Integrating Forages into Multi-Functional Landscapes:

Enhanced Soil Health and Ecosystem Service Opportunities

Douglas L. KarlenUSDA-ARS

Presented at the 5th Annual Canadian Forage and Grassland Conference – Bromont, Québec

November 19, 2014

Why is a Soil Scientist interested in forages?

How do forage- or grassland-based crop rotations affect ecosystem services?

How does incorporating forage or grassland into crop rotations affect soil quality/health?

What innovative opportunities can forage and grassland help support? Hint – Bioenergy and/or bio-

products

Presentation Overview

Why Is a Soil Scientist Interested in Grassland?

It’s not necessarily for the buffalo

From H.F. Reetz

Rather -- It’s Because of the Roots!

Selected Plant Root Functions

Input source for soil carbon

Cycling of essential plant nutrients

Source of exudates (food) for microbes

Ability to penetrate compacted zones

Enhance soil structure

Forage & Grassland Ecosystem Services

Food production

Erosion control

Water quality maintenance & improvement

Wildlife habitat

Improved soil quality/health

Water Quality Impact

Incorporating forages and grassland into agricultural landscapes can significantly reduce NO3-N losses and help mitigate soil erosion

Raccoon River Watershed

This watershed is a major source of drinking water for Des Moines, IowaA significant correlation (r = -0.76) was found between the land area cropped to small grain and hay and the NO3-N concentration in the water

Hatfield et al., 2009

Forage & Grassland Effects on SoilsRotations with three years of

forage had:

Lower bulk density

Increased % of water stable aggregates

Higher microbial biomass carbon

Greater average corn yields

Karlen et al., 2006

The Soil Management Assessment Framework

(SMAF)

Minimum Data Set

Soil Function

Indicator

score

Soil Function

Soil Function

Indicator

Indicator

Indicator

score score score

Index Value

Management Goals

Interpreting Dynamic Soil Quality

Soil

Qu

ality

Time

Aggrading

Sustaining

Degrading

Baselin

e

Crop Rotation– Soil Quality Index Values

Karlen et al., 2006

Rotation

Nashua Kanawha

Lancaster

Continuous Corn

0.76 0.92 0.75

Corn – Soybean

0.82 0.92 0.77

Corn-Corn-Oat/

Alfalfa-Alfalfa- Alfalfa

0.85 0.98 0.80

Opportunities for Integrating Forages into Multi-Functional

Landscapes

Windbreak

Riparian Herbaceous Buffer

Switchgrass as a Biofuel Feedstock

Enhanced Alfalfa Production

Use genetic strategies to improve alfalfa and its uses to increase farm and ranch sustainability and profitability

Develop harvest and storage technologies to enhance alfalfa feed quality and develop new products

Develop and evaluate farming systems that strategically incorporate alfalfa on the landscape to reduce the negative environmental impact of row crop and livestock agriculture.

Overall Research Goal

. Environmental Benefits of Alfalfa

(compared to row crops such as corn and soybean)Captures more sunlight/more photosynthesis/more carbon.Captures C for a longer time period during the growing season.

Provides N & improves nutrient cycling .Breaks pest life cycles when rotated with other crops.Less surface runoff.Less phosphorus lost to surface water.

Less soil erosion.More soil carbon sequestration.

Less nitrogen leached to ground water

Approach – An Alfalfa Paradigm Shift

REAP goal – diversify landscape, provide feedstock, improve soil health, & protect water quality

Leaf Stripping and Protein Extraction

Summary & ConclusionsForages and grassland are essential

for long-term sustainable agricultural production

With regard to water quality, changes in cropping patterns were more important than changes in N fertilizer rate

Soil quality was improved by having extended crop rotations with at least three years of forage

New and innovative harvest strategies and uses for alfalfa protein and other components need to be developed.

Any Questions?