Eutrophication. Lakes and estuaries can be described by their nutrient status. The trophic status of a lake or estuary refers to the primary productivity (amount of algae) produced in the water and the amount of nutrients (P and N) in the water. Oligotrophic waters usually have low primary productivity (high water quality and few algae) and are nutrient poor, while eutrophic waters have high primary productivity (low water quality and frequent algal blooms) due to excessive nutrients. Mesotrophic waters lie somewhere in between the two states. Eutrophication is an increase in the nutrients available in a waterbody which can subsequently increase primary productivity and degrade water quality, leading to a reduction in mahinga kai habitat and survival.
Potential impacts of eutrophication on water quality and mahinga kai. Eutrophication. Farming and environmental pollution. New Zealand has had a reputation for being ‘clean and green’ – a country of environmental beauty. Compared to many countries in the world, this is true. However, it’s becoming apparent that New Zealand has an environmental pollution problem. An OECD (Organisation for Economic Co-operation and Development) report (2007) describes deterioration in water and air quality in New Zealand – due, in part, to agriculture.
Water quality Water quality describes the condition of water and includes its chemical, physical and biological characteristics. Standards developed for water quality relate to the suitability of water for a particular purpose, for example, the water quality needed for healthy ecosystems (lakes, estuaries and rivers), human recreation (such as swimming) and drinking. Water pollution Concerns have been raised about the effect of intensification of farming on water quality. Eutrophication Nutrients are carried into lakes, rivers and estuaries. Toxic water Erosion and water Metadata. Fonterra climate change. A diary farm is not greenhouse gas neutral. New Zealand farming and climate change. How dairy farms contribute to greenhouse gas emissions. U.S. Department of Agriculture (USDA) scientists have produced the first detailed data on how large-scale dairy facilities contribute to the emission of greenhouse gases.
This research was conducted by Agricultural Research Service (ARS) scientists at the ARS Northwest Irrigation and Soils Research Laboratory in Kimberly, Idaho. ARS is USDA's principal intramural scientific research agency, and these studies support the USDA priority of responding to climate change. ARS soil scientist April Leytem led the year-long project, which involved monitoring the emissions of ammonia, carbon dioxide, methane and nitrous oxide from a commercial dairy with 10,000 milk cows in southern Idaho.
Concentration data was collected continuously for two to three days each month, along with air temperature, barometric pressure, wind direction and wind speed. 6. – Farming and the environment. Loss of biodiversity Many of New Zealand’s tens of thousands of native species are not found anywhere else in the world. More than 50 species of bird are known to have become extinct since the arrival of humans, and an unknown number of invertebrate animals and plants have also been lost and continue to decline. In 2007 there were 2,788 species (including birds, bats, fish and plants) listed as threatened. The establishment and expansion of farms, orchards, and vineyards – with their exotic plants and animals – have been key drivers of the land clearance and changing patterns of habitat that have led to diminishing biodiversity.
Agricultural activities destroy the habitats of some species and create habitats for other, usually introduced, species. Building biodiversity Proponents of organic farming believe that a holistic approach to production, and not using synthetic fertilisers and pesticides, will benefit not only consumers of organic produce, but also the farm environment. Reducing agricultural air pollution risks. Dairy Farming and Air. Pugging and compaction. Pugging and compaction leave soils less productive. High stock densities combined with prolonged rainfall leave Waikato region soils vulnerable to pugging and compaction. This can be minimised by careful stock and land management. On this page: What is pugging? , What is compaction? When stock intensively trample wet soil, the soil aggregates are broken down, and spaces (pores) in the soil are reduced. Pugging causes: poor drainage – the soil will stay softer and wetter making it more susceptible to further puggingpoor plant growth – a reduction in pasture yieldgreater fertiliser requirements more topsoil and contaminant runoff to waterways.
Soils become compacted when under pressure from machinery (such as tractors or haulers) or livestock. Areas with high water tables (for example Hauraki, Netherton and Te Kowhai), clay soils or intensive stocking rates are at higher risk of pugging and compaction. Farming is very important to the Waikato region's economy. Soil Compaction and Pugging on Dairy Farms. Water conservation & Effluent Management. Managing farm nutrients. Managing nutrients carefully can save you money and improve farm decision-making. Together with soil test results, you can use a nutrient budget to assess farm fertiliser requirements, targeting nutrients where you most need them. Better nutrient management will also reduce fertiliser losses to waterways, protecting water quality and stream life. On this page: Nutrient budgets can save you money, All about nutrient budgets, Nutrient budgets made easy, Find out more The average dairy farm has about $425,000 worth of nutrients in its topsoil.
Fertiliser is the largest expense for many farm businesses. Around 30 percent of North Island dairy farms have twice the level of soil nutrients needed for pasture growth. Nutrient budgets are like financial budgets. A nutrient budget allows you to identify nutrient inputs to the farm, such as: fertiliserpurchased feedclover nitrogen (N) fixationeffluent. It also allows you to identify where nutrients go off the farm (outputs), such as: Fertiliser use and the environment Aug06. Methane emissions | Agricultural greenhouse gases. Measuring methane emissions from flocks of free-ranging sheep. Image - F Kellihier Agriculture The release of methane gas from ruminant livestock (sheep and cattle) amounts to almost 1/3 of New Zealand's greenhouse gas emissions, and it is the largest contributor. Methane also accounts for over 40% of all emissions in terms of global warming potential. Measurements of methane emission rates on sheep and dairy cows have repeatedly shown that the variability of emissions between individual animals is large (e.g. for young sheep grazing the same pasture, emission rates varied from 9 to 35 g/day per sheep).
Johannes Laubach and Frank Kelliher of Landcare Research have developed micro-meteorological techniques for measuring paddock-scale rates of net methane emissions from herds or flocks of freely grazing animals. When applying these techniques, Johannes and Frank collaborate with AgResearch colleagues who make measurements on selected animals from the herd or flock under investigation. Dairy farming and water. 2. Protecting soil from stock damage. Herd homes, feed pads and stand-off pads. Why protect your soil? Soil structural damage can reduce pasture and crop yields and restoring structure can be an expensive and lengthy process. Under certain conditions, stock can cause significant damage.
Pugging is caused by stock when soil is so soft that hooves sink into it, compacting the soil and creating an uneven surface. Pugging is especially bad when the ground is wet after prolonged rain or irrigation and can be made worse by intensive stocking. Cows generally cause more damage than sheep or deer. Silt and clay loams are most susceptible to pugging as they hold more water and are made up of finer particles. What are the benefits of protecting your soil? Stock damage to soil is reduced, protecting the physical structure of the soil during wet periods. Herd homes, stand-off pads and feed pads help to prevent or minimise soil structural damage by stock. Herd homes are barns used to house and feed cows.
Minimising muck, maximising money: