Although she began looking to improve wine grape yields, Amanda Davis, a researcher at Oregon State University, opted for the study of organic berries. She joined the research of organic blueberry eminent Bernadine Strik, recently retired after more than 34 years dedicated to berries. Davis began working with Dr. Strik in 2013, becoming a Senior Research Assistant on the faculty and now Acting Leader of the Berries Research Program at Oregon State University's North Willamette Research and Extension Center.

In this program, the study of organic cultivation began in 2006, after understanding that the producers of the state of Oregon had the need to obtain practical knowledge about this type of cultivation in blueberries, which has increased a lot since the beginning of the first decade of the 2000 according to Davis. “So there just wasn't good scientific information on how to grow these plants. People were trying all sorts of different things, with different levels of success, and they really wanted to know, how can we do better?” explains the agronomist.

His research of more than 16 years has given tools to organic producers, and conventional when applicable, to reduce production costs and increase the quality of the fruits. “We do research with both and our industry is both. So I don't want to say that one is better than the other, but there are different impacts on things like the health of the soil, the biology and the microbes that live in the soil”, says Amanda about the benefits of organic farming.

Whether due to beliefs about the harmlessness of the fruit for health or simply concern for the environment and phenomena such as climate change, the truth is that the consumption of organics in the world has had a strong rise. During the pandemic, the demand for this type of crop increased exponentially. In 5 years, the organic market is expected to generate 150 billion dollars worldwide. Blueberries are already the most exported organic fruit from producing countries such as Chile.

Adds Davis: “Consumer demand is one of the biggest reasons people farm organically. They can get a higher price per kilo of fruit if they sell organic products, especially in the fresh market. Some farmers have switched to organic production in recent years just because of rising prices. But it is more expensive to produce them.”

First blueberry plants from the Berries Research Program at Oregon State University's North Willamette Research and Extension Center (2006).

A scary change?

"I think if you're someone who's already farming conventionally, you're totally capable of making the transition to organic, but keeping in mind that it's not going to be exactly the same," explains the organic nutrition expert at California State University. Oregon.

Organic fertilizers and the lower effectiveness of organic herbicides are some of the differences that farmers who decide to change their crops should be aware of. An example is the application of nitrogenous fertilizers. According to Davis, some take longer to decompose than conventional ones or come along with other nutrients, so it is key to apply them earlier than in an inorganic crop and using only what is necessary so that the nutrients that may accompany nitrogen do not unbalance the plant.

“The difficulty is finding a nutrient source that provides only what we need and then distributing it at the right time. Organic growers often use products such as compost, which is high in nutrients and high in pH, which is a major problem for blueberry soil maintenance. That can be particularly challenging in organic,” she expresses.

Regarding organic herbicides, the researcher explains that they tend to be less effective than conventional ones. However, through research they conduct at Oregon State University they were able to discover that “using a black landscape fabric, which we will talk about in my presentation (at the seminar), it is a very good way to control weeds”, says Amanda; “We also did an economic study that showed a lot of savings. Although it is more expensive at the beginning, when you leave it in the field, it is much less expensive to maintain over the long term.”

A common fear about this type of cultivation is the higher cost of production. The current situation, with the pandemic and Russia's invasion of Ukraine, has increased the price of supplies of great importance to blueberries, such as nitrogenous fertilizers. Amanda Davis is blunt: "I think the large-scale producers that are producing, they wouldn't do it organically unless there was money to be made."

“Cost increases are affecting everyone. But organics have that margin where they get a much higher price for their fruit. If you're producing enough fruit, you can definitely pay for yourself," says Davis.

Genetics for organic

In Latin America and the world, the trend is towards the genetic development of plants more resistant to environmental threats and with improved qualities, desired by consumers. And although in blueberries, no new varieties have been developed specifically for organic cultivation, many of the qualities achieved contribute to reducing risks during their production.

“I think there are things that you can look for in various ways. For example, a shrub that is more upright and more open in structure, because it allows good airflow which can help reduce disease pressure," says Amanda Davis, later warning: "for example, the Duke variety, it is much more particular about the pH of the soil and the nutrients it is receiving. Therefore, it is more difficult to grow in organic production than in conventional production because it is more demanding with respect to where it grows and what type of fertilizer it does so with.”

Finally, for the researcher, it is about using the same strategy as with the conventional ones when choosing a variety: evaluate the conditions and risks, and choose according to the variety that delivers more resistant and better quality fruits.

Liberty variety blueberries ready to be harvested (Oregon State University North Willamette Research and Extension Center Berries Research Program)

The long Chilean post-harvest

After the pandemic, the fruit's travel times have increased, taking up to 50 days to arrive from Chile to its destination markets. The importance of pre-harvest and post-harvest care to maintain the condition and quality of the fruit during this time is of vital importance in Chilean blueberry production.

During the pre-harvest of organic crops, for the researcher, the correct use of fertilizers to take care of the nutritional balance of the plant is key: "There are certain things, how to fertilize with the correct amount of nitrogen, which will lead to optimal levels of fruit firmness." . But if you fertilize with too much nitrogen, it can actually soften the fruit,” she warns.

He also considers the time of harvest to be key: “you don't want to do it when the sugars are too low and the fruit doesn't taste very good. You want to do it at that peak of ripeness where it's still firm and sweet, but not overripe, because that will lead to premature softening and rotting of the fruit."

“As soon as they are harvested, they are stored cold or in a cold atmosphere, to take away the heat that should help them last longer. You have to keep them in that cold environment as much as possible between harvest and destination,” says Davis; strategy homologous to that of conventional blueberries.

The researcher at Oregon State University and leader of one of the oldest berry research programs concludes: "If you are managing your organic blueberry field very well and doing everything right, I don't think there is a lower quality or life inherent usefulness of the fruit because it is organic.”

Amanda Davis will be participating in the next XVIII International Blueberry Seminar Chile 2022, on April 7 at the Monticello Conference Center, where he will give a talk on nutrient management in organic blueberries. 

Pruning to improve quantity and quality of organic blueberries from the Berries Research Program at Oregon State University's North Willamette Research and Extension Center.