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22/02/2010 13:45:04
Soil moisture sensors help researchers to grow strawberries with less water
East Malling Research (EMR) is an independent research, development and consultancy organisation that serves the food chain and other sectors of the land-based industry. Research is underway at EMR in a Horticulture Link project (HL0187) co-funded by Defra and a grower industry consortium to find ways to reduce the amount of water required when growing strawberries.
Compared to some other crops, strawberries are not particularly big users of water, but they are a valuable crop for which irrigation is essential to maintain yields and quality, plus most UK strawberry production is in regions in which fresh water is currently abstracted at unsustainable rates. A key element in EMR’s research into strawberry irrigation has been the Decagon Devices soil moisture sensors and data loggers supplied by Labcell.
EMR has run numerous experiments using EC-20 (20cm-long volumetric water content), EC-TE (soil moisture, temperature and electrical conductivity), MPS-1 (dielectric water potential) and 10-HS (dielectric permittivity and volumetric water content) sensors to monitor soil moisture and other parameters. For the strawberry field trials, EC-20 sensors have been employed, together with a few MPS-1 sensors, to monitor soil water content and potential under a range of irrigation scheduling regimes. Field trials were performed in fifteen 12m-long beds; by the end of the 2009 cropping season, these beds contained 45 sensors, with data being logged by nine Em50 data loggers.
The sensors were buried at various depths within the rooting zone of the plants, with data logged continuously; data were logged hourly from Em50 loggers and downloaded twice-weekly to a handheld PC. While EMR used Microsoft Excel to analyse and plot the data, one of EMR’s project partners, Dr Martin Wood of Earthcare Environmental, used the Decagon DataTrac software to study the same data.
In addition to the soil moisture sensors, EMR have used three Decagon leaf wetness sensors during plant establishment in the strawberry plot. In other field and pot experiments, EMR currently use Decagon sensors to measure soil moisture content, water potential, electrical conductivity and temperature under strawberry and potato plants.
Working with data collected from the various sensors, including those supplied by Labcell, EMR’s researchers aim to develop a Partial Rootzone Drying (PRD) irrigation technique for field grown strawberries; this tricks the strawberry plants into growing as if they are in dry soil, which causes them to conserve water by closing the stomata and reducing leaf growth. By watering only half of the root zone on each occasion, the ’dry’ roots produce chemical signals that are required to trigger these shoot responses, while roots in the other half of the root zone receive sufficient water to maintain shoot turgor and fruit production. Irrigation is applied through a drip tape, and is scheduled manually when the sensors indicate that the soil moisture has reached a predefined lower limit. Previous Defra funded research at EMR has shown that experimental PRD regimes on pot grown strawberry plants could maintain commercial yields and, in some cases, improve the flavour, texture and antioxidant properties of the fruit.
The next stage in this project is to run grower trials to identify an irrigation regime that is suitable for use in commercial strawberry production. Moreover, the same approaches and technologies can be adapted to address the specific water requirements of a wide range of crops and horticulture industries.
Dr Wood has used Decagon soil moisture sensors and worked with Labcell previously, but EMR had not. Dr Phillippa Dodds, one of EMR’s scientists, comments: "As a supplier, Labcell has always been very efficient. The pre- (and post-) sales assistance is always friendly and prompt; all requests for quotations and product information are answered quickly and in full. On the one occasion when technical assistance was required, Labcell responded quickly and put us in touch with the relevant member of staff at Decagon. We are happy with the performance of the Decagon instrumentation."
Compared to some other crops, strawberries are not particularly big users of water, but they are a valuable crop for which irrigation is essential to maintain yields and quality, plus most UK strawberry production is in regions in which fresh water is currently abstracted at unsustainable rates. A key element in EMR’s research into strawberry irrigation has been the Decagon Devices soil moisture sensors and data loggers supplied by Labcell.
EMR has run numerous experiments using EC-20 (20cm-long volumetric water content), EC-TE (soil moisture, temperature and electrical conductivity), MPS-1 (dielectric water potential) and 10-HS (dielectric permittivity and volumetric water content) sensors to monitor soil moisture and other parameters. For the strawberry field trials, EC-20 sensors have been employed, together with a few MPS-1 sensors, to monitor soil water content and potential under a range of irrigation scheduling regimes. Field trials were performed in fifteen 12m-long beds; by the end of the 2009 cropping season, these beds contained 45 sensors, with data being logged by nine Em50 data loggers.
The sensors were buried at various depths within the rooting zone of the plants, with data logged continuously; data were logged hourly from Em50 loggers and downloaded twice-weekly to a handheld PC. While EMR used Microsoft Excel to analyse and plot the data, one of EMR’s project partners, Dr Martin Wood of Earthcare Environmental, used the Decagon DataTrac software to study the same data.
In addition to the soil moisture sensors, EMR have used three Decagon leaf wetness sensors during plant establishment in the strawberry plot. In other field and pot experiments, EMR currently use Decagon sensors to measure soil moisture content, water potential, electrical conductivity and temperature under strawberry and potato plants.
Working with data collected from the various sensors, including those supplied by Labcell, EMR’s researchers aim to develop a Partial Rootzone Drying (PRD) irrigation technique for field grown strawberries; this tricks the strawberry plants into growing as if they are in dry soil, which causes them to conserve water by closing the stomata and reducing leaf growth. By watering only half of the root zone on each occasion, the ’dry’ roots produce chemical signals that are required to trigger these shoot responses, while roots in the other half of the root zone receive sufficient water to maintain shoot turgor and fruit production. Irrigation is applied through a drip tape, and is scheduled manually when the sensors indicate that the soil moisture has reached a predefined lower limit. Previous Defra funded research at EMR has shown that experimental PRD regimes on pot grown strawberry plants could maintain commercial yields and, in some cases, improve the flavour, texture and antioxidant properties of the fruit.
The next stage in this project is to run grower trials to identify an irrigation regime that is suitable for use in commercial strawberry production. Moreover, the same approaches and technologies can be adapted to address the specific water requirements of a wide range of crops and horticulture industries.
Dr Wood has used Decagon soil moisture sensors and worked with Labcell previously, but EMR had not. Dr Phillippa Dodds, one of EMR’s scientists, comments: "As a supplier, Labcell has always been very efficient. The pre- (and post-) sales assistance is always friendly and prompt; all requests for quotations and product information are answered quickly and in full. On the one occasion when technical assistance was required, Labcell responded quickly and put us in touch with the relevant member of staff at Decagon. We are happy with the performance of the Decagon instrumentation."
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