Journal of Soils and Sediments

, Volume 13, Issue 8, pp 1327–1334

Stability and saturation of soil organic carbon in rice fields: evidence from a long-term fertilization experiment in subtropical China

SOILS, SEC 1 • SOIL ORGANIC MATTER DYNAMICS AND NUTRIENT CYCLING • RESEARCH ARTICLE

DOI: 10.1007/s11368-013-0741-z

Cite this article as:
Sun, Y., Huang, S., Yu, X. et al. J Soils Sediments (2013) 13: 1327. doi:10.1007/s11368-013-0741-z

Abstract

Purpose

Soil organic carbon (SOC) sequestration in croplands plays a critical role in climate change mitigation and food security, whereas the stability and saturation of the sequestered SOC have not been well understood yet, particularly in rice (Oryza sativa L.) fields. The objective of this study was to determine the long-term effect of inorganic fertilization alone or combined with organic amendments on SOC stability in a double rice cropping system, and to characterize the saturation behavior of the total SOC and its fractions in the paddy soil.

Materials and methods

Soils were collected from a long-term field experiment in subtropical China where different fertilization regimes have been carried out for 31 years. The total SOC pool was separated into four fractions, characteristic of different turnover rates through chemical fractionation. Annual organic carbon (C) inputs were also estimated by determining the C content in crop residues and organic amendments.

Results and discussion

Relative to the initial level, long-term double rice cropping without any fertilizer application significantly increased SOC concentration, suggesting that double rice cropping facilitates the storage and accumulation of SOC. The partial substitution of inorganic fertilizers with organic amendments significantly increased total SOC concentration compared to the unfertilized control. Total SOC increased significantly with greater C inputs and did not show any saturation behavior. Increased SOC was primarily stored in the labile fraction with input from organic amendments. However, other less labile SOC fractions showed no further increase with greater C inputs exhibiting C saturation.

Conclusions

While the paddy soil holds a high potential for SOC sequestration, stable C fractions saturate with increasing C inputs, and thus, additional C inputs mainly accumulate in labile soil C pools.

Keywords

Carbon stability Double-cropped rice Organic amendments Saturation Soil organic carbon fractions 

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Yanni Sun
    • 1
  • Shan Huang
    • 2
  • Xichu Yu
    • 3
  • Weijian Zhang
    • 1
    • 4
  1. 1.Institute of Applied EcologyNanjing Agricultural UniversityNanjingPeople’s Republic of China
  2. 2.Department of AgronomyJiangxi Agricultural UniversityNanchangPeople’s Republic of China
  3. 3.Jiangxi Institute of Red SoilJinxianPeople’s Republic of China
  4. 4.Institute of Crop Science, Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Physiology and EcologyMinistry of AgricultureBeijingPeople’s Republic of China

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