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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Soil Management and Sugarbeet Research » Research » Research Project #440770

Research Project: Soil C Cycling in Irrigated Agroecosystems

Location: Soil Management and Sugarbeet Research

Project Number: 3012-11120-001-016-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jul 15, 2021
End Date: Jul 15, 2024

Objective:
To identify mechanisms and quantify soil C storage and loss in agroecosystems to further develop and refine management practices that minimize environmental impact and increase resilience to climate variability. Increasing soil C sequestration through land-use change and agricultural management practices (reduced tillage, N fertilizer, organic C additions including biochar) is an important climate change mitigation strategy. However, the relative importance of C inputs (aboveground vs belowground), residue chemistry, and microbial processing in stabilizing C is less clear. Understanding of the mechanisms of C storage and loss will be important in developing management practices that sustain soils during climate change and subsequent evaluation of soil health.

Approach:
Soil C storage in irrigated agroecosystems is less than predicted and may be vulnerable to increasing temperature with climate changes. We will use stable and enriched isotope experiments and soil fractionation techniques to gain more detailed quantification of the chemical, physical and biological C pools. These analyses will include labile and stable soil organic C pools, chemistry, isotope composition and compound-specific isotope ratio mass spectrometry. The stable-isotope residue decomposition study will continue and a student will continue taking field measurements for the final 2 years of the project. Soil measurements of compound-specific microbial extracts and plant-derived C sources will help determine the fate of residue in the soil. Project results will be presented at professional meetings and published in professional journals.