Milpa soil microbiome discovery for enhanced crop productivity

Overview

This research program investigates the soil microbial communities found in milpa systems, the ancient polycultural cropping systems of North America that combine maize, pole beans, and squash. These traditional intercropping systems have demonstrated improved plant productivity with minimal external inputs, and this project seeks to identify the beneficial microbes responsible for these outcomes. The goal is to translate insights from centuries-old indigenous agricultural practices into microbial solutions that can enhance yields in conventional and organic farming operations.

The initiative draws on a unique opportunity to study milpa systems still maintained by Abenaki farmers in Vermont, representing approximately 500 years of indigenous agricultural history in the Northern US. By comparing these traditional polyculture systems with paired conventional and organic corn fields, the research aims to identify core microbial taxa associated with the superior productivity of intercropped systems.

Technical specifications

Research approach:

• Comparative microbiome analysis of Vermont milpas versus conventional and organic monoculture corn fields
• Generation of approximately 240Gb of metagenomic data and 24Gb of metatranscriptomic data directly from environmental soil and root samples
• Identification of core root-associated microbial taxa and their genome content unique to milpa systems
• In-house bioinformatics pipeline for quality assessment, read trimming, comparative assembly of contigs and scaffolds, and functional annotation
• Development of targeted microbiological media based on identified key taxa for downstream applications

Scientific basis:

The milpa system provides an ideal semi-contained biological environment for studying plant-microbe interactions. Evidence from milpa systems in Mexico has shown co-occurrence patterns in microbial species enrichment, with beneficial bacteria concentrating near root zones. The three sisters polyculture creates complementary ecological niches: maize provides physical structure, beans contribute nitrogen through biological nitrogen fixation, and squash provides groundcover, collectively supporting diverse and beneficial soil microbial communities.

Technology readiness level

This project is at an early discovery stage, focused on characterizing microbial diversity and identifying candidate beneficial organisms. The research builds on prior characterization work conducted by partner laboratories in Mexico. Current activities involve initial sampling and sequencing from Vermont milpa sites and comparison fields. Subsequent phases will involve designing microbiological media to isolate and cultivate key taxa identified through metagenomic analysis. The ultimate aim is to develop microbial inoculants or consortia that can be applied to conventional agricultural systems to improve crop productivity.