CONNECTICUT- Our changing climate forms a big challenge for local farmers to keep up their yields. An extended period of heavy rain last year, followed by an extreme drought this season, has dramatically impacted soil health in Connecticut.
Both the increase in temperature and the wild swings in precipitation have a significant impact on the soil, said Dr. Margaret Walsh, a senior ecologist in the U.S. Department of Agriculture's Office of Energy and Environmental Policy.
“For pretty much any crop, yields go up as the temperature goes up, until a certain point when it goes down fast,” said Walsh. This increase in yields is also assuming that the nutritional deficiencies and amount of rainwater are sufficient, which often is not the case.
Soil nutrition is key
Temperatures are not the only factor impacting crop yields. Walsh highlighted that the long period of drought, followed by the heavy rain events, have also led to soil erosion. As a result, according to experts, soils are depleted and unable to sustain abundant yields, and even affect the crop’s nutritional levels.
“Soil erosion degrades the soil, meaning that the soil will lose most of its organic matter in the topsoil,” said Dr. Richard Anyah, a natural resources and environment professor at the University of Connecticut. Organic matter is important for the protection of water and nutrients reservoirs within the soil that animals, plants, and microorganisms need to grow.
Dr. Anyah points out that the combination of an increase in water run-off and the disturbance of the soil will lead to a decrease in topsoil. “The increase in precipitation leads to more frequent floods. So, that will mean that we have more run-off, that especially will take away topsoil.”
These impacts did not remain unnoticed by local farmers. Diane Dorfer, owner and full-time farmer of the Cobblestone farm, employs a variety of methods to keep her soil healthy and productive.
Dorfer uses compost and organic soil amendments to maintain high nutrient content in her soil, such as nitrogen, potassium and phosphorus. These inputs were mainly agricultural byproducts like soybean meal and fish emulsion. With a smile on her face, she said her kids particularly liked the latter.
“When my kids were little, I would come into the house and smell not so great, and they would ask me: ‘what is that smell?’ And I am like, ‘fish emulsion.’ And they thought I was saying ‘fishy lotion.’ ‘Oh, mom just put the fishy lotion on.’”
Another local farm employing similar practices is Spring Valley Student Farm. It is a one-acre vegetable garden owned by UConn dining services and run by UConn students. Jessica Larkin-Wells, farm manager and old inhabitant of the student farm, explained that soil health was of high importance.
“As an educational farm, we have the opportunity to pay a lot of good care and attention to our soil health,” said Larkin-Wells. “That is a central part of our mission. We can center that in a way commercial farms are not always able to.”
Like Cobblestone farm, they use organic inputs instead of chemical fertilizers. They also try to keep the soil covered to avoid soil erosion and nutrients loss due to long-term exposure.
“We never leave the soil exposed. There is always something like either cover crop, mulch, or whatever our vegetable crop at the time is,” Larkin-Wells said. “Cover crops are an extremely important part of our growing rotation here and can do some pretty amazing things for the soil.”
She defined cover crops as anything that is grown in the soil not to be harvested. They can prevent erosion, maintain nitrogen levels, or increase aeration in the soil. Dr. Anyah explains that nitrogen is important for the plant to develop healthy and more nutritious fruits. Without these high levels, the nutritious levels of crop yields will be limited.
Changing temperatures, increasing pests
Similarly, to protect their soil, both farmers do not use any damaging chemicals to fight increasing pests. According to Walsh, the increased pest population is an example of an indirect effect of changes in temperature and precipitation. Every vegetable is impacted by insect pressure, making them harder to sell. Many bigger farms use aggressive pesticides to fight these infestations.
Dorfer used two different methods instead: insect-inclusion netting to cover some of her vegetables, and an organic pesticide to disrupt the molting cycle of larva. She explains that this organic pesticide is very specific. It will not affect the soil or any important pollinators like bees, just the larva growing on the plants. The adults will survive but their reproduction cycle will stop, limiting the hungry larva on crops.
At Spring Valley Student Farm they scout and pick the insects by hand, and spray their vegetables with garlic spray. This is a mixture of garlic water and soap, to make each plant less attractive for animals.
When confronted with the question of the future and the concern of climate change, both farmers seemed confident they would be fine, if they continue the methods described above. However, they also realized climate change is unpredictable. In the words of Dorfer:
“Every year gives me more experience, expands my database, and I do adjust.”