Soil erosion reaches 16.7 tons per ha annually

February 3, 2019

TEHRAN – Soil erosion and pollution are the two major important environmental problems in the country, as some 16.7 tons of soil per hectare erodes annually, head of soil protection unit of the Forests, Range, and Watershed Management Organization has announced.

Soil erosion is the displacement of the upper layer of soil, one form of soil degradation, which is caused by the dynamic activity of erosive agents, including, water, ice, snow, wind, plants, animals, and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind erosion, zoogenic erosion, and anthropogenic erosion.

Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality, and damaged drainage networks.

Soil, which is the landscape for the ecosystem and the basic resource for food production, is now threatened by soil pollution, ISNA quoted Hooshang Jazi as saying on Saturday.

The soil acts as a habitat helping vegetation conservation, which increases the permeability of the soil to rainwater, he said, adding it also shelters the soil from winds, which results in decreased wind erosion, as well as forming a more solid mass less susceptible to water erosion and absorbing more rainfall water to the underground resources. 

So, vegetation removal contributes to the increased rate of surface erosion, he further added.

He also lamented that the rate of evaporation from surface water resources in Iran is three times above the global average, so dam construction as the only way to address water storage is inefficient due to high evaporation rates, implying that to meet demand for water, soil protection and aquifers level increase can play a more effective role.

He also noted that being a great source of storing rainwater, soil is of great importance in the country, while it hardly forms consuming long period of time.

Soil erosion rate in the country equals 16.7 tons per hectare per year, he stated, adding that some 125 million hectares of the lands are also exposed to water erosion and wind erosion hits 32 million hectares.

So, the point to be noted is soil erosion prevention on the catchment area of the mountainous and agricultural land must be taken into consideration, Jazi also added.

Referring to soil pollution as part of land degradation, he noted that it is typically caused by industrial activity, agricultural chemicals, and pesticides, or improper waste disposal, which poses serious threat to the food and agricultural production.

Pointing out that several measure are being taken to contain soil erosion growth at an alarming rate, he added that one of the most important one is vegetation cultivation on the slopes to both promote and hinder the stability of the soil against heavy rainfall or flooding.

Moreover, fiber logs creating a natural control area helps establish growth and control soil erosion, he added.

Criticizing plowing regardless of how steep the slope is done in many agricultural lands across the country, Jazi stated that when the plowed land is harvested, the soil is washed off immediately, therefore, the soil erosion rate is much higher in agricultural lands.

The Ministry of Agriculture is the responsible body for the agricultural lands protection, while protecting the country’s total soil is on the Forests, Range, and Watershed Management Organization, he stated, adding, currently, some 26 million hectares being exposed to water erosion are under researches, on which water management operations will be implemented as soon as the budget is provided.

According to the Sixth Development Plan (2016-2021), the Ministry of Agriculture must conduct watershed and aquifer operations on 10 million hectares of lands, which requires an annual budget of 20 trillion rials (around $480 million), he also said.

Elsewhere in his remarks, he lamented that natural resources and soil conservation have been neglected since recent years, however, some 7 trillion rials (about $166 million) from the National Development Fund has been earmarked in this regard, which is only one third of the needed funding for the implementation of watershed management projects.

Unfortunately, 250 million cubic meters of soil annually enter the country's dams, due to improper watershed management and neglected soil conservation, Jazi concluded.

According to Eurostat website, approximately 11.4 % of the European Union (EU) territory is estimated to be affected by a moderate to high level soil erosion (more than 5 tons per hectare per year).

However, Science Direct wrote that that erosion of agricultural soils in the United States is responsible for the loss of an average of 30 tons per hectare per year, about eight times greater than the rate of soil formation in the human lifetime.

FB/MQ/MG

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