Factors governing soil water repellency under tillage management: The role of pore structure and hydrophobic substances

Abstract

Soil water repellency (SWR) has significant effects on soil degradation by changing some soil processes (e.g., carbon sequestration and soil erosion). Understanding the influence factors of SWR under conservation agriculture are playing a vital role in the sustainable development for improving soil quality. However, how soil pore structure influence on SWR remains unclear. We aim to assess the impact of hydrophobic substances and pore structure on SWR. Here we conducted two long‐term experimental fields with three treatments: conventional tillage (CT), reduced tillage (RT), and no‐tillage (NT). X‐ray tomography and the sorptivity method were used to measure soil pore structure and SWR, respectively. We found that soil organic carbon (SOC) and microbial biomass carbon (MBC) were higher in RT and NT treatments than in CT. MBC had significant influences on soil water sorptivity (Sw) and water repellency index (RI; p < 0.001), whereas SOC had no influence on Sw (p > 0.05). MBC also showed a closer relationship with SWR than SOC in redundancy analysis. The RT and NT increased the porosity of 55–165 μm that had a positive relationship with ethanol sorptivity and RI (p < 0.05). Ethanol sorptivity increased with an increase in soil pore porosity and connectivity under RT and NT treatments. However, increasing the pore surface area could decrease Sw due to enhance contact area between hydrophobic substances and soil water. Overall, the RT and NT treatments increased the water repellency index, which was a result of the interactions between pore structure and hydrophobic substances.

Potential and Mechanisms for Stable C Storage in the Post-Mining Soils under Long-Term Study in Mitigation of Climate Change

“…For soil S2, we observed a gradual growing tendency with the remediation time, where it increased over 3 times for S2D (18 years of remediation) in comparison to S2A (1 year of remediation). It is considered that higher hydrophobicity improves the long-lasting aggregate stability of SOM [24,25]. Moreover, this increase in hydrophobicity in remediated soils may strongly affect the water availability to plants and also increase the surface runoff and thus increase the susceptibility of the soil to secondary erosion [26].…”

“…For soil S2, we observed a gradual growing tendency with the remediation time, where it increased over 3 times for S2D (18 years of remediation) in comparison to S2A (1 year of remediation). It is considered that higher hydrophobicity improves the long-lasting aggregate stability of SOM [24,25]. Aromatic structures are considered to be difficult for decomposition, and they also have a long half-life in soil.…”

Nitrogen addition mediates the effect of soil microbial diversity on microbial carbon use efficiency under long‐term tillage practices

“…This was likely because no-tillage creates heterogeneous soil (Sun et al, 2018). Our previous study in this experiment site showed that soil depth had a significant influence on soil moisture, bulk density, porosity, and aggregate stability in 0-20 cm soil depth (Li et al, 2020a), which could lead that microbial properties are different with changing in topsoil depth. In addition, some previous studies also showed the difference in enzyme activities and microbial properties under different topsoil depths (Fierer et al, 2003;Mathew et al, 2012).…”

“…The main reason is that nitrate nitrogen can transport with soil water movement, resulting in nitrogen leached into deeper soil depth . In addition, our previous study showed that NT increased the soil porosity of >55 μm diameter pores compared to the CT treatment, which indicated that NT could increase soil water infiltration and nitrogen leaching (Li, et al, 2020a).…”

Tillage Practice Impacts on the Carbon Sequestration Potential of Topsoil Microbial Communities in an Agricultural Field

“…Therefore, management practices that increase C inputs, such as straw incorporation, which is known to restore SOC content, are applied as integrated approaches. The optimization of tillage management with the return of straw is being promoted for ameliorating soil conditions, which will facilitate soil quality and sustainable crop productivity [5][6][7][8][9][10][11][12]. Moreover, it is of great significance to clarify the response characteristics of soil quality to different tillage methods.…”