Die Bodenkultur - Journal for Land Management, Food and Environment
A. KRAPFENBAUER and K. WRIESSNIG:
Anthropogenie environmental pollution - the share of agriculture
The increase of environmental pollution is in direct relation to the consumption of fossil coal, gas and oil and the progressive growth of the world population. Since 1950 these issues increased considerably and they will continue to increase in the future. At the moment the population increases by 1.9%, the onsumption of energy between 2 and 3% and the environmental pollution up to 3.5% annually.
With the progressive growth of the world population and the increase in prosperity in the developed countries the demand for food increased also progressively and therewith the productivity index of the units of arable land, by growing consumption of fertilizers and the installation of irrigation systems. At the same time the pollution of air, water and soil caused by agriculture also grew progressively. But up to date there is still a shortcoming of reliable statistical facts and figures.
A higher productivity index of the units of arable land in the different ecoclimatic zones of the earth leads to higher production and consumption by an inevitably higher turnover of plant nutrients and diverse gaseous substances, for example carbon mono- and dioxide, diverse compounds of nitrogen etc. At the same time an excess of the „critical loads" for soil, air and water must be expected.
The main items of the emissions produced by an intensified agriculture are, besides carbon mono- and dioxide, methane, nitric and nitrous oxide, ammonia and diverse hydrocarbons. A higher productivity index is consequently related to a higher consumption. This also leads to an intensified turnover of carbon dioxide. There is consequently a progressive input of carbon dioxide resulting from the emissions of burning fossil fuel in the recently produced and consumed biomass. This inevitably leads to a higher level of carbon dioxide in the air.
A main source of emissions of methane and ammonia is animal breeding. In Austria at this time from each of the 3,508.000 hectars of land used by agriculture annual emissions of 63 kg methane and 11 kg ammonia are resulting theoretically. The use of organic and inorganic fertilizers, the growing cultivation of legumes and the emissions of nitrogen compounds resulting from burning processes elevate likewise the pool and the annual turnover of nitrogen compounds by production and consumption of biomass. Inevitably related to it is a growing amount of the annual input of nitrogen compounds to the air, the soil and the water.
A rough approximation says that at present agriculture contributes to the global anthropogenic pollution of the environment (air, soil and water) 85% of the ammonia, 81% of the nitrous oxide, 35% of nitric mono- and dioxide, 70% of the methane, 52% of the carbon monoxide and 21 % of the carbon dioxide.
Not considered in the figure for carbon dioxide is the inevitable increase of the level of CO2 in the air by the elevated turnover of biomass. The world population growth in the future leads to an increasing contribution of agriculture to the anthropogenic environmental pollution.
For the developed countries this is an obligatory challenge to avoid surplus production. On a global scale there must be a sensible reduction of animal breeding to reduce the high emissions of methane and ammonia from this sector of agriculture. It must also be considered, that by feeding animals with vegetable food stuff, which also could be used for direct nutrition of man, the efficiency of it is lowered by a factor of 1:10. In spite of a growing crisis to maintain the alimentation of the growing world population in many countries the nutrition of man must rapidly be centered on vegetable food stuff rich in protein. At the Same time an essential reduction of the environmental pollution resulting from animal breeding could be realized. Beside of it and other reducing issues a continuous growth of the world population, the energy consumption and environmental pollution will make it necessary to observe the development and reactions in the environment by monitoring and phenological observations. The results must be used to counteract finally by looking for adaptation strategies. Considering the realities it must be realized that by all means to mobilize for counteracting the environmental pollution directly, a certain climate change will be inevitable. The consequences will also be an outstanding challenge for the agriculture.
Key-words: agriculture, methane, nitrous oxide, ozone, global warming.