Open AccessSimulated nitrogen deposition significantly reduces soil respiration in an evergreen broadleaf forest in western China
Author(s) -
Shixing Zhou,
Yang Xiang,
Liehua Tie,
Han Bohan,
Congde Huang
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0204661
Subject(s) - q10 , soil respiration , respiration , soil carbon , deposition (geology) , evergreen , zoology , nitrogen , respiration rate , carbon cycle , water content , agronomy , ecosystem , chemistry , environmental science , soil water , biology , soil science , botany , ecology , paleontology , organic chemistry , sediment , geotechnical engineering , engineering
Soil respiration is the second largest terrestrial carbon (C) flux; the responses of soil respiration to nitrogen (N) deposition have far-reaching influences on the global C cycle. N deposition has been documented to significantly affect soil respiration, but the results are conflicting. The response of soil respiration to N deposition gradients remains unclear, especially in ecosystems receiving increasing ambient N depositions. A field experiment was conducted in a natural evergreen broadleaf forest in western China from November 2013 to November 2015 to understand the effects of increasing N deposition on soil respiration. Four levels of N deposition were investigated: control (Ctr, without N added), low N (L, 50 kg N ha −1 ·a −1 ), medium N (M, 150 kg N ha −1 ·a −1 ), and high N (H, 300 kg N ha −1 ·a −1 ). The results show that (1) the mean soil respiration rates in the L, M, and H treatments were 9.13%, 15.8% ( P < 0.05) and 22.57% ( P < 0.05) lower than that in the Ctr treatment (1.56 ± 0.13 μmol·m −2 ·s −1 ), respectively; (2) soil respiration rates showed significant positive exponential and linear relationships with soil temperature and moisture ( P < 0.01), respectively. Soil temperature is more important than soil moisture in controlling the soil respiration rate; (3) the Ctr, L, M, and H treatments yielded Q 10 values of 2.98, 2.78, 2.65, and 2.63, respectively. N deposition decreased the temperature sensitivity of soil respiration; (4) simulated N deposition also significantly decreased the microbial biomass C and N, fine root biomass, pH and extractable dissolved organic C ( P < 0.05). Overall, the results suggest that soil respiration declines in response to N deposition. The decrease in soil respiration caused by simulated N deposition may occur through decreasing the microbial biomass C and N, fine root biomass, pH and extractable dissolved organic C. Ongoing N deposition may have significant impacts on C cycles and increase C sequestration with the increase in global temperature in evergreen broadleaf forests.