Multifunctional woody polycultures and their influence on soil organic carbon

Adoption of woody perennial (WP) polycultures on previously row-cropped soils and marginal lands could enhance a variety of ecosystem services including food production, habitat for biodiversity, and carbon (C) sequestration. Soil organic matter fractions (particulate organic matter [POM], and potentially mineralizable N [PMN]), inherent soil and landscape factors were quantified on samples collected using plot- and grid-based approaches to understand their influence on soil organic carbon (SOC) change. Baseline soil samples were collected in the spring of 2015 from land that was managed for decades with row-crops before multifunctional woody polycultures (MWPs) were established. In the spring of 2022, sites planted in three MPW treatments varying in species composition and stand density (inter-seeded with a grass-legume pasture) and control were resampled. Stocks of SOC increased within the 0-60 cm depth in the 3- and 4-species (3-Sp and 4-Sp) treatments as well as the 3-Sp planted at double density (3-SpX2) and the corn-soybean control (CS). Gains in stock sizes ranged from 0.75 to 4.79 Mg C ha-1 yr-1 and ranked 3-Sp > CS > 3-SpX2 > 4-Sp. Only differences between the 3-Sp and 4-Sp treatments were statistically significant. Landscape position likely explains this difference as SOC change was associated with gains under continuous pasture which accounted for 86% of all MWP plots. Similarly, unexpected gains in control (CS) plots could be influenced by the relatively low slope position, poor drainage, and smaller plot size (one-fifth) associated with that treatment. Grid-based sampling supports this and shows after seven years, POM-C and POM-N changes were greater in the surface soil (0-30 cm) but SOC change was greater at deeper deeps including the 0-45 cm depth. These depth-based changes in SOC as well as Bray I P reveal the dueling influences of vegetative inputs to the surface and landscape controls on soil movement.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Nunez Flores, Mario Alejandro

Contributors dc:contributor

• Wander, Michelle
• Ugarte, Carmen M
• Stickley, Sam

• Agroforestry Systems
• Carbon
• Magnetic Susceptibility
• Multifunctional Woody Polycultures
• Organic Matter
• Potentially Mineralizable Nitrogen
• Particulate Organic Matter
• Soil Organic Carbon
• Topographic Factors

Statement dc:rights

• Copyright 2024 Mario Nunez

Language dc:language

eng, en

Handle dc:identifier

https://hdl.handle.net/2142/124450

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/124450