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Differential responses of auto‐ and heterotrophic soil respiration to water and nitrogen addition in a semiarid temperate steppe
Author(s) -
YAN LIMING,
CHEN SHIPING,
HUANG JIANHUI,
LIN GUANGHUI
Publication year - 2010
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2009.02091.x
Subject(s) - temperate climate , steppe , environmental science , ecosystem , cycling , agronomy , soil water , soil respiration , ecology , soil science , environmental chemistry , hydrology (agriculture) , chemistry , biology , geology , forestry , geotechnical engineering , geography
Evaluating how autotrophic (SR A ), heterotrophic (SR H ) and total soil respiration (SR TOT ) respond differently to changes of environmental factors is critical to get an understanding of ecosystem carbon (C) cycling and its feedback processes to climate change. A field experiment was conducted to examine the responses of SR A and SR H to water and nitrogen (N) addition in a temperate steppe in northern China during two hydrologically contrasting growing seasons. Water addition stimulated SR A and SR H in both years, and their increases were significantly greater in a dry year (2007) than in a wet year (2006). N addition increased SR A in 2006 but not in 2007, while it decreased SR H in both years, leading to a positive response of SR TOT in 2006 but a negative one in 2007. The different responses of SR A and SR H indicate that it will be uncertain to predict soil C storage if SR TOT is used instead of SR H to estimate variations in soil C storage. Overall, N addition is likely to enhance soil C storage, while the impacts of water addition are determined by its relative effects on carbon input (plant growth) and SR H . Antecedent water conditions played an important role in controlling responses of SR A , SR H and the consequent SR TOT to water and N addition. Our findings highlight the predominance of hydrological conditions in regulating the responses of C cycling to global change in the semiarid temperate steppe of northern China.