Challenges and Benefits of Winter Cover Crops in Southern New … · 2020-01-06 · BE BOLD. Shape...

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College of Agricultural, Consumer and Environmental Sciences

The College of Agricultural, Consumer and Environmental Sciences is an engine for economic and community developmentin New Mexico, improving the lives of New Mexicans through academic, research, and Extension programs.

Challenges and Benefits of Winter Cover Crops in Southern New Mexico

Erik A. Lehnhoff1, Prashasti Agarwal1, Makane Mason1, John Idowu2, Soum Sanogo1 and Brian Schutte1

1Entomology, Plant Pathology and Weed Science2Plant and Environmental Sciences

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Cover crops

• Unharvested crops grown in a season between cash crops

• Grown for system benefits, not for harvest

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

• Mycorrhizae are a mutualistic relationship between fungi and plant roots

• Increase access to nutrients, P• Can boost plant chemical defense

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

• Symbiotic relationship between bacteria and plant

• Common beans: <50 lb acre-1

• Cowpeas, fava beans: 250 lb acre-1

• Alfalfa, sweet clover: 250-500 lb acre-1

Nitrogen Fixation by LegumesGuide A-129Revised by Robert Flynn and John IdowuCollege of Agricultural, Consumer and Environmental Sciences, New Mexico State University

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

• During winter and spring• During cash crop growth• Largely a function of cover crop

biomass production• But also allelopathy

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

• Mustards produce secondary metabolites

• Glucosinolate• Break down to isothiocyanate

• Isothiocyanate is biofumigantfor soil borne pathogens

• Plant parasitic nematodes• Verticillium• Phytopthora

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Benefits

https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Cover-Crops/Benefits-of-Cover-Crops

disease

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Benefits

• Nutrient scavengers• Capture and

subsequently release nutrients

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• Increased off-season operation costs• Costs are seen immediately, where

benefits are usually seen gradually• Seed

• Barley $48 acre-1

• Peas, $58 acre-1

• Mustard, $63 acre-1

• Tractor time• Irrigation

Challenges

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• Increased off-season operation costs• Costs are seen immediately, where

benefits are usually seen gradually• Cover crops can be hosts for pests

and pathogens• Beet leaf hoppers, plant parasitic

nematodes, onion maggots?

Challenges

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• Mustard plants are excellent host for beet leafhoppers

• Transmit curly top disease to wide range of crops

• Chile, tomato, lettuce, spinach, hemp, cucumbers

• Mustard plants may also host root knot nematode

• Affects chile, tomato and corn

Challenges

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• Increased off-season operation costs• Costs are seen immediately, where

benefits are usually seen gradually• Cover crops can be hosts for pests

and pathogens• Beet leaf hoppers, plant parasitic

nematodes, onion maggots?

• Water use• Use water at expense of cash crop• May require irrigation

Challenges

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https://www.currentresults.com/Weather/US/average-annual-state-precipitation.php

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Cover crop growing season Cash crop growing season

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• Increased off-season operation costs• Costs are seen immediately, where

benefits are usually seen gradually• Cover crops can be hosts for pests

and pathogens• Beet leaf hoppers, plant parasitic

nematodes, onion maggots?

• Water use• Use water at expense of cash crop• May require irrigation

• Termination and biomass management

Challenges

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• Timing of termination• Especially difficult with mixture

• Difficulty of termination• Some cover crops hard to kill

• Biomass management• Too much of a good thing?

Challenges

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• Choose type of cover crops based on farm objectives

How to Implement Cover Crops

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Grasses• Nutrient scavengers • Add organic matter • Quick establishers

https://roundstoneseed.com/naturalized-grasses/148-annual-rye-grass.html

https://www.gardeningknowhow.com/edible/grains/cover-crops/growing-winter-wheat.htm

https://www.greencoverseed.com/product/1054/

• Weed control

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Legumes

• Organic matter• Close canopy

• Nitrogen fixing

https://natureandnurtureseeds.com/products/hairy-vetch

https://meritseed.com/dutch-white-clover-perennial-coated-pre-inoculated/

http://www.southernexposure.com/austrian-winter-peas-12-lb-p-1813.html

• Increase yield

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Brassicas• Soil compaction• Biofumigant properties:

nematodes, root pathogens, weeds

https://www.youtube.com/watch?v=ZiqiNjD4sQ4

https://www.greencoverseed.com/product/1067/

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• Choose type of cover crops based on farm objectives

• Plant late September through early October

• Barley, 100 lb acre-1

• Peas, 80 lb acre-1

• Mustard, 12 lb acre-1

• Mix• Barley, 30 lb acre-1

• Peas, 80 lb acre-1

• Mustard, 5 lb acre-1

How to Implement

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• Choose type of cover crops based on farm objectives

• Plant late September through early October

• Irrigate as necessary (but how much is necessary?)

How to Implement

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• Choose type of cover crops based on farm objectives

• Plant late September through early October

• Irrigate as necessary (but is it necessary?)

• Terminate

How to Implement

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• Termination methods• Herbicide• Cut and disk• Roller crimper

How to Implement

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• Termination methods for mustard

• Before full bloom• Avoid hottest part of day• Must cut/chop mustard• Incorporate IMMEDIATELY

in top 15-20 cm• Roll or pack soil

How to Implement

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• Choose type of cover crops based on farm objectives

• Plant late September through early October

• Irrigate as necessary (but is it necessary?)

• Terminate• Irrigate

How to Implement

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Our projects and some results…

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• Cereal rye• Mustard • Hairy vetch• 2-way mixes• 3-way mix

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Soil Stability

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Nitrogen

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Corn Yield

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2 irrigations

1 irrigation

3 irrigations

Key

CC Species

B – BarleyM – MustardP – PeaMx - Mix

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2 irrigations

1 irrigation

3 irrigations

Key

CC Species

B – BarleyM – MustardP – PeaMx - Mix

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RESULTS: COVER CROP BIOMASS PRODUCTION

2018 – No irrigation effects on the CC

biomass production, across both sites

a aa

a

a

a

aa

a

a

a

a

a

a

a

a aa a a a

a aa

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EFFECT OF CC SPECIES ON BIOMASS

PRODUCTION

a

a

aa

a

b b

c

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NITROGEN FERTILIZER

REQUIREMENT

**Irrigations had no treatment effect, data was pooled

abab aa

c

ab

c c

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CORN YIELD: COB WEIGHT (kg/ha)**Irrigations had no treatment effect, data were pooled

a aaaaa

bcab

ab

c

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Future work• Other methods for cover crop

termination• Incorporate cover crops with chile

production• Termination date

• To prevent beet leafhopper attack of chile

• To make sure isothiocyanate does not affect chile

• Can cover crops be used as part of integrated weed management plan?

• Economic analysis

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Summary / ConclusionBenefits• Improves soil

stability• Increases nutrients• May reduce pest

pressure• May increase cash

crop yield

Challenges• Increased up-front

cost• Increased risk for

certain diseases• Water use• Termination

difficulties

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Acknowledgements

Students and staff

Edward Morris

Joshua BleiweissDavid Duran

Andres Indacochea

Asmita Nagila

FundingUSDA – NIFA, AFRI,

Foundational Knowledge of

Agricultural Production Systems Program

New Mexico State University –Agricultural

Experiment Station