permaculture

["Saor Stetler" <sstetler@earthlink.net>]

Self Seeding: An Innovative Management System





by Staff Writers


Madison WI (SPX) Apr 17, 2008
Winter cover crops provide important ecological functions that include
nutrient cycling and soil cover. Although cover crop benefits to
agroecosystems are well documented, cover crop use in agronomic farming
systems remains low. Winter cover crops are usually planted in the fall
after cash crop harvest and killed the following spring before planting the
next cash crop.

Recent research has identified time and money as major impediments to farmer
adoption of winter cover crops. Developing innovative cover crop management
systems could increase the use of winter cover crops.

A scientist with the USDA Agricultural Research Service National Soil Tilth
Lab and colleagues at Iowa State University investigated the potential for
winter cereal cover crops to perpetuate themselves through self-seeding,
thereby eliminating the cost of planting a cover crop each fall and time
constraints between cash crop harvest and the onset of winter. Results from
the study were published in the March-April 2008 issue of Agronomy Journal.

In the research investigation, winter rye, triticale, and wheat were planted
and managed chemically and mechanically in varying configurations to
facilitate self-seeding. After soybean harvest in the fall of 2004 and 2005,
establishment and green ground cover of self-seeded winter cover crops was
measured because of their important relationships with nutrient uptake
capacity and soil erosion protection.

The study revealed that plant establishment through self-seeding was
generally accomplished within one week after soybean harvest. Green ground
cover and self-seeding was consistently higher with wheat.

"The significance of this research, in addition to lowering the cost and
risk of establishing cover crops, is to extend the ecological functions that
cover crops perform beyond the normal cover crop termination dates between
mid-April and early May," says Dr. Jeremy Singer of the National Soil Tilth
Lab. "Furthermore, producers using organic crop production techniques could
adopt these systems because of the potential for enhanced weed suppression
without soil disturbance."

According to Singer, increasing the presence of cover crops on the landscape
can increase nutrient capture and lower soil erosion, both of which can
improve water quality.

Research is ongoing at the National Soil Tilth Lab to identify self-seeded
cover crop systems that minimize competition with cash crops and maximize
the effectiveness of self-propagation. The impacts of cover crops on soil
quality in systems with biomass removal are also being investigated because
cover crops can help offset the carbon and nutrient losses that occur when
biomass is harvested in row crop production systems.