The importance of soil carbonates for available water holding capacity in arid ecosystems of the Americas

TitleThe importance of soil carbonates for available water holding capacity in arid ecosystems of the Americas
Publication TypeConference Paper
Year of Publication2006
AuthorsDuniway MC, Herrick JE, H. Monger C
Conference NameEcology International Congress
Date PublishedJanuary 10, 2006
Conference LocationMerida, Mexico
ARIS Log Number204806
Keywordscalcic, Petrocalcic, semi-arid
AbstractPetrocalcic and calcic soil horizons develop extensively in arid and semi-arid ecosystems across more than 15% of the Americas. Many of these horizons occur within the rooting zone of grasses and row crops and all are within the rooting depths of deep rooted desert shrubs. The accumulation of calcium carbonate in coarse textured soils can produce a dramatic change in water holding capacity through the conversion of a soil horizon dominated by large pores to a fine pore matrix. Understanding soil available water holding capacity (AWHC) is important for both forage and row crop production systems. Soil AWHC can control production and plant community composition by affecting the spatial and temporal patterns of plant available water. We conducted laboratory experiments and field surveys assessing the importance of carbonate accumulation for soil profile AWHC and the temporal availability of plant available water in high carbonate soils in southern New Mexico, USA. The added water holding capacity due to carbonates more than doubled the AWHC of some coarse textured soils but was less important in fine textured soils. Many high carbonate soil horizons, even horizons cemented with calcium carbonate, received substantial increases in soil water content during periods of winter recharge. Petrocalcic and partially indurated calcic horizons are often overlooked when assessing soil profile available water. This study indicates that petrocalcic and calcic horizons can contain significant amounts of plant available water and are important when assessing soil available water holding capacity.