what is tillage erosion

Full Answer

What is Tillage erosion and why is it important?

Tillage erosion is what it says: the actual movement of soil by tillage. “It is far and away the biggest cause of soil loss, more than wind and water erosion,” he says. “It is the one (erosion form) that dominates the landscape in Canada, the U.S., and every country we looked at around the world.” It also can key wind and water erosion.

What causes soil erosion?

Still, the cause of much erosion sits in the sheds of many farms: tillage tools. That’s what David Lobb, a University of Manitoba soil scientists, told those attending this week’s Conservation Tillage Conference in St. Cloud, Minnesota. Tillage erosion is what it says: the actual movement of soil by tillage.

What causes more Tillage erosion moldboard or disk?

Tandem disks cause twice as much tillage erosion than a moldboard plow, due to the amount of soil they churn at higher speeds, says Lobb. High disturbance seeders – popular on the Canadian prairies – also throw lots of soil as they pass through a field, which magnify tillage erosion.

Why is tillage bad for the soil?

The newly exposed subsoil is highly susceptible to the damaging forces of rain. Because tillage moves the dirt to low spots where surface water concentrates, it causes significant soil loss on upper-slope positions, while resulting in unwanted accumulation in the field’s lowest areas.

What is meant by tillage erosion?

Tillage erosion refers to the net soil translocation on the hillslope due to tillage operations, expressed in units of volume, mass, or depth per unit width of tillage. The transport and resultant displacement of soil during tillage is referred to as tillage translocation.

How does tillage cause erosion?

Since tillage fractures the soil, it disrupts soil structure, accelerating surface runoff and soil erosion. Tillage also reduces crop residue, which help cushion the force of pounding raindrops. Without crop residue, soil particles become more easily dislodged, being moved or 'splashed' away.

Is tillage a type of soil erosion?

There is growing evidence that tillage erosion is a major soil erosion process in agricultural lands, surpassing water and wind erosion in many fields all around the world, especially on sloping and hilly lands A signature spatial pattern of soil erosion shown in many water erosion handbooks and pamphlets, the eroded ...

What is the difference between tillage erosion and water wind erosion?

Tillage erosion not only redistributes soil within a landscape, it also leaves the soil more susceptible to wind and water erosion by exposing subsoil which is more erodible and by delivering topsoil to areas of the landscape where water erosion is more severe.

How does tillage reduce soil erosion?

Conventional tillage, such as moldboard plowing, leaves the soil surface bare and loosens soil particles, making them susceptible to the erosive forces of wind and water. Conservation tillage practices reduce erosion by protecting the soil surface and allowing water to infiltrate instead of running off.

Why is tillage bad for the environment?

Tillage loosens and aerates the soil, which allows for the deeper penetration of roots. It controls weeds and mixes organic matter, fertilizer and manure with the soil. However, tillage can contribute to the loss of soil moisture, lead to increased wind and water erosion and consume significant amounts of fuel.

What are the types of tillage?

TypesPrimary and secondary tillage. Primary tillage is usually conducted after the last harvest, when the soil is wet enough to allow plowing but also allows good traction. ... Reduced tillage. ... Intensive tillage. ... Conservation tillage. ... Zone tillage.

What is soil tillage?

Tillage—turning the soil to control for weeds and pests and to prepare for seeding—has long been part of crop farming. However, intensive soil tillage can increase the likelihood of soil erosion, nutrient runoff into nearby waterways, and the release of greenhouse gases into the atmosphere.

What is the important of tillage?

Tillage has many roles in crop production, including seedbed preparation, seed placement, incorporation of nutrients and other amendments, and management of water and pests. Tillage also affects a variety of biophysical processes that impact the environment.

What are the 4 types of erosion?

Rainfall produces four types of soil erosion: splash erosion, sheet erosion, rill erosion, and gully erosion.

What are the 4 types of soil erosion?

Different Soil Erosion Causes1) Sheet erosion by water;2) Wind erosion;3) Rill erosion – happens with heavy rains and usually creates smalls rills over hillsides;4) Gully erosion – when water runoff removes soil along drainage lines.5) Ephemeral erosion that occurs in natural depressions.

What are the two types of erosion?

Sheet erosion occurs when a thin layer of topsoil is removed over a whole hillside paddock—and may not be readily noticed. Rill erosion occurs when runoff water forms small channels as it concentrates down a slope.

How do aggressive tillage practices affect wind erosion?

Tillage, historically used to prepare fields for planting, creates soil conditions susceptible to wind erosion by breaking down soil aggregation, destroying residue, and drying the soil. Without moisture to hold the particles together, wind can detach soil particles and transport them across the fields.

What are causes of soil erosion?

Following are the important causes of soil erosion:Rainfall and Flooding. Higher intensity of rainstorms is the main cause of soil erosion. ... Agriculture. The farming practices are the major cause of soil erosion. ... Grazing. ... Logging and Mining. ... Construction. ... Rivers and Streams. ... Heavy Winds. ... Loss of Arable Land.More items...

What are the factors affecting soil erosion?

Vegetation, rainfall, soil, and topography are the primary factors influencing soil erosion, although other factors may be involved. The kinetic impact of rain hitting the soil causes water erosion [5, 6], and water erosion will occur when rainfall exceeds a certain value in a single rainfall event.

What causes sheet and rill erosion?

Sheet erosion occurs when a thin layer of topsoil is removed over a whole hillside paddock—and may not be readily noticed. Rill erosion occurs when runoff water forms small channels as it concentrates down a slope. These rills can be up to 0.3m deep.

What is tillage erosion?

Tillage erosion is a form of soil erosion occurring in cultivated fields due to the movement of soil by tillage. There is growing evidence that tillage erosion is a major soil erosion process in agricultural lands, surpassing water and wind erosion in many fields all around the world, especially on sloping and hilly lands A signature spatial ...

How does tillage affect erosion?

Cultivated fields are subject to not only tillage erosion but also water and wind erosion. There are linkages and interactions between these erosion processes. Linkages and interactions refer to the additive and non-additive effects, respectively, between different erosion processes. Total soil erosion may be increased or decreased due to positive and negative linkages, respectively, between different erosion processes. Interactions occur when one erosion process changes the erodibility of the landscape for another erosion process, or when one process works as a delivery mechanism for another erosion process. For example, soil degradation caused by tillage erosion likely will increase the erodibility of the soil to water and wind erosion. Another example is the interactions between tillage and water erosion around water eroded channels, especially ephemeral gullies. Tillage is often used to eliminate these channels and ephemeral gullies, in which tillage translocation essentially serves as a delivery mechanism to transport soil to areas most susceptible to water erosion.

What is Tilleri model?

The Tillage Erosion Risk Indicator ( TillERI) is a simplified tillage erosion model used to estimate the risk of tillage erosion in agricultural lands at the national scale in Canada. It is one of the erosion indicators as part of the Agri-Environmental indicators developed under the National Agri-Environmental Health Analysis and Reporting Program (NAHARP). Input data include hillslope length, slope gradient of the eroding segment, and the erosivity of the tillage operations (β value). Output data from the model include tillage erosion rate at the erosion segment and the risk level for tillage erosion for that hillslope.

What is the meaning of T M in soil?

where T M is tillage translocation ; α is the tillage translocation on flat soil surface; β and γ are coefficients which describe the additional translocation resulting from slope gradient and slope curvature, respectively. Tillage erosion, which is the net tillage translocation, is then calculated as:

How to measure soil erosion?

Tillage erosion can be measured via the measurement of tillage translocation or the measurement of soil loss and accumulation. Tillage translocation is normally measured with a tracer that is incorporated into the soil in plots. The distributions of the tracer before and after tillage are used to calculate tillage translocation. Two types of tracers, point tracers, and bulk tracers are being used. Whereas point tracers are easy to implement, bulk tracers can provide more information regarding the dispersion of the soil during the translocation process. Soil loss and accumulation by tillage erosion can be estimated from changes in surface elevation. For example, elevation of a tilled field can be compared to an adjacent reference object that has not been eroded such as a fence line or hedgerow. Decreases in surface elevation indicate soil losses while increases in elevation are evidence of soil accumulations. Elevation change can also be determined by taking repeated measurements of the soil surface elevations with high accuracy topographic survey techniques such as RTK GPS, total station and close range photogrammetry. Another way to estimate soil loss and accumulation is to measure the changes in soil properties , such as soil organic matter content. However, soil organic matter can be affected by many factors so it is not a very reliable method. Since 1980s, radioisotopes such as Cs-137 and Pb-210 have been used to provide much more accurate soil erosion estimates.

What is Dirtillem in soil erosion?

The Directional Tillage Erosion Model ( DirTillEM) is an upgraded version of TillEM. The DirTillEM calculates the incoming and outgoing soil in each of the four directions for each cell in a DEM and determines the tillage erosion for that cell by summing up all incoming and outgoing soil. This calculation structure allows the DirTillEM to treat each cell independently so that it can simulate tillage erosion under complicated tillage patterns (e.g., circular pattern) or irregular field boundaries.

What are the spatial patterns of tillage erosion?

Typical spatial patterns of tillage erosion observed in cultivated field are either local topography related: soil loss from hilltops (convexities) and soil accumulation in depressions (concavities); or field boundary related: soil loss from the downside of a field boundary and soil accumulation in the upper-side of a field boundary. Local topography related tillage erosion is most pronounced in hummocky landscapes with eroded hilltops that often exhibit a light soil color due to the loss of organic-rich topsoil, a phenomenon often mistakenly assumed to be the result of water erosion. Field boundary related tillage erosion is determined by not only topography but also tillage directions and it is responsible for the forming of tillage banks and terraces.

What is erosivity in tillage?

Tillage erosivity is defined as the propensity of a tillage operation, or a sequence of operations, to erode soil, and is a function of the design of the tillage implement (combination, arrangement, and shape of tillage tools), the operation of the tillage implement (depth and speed), the suitability of the tractor–implement match, and the behavior of the tillage operator. Tillage depth determines the amount of soil translocated and tillage speed determines the amount of energy imparted by the tillage tools on the translocated soil. Each tillage implement has a recommended depth and speed of operation. When operated as recommended, tillage depth and speed vary in complex landscapes in response to changing power requirement and availability. Variation in tillage depth and speed causes tillage translocation to vary and, therefore, causes tillage erosion. This variation in tillage depth and speed is amplified if an implement is operated in excess of recommended depth and speed, or if the tractor used has less than the recommended available power to draw the implement. The manner in which the operator manipulates tillage depth and speed in response to changing power requirement and availability can also affect the erosivity of tillage, for example, it is an erosive practice to employ high speeds during downslope tillage to recover working time lost due to deceleration during upslope tillage. Typically, large implements, equipped with aggressive tillage tools, operated at great depths and high speeds are highly erosive, with more passes resulting in more erosion.

Why is tillage bad for soil?

Tillage has been described as being ‘addictive’ for soils because of the vicious cycle that can be established. Soils are tilled to disrupt surface crusts, compacted zones, or other real or perceived limitations to crop production. Doing so may provide short-term improvements in tilth and nutrient cycling, but these periods of improvement become shorter and shorter as more of the organic matter is lost through oxidation. Ultimately the soils may be ‘burned out’ and must either be abandoned until natural processes (e.g., wetting and drying; plant root proliferation, exudation, death, and decay; weathering) can restore the tilth or management practices (e.g., crop rotation, tillage, water management) are changed. As a result of these interactions, monitoring of soil tilth may provide a useful indicator of the sustainability of an agricultural system.

Why is crop residue important?

The presence of crop residue on the soil surface (mulching) is extremely important for minimizing soil loss from water, wind, and tillage erosion and for improving soil organic C, soil fauna activity, and ultimately soil quality (Delgado, 2010 ). As such, practices that increase the return of crop residue to the soil, especially with crops such as maize that have large amounts of residue and are deep rooted, can contribute to agricultural productivity and help famers to adapt to climate change and variability. Carbon sequestration is important in climate change adaptation efforts because it contributes to so many soil functions and properties that are related to productivity, e.g., soil C helps improve soil properties, such as soil structure and aggregate formation, which contribute to increases in available water-holding capacity. The fact that SSFs in Kalomo do not use mulch much lowers their productivity, adaptive capacity, and resilience under a changing climate, as their fields are more prone to erosion, soil C loss, and reduced soil faunal activity.

How do invasive species affect soil?

Invasive species of plants and animals also influence changes in soils and biotic communities. The movement of plants, people, and machinery has not only increased the numbers of species invasions into soils globally, but has significantly increased impacts on soil biodiversity and some characteristic of the ecosystem (e.g., nutrient cycling, species richness and or abundance, plant factors, soil physical or chemical factors) and increased costs of eradication. An earthworm species introduced to New York has changed forest-floor litter quality and composition, soil chemistry, and water infiltration rates. European nations are examining ways to eradicate the Australian planarian flatworm, Artioposthia triangulata, a predator of earthworms. This invasive species has impacts aboveground (removing the food source for birds) and belowground (removing an animal species that influences organic matter transformation, soil hydrology, and structure). Invasive plant species with differing rooting depths and plant chemical composition can have repercussions for soil communities. Woody plant invasions into grasslands of the Great Plains of the USA have greater rooting depths (affecting soil carbon storage) and, at these depths, a more depauperate nematode community.

What are transport coefficients for tillage?

Tillage transport coefficients are available in, or calculated from, the literature, for different implements, tillage directions, tillage speed, and tillage depth . In addition, bulk density of soil can also be incorporated.

How does land use affect biodiversity?

Land-use change is the major driver affecting soil biodiversity and future soil sustainability. Land-use changes (tillage, erosion, dams, change in plant species) affecting soil physical and chemical properties, soil structure, and the base of the soil food web (chemical composition of plants, amount of organic matter, oil, pollution, manure) have direct impacts on species composition. The conversion of a natural grassland or forest to a managed system for agriculture, pasture, urban, or industrial use, changes the determinants of soil biodiversity, the vegetation, soil structure, and microclimate. The disruption to the natural vegetation and the soil habitat with land-use change decouples the nutrients provided by the decomposition food web from plant uptake. The result is a loss in soil fertility provided by the original soil and its inhabitants. Additional fertilizer is required, and pesticides may be necessary, especially with more intensive agriculture, because the new soil food web generally has fewer predators, resulting in a change in or loss of biocontrol of plant pathogens. While tillage methods are beneficial in conserving carbon in soils and creating a food web that is more detritus-based, some lower level of herbicides and pesticides is generally used. There are examples from tropical wet and dry forests, grasslands, deserts, and other ecosystems showing that these land-use changes affect the total soil biota (macrofauna, microfauna, and microflora), generally reducing species diversity. Desertification resulting from land-use change has a considerable impact on soil processes, including soil carbon, soil structure, soil biota, and soil fertility.

How does surface residue affect soil?

One principal function of surface residue is to decrease the force of wind on the soil surface, because the impacts of forces that can erode the soil particles are reduced when the force of the wind is transferred to the residue . However, under long-term managed vegetable fields of clay loam soil ( Basher and Ross, 2002); most of the soil redistribution is caused by water erosion rather than tillage erosion. On an equal-weight basis, the residues of small grains are more effective than those of sorghum or corn residues, which in turn are more effective than those of cotton or soybeans (Woodruff and Siddoway, 1973 ). Graham et al. (2007) concluded that only 28% of corn stover could be removed under current production practices, if soil erosion were to remain below 0.5 t ha − 1. Izaurralde et al. (2007) stated that with improved tillage management practices in upper layers of the soil, the adoption of NT tends to reduce erosion, retains soil nutrients, and reduces C loss over CT. Guy and Lauver (2007) also reported that the presence of crop residues on the surface retained soil water and reduced soil erosion. Even with no-till practices, removal of corn stover was shown to increase soil bulk density and reduce soil water content in a 1-year field experiment ( Blanco-Canqui et al., 2006, 2007 ).

Definition

Tillage erosion. Tillage erosion refers to the net soil translocation on the hillslope due to tillage operations, expressed in units of volume, mass, or depth per unit width of tillage. The transport and resultant displacement of soil during tillage is referred to as tillage translocation.

Introduction

In agricultural practices, tillage has been used to prepare the soil for seeding, to improve soil physical properties, to enhance a rapid release of nutrients from the soil organic material, to control weeds, and the like. However, a major drawback of tillage arises when it becomes intensive and continuous, which causes soil erosion.

What is tillage erosion?

Tillage erosion is what it says: the actual movement of soil by tillage. “It is far and away the biggest cause of soil loss, more than wind and water erosion,” he says. “It is the one (erosion form) that dominates the landscape in Canada, the U.S., and every country we looked at around the world.”. It also can key wind and water erosion.

What caused soil erosion in the 1930s?

Environment can magnify soil erosion, such as when drought and wind combined with the exposure of bare soil during the Dust Bowl days of the 1930s. Still, erosion was also rampant in the Heavy 70s (as Lobb terms the 1970s) when farmers combined intense cropping systems with intense tillage.

Why do Tandem disks cause erosion?

Tandem disks cause twice as much tillage erosion than a moldboard plow, due to the amount of soil they churn at higher speeds , says Lobb. High disturbance seeders – popular on the Canadian prairies – also throw lots of soil as they pass through a field, which magnify tillage erosion.

Where do farmers move topsoil?

Some farmers around the world move topsoil that’s deposited at the bottom of fields to hilltops. In some countries, land-tenant agreements have stipulated that farmers do this. In some areas like Manitoba and Ontario, farmers have moved excess topsoil from bottom areas to hilltops using tools like earth scrapers.

Does conservation tillage help with soil erosion?

Even though tools like conservation tillage have helped to slow soil erosion losses in recent decades, economic soil erosion losses remain high. Soil erosion losses are now magnified, as Canadian farmers are now growing high value crops like soybeans compared to wheat and barley as they did in the early 1970s.

Is a moldboard plow bad for erosion?

Tillage erosion is magnified when mechanized tillage occurs. “You will have waves of soil moving in front of an implement,” he says. Some tillage tools are worse than others. A moldboard plow is bad for erosion, but there are more tillage operations more erosive, Lobb says.

Overview

Physical process

Spatial patterns

Measurement

Modeling

Effects

Mitigation