Document: CRI-3-59-86

Parent material controls over carbon and nitrogen storage in California.

CASTANHA, C.* and R.AMUNDSON

UC Berkeley, Berkeley, CA 94720-3050 USA ¹

Abstract:
To be applicable at regional scales, soil organic matter (SOM) models need to be parameterized on the basis of easily acquired information, and therefore generally incorporate mean annual air temperature and precipitation, soil texture, and vegetation class. But, SOM models do not explicitly incorporate parent material, which, along with climate, influences clay content and organic matter storage patterns. Our goal is to assess the importance of parent material on SOM stocks by quantifying its observed relationship to C and N storage and to properties relevant to C cycling. Here, we examine the statistical relationships between the predictor variables parent material, climate, and clay and the response variables total organic C, total N, and clay. The data represent 334 well-drained upland soils formed from 7 rock types, each spanning approximately the same mean annual temperature and precipitation range. We test the effect of parent material on a) organic C and N storage, b) sensitivity of C and N to clay, and c) the depth distribution of C and N. We conclude that parent material a) has a statistical effect on C and N storage, b) moderates the sensitivity of C and N to clay, and c) influences the depth distribution of C and N.

Keywords: Parent Material, soil carbon, soil nitrogen, soil organic matter models

This abstract is being presented at: 1:30 PM in session:
Oral Session #52: Carbon Storage in Ecosystems.