Lecture 13b Nutrient Uptake

1
Lecture 13b Nutrient Uptake Sustainable
Agriculture

• A deficiency of an element makes it difficult or
  impossible for the plant to complete a vegetative
  or reproductive stage of development
• A deficiency can be prevented or corrected by
  supplying the element

Ikisan.com
2

• Soil pH affects nutrient availability
• In Minnesota P, Zn, Fe

3
Nutrient Uptake from soil to plant via root

• Movement to the roots
• 1) Root extension - exposure to soil and new
  supplies of nutrients - roots could contact 3 of
  the soil or nutrients in the soil.
• 2) Mass Flow
• water absorbed by the root creates a water
  deficit near the root,
• more water moves to the root carrying nutrients
  with the water.
• Important for nutrients in large quantities in
  the soil solution - N, K Ca

4
Nutrient Uptake

• 3) Diffusion - movement of nutrients due to an
  imbalance of concentration ( diffusion gradient)

biologycorner.com
blobs.org/science/diffusion
HPO4-
HPO4- HPO4- HPO4-
root random
thermal movement
5
Requirements for nutrient uptake b y plants

• Actively growing plants - anything that affects
  the metabolism of the plant will affect nutrient
  uptake
• Metabolic energy is required. Plant roots must
  be able to respire. Soils must have oxygen

6
Conditions required for Nutrient Uptake by plants

• 3) Root hairs are the most active points of
  nutrient uptake.
• 4) Process is selective - a carrier ion moves
  from plasmalemma across the plasma membrane into
  the outer space of the walls of the cells of the
  cortex and picks up a nutrient ion and moves back
  across the membrane.

7
Nutrient Uptake
outer space
NO3-
Carrier ion
NO3-
NO3-
K
Inner space
Free Space
Energy Required to move carrier across the
membrane
Plasma Membrane
8
Nutrient Uptake
H H
Ca
Root Hair
NO3-
HCO3-
Nutrient absorption results in increased acidity.
9
Sustainable Agriculture

• What is it? Or What isnt it!

10
Your Call

• What do you think Sustainable Agriculture should
  be?

11

• As it pertains to agriculture, sustainable
  describes farming systems that are capable of
  maintaining their productivity and usefulness to
  society indefinitely.
• Such systems must be resource-conserving,
  socially supportive, commercially competitive,
  and environmentally sound.

• Some terms defy definition. "Sustainab le
  agriculture" has it b ecome one of them?

12
1990 Farm Bill defined Sustainable Agriculture"

• Under that law, "the term sustainable
  agriculture means an integrated system of plant
  and animal production practices having a
  site-specific application that will, over the
  long term
• satisfy human food and fiber needs
• enhance environmental quality and the natural
  resource base upon which the agricultural economy
  depends
• make the most efficient use of nonrenewable
  resources and on-farm resources and integrate,
  where appropriate, natural biological cycles and
  controls
• sustain the economic viability of farm operations
  
• enhance the quality of life for farmers and
  society as a whole.
• Leopold Center for Sustainable Agriculture -
  http//www.leopold.iastate.edu/

13
What is Sustainable Agriculture?

• Conventional farmers, organic farmers, giant
  agribusiness companies, environmentalists all
  have varying views on what sustainable
  agriculture really means.
• Perhaps not for long or by 2012
• The Leonardo Academy, an environmental think tank
  in Madison, Wisc., is busy refereeing a debate
  over a new National Sustainable Agriculture
  Standard, under the guidelines of the American
  National Standards Institute.
• One outcome of this effort could be a new
  sustainable agriculture label stamped on food
  similar to the way some food is now marketed as
  organic. It could also create a system that
  rewards farmers for doing things like reducing
  the amount of nitrogen fertilizer they use.
• Source Jared Flesher - New York Times, July 7,
  2009.

14
fas.usda.gov
15
(No Transcript)
16
newfarm.org/depts/NFfield_trials/1003/carbonseques
t.shtml
17
The End