Residue impacts on runoff and soil erosion for different corn plant populations

The year to year carry-over effects of biomass additions under different plant populations on runoff and erosion are unclear. The objective of this study was to quantify the impact of different plant populations on residue cover to elucidate the effects of residue cover on runoff and erosion. The residue management system involved shredding of corn (maize) biomass after harvest, incorporating the residue in the spring, and leaving the land fallow until it was no-till planted the following spring. Runoff and soil losses were measured on 18 runoff plots with plots arranged in two areas with each having three randomized treatments (0%, 50%, and 100% plant population) with three replications. The two areas were managed as a fallow/no-till corn rotation in two cycles of alternating years. Surface residue cover was highly dynamic with significant changes between cycles and seasons in response to the management practices. The annual soil losses were reduced by 47% and 54% for the 50% and 100% plant populations, respectively compared to the control. However, the annual soil loss even for the 100% plant population was still nearly seven times the tolerable soil loss limit of 7 ton ha⁻¹. The normal erosion protection afforded by no-till practices was lost by the incorporation of residue the previous year.     

Uncertainty of factors determining runoff and erosion processes as quantified by rainfall simulations

Rainfall simulations at different scales have been used for understanding the influence of different factors on runoff generation and erosion. They are an accepted method for calibrating and validating physically based rainfall and erosion models. Nevertheless, it is proven that not only the patterns of rainfall are highly variable over space and time. Soil parameters responsible for runoff generation and erosion – e.g. infiltration capacity, soil moisture, aggregate stability – are highly variable, too. The results of more than 100 plot scale rainfall simulations on abandoned fields in different areas of Spain are analysed for identifying and quantifying factors affecting runoff and erosion processes. The variability of superficial runoff and suspended sediment yield is very high within most of the test areas, reaching values up to a runoff coefficient of 1 and yielding 130 g per experiment. Only within the semi-arid areas we can find a significant and high correlation between vegetation cover and sediment yield (and sediment concentration), whereas most of the other investigated surface parameters show no influence on runoff and erosion.     

不同土壤坡面细沟侵蚀差异与其影响因素

采用室内纯净水人工模拟降雨试验,在坡度为10°、15°、20°、25°坡面,土槽为5 m、10 m两种规格,对两种土壤((土娄)土与黄绵土)分别进行雨强为1.5 mm min-1,的降雨实验,利用三维激光扫描仪对每一场降雨后的坡面进行监测,分析不同坡度对细沟侵蚀的影响,比较两种土壤坡面细沟侵蚀的差异,以及其差异的影响因子.结果表明:(土娄)土土壤颗粒以粉粒与黏粒为主,粉粒占总质量的64.12％,黏粒为28.42％.黄绵土的土壤颗粒以粉粒为主占总质量的67.95％,黏粒与沙粒含量较少,黏粒占14.52％,沙粒占17.53％.在相同条件下,(土娄)土降雨过程中人渗缓慢,产流时间、坡面流速均快于黄绵土,跌坎出现时间也较早,使其更容易产生细沟.(土娄)土的径流量高于黄绵土,在降雨过程中,径流稳定时间较早.(土娄)土侵蚀量高于黄绵土,(土娄)土产沙率呈增加趋势,黄绵土含沙量变化不明显.从坡面细沟发育来看,(土娄)土坡面细沟成平行状分布,黄绵土细沟为较宽树枝状.     

Extent of soil erosion and surface runoff associated with large-scale infrastructure development in Fujian Province, China

We examined runoff and sediment transport associated with large-scale construction projects in Fujian Province, China. Six experimental plots, comprised of four plot types, were designed to mimic typical conditions immediately following disturbance. It was found that natural vegetative cover reduces both runoff and erosion by approximately 36 and 7457 times over bare ground, and 16 and 1801 times over typically planted grasses, respectively. The increase in erosion associated with the replacement of native vegetation with bare ground or grasses due to large-scale infrastructure projects in Fujian from 1999 to 2004, amounted to an estimated loss of 1.76 × 10⁷ tonnes of top soil and 3.04 × 10⁸ m³ of surface runoff from the province during the bare soil construction phase, and an additional 4.25 × 10⁶ tonnes of top soil and 1.35 × 10⁸ m³ of surface runoff from the province associated with the first year of operation for each project. This has implications for frequency and occurrence of landslides and other geographic hazards, the transport of chemicals into waterways, the transport of goods through shipping passages, and the fertility of land in Fujian.     

Soil erosion and runoff in different vegetation patches from semiarid Central Mexico

Vegetation patches in arid and semiarid areas are important in the regulation of surface hydrological processes. Canopy and ground covers developed in these fertility islands are a natural cushion against the impact energy of rainfall. Also, greater levels of organic matter improve the soil physicochemical properties, promoting infiltration and reducing runoff and soil erosion in comparison with the open spaces between them. During the 2006 rainy season, four USLE-type plots were installed around representative vegetation patches with predominant individual species of Huisache (Acacia sp), Mesquite (Prosopis sp), Prickly Pear or Nopal (Opuntia sp) and Cardon (Opuntia imbricata), to evaluate soil erosion and runoff, in semiarid Central Mexico. A comparative bare surface condition (Control) was also evaluated. Vegetative canopy and ground cover were computed using digital images. Selected soil parameters were determined. Soil erosion was different for the studied vegetation conditions, decreasing as canopy and ground cover increased. There were not significant differences in runoff and soil erosion between the Control and O.imbricata surfaces. Runoff was reduced by 87%, 87% and 98% and soil loss by 97%, 93%, and 99% for Acacia farnesiana, Prosopis laevigata and Opuntia sp, respectively, as compared to the Control. Soil surface physical conditions were different between the low vegetation cover conditions (Control and O.imbricata surfaces) and the greater vegetation cover conditions (A.farnesiana, P.laevigata and Opuntia sp), indicating a positive effect of vegetation patches on the regulation of surface hydrological processes.     

Modelling runoff and soil erosion in logged forests: Scope and application of some existing models

Predictive erosion models are useful tools for evaluating the impact of land-use practices on soil and water properties, and as often used by environmental protection authorities, for setting guidelines and standards for regulation purposes. This study examines the application of three erosion models of varying complexity and design for predicting runoff and soil erosion from logged forest compartments in south eastern Australia. These are: the Universal Soil Loss Equation (USLE), the Water Erosion Prediction Project (WEPP), and TOPOG, a physically based hydrologic modelling package. Data on rates of soil loss and redistribution collected during a series of large-scale rainfall simulator experiments were used as model input parameters and validation. The models were evaluated in terms of general ease of use, input data requirements and accuracy of process understanding and prediction. Results suggest that in this application the USLE overestimated soil loss, and have the limitation that it does not predict sediment yield or sediment redistribution for specific storm events. When used at the hillslope scale, WEPP and TOPOG have predicted runoff and soil loss reasonably well, particularly on disturbed surfaces such as skid trails. On less disturbed surfaces such as the general harvesting area, both models performed less accurately, generally under-predicting soil loss and sediment yield, notably on sites with low observed values. The complexity and data requirements of WEPP and TOPOG limit their usability as a general-purpose, erosion hazard predicting tool. In terms of process understanding, none of the existing models accurately depict the nature and extent of sediment redistribution quantified in the rainfall simulator experiments. In order to advance the application and accuracy of modelling tools in forestry environments, this redistribution process should be considered integral to the refinement and redevelopment of future models.     

Effects of 30-year-old Aleppo pine plantations on runoff,soil erosion,and plant diversity in a semi-arid landscape in south eastern Spain

Forest management policies in Mediterranean areas have traditionally encouraged land cover changes, with the establishment of tree cover (Aleppo pine) in natural or degraded ecosystems for soil conservation purposes: to reduce soil erosion and to increase the vegetation structure. In order to evaluate the usefulness of these management policies on reduced erosion in semi-arid landscapes, we compared 5 vegetation cover types (bare soil, dry grassland, shrublands, afforested dry grasslands and afforested thorn shrublands), monitored in 15 hydrological plots (8 × 2 m), in the Ventós catchment (Alicante, SE Spain), over 4 years (1996 to 1999). Each cover type represented a different dominant patch of the vegetation mosaic on the north-facing slopes of this catchment. The results showed that runoff coefficients of vegetated plots were less than 1% of the precipitation volume; whereas runoff in denuded areas was nearly 4%. Soil losses in vegetation plots averaged 0.04 Mg ha^− 1 year^− 1 and increased 40-fold in open-land plots. The evaluation of these forest management policies, in contrast with the natural vegetation communities, suggests that: (1) thorn shrublands and dry grassland communities with vegetation cover could control runoff and sediment yield as effectively as Aleppo pine afforestation in these communities, and (2) afforestation with a pine stratum improved the stand's vertical structure resulting in pluri-stratified communities, but reduced the species richness and plant diversity in the understorey of the plantations.     

A GIS based approach to modelling the effects of land-use change on soil erosion in New Zealand

Abstract. The problem of soil erosion is particularly evident in New Zealand, given the combination of coarse-textured soils, steep relief, high rainfall, and intensification of agriculture. A study was undertaken to assess the effects of land use change on soil erosion and sediment transport for the Ngongotaha catchment in New Zealand's North Island, using a GIS based decision support and modelling system. Model simulations considered the effect of increased catchment area under deer farming and forestry on the amount of sediment delivered to the catchment outlet, averaged over a period of six years. The simulations predicted that sediment loss from land under deer farming was considerably greater than from land under other livestock or forestry. Further model simulations testing best management practices demonstrated that sediment yield could be halved if deer farming was restricted to slopes under 20%.     

The impact of vegetative cover type on runoff and soil erosion under different land uses

The effects of different vegetation types on runoff generation and soil erosion were investigated. The study was conducted at the Southern part of West Bank, about 10 Km north-west of Hebron city, during 2005, 2006 and 2007. Five treatments were implemented; forests planted with P. halepensis (F), natural vegetation dominated by S. spinosum (W.S), natural vegetation where S. spinosum was removed (W/o.S), cultivated land (C), and deforestation (Df). Three types of data were estimated in each plot: runoff after each rainfall event, sedimentation at the end of the rainy season, and chemical and physical soil properties. The obtained results indicate that there are significant and important differences in runoff generation and sediment production with respect to the different types of vegetative cover. Forest and natural vegetation dominated by S. spinosum treatments exhibited the lowest amounts of runoff, with averages of 2.02 and 1.08 mm, respectively, in comparison to other treatments. The removal of S. spinosum significantly increased the total amount of runoff and sedimentation compared to the forest and S. spinosum treatments. In addition, runoff significantly increased (4.03 mm) for the Df treatment compared to that of the forest site. The greatest amount of sedimentation was observed in cultivated land and with deforestation.     

Harvest intensity of aromatic shrubs vs. soil erosion: An equilibrium for sustainable agriculture (SE Spain)

In the Mediterranean Europe, where rainfall is scarce and irregular but often of high intensity, wild shrubs protect the soil against erosivity of raindrops. Moreover, some of these plants are the economic income for local farmers. Particularly in SE Spain, soil erosion is a core factor in environmental degradation attributed primarily to the cultivation practices and human pressure on the land. Over a four-year period, soil erosion and runoff were monitored in erosion plots on a mountainside, comparing four harvest intensities of four aromatic shrubs (Lavandula lanata L., Santolina rosmarinifolia L. Origanum bastetanum, and Salvia lavandulifolia V.): 0% (HI-0), 25% (HI-25), 50% (HI-50), and 75% (HI-75). Also, the fresh biomass and essential-oil content were quantified in each treatment. The erosion plots were located in Lanjarón (Granada, SE Spain) on the southern flank of the Sierra Nevada Mountains, on a 20% slope, and of 96 m² in area. The average soil loss for HI-0, HI-25, HI-50, and HI-75 during the study period was 144.6, 187.2, 256.0, and 356.0 kg ha^− 1, respectively, and runoff 2.6, 3.2, 3.4, and 4.7 mm, respectively. The lowest average soil erosion and runoff rates for the study period were recorded with plant cover of S. lavandulifolia V. 67.6 kg ha^− 1 and 1.3 mm, respectively. Since no significant differences were found between HI-25 and HI-50 for soil erosion and runoff, and harvest and distillation of wild-aromatic plants currently persists as an important economic activity in mountainous areas of the study zone, we recommend a rational harvest (HI-50), leaving the 50% of the plant biomass in the field (especially for sage and lavender) to avoid the soil degradation. In this sense, the harvest of 50% of fresh herb of sage, santolina, lavender, and oregano produced reasonable essential-oil yield of 12.7, 14.0, 19.7, and 18.3 L ha^− 1, respectively. The inappropriate harvest of aromatic plants and the intensity farming systems of mountain areas endanger land conservation, and there is an urgent need to implement appropriate land management which has a large-scale perspective but acts at the local level.     

Effects of intra-storm variations in rainfall intensity on interrill runoff and erosion

Five simulated rainstorms, each with a different rainfall intensity pattern but all delivering the same total kinetic energy to the soil surface, were applied to three different soils in a laboratory flume. The storm patterns were: constant rainfall intensity, increasing intensity, decreasing intensity, increasing then decreasing intensity and decreasing then increasing intensity. The three soils were: a clay loam, a sandy loam and a sandy soil. No differences in total runoff were observed that were consistent across the three soil types. However, consistent differences were observed in the amount and size distribution of the eroded sediment. In particular, the constant-intensity storm yielded an average soil loss of 75% of the varying-intensity storms, and the eroded sediment from the constant-intensity storms had a lower clay content than that from the varying-intensity storms. In contrast to the differences in amount and size distribution of eroded sediment, splashed sediment exhibited much smaller differences. Interrill erosion rates are widely assumed to vary with rainfall intensity to the power 2, but this relationship has been obtained from experiments over a range of rainfall intensities, but in which rainfall intensity has been constant in each experiment. The experiments reported here, undertaken using variable rainfall intensity within each experiment, indicates an exponent of 2.55. The experiments demonstrate that the assumption that a given rainfall intensity falling on a given soil for a given amount of time will result in a given amount of runoff and erosion is unsound. They point to the need for a greater understanding of the processes of interrill sediment detachment and transport in order to model successfully erosion under temporally varying rainfall.     

Evaluation of soil erosion protective cover by crop residues using vegetation indices and spectral mixture analysis of multispectral and hyperspectral data

Crop residues are efficient in reducing erosion and surface water runoff on agricultural soils. Evaluating the crop residue cover fraction and its spatial distribution is important to scientists involved in the modelling of soil erosion and surface runoff, and also to authorities wishing to assess soil conservation adoption by farmers. This study focuses on the evaluation of four remote sensing techniques to estimate the cover fraction of cereal crop residues (i.e., wheat and corn) from multispectral and hyperspectral measurements. These are the Soil Adjusted Corn Residue Index (SACRI), the Crop Residue Index Multiband (CRIM), the Normalized Difference Index (NDI) and the spectral mixture analysis technique (SMA). Field campaigns that were carried out by the FLOODGEN project in Sainte-Angèle-de-Monnoir, Québec, Canada and in the Pays-de-Caux located in the Normandy region of France, allowed us to gather digital photographs, spectra and other measurements to determine the actual ground cover fraction. A linear regression analysis between results derived from Landsat-5 TM simulated field spectra and the actual ground cover fractions showed best results for the CRIM on the Ste-Angèle-de-Monnoir study site (R² = 0.96), and equally good results for the Pays-de-Caux study site (R² = 0.94). Results were not as good when SMA was applied to the same Landsat-5 TM simulated field spectra with R² values of 0.70 and 0.68 for both sites, respectively. However, results improved significantly when SMA was applied to the hyperspectral data in which case the R² values increased to 0.92 for the Sainte-Angèle-de-Monnoir site and 0.89 for the Pays-de-Caux study site. Results obtained with the NDI and SACRI from both simulated TM and hyperspectral field spectra were not conclusive.     

Impact of climate change on soil erosion, runoff, and wheat productivity in central Oklahoma

The potential for global climate changes to increase the risk of soil erosion is clear, but the actual damage is not. The objectives of this study were to evaluate the potential impacts of climate change on soil erosion, surface runoff, and wheat productivity in central Oklahoma. Monthly projections were used from the Hadley Centre's general circulation model, HadCM3, using scenarios A2a, B2a, and GGa1 for the periods of 1950–1999 and 2070–2099. Projected changes in monthly precipitation and temperature distributions between the two periods were incorporated into daily weather series by means of a stochastic weather generator (CLIGEN) with its input parameters adjusted to each scenario. The Water Erosion Prediction Project (WEPP) model was run for four climate scenarios including a recent historical climate and three tillage systems (conventional tillage, conservation tillage, and no-till). HadCM3-projected mean annual precipitation during 2070–2099 at El Reno, Oklahoma decreased by 13.6%, 7.2%, and 6.2% for A2a, B2a, and GGa1, respectively; and mean annual temperature increased by 5.7, 4.0, and 4.7 °C, respectively. Predicted average annual soil loss in the tillage systems other than no-till, compared with historical climate (1950–1999), increased by 18–30% for A2a, remained similar for B2a, and increased by 67–82% for GGa1. Predicted soil loss in no-till did not increase in the three scenarios. Predicted mean annual runoff in all three tillage systems increased by 16–25% for A2a, remained similar for B2a, and increased by 6–19% for GGa1. The greater increases in soil loss and runoff in GGa1 were attributed to greater variability in monthly precipitation as projected by HadCM3. The increased variability led to increased frequency of large storms. Small changes in wheat yield, which ranged from a 5% decrease in B2a to a 5% increase in GGa1, were because the adverse effects of the temperature increase on winter wheat growth were largely offset by CO₂ rise as well as the bulky decrease in precipitation occurred outside the growing season. The overall results indicate that no-till and conservation tillage systems will be effective in combating soil erosion under projected climates in central Oklahoma.     

Evaluating the applicability of the water erosion prediction project (WEPP) model to runoff and soil loss of sandstone reliefs in the Loess Plateau,China

Soil erosion is one of the most serious environmental issues, especially in vulnerable areas such as the Pisha sandstone regions located in the Loess Plateau (China). In these types of reliefs, long-term studies monitoring runoff and soil loss are scarce, and even more considering the efficiency of different soil management techniques applied to reduce land degradation. In this study, seven years (2014–2020) of in-situ measurements of surface runoff and soil loss for different land uses (forestland, shrubland, grassland, farmland, and bare land) in a Pisha Sandstone environment at the Loess Plateau were conducted. We applied the Water Erosion Prediction Project (WEPP) model combining the large database with the precipitation regimes. Our results showed that runoff volume coming from observed and simulated data exhibited significant differences among them depending on the different vegetation types. Runoff and soil loss were different among diverse land use types as follows: farmland > grassland > shrubland > forestland. After conducting a calibration, we found satisfactorily simulated surface runoff and sediment yield based on precipitation regimes and land uses at sandstone reliefs. Simulation performance of surface runoff was better than sediment yield. The range of standard error of the model simulation for event and annual values of runoff were 4.71 mm and 12.19 mm, respectively. The standard error for event and annual values of soil loss were 4.19 t/hm² and 21.86 t/hm². In the calibration group, R² of runoff and soil loss were 0.92 and 0.86 respectively, while Nash-Sutcliffe coefficient (E) reached 0.90 and 0.85, respectively. In the validation group, the R² for both runoff and soil loss were 0.82 and 0.56, respectively. Nash-Sutcliffe coefficient (E) were 0.77 and 0.54 for the runoff and sediment yield. We concluded that using a detailed monitoring dataset, the WEPP model could accurately simulate and predict water erosion in the hillslopes of Pisha sandstone area.     

Influence of vegetation recovery on water erosion at short and medium-term after experimental fires in a Mediterranean shrubland

This paper reports the influence that vegetation recovery has exerted on the soil behaviour to erosion by water during both the first and eight years after experimental fires. The work was carried out at La Concordia Experimental Station (Valencia, Spain), which includes nine plots (4 m wide × 20 m long) installed on a calcareous hillside representative of Mediterranean shrubland areas. In June 1995 a set of experimental fires were carry out at two intensity levels (high and moderate) with three plots replication for each treatment. The remaining three plots were used as the control. Rain events between June 1995 to June 1996 and from June 2002 to June 2003 were monitored and their effect on soil erosion processes determined. The vegetation changes (biomass amount and plant cover) for each studied period were also assessed.     

Field studies of the effects of jute geotextiles on runoff and erosion in Shropshire, UK

Abstract. Jute geotextiles are widely used to stabilize steep banks and road cuttings. Jute protects bare surfaces until seeded grass becomes established, then after several years, the jute decays. To evaluate two types of jute geotextiles, eight erosion plots were established in July 1994 at the Hilton Experimental Site, Shropshire, UK. On 10 April 1995, the plots were treated as follows:

• (1)

  jute geotextile net;

       
  
  

The influence of vegetation species and plant properties on runoff and soil erosion: results from a rainfall simulation study in south east Spain

Abstract. To study the influence of different vegetation species and plant properties on the generation of surface runoff and soil erosion in south east Spain, a series of rainfall simulation experiments was conducted on small ( c . 1.5 m²) plots. These were carried out in October 1993 and May 1994 on two sites close to Murcia. Six vegetation types were studied, with some at different stages of maturity, giving a total of nine vegetation treatments and two bare soil treatments. Four replicates of each treatment were exposed to a rainstorm of 120 mm/h for 15 minutes. The results of the experiments show that there are few significant differences in the ability of the vegetation types studied to control runoff or soil erosion. Of the plant properties considered, only plant canopy cover showed a significant relationship with soil loss and runoff with the greatest reduction in soil loss taking place at canopy covers greater than 30%. The implications of this research are that future efforts should be directed at developing ecological successions and revegetation methods which promote a substantial and sustainable canopy cover.     

The role of soil surface conditions in regulating runoff and erosion processes on a metamorphic hillslope (Southern Spain): Soil surface conditions,runoff and erosion in Southern Spain

This study presents the results of an analysis into the role of soil surface conditions in the regulation of soil hydrology and erosive processes at one hillslope under dry Mediterranean climatic conditions. The methodology was based on the analysis of hillslope surface components and their hydrological and erosive function on a patch to scale by means of rainfall simulation and experimental plots. The results showed the existence of a complex eco-geomorphological system composed of a multitude of vegetation patches distributed at random on the hillslope, and where the presence of different surface conditions on the soil can have a sizeable influence on hydrological and erosive behavior. From the hydrological point of view, the runoff generation mechanisms follow a seasonal pattern depending on the moisture of the soil with a different spatial condition, with frequent hydrological disconnections between parts of the hillslope, as in other Mediterranean mountainous regions. Soil surface rock fragments, the layout of tussocks intra-hillslope and previous soil moisture as dynamic control factors in the hydrological and erosive processes are all important.     

Analysis of the effects of soil management on runoff generation in olive orchards using a physically based model.

Abstract. A numerical model that incorporates the spatial variability of infiltration, surface storage and resistance to overland flow was developed, calibrated and validated for olive orchards. The model reproduced accurately amounts of runoff used in validation, and predicted runoff in olive orchards managed in different ways, in line with published results. The model was used to analyse the runoff generation in a virtual, 180 m length, 5% steep, olive grove, using 54 different scenarios which combined three different soil types, two tree canopy sizes and nine soil management techniques (four tillage scenarios: freshly or degraded tillage with and without a compacted plough layer; no-till, and four cover crops in strips differing in width and plant density). The results of the numerical experiment showed that no-till had the highest runoff coefficient, while a dense cover crop had the lowest. Recently tilled soils also exhibited some of the lowest runoff coefficients. The effects of increasing soil cover due to a greater tree canopy on runoff were significant and caused by the greater area of high infiltration beneath the canopy. Effects of tree canopy size were less important than the impact of soil management practices on runoff.     

Soil resistance to interrill erosion: Model parameterization and sensitivity

Interrill erosion, which is less visible in the landscape than rill and gully erosion, may cause major sediment deposits in the lower part of cultivated fields. It is often associated with runoff resulting from sealing and crusting, and soil properties such as soil detachability or soil aggregate stability have been used to express soil resistance to interrill erosion processes, i.e., interrill erodibility. From a literature review including more than fifteen erosion models, we have identified three main methods used to measure these properties: aggregate stability and splash cup detachability, methods performed in the laboratory using only a few grams of soil, and standard plot methods that are based on field plot measurements. This difference makes the parameters involved in assessing interrill erodibility dependent upon the scale and the hydrological processes involved and difficult to compare. According to the literature, the sensitivity of actual erosion models to interrill erodibility is lower than the sensitivity to hydrological properties and rill erodibility parameters. This numerical study shows that erodibility measurements from the three major assessment methods give different results regarding the contribution of interrill erosion and show that the sensitivity of erosion modeling to interrill erodibility may in fact be greater than shown in the literature on global sensitivity analysis.