Amendment of straw biochar increased molecular diversity and enhanced preservation of plant derived organic matter in extracted fractions of a rice paddy

Shuotong Chen; Yuanjun Ding; Xin Xia; Xiao Feng; Xiaoyu Liu; Jufeng Zheng; Marios Drosos; Kun Cheng; Rongjun Bian; Xuhui Zhang; Lianqing Li; Genxing Pan

doi:10.1016/j.jenvman.2021.112104

Amendment of straw biochar increased molecular diversity and enhanced preservation of plant derived organic matter in extracted fractions of a rice paddy

J Environ Manage. 2021 May 1:285:112104. doi: 10.1016/j.jenvman.2021.112104. Epub 2021 Feb 17.

Authors

Affiliations

¹ Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, PR China; Department of Soil Science, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, PR China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, China.
² Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, PR China; Department of Soil Science, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, PR China.
³ Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, PR China; Department of Soil Science, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, PR China. Electronic address: gxpan@njau.edu.cn.

PMID: 33609976
DOI: 10.1016/j.jenvman.2021.112104

Abstract

While biochar enhanced carbon sequestration and stability of soil organic matter (SOM), changes in organic molecular composition in biochar-amended soils had been poorly addressed. In this study, molecular composition changes of a paddy topsoil 2 years following amendments at 10 t ha^-1 OC equivalent with untreated (CS), manured (CM) and charred (CB) maize straw were compared to no amendment (CK). Topsoil SOM was sequentially extracted with ultrapure water (UWE), solvent (TSE), base hydrolysis (BHY) and CuO oxidation (CUO) and molecular compounds in these extracted fractions were detected quantitatively by GC/MS. Compared to CK, SOC content was increased respectively by 12% under CS and CM, and by 36% under CB. Fraction abundance both of UWE and CUO was increased but that of TSE unchanged under CS and CM, while that of BHY unchanged under CS but increased by > 60% under CM and CB, respectively. Under CB relative to CS and CM, abundance of TSE and BHY fractions was greatly increased but that of UWE and CUO unchanged. Specifically, abundances of water-soluble monosaccharides, low molecular weight organic acids and lignin-derived phenols, especially cinnamyl-based monomers, were all enhanced under CS, but abundances of n-alkanols, fatty acids in free lipids and di-acids and hydroxyl fatty acids in bound lipids were decreased under both CS and CM. In contrast, CB amendment increased abundances of n-alkanols, alkanes and sterols in free lipids while enhanced molecular and functional group diversity of UWE and TSE fractions. Overall, short-term crop residue amendment altered the abundance and molecular diversity of OM mainly associated with short-lived UWE and labile TSE fractions and biochar enhanced preservation of plant derived molecules mainly in lipids. Thus, returning crop residue as biochar could be a sustainable approach to enhance not only SOM pool but molecular diversity also in agricultural soils.

Keywords: Biochar; Crop residue return; Molecular diversity; Rice paddy; Soil organic matter.

MeSH terms

Agriculture
Charcoal
Oryza*
Soil

Substances

Soil
biochar
Charcoal