Peak strawberry season depends on what region of the U.S. you live in. In Louisiana, strawberry harvest begins in April. In the upper Midwest it’s July. But no matter where you live, fresh strawberries are a cause for celebration.
Keeping a consistent food supply is the work of farmers, certainly. They are backed by agronomists and crop scientists, who look for new varieties and growing strategies that are tasty and sustainable.
Research is helping strawberries become disease resistant and adaptable to climate change. Another factor being researched is how different types of fertilization can affect the nutrient content of strawberries, increasing their superfood status.
Here are some specific examples of ongoing research about summertime’s favorite fruit collected from presentations at the 2020 ASA-CSSA-SSSA Annual Meeting:
- Clues to disease resistance
Soil-borne diseases can be devastating to strawberry crops. Surrounding the roots of strawberry plants in the soil are good microbes as well as microbes that can cause disease. Plants can recruit these good microorganisms that could colonize the roots. And these colonies can provide the last barrier of plant defense against pathogens.
This is similar to humans having a good gut microbiome, which can prevent disease and recover more quickly when we get sick.
Cristina Lazcano and her team at UC-Davis are looking at how various disease-resistant strawberry cultivars recruit good microorganisms from the soil environment. In 2017, the team infected some sets of strawberries with diseases in a controlled environment. They compared the microbiome from these disease-infected plants with a control group of healthy plants. The team collected and compared samples at various times: transplant, vegetative growth, flowering, ripening and harvest.
Their findings show that the root microbiome became more diverse and enriched with soil bacteria through plant development. This could inform further research that can reduce the need for pesticides to grow delectable strawberry fruits.
- Using biostimulants to promote strawberry health
Mary Maher and her team at Cal Polytech-San Luis Obispo are researching the use of growth-promoting bacteria and fungi as biostimulants for growing strawberries. Studies have shown these biostimulants can have positive effects on plant health, fruit yield, or disease management for other crops. These biostimulants can act like energy drinks that naturally boost the performance of plants.
But previously, no information was available for summer’s popular fruit. Gathering this information is valuable, especially for organic growers who have limited products registered for use.
Strawberry plants were grown in two different soil types, either sandy or clay-heavy. In fall 2018, strawberry plants were grown outdoors in pots. They were either treated monthly with a single bacterial biostimulant product or left untreated as a control group. Fruit yield weight, fruit sugar content, and disease status were measured weekly throughout the 2019 growing season.
They followed up in spring 2020 with a larger field trial. The team’s findings will inform organic strawberry growers on best practices to grow strawberries with biostimulants that improve crop health.
- Improving the phytonutrient content of strawberries
Strawberries naturally contain good amounts of phytonutrients. Phytonutrients are natural chemicals believed to be beneficial to human health. Growers know that lower concentrations of nitrogen fertilizer can increase the phytonutrient content in some fruits. Bhupinder Jatana, Clemson University, studies the effects of various nitrogen fertilizers and rates on strawberries.
The biggest issue is that while lower nitrogen rates increase phytonutrients, they decrease the yield of strawberries. Jatana found the optimal levels of a specific nitrogen fertilizer for strawberries. It maximizes economic yield and phytonutrient content. It also influences the sugar concentration in the berries.
- Using microalgae to improve soil health
Heliae Development, LLC created a microalgae solution for the soil that benefits strawberries. Their solution is applied directly to soil. Microalgae have demonstrated benefits in both the soil microbiome and soil health and quality. The microalgae solution also increases the amount of active and passive carbon in the soil.
The microalgae solution is a nutrient-rich superfood for crops, including proteins, lipids, and carbohydrates – much like your superfood shakes! The microalgae stimulate microbial content in sandy loam, silty loam, and clay loam soils, regardless of soil organic matter content.
The trials the team completed were in Florida during 2019. They found a very good return on investment on the plots that applied the microalgae solution. In addition, the number of marketable fruits per plant improved by 5%. All these results suggest how microalgae would potentially be beneficial in the production of specialty crops, such as strawberries.
Compiled by Susan V. Fisk, American Society of Agronomy, Crop Science Society of America & Soil Science Society of America
About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.