ASHS Press Releases

American Society for Horticultural Science

  • Increase font size
  • Default font size
  • Decrease font size
Home HortScience Pecan Orchards Thriving in Clover
E-mail Print

TIFTON, GA—Pecans are one of the few native North American plants that have become a significant commercially produced agricultural crop in the United States. In 2010, the U.S. Department of Agriculture estimated pecan crop value at a remarkable $369 million. In a study published in HortScience, scientists turned back the clock to reconsider early management techniques that could help sustain the country's valuable pecan orchards.

"In the early years of the Southeastern pecan industry legumes and manure from cattle grazing the orchards were commonly used to provide fertilizer nitrogen for pecan trees," explained M. Lenny Wells, Assistant Professor in the University of Georgia's Department of Horticulture. "After World War II, however, pecan producers began using synthetic fertilizer on a large scale. As sprayers became available and fungicide and insecticide applications became more common, most growers stopped grazing cattle in the pecan orchards."

Recent trends toward sustainability and environmentally safe crop production are compelling reasons for producers to reconsider the use of proven natural orchard management techniques. "Instability in fuel and fertilizer prices have led pecan producers to once again consider the use of legumes such as crimson clover as an orchard floor cover to supplement pecan trees' critical nitrogen requirements," said Wells. "Soil amendment with organic materials such as poultry litter and/or legumes such as clover should improve southeastern U.S. pecan orchard soils, thus enhancing their sustainability."

Wells' study examined the effect of poultry litter application and the use of crimson clover as a cool-season cover crop on soil chemistry and soil quality biological indicators, including mycorrhizal inoculums potential (MIP), microbial biomass carbon (MBC), and phosphatase activity in a southeastern U.S. Coastal Plain pecan orchard system. The results showed the use of clover between tree rows provided multiple benefits for pecan orchard soil quality, including increased MIP and MBC. Soil phosphatase activity was also enhanced by clover during two of the three years of study.

"Soil elemental properties, including total nitrogen, and soil organic matter were also enhanced by clover and/or poultry litter, although there was an obvious time lag in the response of soil nitrogen to the treatments," Wells noted. "Poultry litter application increased soil phosphorus but did not consistently enhance soil biological activity parameters. At times, poultry litter appeared to neutralize or minimize the positive effects of clover on MIP."

"These findings underscore the value of clover as a cool-season orchard floor cover and its potential benefits for soil conservation, soil quality improvement, and sustainability in southeastern U.S. pecan orchards," said Wells.

# # #

The complete study and abstract are available on the ASHS HortScience electronic journal web site:

Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at


Original Article:

Response of Pecan Orchard Soil Chemical and Biological Quality Indicators to Poultry Litter Application and Clover Cover Crops
M. Lenny Wells
HortScience 46:306–310. [Abstract] [Full Text] [PDF]

Corresponding author. E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it