Soil Organic Carbon Sequestration Rates by Tillage and Crop Rotation

TLDR

Agricultural management changes can boost soil organic carbon accumulation, sequestering atmospheric CO₂. The study quantified crop‑specific soil carbon sequestration rates under reduced tillage or increased rotation complexity and estimated the time required for sequestration. Sequestration rates were analyzed using a global database of 67 long‑term experiments comprising 276 paired treatments. Switching from conventional tillage to no‑till sequesters about 57 g C m⁻² yr⁻¹ (excluding wheat‑fallow), while increasing rotation complexity adds roughly 20 g C m⁻² yr⁻¹ (excluding continuous corn to corn‑soy), with peak rates in 5–10 yr and equilibrium reached in 15–20 yr for no‑till and 40–60 yr for rotation, and these rates can inform spatial modeling of regional carbon sequestration.

Abstract

Changes in agricultural management can potentially increase the accumulation rate of soil organic C (SOC), thereby sequestering CO 2 from the atmosphere. This study was conducted to quantify potential soil C sequestration rates for different crops in response to decreasing tillage intensity or enhancing rotation complexity, and to estimate the duration of time over which sequestration may occur. Analyses of C sequestration rates were completed using a global database of 67 long‐term agricultural experiments, consisting of 276 paired treatments. Results indicate, on average, that a change from conventional tillage (CT) to no‐till (NT) can sequester 57 ± 14 g C m −2 yr −1 , excluding wheat ( Triticum aestivum L.)‐fallow systems which may not result in SOC accumulation with a change from CT to NT. Enhancing rotation complexity can sequester an average 20 ± 12 g C m −2 yr −1 , excluding a change from continuous corn ( Zea mays L.) to corn‐soybean ( Glycine max L.) which may not result in a significant accumulation of SOC. Carbon sequestration rates, with a change from CT to NT, can be expected to peak in 5 to 10 yr with SOC reaching a new equilibrium in 15 to 20 yr. Following initiation of an enhancement in rotation complexity, SOC may reach a new equilibrium in approximately 40 to 60 yr. Carbon sequestration rates, estimated for a number of individual crops and crop rotations in this study, can be used in spatial modeling analyses to more accurately predict regional, national, and global C sequestration potentials.