Plant and Soil

, Volume 373, Issue 1, pp 125–141

Soil CO2 efflux in response to the addition of water and fertilizer in temperate semiarid grassland in northern China

Regular Article

DOI: 10.1007/s11104-013-1771-4

Cite this article as:
Jia, X., Shao, M. & Wei, X. Plant Soil (2013) 373: 125. doi:10.1007/s11104-013-1771-4

Abstract

Background and aims

Knowledge about the effects of water and fertilizer on soil CO2 efflux (SCE) and Q10 is essential for understanding carbon (C) cycles and for evaluating future global C balance. A two-year field experiment was conducted to determine the effects of water, fertilizer, and temperature on SCE in semiarid grassland in northern China.

Methods

SCE, as well as environmental factors was measured in two grasslands, one with bunge needlegrass (BNE, Stipa bungeana) and one with purple alfalfa (ALF, Medicago sativa), with four treatments: CK (unwatered and unfertilized); W (50 mm water addition yr−1); F (50 kg phosphorus (P) fertilizer ha−1 yr−1 for ALF, 100 kg nitrogen (N) + 50 kg P fertilizer ha−1 yr−1 for BNE); and W + F.

Results

During the 11-month experimental period from July 2010 to October 2011, the addition of water consistently stimulated mean SCE in BNE and ALF, and the positive effects were relatively stronger during dry seasons. P fertilization consistently enhanced SCE in ALF, and the positive effect was strongly dependent on the availability of soil water. The effects of N plus P fertilization on SCE in BNE varied seasonally from significant increases to small reductions to no response. Water addition increased the Q10 of SCE in ALF by 11 % but had no effect in BNE. Fertilization, however, reduced the Q10 of SCE by 21 % and 13 % for BNE and ALF, respectively. Models that rely only on Q10 underestimated the emissions of soil CO2 by 8–15 % at the study site, which was mediated by species and treatment.

Conclusions

Responses of SCE and its temperature sensitivity to water and fertilizer may vary with species and depend on the period of measurement. Models of SCE need to incorporate the availability of ecosystemic water and nutrients, as well as species, and incorporate different environmental factors when determining the impact of water, nutrients, and species on SCE.

Keywords

Soil CO2 efflux Water addition Fertilization Temperature sensitivity Semiarid grassland 

Abbreviations

AGB

Aboveground biomass

ALF

Alfalfa

BNE

Bunge needlegrass

C

Carbon

F

Fertilization

FRB

Fine root biomass

M

Soil moisture

N

Nitrogen

P

Phosphorus

Pr

Period

SCE

Soil CO2 efflux

T

Soil temperature

W

Water addition

Supplementary material

11104_2013_1771_MOESM1_ESM.doc (1.7 mb)
ESM 1(DOC 1.73 MB)

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  1. 1.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F UniversityYanglingChina
  2. 2.Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of SciencesBeijingChina

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