Perennial possibilities for increasing food and ecosystem security

Perennial possibilities for increasing food and ecosystem security

Jerry Glover USAID Washington, DC [email protected]

“[agriculture]…largest threat to biodiversity and ecosystem function of any single human activity.”

Millennium Ecosystem Assessment (2005)

“[agriculture]…one of the most important drivers of…habitat change, climate change, water use, and toxic emissions.”

UN Environment Program Report (2010)

(CIMMYT, 2010)

(CIMMYT, 2010)

Model systems: Perennial grasslands harvested every year for over 75 years; only atmospheric inputs

Model systems: Perennial grasslands harvested every year for over 75 years; only atmospheric inputs How do they compare to high-input annual cereal production?

• Yields

• Carbon & nitrogen

• Ecosystem processes

Glover et al., 2010. Harvested perennial grasslands provide ecological benchmarks for agricultural sustainability.

DuPont et al., 2010. No-tillage conversion of harvested perennial grassland to annual cropland

Culman et al., 2010. Long-term impacts of high-input annual cropping and unfertilized perennial grass production

AEE, Vol. 137, Issues 1-2, 2010

Perennial grass

Annual wheat

p-value

Harvested nitrogen (kg ha-1)

47.9 47.2

0.909

Farmers are removing roughly equal amounts of nitrogen from both systems; annual crop fields

receive over 60 kg ha-1 yr-1 more nitrogen

Perennial grass

Annual wheat

p-value

Total carbon 182.2 138.8 0.027 Total nitrogen 15.4 11.7 0.013

Soil quality (0 – 1.0 m; Mg ha-1):

perennial wheat

Root C of perennial and wheat fields

Differences not simply artifacts of obsolete farming practices such as poor tillage &

fertilizer practices

Differences not simply artifacts of obsolete farming practices such as poor tillage &

fertilizer practices

DuPont et al: No-tillage conversion of native grassland using best-practices

•reductions in active carbon stocks

•reductions in water stable aggregates

•Negative impacts on soil food webs

Conservation Ag: low tillage, rotations, residue maintenance

Additional examples

•Sustained harvests of unfertilized perennial grasslands (USDA county yield data; Shortridge, 1973; Jenkinson et al., 1994, Silvertown et al., 1994)

•SOC and total soil N not reduced after decades of unfertilized grassland harvests (Jenkinson et al., 2004; Mikhailova et al., 2000, Mikhailova and Post, 2006)

(nasa.gov)

1 mm

Photo credit: Jim Richardson

(nasa.gov)

1 mm

Photo credit: Jim Richardson

Small-scale processes »» Large-scale landscape health

minutes and millimeters

Humans don’t eat hay

Global cropland (% of total area) Fruits &

vegetables 7%

Roots & tubers 4%

Tree crops 2%

Forages 11%

Other 3%

Fiber 3%

Cereals, oil seeds, legumes

68%

From Monfreda et al., 2008

Global cropland (% of total area)

Cereals, oil seeds, legumes

68%

From Monfreda et al., 2008

These are all annual crops

Global cropland (% of total area)

Cereals, oil seeds, legumes

68%

From Monfreda et al., 2008

Provide for more than 70% of our calories needs

Perennial grain crops

Sorghum

Maize

Legumes

Rice

Wheatgrass & wheat

Sunflowers

Oilseeds

Washington State University: Texas A&M:

The Land Institute: perennial sorghum, sunflower, wheat, +.

Yunnan Academy of Agricultural Sciences

CSIRO: perennial wheat

Global perennial grain programs

Mich. State Univ.: perennial wheat & wheatgrass

Swedish University Ag Sci University of Manitoba

Catedra de Cultivos Industriales: Lesquerella

(mustard family)

Nepal: perennial wheat

Cornell: perennial maize

Domestication: Intermediate wheatgrass

Wild 1 -2 cycles

3 cycles

1 m

Domestication: Intermediate wheatgrass

1 m

Domestication: Intermediate wheatgrass

X

Wide hybridization: perennial wheat

wheat/wheatgrass// wheat

wheat/wheatgrass//wheatgrass

wheatgrass

Dr. Dhruba Thapa Nepal Agricultural Research Council Khumaltar Laitpur, Nepal High altitude perennial wheat in western Nepal

“…increase food & forage security significantly in the region.”

“…minimize the workload of farmers,

especially of women in the remote areas.”

Deeper roots: “…more stable grain and biomass yields”

Deeper roots: “…higher uptake of selenium, zinc, iron and other minerals.”

“…some of the 25 lines appear highly resistant to yellow rust.”

Perennial Concerns

• Can perennials produce as much grain?

• Aren’t perennials more vulnerable to pests and disease?

• Will perennials become weeds? • How long will it take?

Perennial Concerns

Yield • Perennials have higher yield potential • Consider within context of whole system • Multifunctionality is key

Perennial Concerns

Pests and disease • Increases potential to diversify rotations,

intercrops, relay systems • Wide crosses introduce new pathways for

resistance

Perennial Concerns

Weediness • Unlike perennial forages, perennial grains are

designed to put their energy into seeds not vegetation

Perennial Concerns

Time • Farmers already use some perennial grain

legumes—pigeon peas • Perennial sorghum & rice: field trials within 5

years; farmer-ready within 15 years • Perennial wheat: farmer-ready in 20 years

Perennial Possibilities

We can transform our farms to function more like natural ecosystems

Perennial grain crops are the next step Mitigation: If agricultural soils can be

used to offset industrial emissions of GHGs, perennial crops will be key

Adaptation: Perennial crops are more resilient

Jerry Glover USAID Washington, DC [email protected]