Nitrogen, phosphorus, and potassium are the three major nutrient pollutants found in agricultural runoff. These nutrients can cause eutrophication, which is a process that leads to excessive plant growth and oxygen depletion in water bodies.

Eutrophication is primarily caused by excess nitrogen and phosphorus, which can come from agricultural runoff, sewage discharge, and other sources. These nutrients stimulate excessive plant growth, leading to oxygen depletion and other water quality problems.

Contour farming, cover cropping, and buffer strips are all BMPs that can help reduce nutrient pollution from agricultural runoff. Contour farming helps control erosion, cover cropping helps absorb nutrients, and buffer strips help filter pollutants before they reach water bodies.

Synthetic fertilizers are the primary source of nitrogen pollution in agricultural runoff. These fertilizers are applied to crops to increase yields, but excess nitrogen can be lost through runoff and leaching, contributing to water quality problems.

Nutrient pollution can affect various water quality parameters, including dissolved oxygen, pH, and turbidity. Excess nutrients can lead to algal blooms, which can deplete dissolved oxygen and cause pH fluctuations. Turbidity can also increase due to suspended solids and algae.

Nitrification is the process by which nitrogen is converted from organic forms to inorganic forms in water bodies. This process is carried out by bacteria and involves the conversion of ammonium to nitrite and then to nitrate.

Methemoglobinemia is a potential health risk associated with nitrate contamination in drinking water. Nitrate can be converted to nitrite in the body, which can interfere with the oxygen-carrying capacity of blood, leading to methemoglobinemia.

Erosion is the primary mechanism by which phosphorus is lost from agricultural fields. Phosphorus is strongly bound to soil particles, and when soil is eroded, phosphorus is carried away with it. This can lead to phosphorus pollution in water bodies.

Terracing, strip cropping, and no-till farming are all BMPs that can help reduce phosphorus pollution from agricultural runoff. Terracing helps control erosion, strip cropping helps slow down runoff, and no-till farming helps keep soil in place.

Animal manure is the primary source of phosphorus pollution in agricultural runoff. Manure contains high levels of phosphorus, and when it is applied to fields in excess or not properly managed, it can be lost through runoff and leaching, contributing to water quality problems.

Phosphorus pollution in water bodies can lead to eutrophication, fish kills, and coral reef degradation. Eutrophication is a process that leads to excessive plant growth and oxygen depletion, while fish kills can occur due to low dissolved oxygen levels. Coral reef degradation can also occur due to the accumulation of phosphorus, which can lead to algal blooms and the smothering of corals.

Leaching is the primary mechanism by which nitrogen is lost from agricultural fields. Nitrogen is highly soluble and can be easily lost through leaching, especially in sandy soils or areas with high rainfall. This can lead to nitrogen pollution in groundwater and surface water.

Split application of fertilizers, use of nitrification inhibitors, and cover cropping are all BMPs that can help reduce nitrogen pollution from agricultural runoff. Split application helps reduce the amount of nitrogen applied at once, nitrification inhibitors slow down the conversion of ammonium to nitrate, and cover cropping helps absorb nitrogen.

Atmospheric deposition is the primary source of nitrogen pollution in urban runoff. Nitrogen oxides from vehicle exhaust and industrial emissions can be deposited on surfaces and washed off by rain, contributing to nitrogen pollution in urban waterways.

Nitrogen pollution in water bodies can lead to eutrophication, fish kills, and climate change. Eutrophication is a process that leads to excessive plant growth and oxygen depletion, while fish kills can occur due to low dissolved oxygen levels. Nitrogen pollution can also contribute to climate change by releasing nitrous oxide, a potent greenhouse gas.