Nutrient Cycling in Agroecosystems

, Volume 93, Issue 2, pp 201–213

An analysis of soil carbon dynamics in long-term soil fertility trials in China

  • Rihuan Cong
  • Minggang Xu
  • Xiujun Wang
  • Wenju Zhang
  • Xueyun Yang
  • Shaomin Huang
  • Boren Wang
Original Article

DOI: 10.1007/s10705-012-9510-4

Cite this article as:
Cong, R., Xu, M., Wang, X. et al. Nutr Cycl Agroecosyst (2012) 93: 201. doi:10.1007/s10705-012-9510-4

Abstract

Soil carbon dynamics would be influenced by fertilization management in the agro-ecosystem. In this study, we analyze carbon inputs and soil organic carbon (SOC) dynamics under wheat-corn double cropping system based on four long-term experimental sites in different climate zones of China. We examine soil carbon responses to various carbon inputs by using linear (S = aA − b) and non-linear (\( S = S_{M} \frac{A}{{A + K_{S} }} - S_{L} \)) equations. The term S is the SOC change rate; a, the proportion of C inputs incorporated into soil; b, minimum change rate of SOC; SM, the asymptotic maximum value at SOC change rate approaching infinity (Mg C ha−1 year−1); SL, the decomposition rate of SOC substrates, and KS, a constant value (or ‘half-saturation constant’). The S value is fitted using linear equation with SOC data over the duration of the experiment. The annual C input (A) is estimated by measured crop biomass and C input from manure. Different amounts of balanced fertilization show little impact on the C inputs derived by plants, reaching to ~3.5 Mg C ha−1 year−1. The SOC change rate is much higher under the manure application than treatments with chemical fertilizers only. Statistical analysis shows that the linear and non-linear equations perform equally well (p < 0.01) within the experimental data interval. But the non-linear equation is more suitable for specific purpose. Using the non-linear equation, we can predict that minimum C input to maintain the current SOC level would be 0.33–1.32 Mg C ha−1 year−1 at the most sites but only 0.03 Mg C ha−1 year−1 at the Changping site. The chemical nitrogen and phosphate fertilization yield sufficient carbon biomass inputs to maintain the current SOC levels. However, to increase SOC at 1 Mg C ha−1 year−1, soils need over 10 Mg C ha−1 year−1 at most sites. Our results suggest that the increment of SOC stocks would be mainly related to the additional carbon inputs for the long-term perspectives.

Keywords

Carbon inputsSoil organic carbonNon-linear equationLong-term fertilizationWheat-corn cropping system

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Rihuan Cong
    • 1
    • 2
  • Minggang Xu
    • 1
  • Xiujun Wang
    • 2
    • 3
  • Wenju Zhang
    • 1
  • Xueyun Yang
    • 4
  • Shaomin Huang
    • 5
  • Boren Wang
    • 1
  1. 1.Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijingChina
  2. 2.Earth System Science Interdisciplinary CenterUniversity of MarylandCollege ParkUSA
  3. 3.Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumuqiChina
  4. 4.College of Resources and EnvironmentNorthwest Agricultural and Forestry Science and Technology UniversityYanglingChina
  5. 5.Institute of Soil and FertilizerHenan Academy of Agricultural SciencesZhengzhouChina