Development of agroforest systems for bioenergy crop production and ecosystem services in the lower Mississippi Alluvial Valley

Development of agroforest systems for bioenergy crop production and ecosystem services in the lower Mississippi Alluvial Valley

Summary

Preliminary results indicate that differing clones utilized in the cottonwood plantings have had similar survival and growth. Stakeholder research and outreach steering committees in three different areas of the lower Mississippi Alluvial Valley have been formed and an initial meeting occurred at one location to guide future efforts on the project. Biomass production yields and ecosystems services from the various cottonwood and switchgrass agroforests will begin to be quantified the second year of the project.

Objectives/Performance Targets

The objectives of this project are to:

1. 1. Quantify biomass production, potential bioenergy (ethanol, syndiesel, etc.) yields, and economics of agroforest systems with a variety of cottonwood and switchgrass compositions.

   2. Quantify ecosystem services (carbon sequestration, nitrogen retention, wildlife habitat, and biodiversity)provided by agroforest systems with a variety of relative cottonwood and switchgrass compositions.

   3. Provide information to farmers, bioenergy industry professionals, county agents, natural resource managers, and regional public officials on the production potential, financial viability, and ecological impacts of cottonwood/switchgrass agroforest biofeedstock systems; demonstrate establishment, harvesting, and bioenergy conversion technologies appropriate to these agroforest systems; and establish a stakeholder research and outreach steering committee to direct current and future project activities concerning these cropping systems.

Accomplishments/Milestones

Crop Establishment
Cottonwood, switchgrass, and soybeans were planted and established during 2009 at the three study sites utilized for this project. Three different cottonwood clones (ST66, S7C20, and mixed) were planted in each of the agroforest plots. We established 70% as the survival goal for the cottonwood at the end of the first growing season. All but one of the twenty seven plots planted with cottonwood met the overall 70% survival goal. This plot had only 56% survival. Growth of the trees varied among sites as well as among plots within a site due the variation of soils and drainage. Average height at the end of 2009 ranged from 63.8 to 101.0 cm.
Successful switchgrass (Alamo) establishment (40% coverage by the end of the growing season) occurred on 55% of the plots at two of the three research sites. At the other research site, low rainfall following planting killed the newly emerged switchgrass and establishment was unsuccessful in all plots. Switchgrass will be replanted during 2010 in plots or portions of plots that did not have successful switchgrass establishment. Soybeans were harvested in the fall of 2009. Yields and weight of crop residue was recorded. Grain sorghum will be planted in spring 2010 in these soybean-sorghum plots.

Ecosystem Services
Initial soil sampling was performed as part of the effort to monitor carbon sequestration by soils within the differing cropping systems. Soil sample analysis is being performed. Tension lysimeters which will be utilized to monitor soil water chemistry and nitrogen loss were installed at each research site.

Outreach and Extension
Stakeholder advisory committees were established for each of the three research sites. Initial advisory meetings for one of the sites occurred in 2009. Initial dates for field days during 2010 and topics for extension factsheets to be written in 2010 were established.

Impacts and Contributions/Outcomes

This project will provide stakeholders with information to assess the economic and environmental viability of using cottonwood/switchgrass agroforest systems for providing bioenergy feedstocks. In addition activities needed for establishing these systems, potential risks or problems associated with conversion to these cropping system, and potential benefits associated with production of these feedstocks will be presented to landowners and other stakeholders through field days, publications, and electronic media.

Collaborators: