LEDD issues in cropland: Italy and Alento

Editor's note 30 Apr 2012: Text source D111.

Soil degradation is a major and widespread environmental problem in Italy which is related to the history of both agricultural and non-agricultural land use. It is estimated that in recent decades, with the modernization of production systems, erosion has exceeded 30 times the tolerable rate of erosion (Pagliai 2004; Pimentel 1993).

About 70 percent of all land is subject to risk of accelerated soil erosion (over 5 t/ha/year) and about 12 percent is prone to high risk (over 10 t/ha/year) (Grimm et al. 2003). While soil erosion risks are exacerbated by a combination of climate and steep topography, erosion has also been aggravated by: poor adoption of soil conservation practices, notably limited soil cover over the whole year, and less than 10 percent of arable land under conservation tillage (European Environment Agency 2005); monoculture cropping systems; and uncultivated land, notably conversion of cultivated mountain terraces to other uses.

Soil compaction risks have grown, mainly in the plains, due to greater use of heavy farm machinery in wet conditions. Three quarters of Italy’s territory was reported to be at a medium risk of susceptibility to soil compaction in the National Agency of Environmental Protection Environmental Data Yearbook of 2009 (ISPRA 2009). Broadly speaking, the areas which are most susceptible to compaction are those characterised by clayey soil and shallow water tables.     

In the South and in the major islands, approximately five percent of land is affected by desertification, including soil salinisation, associated with expansion of intensive agriculture on fragile land; excessive use of groundwater for irrigation, with the consequent intrusion of saline waters; and poor grove tillage practices (APAT 2000; Beaufoy 2001).

Linked to these soil degradation problems, there has been a loss of soil organic matter (SOM). Data from the Environmental Data Yearbook (ISPRA 2009) reveals that organic carbon levels in Italian soil are worryingly low.  Organic matter content, relative to the top 30cm of soil, has been divided into 4 categories (very low:  < 1 percent, low: 1-2 percent, medium:  2-6 percent and high: >6 percent).  Around 80 percent of Italian soil has an organic matter content of less than two percent whilst no single region in the national territory showed “high” levels, more than six percent, at least not on the scale used.  The spatial distribution of organic matter levels follows climatic distribution with an increase in “medium” levels in the North of Italy and along the principal mountain ridges of the country.      

Another process which limits ecological soil functions is soil sealing.  According to the Environmental Data Yearbook (ISPRA 2009), over six percent of the national territory was sealed in 2006 compared with 5.5 percent in 2000. Northern Italy shows the highest percentages of soil sealing whilst values are slightly lower in the south and on the islands.  Indicators show that soil sealing has progressively increased throughout the country over the last 50 years and, as a consequence, soil consumption has also risen.  In recent years soil sealing trends have varied notably between northern and southern Italy.  Northern regions experienced a relatively steady increase in soil sealing between 1994 and 2006.   Central and Southern regions, however, saw a period of relative stability, from 1994 to 2000, followed by a marked increase, though not enough to match levels found in northern Italy.  The highest soil sealing values are reported in the North-West where over seven percent of land surface is sealed.  North-eastern and central regions have figures of between 6-7 percent, whilst in the South and on the islands the figures are largely above five percent.  Sealed areas are concentrated in urbanised areas and along main roads.  This phenomenon becomes particularly concerning in coastal areas and on large plains where the problem of soil sealing by urbanisation is compounded by soil damage caused by intensive farming. The negative effects of land impermeability are already very significant and concern climate changes resulting from annual average temperature rises, the destruction and fragmentation of the habitats of internationally important species (in central Italy, for example, the bear, the wolf and the lynx), the alteration of surface and ground water, the reduced capability to absorb civil and industrial emissions, the irreversibility of the use of land, once transformed by urbanisation and, in short, overall reduced ecological resilience to disturbances and perturbations affecting ecosystem (ISPRA 2009).

Water pollution is still a problem, although it is decreasing. In fact rivers in the Po Valley are still polluted by different activities including agriculture, especially from livestock farms, while in the South eutrophication of reservoirs for drinking water has resulted from excessive fertiliser use. Groundwater is the source of nearly 85 percent of drinking water, but about 25 percent of groundwater supply requires treatment before it is fit for drinking. The reduction in agricultural nutrient surpluses has lowered water pollution. But absolute loadings of nutrients into water bodies remain high, contributing two-thirds of nitrates and one-third of phosphates delivered into rivers, and a major, but decreasing, share of pollution of groundwater, while efficiency of nutrient use is low (ISPRA 2009).

In Italy overall agricultural land use changes since 1960 have been detrimental for biodiversity, with a reduction in semi-natural farmed habitats, including the conversion of permanent pastures and meadows to commercial forestry and crop production (ISPRA 2009). Flooding and landslides are also a problem. The increasing occurrence and severity of droughts, floods and associated landslides are imposing a considerable human and economic cost (Guzzetti 2003). Although some hilly and mountainous land was ploughed in the 1970s and 80s, during the 1990s certain areas reverted to shrub and low forest, which has helped increase water holding capacity. However, the 16 percent decline in farm dams and ponds over the period 1985-2000, has reduced the water retention capacity of agricultural land (ISPRA 2009).

Alento study site

Soil erosion is by far the most important land issue in the Alento study area, mainly due to its on- and off-site effects. In fact it causes severe damage to both agricultural productivity and to infrastructure (mainly dams).  In the Alento, soil erosion is largely caused by the collapse of terrace systems, mainly due to the lack of maintenance and abandonment of agriculture.

The plains and coastline of the study area pose new problems though are still closely linked to those described for hilly areas. The biggest challenge facing plains and coastlines is soil sealing. Soil sealing, especially in the plain areas, is related to three interconnected processes.  The first is a flux in population moving from inland areas to areas with greater socio-economic opportunities, better infrastructure, and more services.  The second is the intensification of agriculture through building of greenhouses and the third is the expansion of the tourist industry.

• < Prev
• Next >