Soil roughness indexes and their relationship with water erosion

Abstract

The objective of this work was to express soil roughness through statistical, geostatistical, and fractal indexes, comparing and relating them to soil and water losses in different experimental conditions. The study was conducted from 2012 to 2015, in the municipality of Lages, in the state of Santa Catarina, Brazil, in a completely randomized design with two replicates. Three treatments were evaluated: T1, scarified soil at the end of the ryegrass (Lolium multiflorum) crop cycle after removal of the shoot residue; T2, scarified soil at the end of the vetch (Vicia sativa) crop cycle after removal of the shoot residue; and T3, scarified soil without cultivation and without cover. The heights of the microrelief were read with a surface roughness tester with rods. Soil roughness was analyzed through the statistical, geostatistical, and fractal indexes. The fractal dimension and intersection distance showed a clear difference between the treatments with cultivation. All indexes, except R1, are associated with soil losses in the treatments with cultivation. As for water losses, there is only an association with the fractal dimension index and only in the treatment without cultivation.

Path coefficient analysis, a different approach to identify soil quality indicators

“…Path coefficient analysis between the basic water loss (WL) variable with the explanatory variables studied, for the treatments with soil cover (HCR and HCV) and surface roughness (HRR, HRV and BHR), in an Inceptisol Table 4. Path coefficient analysis between the runoff velocity of flow (RV) variable with the explanatory variables studied, for the treatments with soil cover (HCR and HCV) and surface roughness (HRR, HRV and BHR), in an Inceptisol WC01 and WC12 -Soil water content in the layers 0-0.10 and 0.10-0.20 m, respectively; TOC -Total organic carbon; GMD -Geometric mean diameter; BD -Soil bulk density; Mi -Micropores; Ma -Macropores; CWI -Constant water infiltration rate; SC -Soil cover; RR -Random surface roughness; ERM -Estimated root mass; r -Pearson's correlation 2-mm variation in the RR index was reflected by SL variations above 10 Mg ha -1 , which agreed with Zangiski et al (2018).…”

“…The lowest random surface roughness (RR) value occurred in the uncultured and scarified soil (BHR, 9 mm); this was low in relation to the average of the scarified treatments containing roots (Table 1). This is justified by the low GMD (stability of aggregates in water) and because of the lack of cultivation, which reduced soil resistance to disaggregation in the BHR (Zangiski et al, 2018).…”

Sistema Santa Fé auxilia na redução do escoamento superficial e melhoria da qualidade da água?

“…Além destes benefícios a conservação dos resíduos vegetais na superfície do solo pode interceptar as gotas de chuva, diminuindo o impacto e evitando a desagregação de partículas (DECHEN et al, 2015). Assim, sistemas conservacionistas que promovam pequena ou nenhuma movimentação mecânica do solo, que mantém grande parte dos resíduos das culturas sobre o solo e que eleva a rugosidade superficial são mais eficientes no que se refere ao controle das perdas de solo e água por erosão hídrica (ZANGISKI et al, 2018). Nesse sentido, algumas pesquisas têm sido realizadas com o objetivo de avaliar como as diferentes formas de manejo têm influenciado no processo de perda de solo e de água (PANACHUKI et al, 2011;PRAZERES et al, 2020;BRAMORSKI;CRESTANA, 2020).…”