Factors Affecting Nitrates

1
Unit

• Factors Affecting Nitrates
• in Groundwater

.
2
Objectives
1. Examine the processes of the nitrogen cycle.
2. Identify the source for most chemical nitrogen
fertilizers.
3
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.
4
Terms
- Nitrification - Nitrite - Nitrogen
cycle - Nitrogen fixation - Nutrients -
Root zone
- Ammonium fixation - Ammonium nitrogen -
Available nutrient - Denitrification - Leaching
5
How the nitrogen cycle works?
6
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.
7
- 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.
8
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.
9
Nitrogen Cycle
10
Where do chemical fertilizers come from?
11
Chemical fertilizers
- are found in many forms and types.
- Fertilizers are found in solid and aqueous
forms.
- Aqueousliquid solutions, ex. Aqua ammonia, 28
liquid nitrogen
12
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.
13
Fertilizer Pattern
-The numbers follow the pattern NPK.
- 20223 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.
14
Nitrogen Compounds
15
NITROGEN REACTIONS IN THE SOIL
16
How does the use of agricultural fertilizers
create potential for groundwater contamination?
17
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.
18
Nitrates
B. The return of nitrates includes leaching
through the soil into the groundwater.
C. Nutrients are elements needed by plants.
19
How can the farmer increase yield while reducing
environmental risk using chemical nitrogen
fertilizers?
20
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.