Essential plant nutrients

Question 1

How do we know that a nutrient is essential?

Answer 1

1. Plants cannot grow and develop without them
2. Nutrient plays a critical role in:
   - directly involved in metabolism as an essential plant constituent
   - or required for a distinct metabolic step
3. the function of the element cannot be replaced by another element
4. deficiency symptoms can be corrected only by supplying the deficient nutrient

Question 2

What are the 17 essential nutrients?

Answer 2

Organic nutrients: C, H, O
Mineral nutrients:
- Primary Macro: N, P, K
- Secondary Macro: Ca, Mg, S
- Mironutrients: B, Cl, Cu, Fe, Mn, Mo, Zn, Ni
- Essential for some plants?: Co, Na, Si, V
( C HOPKN’S CAFE ManaGed By My {Mn} Cousins {CuZn} Mo, Nigel, and Clyde)

Question 3

What is soil pH and what does it affect

Answer 3

Degree of acidity or alkalinity in the soil solution.
Influences:
- soil chemistry and nutrient availability
- soil microbiology
- plant adaptation and growth

Question 4

Name and briefly describe three ways N is added to the soil

Answer 4

1. Biological N Fixation
   - Rhizobium and legumes- symbiotic relationship
   - Organisms are species specific
   - Process is inhibited when mineral N is present
2. Mineralization
   - Conversion of organic compounds to inorganic (minerals)
   > N released by breakdown of soil organic matter, and plant and animals residues
3. N fertilizer
   - Industrial N fixation
   > Anhydrous ammonia, urea, ammonium nitrate, ammonium sulfate

Question 5

Leaching

Answer 5

the movement of nitrate ions out of the rooting zone in percolating water

Question 6

Denitrification

Answer 6

the loss of gaseous N2O and N2 gases from waterlogged soils

Question 7

Ammonium fixation

Answer 7

NH4+ can become fixed in the lattice structure structure of clays, similar to K+

Question 8

Volatilization

Answer 8

gaseous loss of ammonia, NH4+ can be converted to NH3 in alkaline soils
- this is a significant loss pathway for urea and anhydrous ammonia

Question 9

Immobilization

Answer 9

plant or microbial uptake NH4+ or NO3- –> organic N