Impact of soil texture on the distribution of soil organic matter in physical and chemical fractions
Data(s) |
2006
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Resumo |
Previous research on the protection of soil organic C from decomposition suggests that soil texture affects soil C stocks. However, different pools of soil organic matter (SOM) might be differently related to soil texture. Our objective was to examine how soil texture differentially alters the distribution of organic C within physically and chemically defined pools of unprotected and protected SOM. We collected samples from two soil texture gradients where other variables influencing soil organic C content were held constant. One texture gradient (16-60% clay) was located near Stewart Valley, Saskatchewan, Canada and the other (25-50% clay) near Cygnet, OH. Soils were physically fractionated into coarse- and fine-particulate organic matter (POM), silt- and clay-sized particles within microaggregates, and easily dispersed silt-and clay-sized particles outside of microaggregates. Whole-soil organic C concentration was positively related to silt plus clay content at both sites. We found no relationship between soil texture and unprotected C (coarse- and fine-POM C). Biochemically protected C (nonhydrolyzable C) increased with increasing clay content in whole-soil samples, but the proportion of nonhydrolyzable C within silt- and clay-sized fractions was unchanged. As the amount of silt or clay increased, the amount of C stabilized within easily dispersed and microaggregate-associated silt or clay fractions decreased. Our results suggest that for a given level of C inputs, the relationship between mineral surface area and soil organic matter varies with soil texture for physically and biochemically protected C fractions. Because soil texture acts directly and indirectly on various protection mechanisms, it may not be a universal predictor of whole-soil C content. |
Identificador | |
Publicador |
Soil Science Society of America |
Relação |
DOI:10.2136/sssaj2004.0363 Plante, Alain F., Conant, Richard T., Stewart, Catherine E., Paustian, Keith, & Six, Johan (2006) Impact of soil texture on the distribution of soil organic matter in physical and chemical fractions. Soil Science Society of America Journal, 70(1), pp. 287-296. |
Direitos |
Copyright 2006 Soil Science Society of America |
Fonte |
Institute for Sustainable Resources |
Palavras-Chave | #050100 ECOLOGICAL APPLICATIONS #050300 SOIL SCIENCES #soil organic matter, SOM #Stewart Valley, Saskatchewan #microaggregates |
Tipo |
Journal Article |