Biochar application on paddy and purple soils in southern China: soil carbon and biotic activity.

Shen Yan,He Zhang,Kuanxin He,Nianlei Wang,Aigai Zhang,Guoshun Liu,Chengwei Guan,Haitao Yan,Zhengyang Niu,Xianyi Xiao

doi:10.1098/rsos.181499

Abstract

Soil carbon reserves are the largest terrestrial carbon pools. Common agricultural practices, such as high fertilization rates and intensive crop rotation, have led to global-scale environmental changes, including decreased soil organic matter, lower carbon/nitrogen ratios and disruption of soil carbon pools. These changes have resulted in a decrease in soil microbial activity, severe reduction in soil fertility and transformation of soil nutrients, thereby causing soil nutrient imbalance, which seriously affects crop production. In this study, 16S rDNA-based analysis and static chamber-gas chromatography were used to elucidate the effects of continuous application of straw biochar on soil carbon pools and the soil microbial environments of two typical soil types (purple and paddy soils) in southern China. Application of biochar (1) improved the soil carbon pool and its activity, (2) significantly promoted the release of soil CO2 and (3) improved the soil carbon environment. Soil carbon content was closely correlated with the abundance of organisms belonging to two orders, Lactobacillales and Bacteroidales, and, more specifically, to the genus Lactococcus. These results suggest that biochar affects the soil carbon environment and soil microorganism abundance, which in turn may improve the soil carbon pool.

Highlights

IntroductionCommon agricultural practices, such as high fertilization rates and intensive crop rotation, have led to global-scale environmental changes, including decreased soil organic matter, lower carbon/nitrogen ratios and disruption of soil carbon pools
Soil carbon reserves are the largest terrestrial carbon pools
We found that the abundance of the bacterial order Lactobacillales was closely correlated with the Total carbon (TC), total organic carbon (TOC), easily oxidized carbon (EOC), microbial biomass carbon (MBC), AI and carbon pool management index (CPMI) of the soils and those of the bacterial orders Sphingomonadales and Rhizobiales were closely correlated with the dissolved organic carbon (DOC) and A of the soils

Summary

Introduction

Common agricultural practices, such as high fertilization rates and intensive crop rotation, have led to global-scale environmental changes, including decreased soil organic matter, lower carbon/nitrogen ratios and disruption of soil carbon pools These changes have resulted in a decrease in soil microbial activity, severe reduction in soil fertility and transformation of soil nutrients, thereby causing soil nutrient imbalance, which seriously affects crop production. Soil organic carbon (SOC) content is often regarded as an important index for evaluating the potential fertility of soil [2,3], and its dynamic equilibrium has a direct impact on soil fertility and crop yields Human activities, such as high rates of fertilization and intensive crop rotation systems, have resulted in decreases in soil organic matter and carbon/nitrogen ratio, and imbalances in the soil carbon pool on a global scale [4,5]. Biochar addition can improve soil water-holding capacity [21], reduce soil bulk density, promote soil ECE (Cation Exchange Capacity) and pH [22], change soil biochemical reaction conditions and stimulate soil enzyme activity [23] and promote soil microbial reproduction [24]

Methods

Results

Discussion

Conclusion