Diversifying and perennializing plants in agroecosystems alters retention of new C and N from crop residues

Marshall D McDaniel; Jeffrey A Bird; Jennifer Pett-Ridge; Erika Marin-Spiotta; Tom M Schmidt; A Stuart Grandy

doi:10.1002/eap.2784

Diversifying and perennializing plants in agroecosystems alters retention of new C and N from crop residues

Ecol Appl. 2023 Mar;33(2):e2784. doi: 10.1002/eap.2784. Epub 2023 Jan 11.

Authors

Marshall D McDaniel^{1

2}, Jeffrey A Bird³, Jennifer Pett-Ridge^{4

5}, Erika Marin-Spiotta⁶, Tom M Schmidt⁷, A Stuart Grandy²

Affiliations

¹ Department of Agronomy, Iowa State University, Ames, Iowa, USA.
² Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, USA.
³ School of Earth & Environmental Sciences, Queens College, CUNY & The CUNY Graduate Center, New York, New York, USA.
⁴ Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA.
⁵ Life & Environmental Sciences Department, University of California, Merced, California, USA.
⁶ Department of Geography, University of Wisconsin-Madison, Madison, Wisconsin, USA.
⁷ Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA.

PMID: 36478617
DOI: 10.1002/eap.2784

Abstract

Managing soils to retain new plant inputs is key to moving toward a sustainable and regenerative agriculture. Management practices, like diversifying and perennializing agroecosystems, may affect the decomposer organisms that regulate how new residue is converted to persistent soil organic matter. Here we tested whether 12 years of diversifying/perennializing plants in agroecosystems through extended rotations or grassland restoration would decrease losses of new plant residue inputs and, thus, increase retention of carbon (C) and nitrogen (N) in soil. We tracked dual-labeled (¹³ C and ¹⁵ N), isotopically enriched wheat (Triticum aestivum) residue in situ for 2 years as it decomposed in three agroecosystems: maize-soybean (CS) rotation, maize-soybean-wheat plus red clover and cereal rye cover crops (CSW2), and spring fallow management with regeneration of natural grassland species (seven to 10 species; SF). We measured losses of wheat residue (C_wheat and N_wheat ) in leached soil solution and greenhouse gas fluxes, as well as how much was recovered in microbial biomass and bulk soil at 5-cm increments down to 20 cm. CSW2 and SF both had unique, significant effects on residue decomposition and retention dynamics that were clear only when using nuanced metrics that able to tease apart subtle differences. For example, SF retained a greater portion of C_wheat in 0-5 cm surface soils (155%, p = 0.035) and narrowed the C_wheat to N_wheat ratio (p < 0.030) compared to CS. CSW2 increased an index of carbon-retention efficiency, C_wheat retained in the mesocosm divided by total measured, from 0.18 to 0.27 (49%, p = 0.001), compared to CS. Overall, we found that diversifying and extending the duration of living plants in agroecosystems can lead to greater retention of new residue inputs in subtle ways that require further investigation to fully understand.

Keywords: biodiversity; decomposition; dual-labeled litter; microbial biomass; regenerative agriculture; soil organic matter; stable isotope; sustainability.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Agriculture*
Carbon
Crops, Agricultural
Edible Grain
Nitrogen / analysis
Soil* / chemistry
Triticum

Substances

Soil
Carbon
Nitrogen