Contour ploughing[ edit ] Contour ploughing orients furrows following the contour lines of the farmed area. Furrows move left and right to maintain a constant altitude, which reduces runoff.
PDF Abstract Data drawn from a global compilation of studies quantitatively confirm the long-articulated contention that erosion rates from conventionally plowed agricultural fields average 1—2 orders of magnitude greater than rates of soil production, erosion under native vegetation, and long-term geological erosion.
The general equivalence of the latter indicates that, considered globally, hillslope soil production and erosion evolve to balance geologic and climate forcing, whereas conventional plow-based agriculture increases erosion rates enough to prove unsustainable. In recent decades, archaeological studies confirmed pronounced episodes of soil erosion associated with the rise and subsequent decline of civilizations in the Middle East, Greece, Rome, and Mesoamerica, as well as other regions around the globe 4 — 8.
Most commentators, however, generally attribute such erosional episodes to the effects of deforestation 9 — 12 and neglect the role of agriculture in maintaining accelerated erosion in upland environments. Soil erosion is a complex process that depends on soil properties, ground slope, vegetation, and rainfall amount and intensity Changes in land use are widely recognized as capable of greatly accelerating soil erosion 14 — 16and it has long been recognized that erosion in excess of soil production would eventually result in decreased agricultural potential 2317 — Although soil fertility generally declines with accelerated erosion, soil fertility is itself a function of agricultural methods and site conditions such as soil type, nutrient, and organic matter content.
Consequently, in the following analysis, I more narrowly focus on the issue of soil erosion, as the maintenance of soil fertility over the long run still requires maintenance of the soil itself.
Until recently, however, few quantitative data have been available on natural rates of soil production or long-term geological erosion rates against which to compare erosion rates from agricultural fields.
Instead, estimates of anthropogenic increases in soil erosion typically rely on the universal soil loss equation, developed as a planning tool to provide a common empirical framework within which to evaluate local controls on soil erosion rates In addition, using erosion rates determined from small plot studies has been criticized as inappropriate for extrapolation across large spatial scales The other common method for estimating soil erosion based on sediment yield studies 2526 is complicated by deposition in floodplains, which produces a typical decrease in per-unit area sediment yields with increasing drainage area.
Recently, Syvitski et al. Consequently, sediment yield-based estimates of the magnitude of anthropogenic acceleration of upland erosion remain questionable. Even though much of the soil eroded from hillslopes can be redeposited in colluvial or floodplain environments 2428the transfer of sediment to colluvial foot slopes and alluvial valley bottoms can eventually take agricultural uplands out of production, entombing once-productive soils in smaller cultivatable areas, such as occurred on the South Pacific island of Mangaia, where violent conflict over access to arable soils sequestered in localized depositional areas erupted after ancient upland Polynesian agriculture stripped the soil off most of the island Recognizing the potential for accelerated erosion under modern industrial agriculture, the U.
Although studies reporting that only highly erodible land was eroding faster than T values 31 have been interpreted by some as indicating that soil erosion poses little risk to agricultural production 3233other researchers have expressed concern that T values themselves are set substantially higher than soil production rates, because of political and economic considerations To date, the veracity of either claim has been compromised by a dearth of data on both soil production and geological erosion rates and uncertainty over how to interpret differences between modern and geological erosion rates because of their intrinsically different time scales.
In evaluating the long-term effects of agricultural soil erosion, there is a fundamental difference between floodplain agriculture, where annual flooding refreshes mineral soils, and upland agriculture, where soils gradually thin and lose productivity as soil erosion outpaces soil production.
Over time, hillslope soils tend to evolve toward a balance between erosion and soil production, promoting development of a characteristic soil thickness for a particular climate and geologic setting.
In this view, soils, landscapes, and plant communities evolve together through a mutual interdependence on the balance between soil erosion and soil production. Under such a scenario, soil production and erosion would be expected to balance each other over time scales required to produce the equilibrium soil thickness.
In this context, the appropriate metric against which to evaluate sustainable rates of soil erosion is what Bennett and Lowdermilk 37 termed the geological erosion rate, the rate at which soil in a particular environment would erode under native vegetation, which they maintained would match the rate of soil production.Introduction Soil erosion research started in the 's in the USA (Gilley and Flanagan, ).Despite 90 years of research, soil erosion still continues to .
Soil conservation is the preventing of soil loss from erosion or reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination.
Slash-and-burn and other unsustainable methods of subsistence farming are practiced in some lesser developed areas.
Soil conservation is the preventing of soil loss from erosion or reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination.. Slash-and-burn and other unsustainable methods of subsistence farming are practiced in some lesser developed areas.
A sequel to the deforestation is typically large scale erosion, loss of soil . F.J.P.M. Kwaad, physical geographer Home Contact Other websites by the author: Images of soil erosion - Ephemeral gully erosion - Soil erosion control in Europe Introduction The website is a means of rapidly locating information on the economic costs of soil erosion.
#FridaysOnTheFarm: Partnerships Boost Production and Profits This Friday, meet Donny Schneider, a second-generation farmer from Ovid, Colorado whose year partnership with USDA has provided with resources and expertise. Fairfax County, Virginia - The Northern Virginia Soil and Water Conservation District provides soils information to the public and to Fairfax County agencies and helps maintain the Fairfax County soil survey.