Field-aged biochar reduces the greenhouse gas balance in a degraded vegetable field treated by reductive soil disinfestation.

Abstract

Reductive soil disinfestation (RSD) is proposed as a pre-plant, non-chemical soil disinfestation technique to control several soilborne phytosanitary issues. However, limited information is available on the evaluation of greenhouse gas (GHG) balance and soil quality during the soil remediation process as affected by RSD method. A 44-day field experiment including four different treatments was conducted to investigate the effects of conventional RSD and field-aged biochar-amended RSD on GHG balance and soil quality in a degraded vegetable field. Results showed that the conventional RSD application can significantly decrease the soil nitrate (NO3-) concentrations and electrical conductivity (EC) and oxidation-reduction potential (Eh) by 51.4-67.3%, 5.3-23.6%, and 10.9-15.1%, respectively, while significantly increase soil pH and cation exchange capacity (CEC) by 0.37-0.42units and 7.8-32.2%, respectively, in relation to the control (CK). Compared with the conventional RSD treatment, aged biochar-amended RSD significantly reduced soil NO3- concentrations, EC and Eh. No significant differences on CH4 emissions were observed among all the treatments during the experimental period. However, the conventional RSD application significantly increased the cumulative nitrous oxide (N2O) and carbon dioxide (CO2) emissions by 66.2-124.7% and 64.3-130.0%, respectively, and thus resulted in a significant GHG balance of 64.1-130.1% in relation to the CK. On the contrary, although resulted in more N2O emissions compared with the conventional RSD treatment, aged biochar-amended RSD significantly reduced the cumulative CO2 emissions and thus had an overall decrease in GHG balance by 20.7-28.7%. Therefore, aged biochar-amended RSD can simultaneously achieve lower GHG balance and better improvement of soil quality in degraded vegetable field, and thus can be utilized as an effective technology for soil remediation in intensive vegetable production.