Enhancing organic and inorganic carbon sequestration in calcareous soil by the combination of wheat straw and wood ash and/or lime.

Huili Zhao,Jifei Liu,Xiaohong Tian,Huijie Zhang,Yanlong Chen,Songjie Chu,Abdul Ghaffar Shar,Xiujun Wang

doi:10.1371/journal.pone.0205361

Abstract

Increasing organic carbon sequestration in agricultural soils is important for improving soil fertility and mitigating climate change. Wood ash is generally applied as a potassium fertilizer, but the effects of simultaneous incorporation of wood ash and crop straw on the turnover of soil organic carbon (SOC) and inorganic carbon (SIC) are not well understood. In this study, a 118-day lab incubation experiment was conducted using a calcareous soil (with 10 years of continuous maize cropping history) to study the effects of adding wheat straw, wood ash and lime. Our study showed that straw addition led to an increase in both SOC (19%) and SIC (3%). Wood ash and lime addition decreased CO2 emission by 182 and 1210 mg kg-1 and increased SIC by 125 and 1001 mg kg-1 during the incubation, respectively, which was due to supply of CaO from wood ash and lime. The increase of SOC content was 2.4% due to the addition of lime. In addition to straw addition enhanced straw-derived OC content, the addition of lime also increased straw-derived OC content by 34.5%. This study demonstrated that lime was more effective in reducing CO2 emission and and enhancing SOC than wood ash. In conclusion, adding lime to calcareous soil might be an effective method of enhancing carbon sequestration and slowing climate change.

Highlights

Agricultural soils can mitigate the emission of greenhouse gases and enhance soil sustainability, so the potential for carbon sequestration in agricultural soils has received significant attention [1]
Soil organic carbon (SOC) and inorganic carbon (SIC) are important carbon reservoirs in arid and semi-arid regions that play an important role in the global carbon cycle and climate change [2]
Cumulative CO2 emission was significantly affected by main effects of wood ash and lime addition (Table 2)

Summary

Introduction

Agricultural soils can mitigate the emission of greenhouse gases and enhance soil sustainability, so the potential for carbon sequestration in agricultural soils has received significant attention [1]. Soil organic carbon has attracted much attention, and SIC has received much less attention despite its potential for carbon sequestration. Wood ash and lime addition on soil carbon sequestration reported that the SOC and SIC stocks were greater in agricultural land than in non-agricultural land in arid and semi-arid regions. Many reports showed that long-term straw incorporation and manure application in arid cropland led to SOC enhancement and carbon sequestration in the form of carbonate [4,5,6]. These results suggest that there are many ways to increase SIC content in agricultural soils

Methods

Results

Discussion

Conclusion