Building better soils with cover crops - Home | Agronomy · Covers improve soils Blanco-Canqui, H.,...
Transcript of Building better soils with cover crops - Home | Agronomy · Covers improve soils Blanco-Canqui, H.,...
Building better soils with cover cropsDeAnn Presley @soilsdiva @GPGrazing @KStateAgron [email protected]
Credit
• Cite: Dr. DeAnn Presley, Kansas State University, Department of Agronomy.
• All photographs were taken by DeAnn Presley. • Two exceptions are noted, one photo on slide 7 and one on slide 12
• Information and photographs in this file may be used for educational purposes.
• Journalists may contact DeAnn Presley for further explanation. [email protected] Phone: 785-532-1218
Bad news first
• We’ve been hard on soils, and it shows
Stevens County, KS: Wind erosion after corn stalk baling
Pawnee County, KS: Water erosion on endrows going right in a road ditch
Principles of building soil properties
•Reducing soil disturbance
•Covering the soil surface
•Increasing the diversity of the cropping system
•Adding carbon to the system: more plants, manure, compost, etc
Cover crops do all of these things!
Overview
• Importance of soil physical properties• Precipitation capture and storage
•Biological soil properties
• Improving soils
•Cover crop mixtures: species composition and forage quality
Soil Health Definition
•“The capacity of soil to function as a vital living system, within ecosystem and land-use boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health” (Doran and Zeiss, 2000).
Definition of cover crops• “Close growing crop, that
provides soil protection and soil improvement between periods of normal crop production, or between trees in orchards or vines in vineyards.
• When plowed under and incorporated into the soil, cover crops may be referred to as green manure crops.”
• Source: Soil Science Society of America glossary
Photo credit: http://covercropimages.sare.org/
Cover Crop History
• The past:
• In 1938, the USDA Yearbook of Agriculture recommended cover crops to maintain soil organic matter (Pieters and McKee, 1938).
• Present-day Kansas estimates:
• Cover Crops were planted on 2,498 farms, 322,454 acres (US Census of Ag 2012)• Out of 21 million acres of cropland harvested/year
• 1.5% of acres cover cropped each year
Farmer Survey: Why they say they use covers
SARE 2015-2016 Survey
Purposes of cover crops, continued
• Soil improvement and protection from erosion
•Reduce compaction
•Weed control
•Break disease and pest cycles
•Cycle plant nutrients
• Legumes fix N
Sunn hemp, a warm-season legume
Purposes of cover crops, continued
Q: If you graze a cover crop is it still a cover crop or is it a forage?
A: The soil benefits either way, as long as you leave some cover.
Photo credit: http://www.greatplainsgrazing.org/
Evapotranspiration
Sunn hemp
Crotalaria juncea
Covers improve soilsBlanco-Canqui, H., Claassen, M. M., & Presley, D. R. (2012). Summer cover crops fix nitrogen, increase crop yield and improve soil-crop relationships. Agronomy Journal, 104(1), 137-147.
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Nitrogen Application Rate (kg ha-1)
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2.8%
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Infiltration
• Infiltration: Movement of water through the surface: Precipitation capture
• In this no-till experiment, cover crops increased infiltration
• Cover crops planted every other year
Build it and they will come
• Measured worms by digging up soil in December 2009 in grain sorghum stalks.
• How long had it been since the covers were green and living?
• About 13-14 months. Worms still preferred the cover crop plots.
“Worms prepare the ground in an excellent manner for the
growth of fibrous-rooted plants and for seedlings of all kinds.”
Charles Darwin, 1881
Earthworm specifics• Stimulate microbial activity. • Earthworms consume microbes,
many more microorganisms are present in their feces or casts than what they consume (gut)
• They fragment and inoculate with microorganisms
• Available plant nutrients (N, P, & K) tend to be higher in fresh earthworm casts than soil
(Edwards et al., 1995)
Sunn hemp, a warm-season legume
Earthworms, continued
• Earthworms increase mineral N in soil,
• and also readily exchangeable phosphorus (P) (Suarez et al., 2004),
• potassium, calcium and magnesium (Adejuyigbe et al., 2006).
• Productivity and earthworms: very positive relationship, and they must be fed.
Blouin et al., 2013, European J. Soil Sci. https://iees-paris.ufr918.upmc.fr/images/publi/5a9176088a0d2568fa128a053bca0f1d.pdf
0 2 4 6 8 10 12
No cover
Radish
Rye
Rye and radish
Rye, radish, alfalfa
7 way mix
Earthworms per cubic foot
Ottawa Corn-Soybean Cover Crop ExperimentCollected April 2015 Prior to Soybean Planting
Presley et al.’s unpublished data
Soil structure and aggregation
Wet aggregate measurement illustrated
Wet aggregate measurement illustrated
Wet aggregate measurement illustrated
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Wichita Spring 2014
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Olathe Spring 2014
Microbial Biomass Carbon (μg C g-1soil)
p = 0.48 p = 0.19
Both sites: Cover vs. no cover was significant
Infiltration: Movement of water into soil, not as many differences as aggregates
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p = 0.14
LFS soil, CT hard as a rock,Others friable. Pumpkin runners?Where happier?
Evapotranspiration
EvapotranspirationRoller-crimped rye: Reduces soil temperature, which aids in reducing E
“A temperature of 80 to 100° F is found most favorable to the production of a maximum fermentative activity.”Soil: Ferments important in agriculture, Yearbook of the USDA, 1895, p. 73.
Takeaway points
•Methods to improve soil include reducing disturbance, leaving soil covered, diversifying a crop rotation. Cover crops can be used in systems that are no-tilled or tilled, and lead to improvements in the soil.•Will improvements in the soil lead to increased
profit for a farmer? Will the effort pay for itself, or increase profits? Will it save time, save energy? Will grazing a cover crop allow for pastures to rest?
Midwest Cover Crops Council Decision Tool
• Location
• Cash Crop
• Objectives
http://www.mccc.msu.edu/
Questions
This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2012-02355 and 2013-69002-23146.
Learn more about the project at
greatplainsgrazing.org
Building better soils with cover cropsDeAnn Presley @soilsdiva @GPGrazing @KStateAgron [email protected]
No problem can be solved from the same level of consciousness that created it. Albert Einstein
In our every deliberation, we must consider the impact of our decisions on the next seven generations. From the Great Law of the Iroquois Confederacy