Title: Alley cropping affects perennial bioenergy crop root distribution, carbon, and nutrient stocks

Abstract

Abstract This study quantified root biomass distribution; root accrual of C, N, P, and K; and changes in soil organic carbon (SOC) associated with alley‐cropped switchgrass ( Panicum virgatum L.), prairie cordgrass ( Spartina pectinata Bosc ex Link), intermediate wheatgrass [ Thinopyrum intermedium (Host) Barkworth and Dewey ‘Rush’], and a native polyculture planted between rows of ‘NM6’ poplar ( Populus maximowiczii × P. nigra ) and ‘Fish Creek’ willow ( Salix purpurea ) at two Minnesota sites (Empire and Granada). After 4 yr since establishment, SOC declined at each site but was not influenced by species selection. NM6 poplar–prairie cordgrass systems had among the highest root biomass, C, and nutrient accrual, with up to 16.3 Mg root biomass, 7.0 Mg C, 175 kg N, 31 kg P, and 97 kg K ha ⁻¹ . Fine roots were the largest fraction of belowground biomass, although course roots were also a large fraction for poplar and prairie cordgrass. Tree roots extended to 6 m into the crop alley, although 85–89% were within 1 m of tree rows, depending on tree species. Crop fine root biomass was reduced up to 67% at 1 m from tree rows and 20% at 3.5 m and was up to 142% greater in willowmore » than in poplar alleys. Total root C was predominated by poplars at Empire regardless of herbaceous crop type, whereas the proportions of tree and crop root C varied by crop at Granada. These results suggest that prairie cordgrass is well suited to alley cropping and that, due to the competitive ability of poplars, productivity, C sequestration, and nutrient accrual may be greater in willow systems in the long term.« less

Authors:

Gamble, Joshua D.  ^[1];

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Johnson, Gregg A. ^[2]; Current, Dean A. ^[3]; Wyse, Donald L. ^[2]; Zamora, Diomides S. ^[4]; Sheaffer, Craig C. ^[2]

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+ Show Author Affiliations

1. USDA Agricultural Research Service Plant Science Research Unit, St. Paul, MN (United States)
2. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Agronomy and Plant Genetics
3. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Forest Resources
4. Univ. of Minnesota, Minneapolis, MN (United States)

Publication Date:

Fri Jul 03 00:00:00 EDT 2020

Research Org.:

South Dakota State Univ., Brookings, SD (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1801023

Alternate Identifier(s):

OSTI ID: 1650191

Grant/Contract Number:  

FG36-08GO88073

Resource Type:

Accepted Manuscript

Journal Name:

Agronomy Journal

Additional Journal Information:

Journal Volume: 112; Journal Issue: 5; Journal ID: ISSN 0002-1962

Publisher:

Alliance of Crop, Soil, and Environmental Science Societies

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES