A century of change agriculture and eutrophication


Does Agri-agriculture impact on eutrophication risk?

Agriculture’s impact on eutrophication risk may also be overestimated in many catchments, and more accurate accounting of sources, their bioavailabilities and lag times is needed to direct proportioned mitigation efforts more effectively.

What is driving eutrophication of surface waters?

The eutrophication of surface waters has become an endemic global problem. Nutrient loadings from agriculture are a major driver, but it remains very unclear what level of on-farm controls are necessary or can be justified to achieve water quality improvements.

How has the productivity of Agriculture changed over time?

Since 1900 agriculture in developed nations, and to a lesser extent in the developing world, has seen large rises in productivity as mechanization replaces human labor, and assisted by synthetic fertilizers, pesticides, and selective breeding.

How did the development of agriculture affect the human population?

The development of agriculture enabled the human population to grow many times larger than could be sustained by hunting and gathering. Agriculture began independently in different parts of the globe, and included a diverse range of taxa, in at least 11 separate centres of origin.


Is eutrophication and impact of climate change?

How will eutrophication be affected by climate change? New research indicates that the symptoms of cultural eutrophication in lakes and estuaries will be made worse by climate change, adding to the challenge of restoring water quality and biological health.

How does agriculture affect eutrophication?

This excess nitrogen and phosphorus can be washed from farm fields and into waterways during rain events and when snow melts, and can also leach through the soil and into groundwater over time. High levels of nitrogen and phosphorus can cause eutrophication of water bodies.

What impact does eutrophication have on society today?

The known consequences of cultural eutrophication include blooms of blue-green algae (i.e., cyanobacteria, Figure 2), tainted drinking water supplies, degradation of recreational opportunities, and hypoxia.

When did eutrophication become a problem?

The term ‘eutrophication’ came into common usage from the 1940s onwards, when it was realized that, over a period of years, plant nutrients derived from industrial activity and agriculture had caused changes in water quality and the biological character of water bodies.

What causes eutrophication?

Eutrophication is a natural process that results from accumulation of nutrients in lakes or other bodies of water. Algae that feed on nutrients grow into unsightly scum on the water surface, decreasing recreational value and clogging water-intake pipes.

What is the effect of eutrophication?

Eutrophication sets off a chain reaction in the ecosystem, starting with an overabundance of algae and plants. The excess algae and plant matter eventually decompose, producing large amounts of carbon dioxide. This lowers the pH of seawater, a process known as ocean acidification.

How can eutrophication affect the local economy?

We do know that eutrophication diminishes the ability of coastal ecosystems to provide valuable ecosystem services such as tourism, recreation, the provision of fish and shellfish for local communities, sportfishing, and commercial fisheries.

What is eutrophication and why is it a problem?

What is Eutrophication? Eutrophication presents as one of the most serious ecological problems of open water sources such as lakes, oceans and reservoirs. It is characterized by dense algal and plant growth owing to the enrichment by phosphorus and nitrogen nutrients needed for photosynthesis.

How does eutrophication affect the environment?

Eutrophication leads to an increased algal growth (because the level of nutrients increases). It can lead to a shift in species composition to fast growing algae species (including toxic species) and a shift from long lived macroalgae to more nuisance species.

When and where was eutrophication discovered?

Eutrophication was recognized as a water pollution problem in European and North American lakes and reservoirs in the mid-20th century. Breakthrough research carried out at the Experimental Lakes Area (ELA) in Ontario, Canada in the 1970s provided the evidence that freshwater bodies are phosphorus-limited.

How can we prevent eutrophication?

There are two possible approaches to reducing eutrophication: Reduce the source of nutrients (e.g. by phosphate stripping at sewage treatment works, reducing fertilizer inputs, introducing buffer strips of vegetation adjacent to water bodies to trap eroding soil particles).


Clear Lake, Iowa, USA is a shallow, agriculturally eutrophic lake that has changed drastically over the past century. Eight macrophyte surveys since 1896 were pooled and examined to characterize long-term impacts of eutrophication on macrophyte community composition and relative abundance.

Author information

Present address: Oregon Natural Desert Association, 16 N.W. Kansas Avenue, Bend, OR, 97701, USA

What is the origin of agriculture?

The word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, “field”, and cultūra, ” cultivation ” or “growing”. While agriculture usually refers to human activities, certain species of ant, termite and beetle have been cultivating crops for up to 60 million years.

How many people were employed in agriculture in the 21st century?

At the start of the 21st century, some one billion people, or over 1/3 of the available work force, were employed in agriculture. It constitutes approximately 70% of the global employment of children, and in many countries employs the largest percentage of women of any industry.

What were staple food crops?

Staple food crops were grains such as wheat and barley, alongside industrial crops such as flax and papyrus. In India, wheat, barley and jujube were domesticated by 9,000 BC, soon followed by sheep and goats. Cattle, sheep and goats were domesticated in Mehrgarh culture by 8,000–6,000 BC.

Why is fallow period shortened?

This fallow period is shortened if population density grows, requiring the input of nutrients (fertilizer or manure) and some manual pest control. Annual cultivation is the next phase of intensity in which there is no fallow period. This requires even greater nutrient and pest control inputs.

How does industrialized agriculture depend on fossil fuels?

Industrialized agriculture depends on fossil fuels in two fundamental ways: direct consumption on the farm and manufacture of inputs used on the farm. Direct consumption includes the use of lubricants and fuels to operate farm vehicles and machinery. Agriculture and food system share (%) of total energy.

How much of the world’s land is used for livestock production?

Livestock production occupies 70% of all land used for agriculture, or 30% of the land surface of the planet. It is one of the largest sources of greenhouse gases, responsible for 18% of the world’s greenhouse gas emissions as measured in CO 2 equivalents. By comparison, all transportation emits 13.5% of the CO 2.

How does agriculture increase yield?

Agriculture seeks to increase yield and to reduce costs. Yield increases with inputs such as fertilisers and removal of pathogens , predators, and competitors (such as weeds). Costs decrease with increasing scale of farm units, such as making fields larger; this means removing hedges, ditches and other areas of habitat.


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