Fast immersion to test the stability of aggregates in water: consequences for interpreting results from tropical soil classes

Abstract

Aggregates are the primary structural components of soil and have been used as an indicator of soil quality in conservation systems. The objective of this study was to analyse the effect of slow pre-wetting on the results of the aggregate stability test for different classes of tropical soils. Data were arranged in a 2 x 4 factorial design with three replications, in which the first factor comprised the two methods of pre-treatment on soil aggregates: without pre-wetting (WOPW), which considered the moisture of the aggregates in the field, and with pre-wetting (WPW), which considered the slow wetting of aggregates through capillarity on wet filter paper for 24h. The second factor consisted of four soil classes: Typic Dystrustept (Cambissolo Aplico distrófico in Embrapa), Typic Hapludult (Argissolo Amarelo distrófico), Rhodic Kandiudult (Nitossolo Vermelho distrófico), and Anionic Acrudox (Latossolo Vermelho distróferrico) and considered horizons A and B. The pre-wetting significantly increased the values of the weighted average diameter, geometric mean diameter and aggregate stability index. In soils with high organic carbon content, the practice of pre-moistening did not provide variation in aggregation.

Sediment Delivery Ratio from a small Semiarid Watershed of Brazil

“…Soil cover influence in soil surface roughness and the runoff provided by the caatinga vegetation semi-shrub and the litter on soil, so that the soil disaggregation is considerably reduced but, retains water on its surface and decreases runoff volume and velocity compared the condition of uncovered soil. Similar results were obtained by Silva et al (2020) evaluating the effect of different levels of coverage soybean straw on interrill erosion and runoff. The infiltration rates higher showed for soil with semi-shrubby Caatinga vegetation and soil with herbaceous residue in decomposition due roughness height decrease runoff volume favoring to water infiltration capacity, soil roughness potentially affects surface processes such as infiltration (Piscoya et al, 2018b;Dumbrovsky et al, 2019).…”