Unit Factors Affecting Nitrates in Groundwater .
Objectives 1. Examine the processes of the nitrogen cycle. 2. Identify the source for most chemical nitrogen fertilizers.
Objectives 3. Relate the agricultural use of nitrogen fertilizer to the potential for groundwater contamination. 4. Identify best management practices for increasing nitrogen efficiency and maximizing economic yields while reducing environmental risks.
Terms - Nitrification - Nitrite - Nitrogen cycle - Nitrogen fixation - Nutrients - Root zone - Ammonium fixation - Ammonium nitrogen - Available nutrient - Denitrification - Leaching
Nitrogen Cycle -is a continual exchange of nitrogen between biological and environmental elements. - It is a continual process that replaces necessary nutrients and occurs through many stages. -Ammonium fixation is the step where nitrogen is tied to the clay structures in soil.
- Nitrification -is the changing of ammonium to nitrite, first product formed from ammonium, to nitrate. -The nitrate then undergoes Denitrification to reduce the nitrate to atmospheric nitrogen.
Nitrogen fixation -will later take the atmospheric nitrogen to form a product available to plants. - The nitrogen cycle will vary depending on environmental conditions. Water carries soil nutrients down through the process of leaching.
Chemical fertilizers - are found in many forms and types. - Fertilizers are found in solid and aqueous forms. - Aqueous—liquid solutions, ex. Aqua ammonia, 28% liquid nitrogen
Solid -granulated, powder forms, ex. Urea, ammonium nitrate a. The forms of fertilizers are manufactured for different uses. Ammonium nitrogen is a fertilizer commonly used in fertilizers. b. Chemical fertilizer formulas have a standard method of finding the amount of each component.
Fertilizer Pattern -The numbers follow the pattern N–P–K. - 20–2–23 fertilizer will contain 20% N, 2% P, and 23% K. - The plants need the fertilizer at the root zone, the depth of soil penetrated by roots. The plants will use available nutrients, the portion of any element that can be readily absorbed and assimilated by growing plants.
How does the use of agricultural fertilizers create potential for groundwater contamination?
Nitrates A. Nitrates that are above a natural level can lead to excessive nitrate levels in the water and other ecosystems. - Nitrate is used by plants and biological systems. That which is not used by the plants is returned via the nitrogen cycle.
Nitrates B. The return of nitrates includes leaching through the soil into the groundwater. C. Nutrients are elements needed by plants.
How can the farmer increase yield while reducing environmental risk using chemical nitrogen fertilizers?
Fertilizers - Fertilizers have various yield benefits while holding onto certain environmental risks. - Applying fertilizer closer to the growing season will normally improve yield and the nitrate has less time to leach prior to it being needed. - Over application will show decreased yield and increased environmental risk.