape from a crop at the end of a season prior to harvest can be a headache for growers. The company believes its ‘Tape Master’ automated tape retrieval system, mounted on the rear of a tractor, can provide a solution.
Its main winding spool is hydraulically driven with a variable speed operated from the tractor cab, enabling the wind-in speed to be matched to the forward speed of the tractor, with working speeds of four to 12mph, at 1200-1800rpm.
A pivoting arm is attached to the spool so that the tape can be picked up at the row ends without the operator leaving the seat. The tapes are tied in a loop, the arm picks up the tape, and the speed of the spool can be varied as the tractor travels over the field to match the forward speed and quantity of tape on the spool.
According to Wroot, today’s drip irrigation systems are becoming larger each year with a greater element of operation time required. The company is promoting a solution to integrated functionality in the shape of a fully automated system with a central control unit with a radio transmitter. Radio receivers are then situated on the pump, filtration unit, fertigation unit and individual valve stations. The central computer is programmed to the grower’s requirements, with irrigation cycles being programmed in either real time or by water flow.
Prominent irrigation specialist Briggs has also been active in developing new technology for the sector this season. The company successfully completed farm trials last year, with its new R40 mounted irrigation boom now in full production. The largest machine in the mounted boom range, the R40 can be mounted on hosereels from 82/350 to 100/500 and includes an upgraded chassis with larger diameter wheels and wider tyre profile.
In a busy period for the firm, Briggs also unveiled a new range of JCB engine powered pumps at the recent Lamma show, which are said to be economical and quiet running, and comply with tighter emissions regulations.
Briggs has also reported interest in its water saving tied ridger, a machine that forms small dams between ridged crops to reduce run off and conserve water.
Meanwhile Hortech has been talking up the benefits of the Dynamic 40 series of self-cleaning mesh filters. This consists of two self-cleaning filters with automatic regeneration of the filtering element, all of which is managed by a built-in computer which controls a variable duration washing cycle, if a filter clog is detected, or following an interval of time set up by the user.
In both cases, the firm explains, cleaning occurs without interrupting the flow, by means of mobile scanners which adhere to the entire filtering surface. The unit also features pressure transducers, and allows computer controls to filter the operation and manage all stages of use. Applications for the self-cleaning mesh filters include the ability to protect downstream quartzite filters and centrifugal separators. It is said to be ideal for systems requiring high corrosion and oxidation resistance. l
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