Terrestrial pyrogenic carbon export to fluvial ecosystems: lessons learned from the White Nile watershed of East Africa

Transcription

1 Global Biogeochemical Cycles Supporting Information for Terrestrial pyrogenic carbon export to fluvial ecosystems: lessons learned from the White ile watershed of East Africa David T. Güereña, Johannes Lehmann,*, Todd Walter, Akio Enders, Henry eufeldt, Holiance Odiwour, Henry Biwott, John Recha 5, Keith Shepherd, Edmundo Barrios, Chris Wurster 6 Department of Crop and Soil Sciences, Cornell University, Ithaca, Y, USA Atkinson Center for a Sustainable Future, Cornell University, Ithaca, Y, USA Department of Biological and Environmental Engineering, Cornell University, Ithaca Y, USA World Agroforestry Centre (ICRAF), airobi, Kenya 5 The International Livestock Research Institute, airobi, Kenya 6 School of Earth and Environmental Science, James Cook University, Cairns, Australia * Corresponding author, CL7@cornell.edu Contents of this file Tables S-S5 Figures S-S8

2 Table S. Location (UTM coordinates of the weir) and characteristics of the studied headwaters. Catchment Duration of cropping (years) UTM coordinates of the weir Size (ha) FA n/a FB n/a A B A B A B

3 Table S. Geographic coordinates of the sampling locations (UTM) of the rivers sampled in the Lake Victoria Basin. Site UTM coordinates R. Yala 5M R. zoia R. yando 5M R. Awach 6M R. Sondu-Miriu 6M R. Gucha 6M R. Kibuon 6M R. Simiyu 6M R. Kagera 6M R. Mara 6M R. ile at Jinja

4 Table S. Field saturated infiltrability across the Kapchorwa catchments measured by the Cornell Sprinkle Infiltrometers. Simulated rainfall rates of the infiltrometers was 00 mm hr -. o letters are shown since pairwise comparisons were not significant (Tukey s HSD, P<0.05, n=8). FA-CH represents the charcoal production sites located in forest catchment FA, FB-PyCexp represents the researcher applied charcoal plots located in forest catchment FB. Catchment FA 68 FA-CH 08 FB 68 FB-PyCexp 8 0A 0 0B 5 6A 77 6B 75 6A 97 6B P-value 0.0 Field-saturated infiltrability (mm hr - )

5 Table S. Field saturated infiltrability across slope units within the Kapchorwa catchments measured by the Cornell Sprinkle Infiltrometers. Simulated rainfall rates of the infiltrometers was 00 mm hr -. Different letters indicate significant differences (Tukey s HSD, P<0.05, n=8). CH represents the charcoal production sites located in catchment FA. Catchment Field-saturated infiltrability (mm hr - ) CH 08 A % < 60 B -% 08 AB - 8 AB 5-8 AB 0-8 AB 0-59 AB > 08 AB P-value

6 Table S5. Field saturated infiltrability by land-use within the Kapchorwa catchments measured by the Cornell Sprinkle Infiltrometers. Simulated rainfall rates of the infiltrometers was 00 mm hr -. Different letters indicate significant differences (Tukey s HSD, P<0.05, n=8). Land use Field-saturated infiltrability (mm hr - ) Beans Sweet potato Sugarcane Forest Ploughed bare fields apier grass Maize Unploughed soil Fallow Tea Homestead bare soil Kale Eucalyptus Playground bare Pasture Road Riverine vegetation Arrow root Homestead grass Playground - grass ABC ABC 86 ABC 7 A 7 ABC 5 ABC 5 AB 50 ABC 0 ABC 0 ABC 7 ABC 6 ABC 5 BC 9 ABC 9 C BC C 6 ABC 6 ABC 6 ABC P-value <

7 Figure S. Photo of one of the locations in the forest catchment FA where charcoal was produced (July 0). This practice led to spots of concentrated accumulation of PyC in an area of about m (labeled CH in Table and Figure in the main manuscript). 7

8 Weir Kilometers Figure S. Map of locations of the PyC accumulation from charcoal making in forest catchment FA (assessed May 0). 8

9 C #C # Mg (mg%g ha / ) % 9 5 C # 0.08 % 0.6 %Kilometers% Mg (mg%g ha / ) % % 0.%Kilometers% C # (mg%g Mg ha / ) % 9 Mg (mg%g ha / ) % % 0.6 %Kilometers% 0.07% 0. %Kilometers% Mg (mg%g ha / ) % 9 5 %%PyC % Mg (mg%g ha / ) % % 0. %Kilometers% 0.08 % 0.6 %Kilometers% Mg (mg%g ha / ) % 9 Mg (mg%g ha / ) % % 0.%Kilometers% %Kilometers% Figure S. Kriging map of the distribution of topsoil (0-0.5 m) PyC stocks in the Kapchorwa catchments. All catchments are oriented with the weir at the bottom of each map to facilitate comparison of the PyC distribution as a function of slope position. 9

10 %PyC % (mg%g / ) % 9% 0.08 % 0.6 %Kilometers% %PyC % (mg%g / ) % 9% 0.05 % 0.%Kilometers% %PyC % (mg%g / ) % 9% %PyC % (mg%g / ) % 9% 0.08 % 0.6 %Kilometers% 0.07 % 0. %Kilometers% %PyC % (mg%g / ) % 9% %%PyC % (mg%g / ) % 9% 0.07 % 0. %Kilometers% 0.08 % 0.6 %Kilometers% %%PyC % (mg%g / ) % 9% 0.05 % 0.%Kilometers% %%PyC % (mg%g / ) % 9% %Kilometers% Figure S. Kriging map of the distribution of topsoil (0-0.5 m) PyC concentrations in the Kapchorwa catchments. All catchments are oriented with the weir at the bottom of each map to facilitate comparison of the PyC distribution as a function of slope position. 0

11 Concentration [mg L - ] Concentration [mg L - ] Concentration [mg L - ] Concentration [mg L - ] 0.6 Discharge PyC 0. Total C 0. DPyC DOC A A FA A 0.00 Aug Sep Oct ov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Sep Oct ov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Month Month Figure S5. Bi-weekly discharge and stream water concentrations of TOC and PyC in natural and agricultural headwater catchments of the Yala River, Kenya. Discharge in catchment 6B was divided by a factor of three to allow for uniform axes scales. Due to much smaller PyC concentrations, these are shown separately in Figure S6. FB 0B 6B 6B 0 Discharge [mm day - ] Discharge [mm day - ] Discharge [mm day - ] Discharge [mm day - ]

12 Concentration [mg L - ] 0. Discharge PyC DPyC FA FB Discharge [mm day - ] Concentration [mg L - ] A B Discharge [mm day - ] Concentration [mg L - ] A B Discharge [mm day - ] Concentration [mg L - ] A B Discharge [mm day - ] Aug Sep Oct ov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Sep Oct ov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Month Month Figure S6. Bi-weekly discharge and stream water concentrations of total PyC and DPyC in natural and agricultural headwater catchments of the Yala River, Kenya. Discharge in catchment 6B was divided by a factor of three to allow for uniform axes scales (note logarithmic scale of concentration). 0

13 Figure S8. Conceptual sketch of the main questions of this study and corresponding sections in the Discussion.