Responses of Soil Respiration Dynamics and Bacterial Community Structure to Fertilizer and Irrigation Regimes Over 2 Years in Temperate Vineyards in North China

Abstract

Fertilizer and irrigation regimes can have profound effects on soil carbon (C) emissions; however, information regarding the effects of fertilizer and irrigation management on the components of soil respiration (Rs) and the underlying bacterial community characteristics in vineyard ecosystems remains limited. Therefore, a 2-year field experiment was conducted in a wine-grape vineyard (WGV) and table-grape vineyard (TGV). For this experiment, each vineyard included two fertilizer and irrigation regimes: farmers’ practice (FP) and recommended practice (RP). The trenching method was employed to separate Rs into heterotrophic respiration (Rh) and autotrophic respiration (Ra) and soil bacterial community structure was examined after the 2-year experiment. Fertilizer and irrigation regimes have caused no effect on Ra, but RP treatment significantly (P < 0.05) decreased the average daily Rh by 15.13% and 17.11% in the WGV and TGV, respectively, leading to significant (P < 0.05) decreases in annual total Rs values at the scale of whole-vineyard by 8.93% and 11.78%, respectively. The lower annual total Rh was partially ascribed to the significant (P < 0.05) decline in Proteobacteria and Bacteroidetes relative abundance, which decreased the rate of organic matter decomposition. When compared with WGV, the higher fertilizer and water input in the TGV resulted in 11.53% and 15.74% higher annual total Rs and Rh values on the scale of whole-vineyard, respectively, while the lower grapevine density and more frequent summer pruning resulted in an 18.83% lower annual total Ra. Overall, RP treatment was found to be a suitable strategy for reducing soil C emissions and benefiting SOC storage in vineyards around North China.