Depth distribution of humic substances in Andosols in relation to land management and soil erosion

作者：Armas Herrera C M^*; Mora J L; Guerra J A; Arbelo C D; Rodriguez Rodriguez A

来源：Soil Use and Management, 2013, 29(1): 77-86.

DOI：10.1111/sum.12013

• Humic acids
• soil erosion
• soil use and management
• vegetation
• geostatistics

Although Andosols are relatively resistant to water erosion, they can be severely affected by changes in land use, resulting in accelerated erosion and loss of soil organic matter (SOM). We hypothesized that if the contents of specific components of SOM and organometallic complexes (humic acids HAs, fulvic acids FAs, sodium pyrophosphate extractable carbon Cp, aluminium Alp, and iron Fep) consistently tend towards certain ratios in A and B horizons, they could be used to identify soils denuded by erosion. To test this hypothesis, we investigated the vertical distribution of humus components and certain ratios, namely C-HA/C-FA, C-FA/total organic C (TOC), Cp/TOC and (Fep+Alp)/C-FA, in representative profiles of andic soils located in natural ecosystems with different degrees of human disturbance. Furthermore, we analysed these parameters in the topsoil of a natural protected area and in adjacent soils under different land use scenarios (natural reserve vs. traditional exploitation). We found that the ratios of C-HA/C-FA and, to a lesser extent, of C-FA/TOC and Cp/TOC changed with depth in the selected soil profiles, but the values were characteristic of each type of soil horizon. The values of these ratios in the topsoils of the disturbed areas were closer to a B horizon than an A horizon. This pattern may be superimposed on pre-existing gradients, such as those related to the type of natural vegetation. The use of these indices emerges as a possible land use and erosion indicator.

• 出版日期2013-3