Researchers to investigate organic orchard fertilizers

Newly funded research at the Alson H. Smith Jr. Agricultural Research and Extension Center in Winchester is aiming to return nutrients to where they belong: the plants.

Center researchers will be looking at more organic approaches for fertilization in regard to orchard growth this spring.

The center and Dr. Greg Peck, extension specialist and assistant professor of tree-fruit horticulture at Virginia Tech, were awarded a $21,638 grant from the Virginia Agricultural Council this week to conduct this study.

The center’s grant was part of more than $200,000 the council awarded this week to various projects being conducted through Virginia Tech and Virginia State University.

Ashley Thompson, a doctoral candidate at Virginia Tech, is working on the research with Peck and described it as an “agro-ecology project” that will seek to “reduce the amount of synthetic nitrogen fertilizer that’s being applied to apple orchards.”

According to the USDA’s Economic Research Service, a little less than 25.7 billion pounds — or 11.4 million pounds — of nitrogen was in fertilizers used by producers nationwide in 2011.

In simple terms, Peck and Thompson’s work will seek to find ways to return chemicals and nutrients such as nitrogen back into the trees for better growth.

When nitrogen from synthetic leaches into the environment, it can cause harmful effects to the local environment, such as increased algae blooming.

According to the Chesapeake Bay Foundation, nitrogen from synthetic fertilizer accounts for 15 percent of the nitrogen pollution that ends up in the bay.

“One of the reasons we’re so concerned with nitrogen is because we live in the Chesapeake Bay region,” Thompson added. “There might come a time when the amount of nitrogen that we can put on trees is really limited.”

The foundation has noted that algae feeds off of chemicals such as nitrogen and phosphorous and can result in dead zones of less underwater grass. This can result in dead plants as well as fish, in some cases.

The project that Peck and Thompson are conducting will look at two different local types of organic compost fertilizer – yard waste and chicken litter compost – and compare them against traditional fertilizer.

Thompson explained that research look into “what nitrogen sources will best support tree growth and productivity” as well as how the sources affect “overall soil health.”

“We often forget about soil,” she added, “It’s something people tend not to think very much about, other than the fact that you put a plant in it and it anchors the plant.”

Thompson said soil’s role for the plant is much more involved than that.

“There’s a lot microbes that live in soil that are responsible for making … nutrients available to the plants,” Thompson said, adding that the research will also look at the composts’ effect on soil microbes.

“Compost is one way that you can reduce nutrient loss, because you’re not applying a lot of nitrogen all at once,” Thompson explained.

By receiving nitrogen “in smaller quantities,” Thompson said that it does not leave as much nitrogen around that “can be flushed out by a rain event.”

Compost may also have an effect on the microbial communities that, as Thompson noted, play an important role in plant growth.

“Some bacteria and fungi help to prevent plants from getting diseases, and that’s another thing we’re going to looking at,” she said, “what kind of bacteria are there and could they be protecting the plants?”

Thompson said they will be taking soil samples for the project in three to four weeks, with the data analysis taking another year-and-a-half to compile.

This project is part of a larger, long-ranging study that Thompson has been working on with the center since 2013 that looks at the growth of nursery trees.

“We’ve taking data on things like leaf nutrition, soil nutrients and organic matter,” Thompson said, noting that she has also been measuring orchard productivity in that time.

This latest project is “kind iof a foresight,” Thompson said, where the center is “looking to see, how can we start limiting the use of these fertilizers that leach really readily?”

Contact staff writer Kevin Green at 540-465-5137 ext. 155, or

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