Nutrient management training helps Pa. organic growers

June 14, 2012

UNIVERSITY PARK, Pa. -- Organic farmers can access educational workshops and materials on nutrient management, thanks to a program developed by researchers in Penn State's College of Agricultural Sciences.

Elsa Sánchez, associate professor of horticultural systems management, and Heather Karsten, associate professor of crop production and ecology, described their program in a journal article that received the American Society for Horticultural Science Outstanding Extension Publication Award for papers published in 2011. They will be recognized at the ASHS Annual Conference in July.

The article details the development of a training program for agriculture educators from Pennsylvania, New York and New Hampshire who work with university Extension services, the Natural Resources Conservation Service and the Rodale Institute.

The program focused on using organic nutrient sources. During the first year, participants met to learn effective methods to help organic growers with nutrient management. In the second year, they delivered educational sessions on nutrient management to the organic growers.

Organic nutrient sources, such as compost, most often do not supply the correct ratio of nitrogen, phosphorus and potassium needed by the plants. Therefore, it is easy to apply too much compost when meeting nitrogen needs.

"Nutrient management with organic nutrient sources is more complicated because organic nutrients have to go through the process of mineralization to become useable by plants," Sánchez said. "So it's tricky to know when and how much to apply for good crop yields so that there's not an excess accumulation of nutrients."

To address these issues and develop the training program, Sánchez and Karsten met with organic growers to learn about the nutrient-management tools and techniques currently used in their operations. Working with Tom Richard, professor of agricultural and biological engineering, and Rick Stehouwer, professor of environmental soil science, they then developed a program to help agriculture educators advise the growers.

Before attending the program, participants also talked with organic growers about their current nutrient-management plans and took soil and compost tests. They found compost was generally not analyzed before use, and the compost was generally applied by volume rather than based on the plant nutrient needs. Also, soil on several farms had high levels of phosphorus, potassium, magnesium and calcium.

As a result, soil and compost test results were modified during the training program to help organic growers determine the amount of an organic nutrient source to apply and to better understand the hazards of excessive nutrient levels.

Participants in the training program also examined nutrient-management computer programs and provided feedback to three program developers regarding possibilities for use on organic farms.

Finally, participants developed educational materials and workshops. Six articles distributed through university Extension outlets reached more than 350 growers and agriculture educators.

A presentation about using compost for growing organic vegetables was developed and then presented at eight meetings, reaching 235 growers and agriculture educators in Pennsylvania, New York and surrounding states from 2008 to 2010. A class also was developed to guide growers in making nutrient-management plans for their farms.

Educators responded positively to the training program, and growers attending the workshops offered by participants in the training program rated them highly.

"We found that the educators felt their ability to help growers using organic nutrient sources was excellent or above average," Sánchez said. "Growers had improvements in their knowledge of using organic nutrient sources as well.

"We have a whole team of educators who are now better equipped to help organic growers and growers who use organic nutrient sources," Sánchez said.

A publication developed as a result of the research, "Using Organic Nutrient Sources," is available on the Web.

Single copies of the publication can be obtained free of charge by Pennsylvania residents through county Penn State Extension offices, or by contacting the College of Agricultural Sciences Publications Distribution Center at 814-865-6713 or by email at For cost information on out-of-state or bulk orders, contact the Publications Distribution Center.

A related online-only publication, "Deciding which Organic Nutrients to Use and How Much to Apply," which provides a flow chart and formulas to help growers determine what nutrients are needed in their fields, is also available online.

Research was funded by the Northeast Sustainable Agriculture Research and Education Program.

  • Organic nutrient sources, such as compost, shown here, often do not supply the correct ratio of nutrients needed by plants.

    IMAGE: Penn State

(Media Contacts)

Last Updated June 14, 2012