scholarly journals Structural and functional connectivity as a driver of hillslope erosion following disturbance

2016 ◽  
Vol 25 (3) ◽  
pp. 306 ◽  
Author(s):  
C. Jason Williams ◽  
Frederick B. Pierson ◽  
Peter R. Robichaud ◽  
Osama Z. Al-Hamdan ◽  
Jan Boll ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Field Studies ◽  
Rainfall Simulation ◽  
Hydrologic Response ◽  
Hydrologic Modelling ◽  
Erosion Processes ◽  
Flow Formation ◽  
High Runoff ◽  
Hillslope Scale ◽  
Patch Scale

Hydrologic response to rainfall on fragmented or burnt hillslopes is strongly influenced by the ensuing connectivity of runoff and erosion processes. Yet cross-scale process connectivity is seldom evaluated in field studies owing to scale limitations in experimental design. This study quantified surface susceptibility and hydrologic response across point to hillslope scales at two degraded unburnt and burnt woodland sites using rainfall simulation and hydrologic modelling. High runoff (31–47 mm) and erosion (154–1893 g m–2) measured at the patch scale (13 m2) were associated with accumulation of fine-scale (0.5-m2) splash-sheet runoff and sediment and concentrated flow formation through contiguous bare zones (64–85% bare ground). Burning increased the continuity of runoff and sediment availability and yield. Cumulative runoff was consistent across plot scales whereas erosion increased with increasing plot area due to enhanced sediment detachment and transport. Modelled hillslope-scale runoff and erosion reflected measured patch-scale trends and the connectivity of processes and sediment availability. The cross-scale experiments and model predictions indicate the magnitude of hillslope response is governed by rainfall input and connectivity of surface susceptibility, sediment availability, and runoff and erosion processes. The results demonstrate the importance in considering cross-scale structural and functional connectivity when forecasting hydrologic and erosion responses to disturbances.

scholarly journals Effect of Ridge Height, Row Grade, and Field Slope on Nutrient Losses in Runoff in Contour Ridge Systems under Seepage with Rainfall Condition

2021 ◽  
Vol 18 (4) ◽  
pp. 2022
Author(s):  
Juan An ◽  
Jibiao Geng ◽  
Huiling Yang ◽  
Hongli Song ◽  
Bin Wang
Keyword(s):  
Polynomial Regression ◽  
Influential Factors ◽  
Nutrient Loss ◽  
Rainfall Simulation ◽  
N Loss ◽  
Rainfall Condition ◽  
Erosion Processes ◽  
P Loss ◽  
Ridge Height ◽  
Negative Effect

Seepage plays a key role in nutrient loss and easily occurs in widely-used contour ridge systems due to the ponding process. However, the characteristics of nutrient loss and its influential factors under seepage with rainfall condition in contour ridge systems are still unclear. In this study, 23 seepage and rainfall simulation experiments are arranged in an orthogonal rotatable central composite design to investigate the role of ridge height, row grade, and field slope on Nitrate (NO3−–N) and Orthophosphate (PO4+3–P) losses resulting from seepage in contour ridge systems. In total, three types of NO3−–N and PO4+3–P loss were observed according to erosion processes of inter-rill–headward, inter-rill–headward–contour failure, and inter-rill–headward–contour failure–rill. Our results demonstrated that second-order polynomial regression models were obtained to predict NO3−–N and PO4+3–P loss with the independent variables of ridge height, row grade, and field slope. Ridge height was the most important factor for nutrient loss, with a significantly positive effect and the greatest contribution (52.35–53.47%). The secondary factor of row grade exerted a significant and negative effect, and was with a contribution of 19.86–24.11% to nutrient loss. The interaction between ridge height and row grade revealed a significantly negative effect on NO3−–N loss, whereas interactions among the three factors did not significantly affect PO4+3–P loss. Field slope only significantly affected NO3−–N loss. The optimal design of a contour ridge system to control nutrient loss was obtained at ridge height of 8 cm, row grade of 2°, and field slope of 6.5°. This study provides a method to assess and model nutrient loss, and improves guidance to implement contour ridge systems in terms of nutrient loss control.

Long-term evaluation of cover crops on soil and runoff losses under trafficked conditions in olive orchards

2021 ◽  
Author(s):  
Jose Alfonso Gomez ◽  
Gema Guzman
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Soil Management ◽  
Ground Vegetation ◽  
Small Scale ◽  
Erosion Processes ◽  
Runoff Losses ◽  
Hillslope Scale ◽  
Soil Losses ◽  
Runoff Plots

<p>Maintenance of ground cover vegetation in olive orchards has been shown to reduce soil and runoff losses as compared to bare soil. However, extrapolation of its impact at hillslope scale under different conditions still challenging for several reasons. One is the limited duration of available experiments, usually shorter than 3 years, which can´t capture the annual variability in precipitation typical of Mediterranean type of climate. A second reason is the small scale in which many experiments are carried out, which do not capture all the relevant erosion processes at hillslope scale. A third reason, hardly discussed, is the use of the runoff plots that limits traffic resulting in conditions that might not be fully representative of actual orchards.</p><p> </p><p>For evaluating the effect of temporary cover crops on water erosion processes in olives at hillslope scale, runoff and soil losses have been monitored from 2008 to 2019 in La Conchuela. This is an olive farm located in Southern Spain, where average annual precipitation is 655 mm, on Typic Haploxerert (clay content > 50%). Six runoff plots (14x24 m) delimited by steel beams on concrete foundation were established in a 13.4 % slope, containing 3 rows of 4 trees. This allows normal farm operations. Since 2008-2009, two soil management systems, conventional tillage (CT) and temporary cover crops (CC), were tested. In the two CT plots ground vegetation was controlled by 2-3chisel ploughing passes during the year. CC in the other four plots consisted of sowing manually in mid Fall a grass or a mix with grasses every 1 to 3 years without disturbing the soil surface, been mowed in early Spring. The aim of this cover crop was to be grown up spontaneously from seed produced the previous year. Weeds along the tree rows are controlled by herbicides in both cases.</p><p>No significant differences were detected (p < 0.05) for the whole period, although CC showed lower runoff and soil losses values. Runoff data ranged from 157.7 ± 61.2 to 144.5 ± 46.4 mm, and soil losses varied from 24.3 ± 9.1 to 16.4 ± 7.0 t·ha<sup>-1</sup> at the CT and CC treatments respectively. The lack of statistical differences can be explained by the large variability recorded in the measurements at the six plots, especially at the CC due to the specific weather and traffic conditions. Our experiment shows how in a crop, olives, subject to intense traffic during the harvesting season (happening in late fall or early winter, rainy season) and in an orchard on heavy soils, maintenance of a good cover crop is challenging in many years. Our results call for caution when extrapolating the benefits of cover crops in olives from the experimental plots to real world conditions. It also highlights the need for improved soil management under these conditions (e.g. controlled traffic, combination with inert mulch, …) to improve soil and water conservation in intensively cultivated olive orchards in heavy soils.</p><p> </p>

scholarly journals Soil Erosion Processes in European Vineyards: A Qualitative Comparison of Rainfall Simulation Measurements in Germany, Spain and France

Hydrology ◽  
2016 ◽  
Vol 3 (1) ◽  
pp. 6 ◽  
Author(s):  
Jesús Rodrigo Comino ◽  
Thomas Iserloh ◽  
Xavier Morvan ◽  
Oumarou Malam Issa ◽  
Christophe Naisse ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Rainfall Simulation ◽  
Qualitative Comparison ◽  
Erosion Processes

SEDIMENT AND RUNOFF WATER CHARACTERISTICS AS INFLUENCED BY CROPPING AND TILLAGE PRACTICES

1989 ◽  
Vol 69 (3) ◽  
pp. 639-647 ◽  
Author(s):  
G. J. BEKE ◽  
C. W. LINDWALL ◽  
T. ENTZ ◽  
T. C. CHANNAPPA
Keyword(s):  
Sediment Quality ◽  
Sprinkler Irrigation ◽  
Nutrient Loss ◽  
Rainfall Simulation ◽  
Hordeum Vulgare L ◽  
Runoff Water ◽  
Total N ◽  
Erosion Processes ◽  
Water Characteristics ◽  
Bare Fallow

Rainfall simulation by sprinkler irrigation was used to evaluate the characteristics of sediment and runoff water from erosion plots on a Dark Brown Chernozemic soil near Lethbridge, Alberta. Replicated land treatments consisted of bare fallow, perennial alfalfa/wheat grass forage (Medicago sativa L./Agropyron riparium Scribn. & Smith) planted in rows parallel to the slope, barley (Hordeum vulgare L.) planted in rows parallel to the slope (barley-S) and barley on contour (barley-C). The eroded sediment from all four treatments was generally enriched in organic matter (OM), NH4-N, total N (TN), and PO4-P, but not in NO3-N or total P (TP). The sediment from the bare fallow treatment was enriched in silt-size particles and had the highest OM enrichment. Maximum NH4-N and TN enrichment occurred in the sediment from the barley-S treatment, and maximum PO4-P in that from the forage treatment. This selective removal of plant nutrients was attributed mainly to erosion processes and to cropping-induced differences in C:N:P ratios of organic complexes. The runoff water from all four treatments was enriched in NO3-N, TN, and PO4-P. For the three cropping treatments in this experiment, nutrient enrichment of the runoff water decreased from forage > barley-S > barley-C treatment. In general, more NO3-N was lost in the runoff water than in the sediment. Key words: Erosion, sediment quality, water quality, nutrient loss, nitrogen forms, phosphorus forms.

scholarly journals Innovative Technologies In The Assessment Of Accumulation And Erosion Processes In The Channels

2021 ◽  
Vol 12 (4) ◽  
pp. 110-114
Author(s):  
Aybek Arifjanov, Et. al.
Keyword(s):  
Field Studies ◽  
Left Bank ◽  
Channel Changes ◽  
The Past ◽  
Erosion Processes ◽  
Gis Data ◽  
Deformation Processes ◽  
Using Data ◽  
Landsat Satellite ◽  
The Right

The article discusses the possibilities of assessing the state of river beds and changes in them using remote sensing technologies (RS) and geographic information systems (GIS). With the help of geoinformation technologies, an assessment of deformation phenomena over the past 25 years in the channel of the Sokh river, which was chosen as the object of research, was given. Channel phenomena have been studied using data obtained from satellites. To analyze the situation, a model of the Landsat satellite was selected. The currently widely used official Glo Vis website was used to download the data. Data analyzed using ArcMap software. The results of the GIS data analysis were compared with the data of field studies. Over the past 20 years, along the channel, changes have been observed on the right bank, filling a part of the left bank with sediment particles, germination of moisture-loving plants and the process of erosion of the left bank. Over the past 5 years, about 30 meters of irrigated areas have eroded along the right bank between pickets PK3 and PK4. These changes average 5-6 meters per year. An analysis of the deformation processes occurring in the Sokh channel is carried out and conclusions are drawn.

scholarly journals Influences of sand cover on erosion processes of loess slopes based on rainfall simulation experiments

2018 ◽  
Vol 10 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Xiang Zhang ◽  
Zhanbin Li ◽  
Peng Li ◽  
Shanshan Tang ◽  
Tian Wang ◽  
...  
Keyword(s):  
Rainfall Simulation ◽  
Simulation Experiments ◽  
Erosion Processes

scholarly journals Surface Detention on Cropland, Rangeland, and Conservation Reserve Program Areas

2018 ◽  
Vol 61 (3) ◽  
pp. 955-966
Author(s):  
John . E Gilley
Keyword(s):  
Overland Flow ◽  
Thin Sheet ◽  
Conservation Reserve Program ◽  
Soil Surface ◽  
Field Studies ◽  
Rainfall Simulation ◽  
Vegetative Cover ◽  
No Till ◽  
Corn Residue ◽  
Study Sites

Abstract. One of the factors contributing to overland flow on upland areas is water stored temporarily in a thin sheet on the soil surface as surface detention. This study was conducted to quantify surface detention on selected cropland, rangeland, and Conservation Reserve Program (CRP) sites. Surface detention was determined from the recession portion of runoff hydrographs corresponding with the period when rainfall had ceased but runoff continued. The hydrographs were generated from six previously reported rainfall simulation studies conducted on paired 3.7 m wide × 10.7 m long plots on which approximately 128 mm of rainfall was applied. Surface detention values were found to increase as crop residue or vegetative cover increased. Eleven fallow cropland sites in the eastern U.S. had surface detention values that varied from 1.7 to 4.6 mm. Surface detention on plots in southwestern Oklahoma containing Old World bluestem, no-till wheat, and conservation-till wheat was 9.4, 7.3, and 5.2 mm, respectively. No-till sorghum, tilled sorghum, no-till wheat, and tilled wheat plots in southeast Nebraska had surface detention values of 6.7, 4.5, 6.7, and 4.6 mm, respectively. Mean surface detention on no-till and tilled cropland sites in southwest Iowa containing corn residue was 7.2 and 5.9 mm, respectively. CRP study sites in southwestern Iowa had mean surface detention of 10.8 mm. When data from the six field studies were combined, mean surface detention values for fallow cropland, tilled cropland, no-till cropland, rangeland, and CRP areas were 3.1, 5.0, 6.9, 9.6, and 10.8 mm, respectively. Keywords: Depressional storage, Hydrographs, Hydrologic modeling, Overland flow, Runoff volume, Surface detention.

scholarly journals Erosion Process and Temporal Variations in the Soil Surface Roughness of Spoil Heaps under Multi-Day Rainfall Simulation

2020 ◽  
Vol 12 (14) ◽  
pp. 2192
Author(s):  
Jiaorong Lv ◽  
Yongsheng Xie ◽  
Han Luo
Keyword(s):  
Surface Roughness ◽  
Erosion Rate ◽  
Soil Surface ◽  
Rainfall Event ◽  
Rainfall Simulation ◽  
Rainfall Events ◽  
Erosion Processes ◽  
Spoil Heap ◽  
Soil Surface Roughness ◽  
Spoil Heaps

The extensive artificially accelerated erosion of spoil heaps on newly engineered landforms is a key ecological management point requiring better understanding. Soil surface roughness is a crucial factor influencing erosion processes; however, study on spoil heap erosion with a view of surface roughness is lacking. This study investigated the erosion processes and the spatiotemporal variation of surface roughness on spoil heaps, and then, analyzed how the roughness affected the hydrological and sediment yield characteristics. Sequences of four artificial rainstorms with constant rainfall intensity (90 mm/h) were applied to cone-shaped spoil heaps (ground radius 3.5 m, height 2.3 m) of a loess soil containing 30 mass percent rock fragments. The surface elevation was sampled by a laser scanner. For the surface roughness indicators, the root mean square height (rmsh) and the correlation length (cl) increased sharply during the first rainfall event, and in the last three rainfall events, rmsh increased slightly and cl showed a relative decrease. The initial rmsh/cl of the whole slope surface ranged from 0.063 to 0.135, and increased with the rainfall sequence, thus, indicating that the spoil heap surface became rougher. Increasing soil roughness in the rainfall sequence delayed the initial runoff time and increased the runoff yield. The average runoff coefficient of the spoil heaps was 0.658. The average erosion rate of each rainfall event can be simulated by a regression equation of the corresponding average runoff rate and median cl (R-square of 0.816). Soil slumping with an average volume of 0.014 m3 occurred in the first two rainfall events, thus, significantly changing the roughness and peak instant erosion rate. Together, the results revealed the effects of surface roughness on the erosion of spoil heaps and would provide a useful reference for soil loss prediction and control.

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