Integrated Crop and Livestock Systems for Enhanced Soil Carbon Sequestration and Microbial Diversity in the Semiarid Texas High Plains

Project Overview

LS10-229
Project Type: Research and Education
Funds awarded in 2010: $160,000.00
Projected End Date: 12/31/2013
Region: Southern
State: Texas
Principal Investigator:
Dr. Jennifer Moore-Kucera
Texas Tech University

Annual Reports

Information Products

Commodities

  • Agronomic: cotton, millet, sorghum (milo), wheat, grass (misc. perennial), hay

Practices

  • Animal Production: grazing management, pasture fertility, range improvement, grazing - rotational, stocking rate, winter forage, feed/forage
  • Crop Production: conservation tillage
  • Education and Training: demonstration, farmer to farmer, on-farm/ranch research, workshop
  • Farm Business Management: whole farm planning
  • Natural Resources/Environment: carbon sequestration, biodiversity
  • Production Systems: agroecosystems, integrated crop and livestock systems
  • Soil Management: organic matter, soil analysis, soil microbiology, soil chemistry, soil quality/health
  • Sustainable Communities: local and regional food systems

    Abstract:

    We determined the effects of integrated crop-livestock (ICL) systems on soil microbial community composition, C sequestration potential, and global warming potential (GWP) in the semiarid Southern High Plains (SHP). ICLs, especially perennial components, had multiple positive effects on ecosystem health including increased C sequestration potential, macroaggregate formation (increased stability), & enhanced nutrient cycling. These ecosystem benefits were associated with higher fungal diversity and specifically the relative abundance of arbuscular mycorrhizal fungi (AMF) and Gram negative (GM-) bacteria. Among ICLs, the GWP of the dryland ICL was estimated to be near neutral, whereas the deficit-irrigated ICL was a net C-source.

    Project objectives:

    Our hypothesis is that the integrated crop and livestock systems will support a more diverse microbial community, sequester more C in long-term pools and produce lower emissions of GHGs, compared to the continuous cotton system. Furthermore, we believe that despite water limitations these systems in a semi-arid environment will prove to be a valuable player in the global search for C sequestering systems. To achieve this goal we will use existing SARE-funded long-term replicated, integrated crop and livestock systems (irrigated and non-irrigated) and three on-farm producer crop and livestock systems that are a part of the TAWC.

    Specific objectives are to:

    1. Measure the amount of C stored in active, intermediate and passive SOM pools using a detailed physical fractionation method, which provides eight different soil aggregate fractions.
    2. Evaluate greenhouse gas fluxes (CO2 and N2O) to calculate global warming potential within each system.
    3. Characterize soil microbial community structure using fatty acid methyl ester (FAME) profiling and microbial biomass C (MBC) including bacterial diversity in whole soil and different soil aggregate fractions using a novel molecular biological tool (i.e., pyrosequencing).
    4. Translate results from Objectives 1 through 3 into practices incorporated in agriculture in the THP and similar ecosystems. Specifically, we will increase producer and consultant awareness regarding the direct and indirect positive effects for managing agricultural lands to achieve enhanced soil functioning.

    Our long-term objective is to use the data acquired under the proposed research to guide policy-makers and agricultural and land managers to make the best ecological and socio-economical-supported decisions possible. In doing so, they will meet the increased agricultural demands for food and fiber while sustaining natural resources to preserve and enhance local communities. Information we acquire will supplement past and concurrent data, including an additional Ph.D. research project (in progress) that is evaluating energy use, efficiency and economics in the proposed sites. These established long-term replicated integrated research sites as well as access to grower-managed farms with known histories and similar systems, provides an unparalleled opportunity enabling us to achieve such an important yet complex goal. Subsequent funding will enable us to provide detailed assessment of C sequestration potential and soil microbial biodiversity estimates in these semiarid agroecosystems; systems which may serve as models for sustainable agricultural production across this agriculturally, socially, and economically important eco-region.

    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.