Studies in the United States have shown the important role soil biology plays in managing high sodium levels in lettuce crops. To assist growers with managing their salt, a biological product has been developed – and the benefits have been wide-ranging, including improved crop quality and higher yields.

Irrigation water quality can have a profound impact on lettuce production. Lettuce yields can decline by 10 per cent with levels as low as 1.4 dS/m, which is approximately 770 parts per million (ppm) depending on types of salts. This would be considered low by many lettuce producers who have experienced continued drought in many production regions.

Recent research from California has demonstrated the role that soil biology plays in managing high salt. Serenade® Prime from Bayer contains Bacillus amyloliquefaciens (strain QST 713), which forms a symbiotic relationship with the lettuce roots when used as directed. After colonisation on roots, the QST 713 bacteria releases compounds in the soil surrounding the roots to improve and regulate nutrient uptake. This can result in a much larger root surface area with which to explore the surrounding soil resources.

Research analysis

This greenhouse study demonstrated the effect on lettuce grown under drip irrigation with salinity of 1.5 dS/m. Lettuce plants treated with Serenade Prime at 7 L/ ha, showed a dramatic increase in head weight (53 per cent) and root surface area (21 per cent) compared to the untreated. Leaf analysis showed improved nutrient uptake, especially calcium at 83 per cent, and several soil immobile micronutrients that can only be absorbed via direct root contact.

The results of this study are consistent with observations made in other crops around the world, where the use of this product as a soil ameliorant mitigates the uptake of sodium. Combined with careful irrigation practice and variety section, it would appear to offer a valuable addition in profitable lettuce production.

Untreated control (top); Serenade Prime (bottom), 36 days after application.

An organic approach

In addition, this product is organically certified. ACO Certification Ltd has certified it as an Allowed Input, meaning that it is also suitable to be used in certified organic production systems.

Bayer has produced many resources that are science-based and support the use of this product. A great example of one of these resources is a video featuring Paul Windolf from Windolf Farms.

Based in Queensland’s Lockyer Valley region, Paul shares his experiences in improving soil health. Mixed species cover cropping, crop rotation, compost and the use of Serenade Prime are the combination Paul uses in his holistic approach to vegetable production.

Click here to download the Serenade Prime online resources.

Find out more

Please visit the Bayer Australia/New Zealand website. 

Serenade® is a Registered Trademark of the Bayer Group.

Cover image: Untreated control (left); Serenade Prime (right), 28 days after application. 

This article first appeared in Vegetables Australia – Summer 2020/21. To read the full publication, please click here.