Is soil respiration of a chernozem under shallow cultivation similar to moldboard plowing or no-tillage?

Herein, we report a 6–year–long investigation on the CO 2 emission (soil respiration) of a chernozem soil under conventional moldboard plowing (MP) and two conservation tillage techniques, namely shallow cultivation (SC) and no-tillage (NT). This study aims to compare soil respiration data among SC, and MP or NT treatments and investigate the underlying processes influencing the magnitude of soil-derived emissions. CO 2 fluxes were measured using static and dynamic chamber methods in seven replicates weekly during and biweekly to monthly outside growing seasons. We investigated postharvest yield and root biomass, post-tillage mulch thickness, soil water content (SWC) and temperature (Ts) via a monitoring system and portable instruments, soil chemical parameters via wet chemical analyses, and community-level physiological profiles of the soil microbial community using the MicroResp™ technique. The 6-year average soil respiration under SC (0.093 mgCO 2 m −2 s −1 ) was the same as the mean emission in NT. Both of these conservation treatments showed significantly elevated CO 2 emissions compared with the mean soil respiration under conventional MP (0.081 mgCO 2 m −2 s −1 ). We found that vegetation biomass via root respiration and denser straw residue cover could be major factors of higher CO 2 emission under SC. Additionally, the higher soil respiration in SC compared with MP could result from the high soil organic carbon (SOC) content. Similarly, elevated soil respiration in NT can occur because of the highest mean SOC and SWC as well as the densest straw residue layer among the three treatments. MicroResp™ measurements revealed differences in the substrate use efficiency of the microbial community under the three treatments, therefore suggesting that the treatment effect on CO 2 emission is caused by differences in microbial communities. Following crop production and soil respiration together, the CO 2 emission to yield ratio was the lowest under SC, similar to MP, and highest under NT treatment. The CO 2 emissions of the treatments exhibited variability over the years. Therefore, longer experimental time is essential to find more established conclusions of different tillage techniques. • Topsoil carbon sequestration occurs under conservational tillage techniques. • Elevated CO 2 emission can be expected under conservational tillage on Chernozem soil. • No-tillage is a beneficial method for preserving soil moisture. • Different factors affect CO 2 emission in shallow cultivation than in no-tillage. • The conservational shallow cultivation results in a low CO 2 emission to yield ratio.