Environmental Impact of the Dairy Sector

There exists a strong debate within the international scientific community about the environmental impact of dairy products. From the late 1990s, some authors (Willeke- Wetstein, 1997) have associated environmental impacts with landscape transformation due to the intensification of agricultural activities; others (Milne and Osoro, 1997), with a subtle line of departure from the considerations given by their former colleagues, link the side effects posed on the environment the desertion of dairy production. Others (Burel et al., 1998) argue that it is not an easy task to determine the real effects of dairy farming on the environment: first, because the diversity among species can have different responses to the potential stresses caused by dairy farming and second, because somehow many local dairy farming activities have the capacity to be sustainable.

In this section, the analysis of environmental impacts of the dairy farming focuses on landscape, biodiversity, soil, water, air, greenhouse gases (GHGs) and energy use.

Landscape can be considered an integral part of the dairy farming process. The intensive dairy production systems, almost all over Europe, merge with other attributes of the landscape such as the aesthetic view or cultural activities. If this intensive system eases local adaptation of high demanding and productive animals in terms of food and medical support on one hand, on the other the too-simplified farm structure causes land degradation and abandonment. Also, the intensive production system favors the establishment of woodlands and brushes over meadows, causing hydro-geological risks of open grasslands.

The main effects of dairy production on biodiversity are due to the use of intensive fertilizers and forage on the grassland such to compromise the system stability of ecosystems. This is particularly relevant for dairy farming near aquatic environments and Mediterranean areas.

Soil is affected by chemical and ecosystem changes due to dairy farming. Farms that adapt well to the local environment should not alter the soil productivity. These types of farms generally provide positive changes in terms of ecological and structural stability of soils. On the other hand, farms find it difficult to cope with the equilibrium of soil-based processes affecting soil productivity in the form of animal waste and increased soil contaminants. Irrigation may also provide some altering mechanisms due to high concentrations of salt in water streams in dry climates. Potential damages on nutrient cycles can be relevant in terms of fauna and bird populations due to increases of additives such as heavy metals as copper, cadmium, and zinc. Also, if nutrients dissolve with water, then they can be released as pollutants and affect other ecosystems; contrarily, if nutrients do not dissolve with water, they remain in the soil, altering its structure. Dairy farming intensification activities also increase waste products such as manure and may affect ground as well as surface water courses.

As for water, main effects, as already suggested, derive from intensive use of pesticides and fertilizers. Also, changes occurred in the distribution of inputs (timing and/or manner) in the dairy farming process can overload the carrying capacity of water courses. Intensive dairy farming can also affect surface water courses, causing eutrophication of algae in Southern Mediterranean countries.

Air is particularly affected by the release of polluting substances such as nitrous oxide emissions, methane and ammonia particles, and carbon dioxide emissions. Generally, ammonia has greater impacts on the atmosphere in areas with intensive managed dairy farming. Methane, on the other hand, seems to affect managed areas with low inputs use. Carbon dioxide and nitrous oxide emissions from dairy farming activities produce their effects indirectly from energy use for housing and manufacturing processes in the daisy sector.

A useful quantitative guide to the links between agricultural nutrients and environmental impacts is provided by the Gross Nutrient Balance (GNB) (Eurostat, 2015). The GNB indicates the potential damage caused by nitrogen (N) and phosphorous (P). The higher their surpluses, the higher are the damages caused to the environment. Also, one can distinguish the input side of the balance, which is the amount of nitrogen or phosphorous used in the agricultural processes, and the output side, which is given by the amount of polluting substances removed, through harvesting, from the fields.

As already described, manure is one of the problems affecting soil productivity and is mainly caused by intensity of management of farming activity. Figures and illustrate the amount of nitrogen and phosphorous from manure in EU-28 and the data on nitrous oxide and ammonia during the period 2009-2012. In both figures, note that cattle is the main source of nitrogen from manure production in more than 50% of the countries listed.

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