Determining How the Ubiquitous Fungi Mortierella Regulates Belowground N Dynamics Under Different Crop Rotation Systems

Project Overview

GS20-224
Project Type: Graduate Student
Funds awarded in 2020: $16,144.00
Projected End Date: 08/31/2021
Grant Recipient: University of Florida
Region: Southern
State: Florida
Graduate Student:
Major Professor:
Dr. Hui-Ling Liao
University of Florida

Commodities

  • Agronomic: cotton, grass (misc. perennial)

Practices

  • Crop Production: nutrient management

    Proposal abstract:

    Nitrogen (N) is a main limiting factor for plant growth in agroecosystems. Given the unintended consequences for climate change and environmental impacts caused by highly inefficient N use in modern agroecosystems, increasing nitrogen-use efficiency in agriculture is a central focus of intensive research in agriculture. Mortierella elongata, a member of the early-diverging Mortierellomycota, is a dominant fungus among agricultural soils and functions as saprotroph and root endophyte, affecting several soil processes. Little is known about the effects of M. elongata on soil N transformation processes and the structure of the nitrifying community. Our preliminary results show that M. elongata isolates have a great ability to promote crop growth, but it remains unknown whether the promoting effects of M. elongata on crop growth are associated with its regulation of soil N dynamics and plant-available N. Our recent work shows that integrating two years of bahiagrass (Paspalum notatum) into conventional peanut (Arachis hypogea L.) and cotton (Gossypium hirsutum L.) cropping systems, known as sod-based rotation (SBR), has greater N availability compared with a conventional peanut-cotton-cotton rotation (CR). The proposed work focuses on a plant bioassay using cotton grown in soil from SBR and CR. We will combine stable isotope analysis with molecular tools to quantify the effects of M. elongata on microbially-derived N transformation processes and plant-available N dynamics, as well as on crop productivity under different crop rotations. Our objective is to better predict soil N transformations, helping growers improve economic viability with less external inputs while making agriculture more sustainable.

    Project objectives from proposal:

    Objectives

    1) Determine the molecular role of Mortierella in regulating soil N transformations and plant N dynamics under different crop rotation systems using 15N tracers;

    2) Measure the effects of Mortierella on community structure and functional genes of the soil nitrifying microorganisms under different crop rotations;

    3) Quantify the consequences of objectives 1 or/and 2 on cotton productivity.

    Hypothesis

    1) Mortierella induces higher plant-available N and soil N content and reduces N2O emission under sod-based rotation (SBR) compared to conventional rotation (CR);

    2) Mortierella increases the abundance and functional gene activity of the nitrifying community in SBR systems in comparison to CR;

    3) The SBR system inoculated with Mortierella will have the highest cotton productivity.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.