Quantifying the changes of soil surface microroughness due to rainfall impact on a smooth surface

Abstract

Abstract. This study examines the rainfall-induced change in soil microroughness of a bare smooth soil surface in an agricultural field. The majority of soil microroughness studies have focused on surface roughness on the order of ∼ 5-50 mm and have reported a decay of soil surface roughness with rainfall. However, there is quantitative evidence from a few studies suggesting that surfaces with microroughness less than 5 mm may undergo an increase in roughness when subject to rainfall action. The focus herein is on initial microroughness length scales on the order of 2 mm, a low roughness condition observed seasonally in some landscapes under bare conditions and chosen to systematically examine the increasing roughness phenomenon. Three rainfall intensities of 30, 60, and 75 mm h −1 are applied to a smoothened bed surface in a field plot via a rainfall simulator. Soil surface microroughness is recorded via a surface-profile laser scanner. Several indices are utilized to quantify the soil surface microroughness, namely the random roughness (RR) index, the crossover length, the variance scale from the MarkovGaussian model, and the limiting difference. Findings show a consistent increase in roughness under the action of rainfall, with an overall agreement between all indices in terms of trend and magnitude. Although this study is limited to a narrow range of rainfall and soil conditions, the results suggest that the outcome of the interaction between rainfall and a soil surface can be different for smooth and rough surfaces and thus warrant the need for a better understanding of this interaction.

Assessment of crusting effects on interrill erosion by laser scanning

“…4, Table 3). Therefore, with limited laser scanning data and pairwise comparison of height distributions, our observations corroborate previous studies where the changes of soil surface microtopography during rainfall events were effectively quantified by laser scanning (Huang & Bradford, 1992;Abban et al, 2017). Furthermore, our findings show that with laser scanning an improved quantitative interpretation of interrill erosion experiments is possible, which would otherwise have been attributed just…”

“…Huang & Bradford (1992) demonstrated that laser scanning at a 0.5-mm grid resolution can be used to replace speculative explanations of soil erosional responses with more quantitative interpretations. Abban et al (2017) employed a laser scanner and several indices derived from the obtained data to decipher the role of rain splash on surface roughness. All these studies illustrate that laser scanning has the potential for closing the gap between the ideal quality of data required to assess crusting effects on interrill erosion and a feasible acquisition of soil microtopography in a laboratory setting.…”

Cropping pattern changes diminish agroecosystem services in North and South Dakota, USA

“…Conversion from grasses to row crop systems alters surface hydrology by removing the protective vegetative canopy cover during the nongrowing season, as well as varying amounts of surface residue based on tillage incorporation and crop type (Baumhardt, Schwartz, Scanlon, Reedy, & Marek, ). During rain events, the kinetic energy from the raindrops is transferred directly into the soil surface, rather than being intercepted by vegetation, thereby dislodging soil particles and degrading surface aggregates (Abban et al., ). Tillage events further fragment soil structure by breaking apart soil aggregates and exposing organic material to oxidation processes (Hatfield, Wacha, & Dold, ).…”

The Role of Hydraulic Connectivity and Management on Soil Aggregate Size and Stability in the Clear Creek Watershed, Iowa

“…This is particularly true with regards to the row orientation relative to the Soil surface roughness produced by the various tillage practices introduces a level of overland flow control within a field, which affects hydraulic connectivity [49], and, thus, the hydraulic forcing on surface aggregates [21]. This is particularly true with regards to the row orientation relative to the direction of the main flow pathway in a field (oriented roughness), which has implications to the redistribution and downslope delivery of eroded material along the flow pathway [88]. For CRT-LI and CT-HI, where the rows were oriented perpendicular to the flow pathway, a sequence of "steps and pools" has been observed along the downslope [85].…”