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Soil Carbon and Nitrogen Dynamics Following Application of Pig Slurry for the 19th Consecutive Year I. Carbon Dioxide Fluxes and Microbial Biomass Carbon
Author(s) -
Rochette Philippe,
Angers Denis A.,
Côté Denis
Publication year - 2000
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2000.6441389x
Subject(s) - slurry , decomposition , soil water , carbon dioxide , manure , biomass (ecology) , chemistry , zoology , environmental chemistry , nitrogen , environmental science , soil carbon , total organic carbon , agronomy , soil science , environmental engineering , biology , organic chemistry
Agricultural soils often receive annual applications of manure for long periods. The objective of this study was to quantify the effects of 19 consecutive years of pig ( Sus scrofa ) slurry (PS) application on CO 2 emissions and soil microbial biomass. Soil temperature, soil moisture, and extractable soil C were also determined to explain the variations in CO 2 emissions and soil microbial biomass. Long‐term (19 yr) treatments were 60 (PS60) and 120 Mg ha −1 yr −1 (PS120) of pig slurry and a control receiving mineral fertilizers at a dose of 150 kg ha −1 yr −1 each of N, P 2 O 5 , and K 2 O. Very high CO 2 emissions (up to 1.5 mg CO 2 m −2 s −1 ) occurred during the first 2 d after PS application. Following that peak, decomposition of PS was rapid, with one‐half the total emissions occurring during the first week after slurry application. The rapid initial decomposition was exponential and was attributed to the decomposition of the labile fraction of the slurry C. The second phase was linear and much slower and probably involved more recalcitrant C material. Cumulative annual decomposition was proportional to the application rate, with 769 and 1658 kg C ha −1 lost from the 60 and 120 Mg ha −1 doses, respectively. Pig slurry application caused a rapid increase in soil microbial biomass (from ≈100 to up to 370 mg C kg −1 soil), which coincided with a peak in the concentration of extractable C and in CO 2 emissions. Field estimates of the microbial specific respiratory activity suggested that the difference in soil respiration between the two slurry treatments was due to differences in the size of the induced microbial biomass rather than to differences in specific activity.