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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #409929
Research Project: Optimizing Carbon Management for Enhancing Soil and Crop Performances

Location: Soil, Water & Air Resources Research

Title: Miscanthus increases soil amino compounds regardless of nitrogen fertilizer rate

Author
item KHALEEL, ALA - Iowa State University
item THOMPSON, MICHAEL - Iowa State University
item Olk, Daniel - Dan
item MCDANIEL, MARSHALL - Iowa State University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/20/2023
Publication Date: 10/29/2023
Citation: Khaleel, A., Thompson, M.L., Olk, D.C., Mcdaniel, M.D. 2023. Miscanthus increases soil amino compounds regardless of nitrogen fertilizer rate [abstract]. ASA-CSSA-SSSA Annual Meeting. Paper No. 154264.

Interpretive Summary:

Technical Abstract: Growing interest in miscanthus (Miscanthus × giganteus Greef et Deu.) as a perennial biomass crop is in part driven by exceptional environmental benefits – including efficient cycling of nitrogen (N). Thus, it is somewhat paradoxical that several studies have now observed increased potential net N mineralization from soil under miscanthus compared to annual biomass crops such as maize. We explored the mechanisms that might explain this paradox from a long-term experiment crossing two interacting treatment factors: (1) cropping systems (maize and miscanthus), and (2) N fertilization (0, 112, 224, and 336 kg N ha-1 year-1). In response to these treatments, we measured: potentially mineralizable N (PMN), potential enzyme activity (PEA), and amino sugar and amino acid concentrations. First, we hypothesized that miscanthus would increase potentially mineralizable N (PMN), amino compounds, and extracellular enzymes used in N-acquisition [Tyrosine aminopeptidase (TAPase), N-acetyl-ßglucosaminidase (NAGase), and leucine-aminopeptidase (LAPase)]. Second, we hypothesized that increased N inputs would increase the activity of the C- acquisition enzyme, ß-glucosidase (BGAse), but reduce N-acquiring and oxidative enzymes; : Phenol oxidase (PPOase) and peroxidase (PERase). Miscanthus did increase PMN by +30% compared to maize. Potential enzyme activity results were mixed, with little crop effect and N only reduced TAPase at greater N rates (224N and 336N). Miscanthus increased total amino compounds by +26% compared to maize but strongest effects were found with amino sugars. Overall, these results suggest that greater potential net N mineralization often found in miscanthus compared to other crops is not by increasing PEAs, but rather from increasing pools of amino compounds.