Effect of different fertilization modes on soil organic carbon sequestration in paddy fields in South China: A meta-analysis

Evidences have shown that fertilizer application could affect soil organic carbon (SOC) content in cropland. South China is the main production region of rice, in which many different fertilization practices have been widely used during the last several decades, but the effect of different fertilization modes on SOC sequestration in paddy fields in this region was scarcely studied. Based on 274 samples taken from 44 paddy field experimental sites in South China, a meta-analysis was performed to quantify the relative annual change of SOC content (RAC) and SOC sequestration duration in paddy fields under five fertilization modes (inorganic nitrogen fertilization, N; inorganic nitrogen and phosphorus fertilization, NP; inorganic nitrogen, phosphorus, and potassium fertilization, NPK; organic fertilization, 0; and inorganic combined with organic fertilization, OF). The results showed that the RAC under the five fertilization modes was 0-0.4gkg(-1) yr(-1), with increments of 0.19 and 0.23 g kg(-1) yr(-1) in double cropping systems and triple cropping systems, respectively. The RAC under the 0 and OF treatments was higher than that under the N, NP and NPK treatments and was the highest (0.32 g kg(-1) yr(-1)) under OF among the five treatments. The SOC accumulation rate decreased with time, and the SOC sequestration duration under N, NP, NPK, 0 and OF was approximately 23, 28, 46, 64 and 55 years, respectively. The accumulation enhancement rate of SOC over the whole SOC sequestration period under the N, NP, NPK, 0 and OF treatments was approximately 12.9%, 23.4%, 29.3%, 47.2% and 55.1%, respectively. The OF treatment performed the largest potential for SOC sequestration in paddy fields in South China under long-term conditions. (C) 2015 Elsevier Ltd. All rights reserved.