TY - JOUR
T1 - Lack of increased availability of root-derived C may explain the low N2O emission from low N-urine patches
AU - Carter, M.S.
AU - Klumpp, K.
AU - Roux, X. Le
N1 - This article may be downloaded for personal use only. Any other use requires prior permission of the author and the publisher
PY - 2006
Y1 - 2006
N2 - Urine deposition on grassland causes significant N2O losses, which in some cases may result from increased denitrification stimulated by labile compounds released from scorched plant roots. Two 12-day experiments were conducted in C-13-labelled grassland monoliths to investigate the link between N2O production and carbon mineralization following application of low rates of urine-N. Measurements of N2O and CO2 emissions from the monoliths as well as delta C-13 signal of evolved CO2 were done on day -4, -1, 0, 1, 2, 4, 5, 6 and 7 after application of urine corresponding to 3.1 and 5.5 g N m(-2) in the first and second experiment, respectively. The delta C-13 signal was also determined for soil organic matter, dissolved organic C and CO2 evolved by microbial respiration. In addition, denitrifying enzyme activity (DEA) and nitrifying enzyme activity (NEA) were measured on day -1, 2 and 7 after the first urine application event. Urine did not affect DEA, whereas NEA was enhanced 2 days after urine application. In the first experiment, urine had no significant effect on the N2O flux, which was generally low (-8 to 14 mu g N2O-N m(-2) h(-1)). After the second application event, the N2O emission increased significantly to 87 mu g N2O-N m(-2) h(-1) and the N2O emission factor for the added urine-N was 0.18%. However, the associated C-13 signal of soil respiration was unaffected by urine. Consequently, the increased N2O emission from the simulated low N-urine patches was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots.
AB - Urine deposition on grassland causes significant N2O losses, which in some cases may result from increased denitrification stimulated by labile compounds released from scorched plant roots. Two 12-day experiments were conducted in C-13-labelled grassland monoliths to investigate the link between N2O production and carbon mineralization following application of low rates of urine-N. Measurements of N2O and CO2 emissions from the monoliths as well as delta C-13 signal of evolved CO2 were done on day -4, -1, 0, 1, 2, 4, 5, 6 and 7 after application of urine corresponding to 3.1 and 5.5 g N m(-2) in the first and second experiment, respectively. The delta C-13 signal was also determined for soil organic matter, dissolved organic C and CO2 evolved by microbial respiration. In addition, denitrifying enzyme activity (DEA) and nitrifying enzyme activity (NEA) were measured on day -1, 2 and 7 after the first urine application event. Urine did not affect DEA, whereas NEA was enhanced 2 days after urine application. In the first experiment, urine had no significant effect on the N2O flux, which was generally low (-8 to 14 mu g N2O-N m(-2) h(-1)). After the second application event, the N2O emission increased significantly to 87 mu g N2O-N m(-2) h(-1) and the N2O emission factor for the added urine-N was 0.18%. However, the associated C-13 signal of soil respiration was unaffected by urine. Consequently, the increased N2O emission from the simulated low N-urine patches was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots.
KW - Samfund og systemer
U2 - 10.1007/s10705-006-9014-1
DO - 10.1007/s10705-006-9014-1
M3 - Journal article
SN - 1385-1314
VL - 75
SP - 91
EP - 100
JO - Nutrient Cycling in Agroecosystems
JF - Nutrient Cycling in Agroecosystems
IS - 1-3
ER -