Biostimulant Bridgeway proven to combat heat stress in potatoes
Stress-busting benefits confirmed for 4th year
Independent field trials have shown for a 4th year that amino acid + peptide biostimulant Bridgeway helps to combat the effects of heat stress in potato crops, enabling photosynthesis and tuberisation to be maintained. Importantly for growers it helped secure yield with significant increases and margin gains over untreated crops achieved in all the trials over the 4 years.
Keeping potatoes stress-free is not an easy task, with crops often subjected to prolonged heat stress periods at key growth timings. The replicated trials conducted by CMI Ltd in 2017-2019 and Green Crop Information (part of Dyson Farms) in 2021, showed that mean temperatures regularly exceed the optimum of 20ºC, impacting the rate of tuber bulking and final yield.
The trials investigated the influence of different application timings and sequences of Bridgeway on the growth and yield of potatoes. Regular test digs showed heat stress slowed the rate of tuber bulking in untreated crops, whilst in potato crops treated with Bridgeway, bulking was maintained and this led to significantly higher yields by the end of the season. In fact tubers reached marketable yields faster enabling burndown to start sooner.
Heat stress slows tuber bulking
- Potato potential including the number of progeny tubers and the rate of tuber bulking is established early in the season at about the time tubers reach 10mm in size. Stressful growing conditions during this time can therefore have a big influence on crop yield.
- Once tuber bulking has started, the rate cannot be increased but can be reduced or interrupted by stress.
- The earlier in the season heat stress occurs, the more negative its impact on the growth and yield of the crop as potatoes grow best in cool, frost-free environments.
- Every 5ºC increase above the optimum temperature of 20ºC can decrease the rate of photosynthesis by 25%.
- Potatoes start to suffer from high temperature stress as temperatures exceed 25ºC, when the rate of photosynthesis begins to decline, significantly reducing the partitioning of sucrose translocation to tubers.
- Heat stress can therefore reduce the rate of bulking, at 30ºC it can pause it altogether as the rate of energy used by respiration to keep cool, exceeds the rate at which energy is produced by photosynthesis.
Bridgeway increased bulking by up to +2.8 t/ha per week
With the potato tuber being mainly composed of photoassimilates, mostly starch, any mechanism to stimulate photosynthesis and translocation of the end product to the underground stem offers the possibility to increase tuber yield. Biostimulant applications applied at the onset of bulking have the greatest potential to mitigate the effects of stress on the crop’s bulking and yield potential and trials show Bridgeway is more than up for the task, with benefits of +2.8 t/ha per week seen in 2021 trials.
The trials investigated the influence of different application timings and sequences of Bridgeway on the growth and yield of potatoes. In all trials, crop husbandry was even across the site and management aimed to remove all constraints other than those under investigation – all sites were irrigated. Bridgeway was applied to the foliage of potatoes at a rate of 2 litres per hectare at each application timing investigated. Test digs were conducted during the season to establish the impact of Bridgeway on the rate of bulking per week, and data from individual harvests were analysed by analysis of variance.
2017 trials looked at the effect of Bridgeway on the potato crop from emergence to max canopy size
2018 trials investigated Bridgeway timings around full canopy (CMax) – up to 2 weeks before and 2 weeks after
Trials in 2019 and 2021 investigated application number around tuber bulking
Ob = Onset of tuber bulking
Ob2 = Onset of tuber bulking + 2 weeks
Ob4 = Onset of tuber bulking + 4 weeks
As in previous years, 2021 was full of heat-stress periods
2021 trial observations and results by Greencrop Information Ltd
- A period of high temperature stress began in mid July, a week after the first Bridgeway application
- The rate of tuber bulking in untreated plots was reduced after stress
- Treatment with Bridgeway appeared to provide protection against stress, rather than preventing it, as rates of tuber bulking were still reduced compared with pre-stress rates but by less than were rates in untreated plots
- Bridgeway application had a positive, significant effect on post-stress rate of bulking
- All Bridgeway treatments increased tuber yield over the untreated
- In 2021 there was no statistical difference between 2 and 3 Bridgeway applications
- High temperatures occurred throughout the growing season, which slowed the rate of tuber bulking in untreated crops – 2018 was particularly stressy
- All Bridgeway applications made from emergence to max canopy size were beneficial
- All applications increased the rate of tuber bulking per week and overall tuber yield
- Post stress tuber bulking was significantly higher compared to untreated crops (when applied from the onset of stolon tip swelling)
- Bridgeway applications closest to the heat-stress periods had the biggest impact on rate of bulking and yield
- With frequent heat stress events during tuber bulking, the best results across all trials came from a Bridgeway programme of 2-3 applications applied closest to the heat stress periods
Bridgeway recommendations in potatoes
Apply 2 L/ha from stolon tip swelling and repeat in season to eliminate abiotic stress, stimulate growth and enhance translocation of assimilates to tubers.
2-3 applications optimal, depending on the season.
For best results target applications before prolonged heat stress is forecast to protect crops.
Sister product Zonda is available to purchase through Agrii.
Bridgeway product information
For information on Bridgeway and how it helps combat abiotic stress in a wide range of crops, please download our latest handbook here. Its packed full of trials information and guidance on how to use. If you’d rather speak with our technical team, please contact Stuart below – he’ll be happy to help.