Erratum to: An in-depth look into a tropical lowland forest soil: nitrogen-addition effects on the contents of N₂O, CO₂ and CH₄ and N₂O isotopic signatures down to 2-m depth

Erratum to: Biogeochemistry DOI 10.1007/s10533-012-9711-6

The authors would like to make the following corrections to the online published article:

In the calculations of the depth-integrated area-based gas contents in soil air and water we conducted a mistake by summing up the volume-based gas contents and multiplying them with the volumes of the topsoil and subsoil. This resulted in overestimations of the respective values in Table 2. We corrected the integration over depth using the trapezoidal rule, and give the resulting values in the corrected Table 2. A few slight changes in the result paragraphs about the soil gaseous contents are highlighted in bold font in the text below, and the reader is asked to refer to these instead of to the ones in the article. We may not anymore support the statement in the abstract that ‘the pronounced seasonality in soil respiration was largely attributable to enhanced topsoil respiration’ because in the corrected analysis also the subsoil CO₂-C contents in the soil air of the control plots were larger during wet than dry season, and the fractions of CO₂-C contents in the topsoil were not consistently larger during wet than dry season as previously the case. The respective three sentences in the discussion about the dynamics of carbon dioxide in the control plots (i.e. ‘Soil respiration in the studied lowland forest’ to ‘as well as fine root growth, biomass and turnover during wet than dry season at our site’) are therefore not anymore valid. Also, in the second to last sentence of the discussion section about methane the information in brackets is not anymore valid but this does not change the interpretation. Apart from these, the results, interpretations and conclusions remain unchanged throughout the article.

Abstract

Long-term N-addition did not affect dry-season soil N₂O-N contents, increased wet-season soil N₂O-N contents, did not affect ¹⁵N signatures of NO ⁻₃ , and reduced wet-season ¹⁵N signatures of N₂O compared to the control plots. (…) The N-addition plots showed reduced dry-season topsoil CH₄-C contents and threshold CH₄ concentrations were reached at a shallower depth compared to the control plots, revealing an N-induced stimulation of methanotrophic activity.

Results

Nitrous oxide

In both treatments, N ₂ O-N contents were generally larger during wet than dry season ( P < 0.047, except for the contents in topsoil air in the control plots with P = 0.729; Table 2). Dry-season N₂O-N contents did not differ between treatments but wet-season N₂O-N contents were larger in the N-addition compared to the control plots in soil air ( P < 0.039) and in subsoil water ( P = 0.009). The fractions of N₂O-N contents located in the topsoil did not differ seasonally in either the control or N-addition plots. During dry season, the N ₂ O-N fractions located in the topsoil were larger in the control than in the N-addition plots ( P = 0.039; Table  2). In both treatments and seasons, the water phase contained 52–60 % of the overall soil N₂O-N contents (Table 2).

Carbon dioxide

In both treatments, topsoil CO ₂ -C contents were larger during wet than dry season ( P < 0.044). The same was the case for the subsoil of the control plots ( P < 0.021), and, albeit not significant on the 5 % significance level, a similar trend appeared in the subsoil of the N-addition plots ( P = 0.089 in air and P = 0.052 in water). Seasonal soil CO₂-C contents were unaffected by N-addition (Table 2). In the control plots, the fractions of CO ₂ -C content located in the topsoil water were larger during wet than dry season ( P = 0.044). They did not differ seasonally in the subsoil water or in soil air, and did not differ in any season or depth in the N-addition plots or between treatments. In both treatments and seasons, the water phase contained 64–69 % of the overall soil CO₂-C contents (Table 2).

Methane

In both treatments, CH ₄ -C contents in soil air were larger during dry than wet season ( P < 0.028 in the topsoil and P < 0.030 in the subsoil; Table  2) while the contents in soil water did not differ seasonally. Dry-season CH₄-C contents in topsoil air were smaller in the N-addition than the control plots by 28 % (P = 0.016). Dry-season CH₄-C contents in subsoil air and water and wet-season CH₄-C contents did not differ between treatments (Table 2). The fractions of CH₄-C content located in the topsoil did not differ seasonally in either the control or N-addition plots, and did not differ between treatments (Table 2). In both treatments and seasons, the water phase contained 5–7 % of the overall soil CH₄-C contents (Table 2).

Corrected Table 2 Mean (± SE) N₂O-N, CO₂-C and CH₄-C contents in soil air and water of the topsoil (0.05–0.40 m depth) and subsoil (0.40–2.00 m depth) during dry season (DS) and wet season (WS) in the control and 9–11-year N-addition plots