stop the drift

How did the Europeans manage to reduce the erosion of agricultural land by 20 percent in the last decade, thus saving billions?

By Dr. Daniel Mader, Zivata, Science and Environment News Agency

Have you ever felt the ground drop from under your feet? This is not just a feeling, but the reality: exposed soils are constantly eroded by water, wind and vehicles and because of them soil moves from one point to another, usually from higher places to lower areas. That's why mountains tend to be rugged and covered in rocks, while in valleys the ground is deeper. What else affects the drift are the type of soil and the fact that mountains are exposed to strong winds and climatic conditions that reduce the ground cover in vegetation.

The most significant factor in holding land and creating new land is the plant - the roots hold it and reduce the chance that it will drift further. The leaves and branches reduce the force of the wind and the impact of the raindrops that separate the grains and allow them to drift. Plants also absorb flying dust and cause it to accumulate more in their environment. When the plants die, they decompose and enrich the soil with organic matter, thus creating new soil. Plants can also break down (slowly) rock, similar to water, wind and temperature change.

Modern agriculture sanctifies bare soil. The clearest example is in field crops, where before and after each crop the soil is cleared of all vegetation to reduce competition with the crops, and it remains exposed to drift for a long period of time, until the next crop. An active field is also subject to the exact same problem - most fields have rows and furrows between which there is no vegetation so that tractors and other agricultural tools can pass between them. Sometimes such a structure leaves half of the field exposed for a significant part of the growing season. The same thing happens in orchards: the ground is often left bare and clean of grasses, shrubs and dry organic matter. Using heavy agricultural tools compacts the soil, reduces its permeability to rainwater and increases surface runoff. All of these greatly increase the erosion of agricultural land, which is very expensive.

When the rate of land erosion exceeds the rate of its creation, its condition deteriorates. Less land means less agricultural crops that can be grown, as well as damage to the variety of wild plants in the area and all the biodiversity that relies on this vegetation.

bare ground

In the European Union, there are programs that evaluate the loss and erosion of soil on the continent, and work to reduce them. New research He used a model for mapping soil erosion in the EU countries, and found that soil loss in Europe averages 0.25 tons per acre each year. About 13 percent of Europe's land is being eroded at more than 0.5 tons per acre, and this happens mainly in agricultural, semi-arid mountainous or sparsely vegetated areas. In these areas, almost half a centimeter of soil is lost every year.

The most threatened area in Europe is the Mediterranean basin, where there is a combination of intensive agriculture with a relatively sparse vegetation cover. In the most extreme areas, land erosion of 32 tons per acre was recorded, with the countries leading the land loss being the Mediterranean countries, Italy, France and Spain. The most exposed crops in these areas are orchards and vineyards.

The research findings show that the soil erosion reduction policy in the last decade resulted in a decrease of almost ten percent in the average soil erosion in Europe, and a 20 percent decrease in agricultural soil erosion. This policy is based on planting vegetation in areas exposed in nature, and in agriculture using a reduction or cessation of plowing, leaving vegetation in the field after harvesting the crop, sowing cover vegetation until the next crop, tilling fields and orchards parallel to elevation lines (contour farming), leaving wild vegetation between agricultural and agricultural plots on the terraces

The economic cost of land loss is enormous. Besides the lack of land for agriculture, the drifting soil damages neighboring agricultural areas, clogs canals and drainage systems and harms ecosystems. The drift in the agricultural area itself often requires actions to reduce the damage such as filling in washed away areas. in another study Researchers have estimated that actions to prevent erosion in agricultural lands prone to erosion in the European Union could have an economic value of almost seven billion NIS per year (1.35 billion euros, in 2010 values).

Israel is drifting

In Israel, the damage of landslides was already known 80 years ago, and in 1941 a formula was Mandatory order to reduce land erosion, but until a few years ago the policy of the Ministry of Agriculture was not widely implemented by the farmers and no vigorous actions were taken to preserve the land. In recent years, things have changed - the Ministry of Agriculture conducts research, holds conferences on the subject and supports farmers who carry out actions to preserve land.

Today there is a soil conservation and drainage division in the Ministry of Agriculture that works to preserve this resource. According to the data in the hands of the division's personnel, the average annual drift in agricultural lands in Israel is four mm per year - a drift rate twice the average in agricultural areas in Europe.

Working of the Ministry of Agriculture found that approximately 70 percent of all cultivated land in Israel is in medium and severe danger of drift. The estimate that comes out there is that the restoration of a 120 dunam flooded field and preparation for multi-year treatment that will reduce future erosion requires an investment of NIS 161 (2009 estimates).

It is further estimated in this work that the cost of annual cultivation of an erosion prevention guard throughout the country in areas prone to disasters can reach 230 million NIS (2009 estimates). These are of course huge amounts that are difficult for farmers and the state to meet. Although, There are methods Cheaper, or ones that pay off in the long term. For example, planting rows of plantations parallel to elevation lines so that the soil does not move downwards, or leaving a ground cover instead of a regular and systematic uncovering and sowing with a no-spill method in which the residues from last year are sown without damaging the soil cover. It is hoped that enough will be done to save the land, because no one wants to wake up one day and find that instead of land there are only rocks left.