Conservation Tillage and Cover Crops

Jeremy SingerResearch AgronomistNational Soil Tilth Laboratory

NSTL Cover Crop Team Members

• Tom Kaspar and Ben Knutson• Keith Kohler• Dan Jaynes• Tim Parkin

Outline

• Define conservation tillage and cover crops• Use examples from the scientific literature• Present current research projects

Conservation Tillage (CT)

• Any tillage and planting system that covers 30 percent or more of the soil surface with crop residue, after planting, to reduce soil erosion by water (CTIC).

• Types of CT include no-tillage/strip-tillage, ridge-tillage, mulch-tillage, and reduced-tillage.

Cover Crops• Cover crops are planted to provide soil cover,

which can then function to: reduce soil erosion, increase water infiltration, decrease water runoff, conserve soil water, increase soil organic matter, reduce soil compaction, reduce nitrate leaching, supply nitrogen to subsequent crops, suppress weeds, attract beneficial insects, and other functions

• http://www.sarep.ucdavis.edu/ccrop• Managing Cover Crops Profitably, 2nd Ed.,

Sustainable Agriculture Network ($19)

Erosion Measurements

After Simulated Rainfall

NO COVER CROP OAT COVER RYE COVER

Erosion Example

0

0.5

1

1.5

2

2.5

3

g m

-2 s

-1

1997 1998

Rill Erosion Rates in April Following No-Tillage Soybean

Rye OatControl

Kaspar et al., 2001, J. Soil Water Conserv.

Nitrate Loss Example

Parkin et al., unpublished data

Current Research

• To evaluate corn and soybean responses to different cover crops.

Cover Crops

• Winter annuals – rye, wheat, triticale• Legumes – red clover, alfalfa, birdsfoot

trefoil, kura clover

196 198 197 197 195183

020406080

100120140160180200220

bu/a

cre

Compost No Compost

6 yr Average Corn Yield (1999-2004)

IntensiveModerateNo-tillage

59 5760

5754 56

01020304050607080

bu/a

cre

Compost No Compost

6 yr Average Soybean Yield (1999-2004)

IntensiveModerateNo-tillage

Cover Crop Reseeding

• Work with annual legumes in the southern USA (crimson clover, berseem clover, arrowleaf clover, subterraneum clover, and big flower vetch.

• In northern locations, winter hardiness is critical.

Living Mulches

• Reasonably large body of scientific papers published on living mulches (LM). Most LM systems are corn-based.

• We established an LM system in a corn-soybean-forage rotation.

Summary

• Integrating cover crops and conservation tillage is feasible.

• Economics and additional management currently hinder adoption.

• Future research will address these issues and strive to develop competitive systems that provide similar ecosystem functions.

Questions?singer@nstl.gov515-294-5502