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Have we overestimated the contribution of organic matter on soil water retention.

Our colleagues from the University of Sydney published new insights on the relationship between soil OC and available water capacity that contradict earlier assumed controls. This controversial paper can be found in European Journal of Soil Science: doi: 10.1111/ejss.12475

From a large number of studies and databases they analysed,
they concluded that the effect of addition of OM on soil-available
water capacity was modest, with average values of between 1.4
and 1.9mm 100mm−1 per 10 g kg−1 increase in OC. Sandy soil
was more responsive to the increase in OC, whereas the effect on
clayey soil was almost negligible. The largest effect of OC was in
large pores, possibly from the formation of macroaggregates, and
its effect decreases with a decrease in size of pores.
The results also suggest that the gradual loss of organic matter
from soil would have a minimal effect on the hydrological cycle.
Global warming might cause a loss in soil carbon, but the effects
on soil water availability to plants and consequent effects on the
hydrological cycle might be less than thought previously. The
negative feedback could be less serious. In addition, suggestions
that sequestering carbon would increase soil water storage are questionable.
They state that even with the best scenario of farm
management practices, available water capacity cannot be increased
meaningfully. Nevertheless, storing carbon in the soil should still be
pursued for improving soil structure, atmospheric CO2 attenuation
and nutrient cycling. Macropores created by organic matter can still
have important effects in increasing infiltration and gas transport.

Meetings - Reports - Publications
3rd ISMC Conference Aug 16, 2019
AGU abstracts, Conferences and Workshops Jul 31, 2019
AGU 2019 Jul 03, 2019
ISMC Chair Jul 03, 2019
Events, DO-LINK, Soil-MIPand CROSS-CONNECT Jun 26, 2019
News on Data and Model Intercomparison, Courses, and Partners May 09, 2019
April News Apr 07, 2019
March News Mar 26, 2019
World Soils 2019 Mar 05, 2019
Reminder: Eurosoil 2020 Session Proposals Deadline Feb 28, 2019
EGU 2019 Feb 28, 2019
Annual Report 2018 Feb 22, 2019
Second International Crop Modelling Symposium (iCROPM2020) Jan 22, 2019
Input Needed: National Academies CORES study Jan 22, 2019
Report of Findings, ISMC presentation, and EGU Jan 09, 2019
Wageningen Soil Conference 2019 (WSC2019) Dec 15, 2018
Come to the AGU ISMC Meeting 9th Dec. Dec 09, 2018
Submit to EGU 2019 - Abstracts due: 10th Jan. 13:00 CET Nov 30, 2018
9th PEDOFRACT July 2019 Conference in Barco de Avila, Spain Nov 29, 2018
Syvitski Student Modeler Competition 2019 Nov 28, 2018
Soil Works on 28 Jan. 2019 (BE) Nov 28, 2018
Announcement for ISMC co-Chair Nov 26, 2018
SoPhie - Soil Hydro-Physics Data - next workshop in Gembloux - 30 Jan 2019 Nov 19, 2018
Award winners Nov 15, 2018
Enabling FAIR Data Nov 13, 2018
ISMC at AGU 2018 and AGU's Soil SWIRL Oct 23, 2018
Call for Soil Hydraulic data! Oct 18, 2018
2019 Soil Systems Travel Award—Deadline: 31 December 2018 Oct 18, 2018
21st World Congress Soil Science 2018 - IUSS Sep 04, 2018
Conference Programme and Important Updates Aug 29, 2018
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