Tuesday, November 6, 2007 - 3:25 PM
149-12

Combining Short-Term and Long-Term Research on Organic Farming Systems at the Center for Environmental Farming Systems.

S. Chris Reberg-Horton1, J. Paul Mueller1, and Nancy G. Creamer2. (1) North Carolina State University, Department of Crop Science, Campus Box 7620, Raleigh, NC 27695-7620, (2) North Carolina State Univ, Ctr for Environmental Farming Systems, Campus Box 7609, Raleigh, NC 27695

The Center for Environmental Farming Systems (CEFS) is an 810 hectare facility established in 1994 as a partnership between North Carolina’s two Land Grant Universities, North Carolina State University, North Carolina Agricultural and Technical State University, and the North Carolina Department of Agriculture and Consumer Services.  A long-term cropping systems experiment was established at the center in 1998 to compare various means of agricultural production including organic systems.  Four types of systems are under investigation: conventional short-rotation best management practices, integrated cropping and animal husbandry, organic production, and plantation forestry/woodlot production.  Within each system, sub-plots are included to examine several possible rotations.  Experimental plots were kept large, averaging 5.4 ha in size, to maximize the potential for larger scale ecological interactions.

Within the organic system, multiple strategies for transitioning to organic have been tested.  An immediate substitution of all conventional inputs with organic practices resulted in a 12% decline in yields.  Slower transitions resulted in less dramatic yield declines.  A system that substituted organic fertilizers for two years prior to total transition to organic resulted in only a 3.3% yield decline.  Results for other slow transition strategies were mixed.

In conjunction with organic long-term plots, short-term experiments are being conducted on a newly developed Organic Research Unit to address the needs of farmers who have already transitioned to organic.  A panel of these farmers have prioritized their research needs for the center.  Many of the identified research questions are basic agronomic questions that must be reexamined in the organic context.  In a series of experiments examining weed control in organic soybeans, the effect of seeding rate was as large as many cultivation strategies.  Soybean seeding rates 2.2 times the recommended seeding rate were able to reduce weed counts by 68%.  The use of blind cultivation tools, such as the rotary hoe, were found to be highly effective at weed control, but can reduce yields by 22% when used as frequently as in current common practice.  Results from the short-term experiments are being used to improve the long-term experiments over time and to inform on-farm trials conducted by county based faculty.