scholarly journals Root density drives aggregate stability of soils of different moraine ages in the Swiss Alps

2021 ◽  
Author(s):  
Konrad Greinwald ◽  
Tobias Gebauer ◽  
Ludwig Treuter ◽  
Victoria Kolodziej ◽  
Alessandra Musso ◽  
...  

Abstract Aims The stability of hillslopes is an essential ecosystem service, especially in alpine regions with soils prone to erosion. One key variable controlling hillslope stability is soil aggregate stability. We aimed at identifying dominant controls of vegetation parameters on aggregate stability and analysed their importance for soil aggregate stability during landscape development. Methods We quantified the aggregate stability coefficient (ASC) and measured plant cover, diversity, root mass and root length, density (RMD, RLD) along two chronosequences with contrasting bedrocks (siliceous, calcareous) in the Swiss Alps. Results We found that ASC developed slower along the calcareous chronosequence. Furthermore, we observed a significant positive effect of vegetation cover and diversity on ASC that was mediated via root density. These relationships developed in a time-depended manner: At young terrain ages, vegetation parameters had a strong effect on aggregate stability compared to older stages. Moreover, RLD was the most powerful predictor of ASC on young terrain, whereas on older moraines RMD became more important. Conclusions We highlight that root density plays a major role in governing ASC for soils differing in moraine ages. The changing importances of RLD and RMD for ASC development suggest different mechanistic linkages between vegetation and hillsope stability during landscape development.

2021 ◽  
Author(s):  
Konrad Greinwald ◽  
Tobias Gebauer ◽  
Ludwig Treuter ◽  
Victoria Kolodziej ◽  
Alessandra Musso ◽  
...  

<p><strong>Aims:</strong></p><p>The stability of hillslopes is an essential ecosystem service, especially in alpine regions with soils prone to erosion. One key variable controlling hillslope stability is soil aggregate stability. However, there is comparatively little knowledge about how vegetation dynamics affect soil aggregate stability during landscape evolution.</p><p><strong>Methods:</strong></p><p>We quantified soil aggregate stability by determining the Aggregate Stability Coefficient (ASC), which was developed for stone-rich soils. To reveal how hillslope aging and corresponding changes in vegetation affect the evolution of ASC, we measured plant cover, diversity, and root traits along two chronosequences in the Swiss Alps.</p><p><strong>Results:</strong></p><p>We found a significant positive effect of vegetation cover and diversity on ASC that was mediated via root traits. These relationships, however, developed in a time-depended manner: At young terrain ages, above- and belowground vegetation characteristics had a stronger effect on aggregate stability than species diversity, whereas these relationships were weaker at older stages.</p><p><strong>Conclusions:</strong></p><p>Our findings highlight the importance of vegetation dynamics for the evolution of aggregate stability and enhance our understanding of processes linked to hillslope stabilization, which is a key priority to avoid further soil degradation and connected risks to human safety in alpine areas.</p>


2021 ◽  
Author(s):  
Fabian Maier ◽  
Ilja van Meerveld

<p>Overland flow (OF) and subsurface flow (SSF) are key processes that determine the streamflow response to precipitation, as well as water quality, but are affected by the land surface and soil characteristics. They can also modify the shape of our landscape. However, our understanding of the evolution of OF and SSF characteristics and the feedback mechanisms between hydrological, pedological, biological and geormorphological processes that affect OF and SSF during landscape evolution is still limited.</p><p>We used a space-for-time approach and studied 3 plots (4m x 6m each) on four different aged moraines (several decades to ~13.500 years) on the Sustenpass near the Steinglacier and in the karstic glacier foreland of the Griessfirn near Klausenpass (total of 24 plots) to determine how OF & SSF change during landscape evolution. We used artificial rainfall experiments with high rainfall intensities to determine runoff ratios, peak flow rates, timing and duration of OF & SSF. The addition of tracers (<sup>2</sup>H and NaCl) to the sprinkling water and sampling of soil water allowed us to determine the degree of mixing of the applied rainfall with water in the soil. Measurements during natural rainfall events helped to determine the impact of the rainfall volume and intensity on the runoff generation. In addition, the runoff samples and sensor-based turbidity measurements of OF provide an estimate of the erosion rates during extreme events. In order to link the differences in runoff generation with the pedological and biological characteristics of the slopes, vegetation cover, root density, soil texture, soil aggregate stability, and the saturated hydraulic conductivity (K<sub>sat</sub>) were measured as well.</p><p>The results show that K<sub>sat</sub> at both study areas decreases with moraine age and soil depth and is mainly driven by the increase in silt and clay content. Despite the high K<sub>sat</sub> values, local OF occurs frequently on the youngest moraines due to the large rock and stone cover. Sediment flux and the related erosion rates are largest for the young moraines, since vegetation cover and soil aggregate stability are small. Soil and vegetation development change major OF and SSF characteristics during landscape development, such as the mixing processes and the pre-event water fraction in OF & SSF, which both increase for the older moraines. However, the rate of these changes during landscape evolution is controlled by the parent material. These results can be used to inform landscape evolution models and help us to understand processes within the critical zone during the first millennia of soil development.</p>


Author(s):  
Surachet Aramrak ◽  
Natthapol Chittamart ◽  
Worachart Wisawapipat ◽  
Wutthida Rattanapichai ◽  
Mutchima Phun-Iam ◽  
...  

2021 ◽  
Vol 13 (3) ◽  
pp. 1541
Author(s):  
Xiaolin Shen ◽  
Lili Wang ◽  
Qichen Yang ◽  
Weiming Xiu ◽  
Gang Li ◽  
...  

Our study aimed to provide a scientific basis for an appropriate tillage management of wheat-maize rotation system, which is beneficial to the sustainable development of agriculture in the fluvo-aquic soil areas in China. Four tillage treatments were investigated after maize harvest, including rotary tillage with straw returning (RT), deep ploughing with straw returning (DP), subsoiling with straw returning (SS), and no tillage with straw mulching (NT). We evaluated soil organic carbon (SOC), dissolved organic carbon (DOC), permanganate oxidizable carbon (POXC), microbial biomass carbon (MBC), and particulate organic carbon (POC) in bulk soil and soil aggregates with five particle sizes (>5 mm, 5–2 mm, 2–1 mm, 1–0.25 mm, and <0.25 mm) under different tillage managements. Results showed that compared with RT treatment, NT treatment not only increased soil aggregate stability, but also enhanced SOC, DOC, and POC contents, especially those in large size macroaggregates. DP treatment also showed positive effects on soil aggregate stability and labile carbon fractions (DOC and POXC). Consequently, we suggest that no tillage or deep ploughing, rather than rotary tillage, could be better tillage management considering carbon storage. Meanwhile, we implied that mass fractal dimension (Dm) and POXC could be effective indicators of soil quality, as affected by tillage managements.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dan Li ◽  
Ningning Yin ◽  
Ruiwei Xu ◽  
Liping Wang ◽  
Zhen Zhang ◽  
...  

AbstractWe constructed a mining soil restoration system combining plant, complex substrate and microbe. Sludge was added to reconstructed mine substrates (RMS) to accelerate the reclamation process. The effect of sludge on plant growth, microbial activity, soil aggregate stability, and aggregation-associated soil characteristics was monitored during 10 years of reclamation. Results show that the height and total biomass of ryegrass increases with reclamation time. Sludge amendment increases the aggregate binding agent content and soil aggregate stability. Soil organic carbon (SOC) and light-fraction SOC (LFOC) in the RMS increase by 151% and 247% compared with those of the control, respectively. A similar trend was observed for the glomalin-related soil protein (GRSP). Stable soil aggregate indexes increase until the seventh year. In short, the variables of RMS determined after 3–7 years insignificantly differ from those of the untreated sample in the tenth-year. Furthermore, significant positive correlations between the GRSP and SOC and GRSP and soil structure-related variables were observed in RMS. Biological stimulation of the SOC and GRSP accelerates the recovery of the soil structure and ecosystem function. Consequently, the plant–complex substrate–microbe ecological restoration system can be used as an effective tool in early mining soil reclamation.


2014 ◽  
Vol 78 (4) ◽  
pp. 1168-1176 ◽  
Author(s):  
Baptiste Algayer ◽  
Yves Le Bissonnais ◽  
Frédéric Darboux

2018 ◽  
Vol 182 (2) ◽  
pp. 159-166 ◽  
Author(s):  
Gabriela Vargas ◽  
José Verdejo ◽  
Adrian Rivera ◽  
Domingo Suárez ◽  
Cristian Youlton ◽  
...  

2019 ◽  
Author(s):  
Fayong Li ◽  
Xinqiang Liang ◽  
Hua Li ◽  
Yingbin Jin ◽  
Junwei Jin ◽  
...  

Abstract Background Colloid-facilitated phosphorus (P) transport is a recognized important pathway for soil P loss in agricultural systems, but limited information is available on the soil aggregate-associated colloidal P. To elucidate the effects of aggregate size on the loss potential of colloidal P (P coll ) in agricultural systems, soils (0-20 cm depth) from six land use types were sampled in Zhejiang province in the Yangtz river delta region, China. The aggregate size fractions (2–8 mm, 0.26–2 mm, 0.053–0.26 mm and <0.053 mm) separated by wet-sieving method were analyzed.Results Results showed that the 0.26–2 mm small macroaggregates had the highest total P (TP) content. For acidic soils, the highest P coll content was also found in the 0.26–2 mm aggregate size, while the lowest was found in the <0.053 mm (silt+clay)-sized particles, the opposite of that found in alkaline soils. Paddy soils contained less P coll than other land use types. The P coll in total dissolved P (TDP) was dominated by <0.053 mm (silt+clay)-sized particles. Aggregate size did strongly influence the loss potential of P coll in paddy soils, where P coll contributed up to 83% TDP in the silt+clay sized particles. The P coll content was positively correlated with TP, Al, Fe and mean weight diameter (MWD). Aggregate associated total carbon (TC), total nitrogen (TN), C/P, and C/N had significant, but negative effects on the contribution of P coll to potential soil P losses. The P coll content of the aggregates was controlled by aggregate associated TP and Al content as well as soil pH value, with P coll loss potential from aggregates being controlled by its organic matter content.Conclusion Therefore, we conclude that management practices that increase soil aggregate stability or its organic carbon content will limit P coll loss from agricultural systems.


Sign in / Sign up

Export Citation Format

Share Document