1. Measurement of soil redox potential
The most frequently occurring redox species in the soil N S Fe Mn
Aerated soil : oxidative conditions
Soil covered with water: reductive condition

2. Measurement of soil redox potential
Related to the concentration of oxidized and reduced substances
suitable for characterizing the extent of reducing (or oxidizing) nature of the medium (-0.35V V)
Why is long-term reducing condition harmful?

3. Movement of nutrients into the soil in the root surface
Movement of nutrients in the root surface
Movement of nutrients into the soil in the root surface
interception
mass flow
diffusion

4. Movement of nutrients into the root surface

5. The ratio of cations
Antagonism, Ehrenberg law
Ideal soil:
Ca: 65-80%
H: max 10%
K:4-8%
Mg: 15-25%
Na: max 1%

6. nutrient uptake through leaves
through stomata
Or by active transport

7. Plant nutrient uptake
CO2

8. Relationship between nutrient supply and the yield
Liebig law
Plant growth is determined by the minimum nutrient available to it.
If one growth factor is limited plant growth is also limited, even if all other Nutrients are Adequate of
As the capacity of the barrel is limited by the shortest stave

9. Mitscherlich law
yield
Nutrient supply

10. Mitscherlich law (diminishing response curve)
yield
Fertilizer Doses
with successive applications of fertilizers the yield increments become progressively smaller.

11. The effect of nutrient supplyon the quality of the crop
HoHow can quality can be characterized?
The effect of : N
P, K, B

12. N in soil total N: 0.02-0.4 % N forms in the soil, there ratio
N forms available for plants

13. N in soil soil enrichment processes: N fixation fertilization
Sources and losses (Fig on the board)
soil enrichment processes:
N fixation
fertilization
organic manures
lightning
symbiotic bacteria (legumes) nad non- symbiotic
what is symbiosis

14. N in the soil (sources of loss)
. Maize yields for example:
approx. 8 tons / ha

15. N in the soil (sources of loss)
The concept denitrification
rate of denitrification loss

16. N in the soil (sources of loss)
Nitrate leaching depends on:
season
soil texture
leaching rate
(20-50kg / ha)
ammonia volatilization
fixation

17. N in the soil, N turnover
conversion of organic nitrogen forms to inorganic forms
Aminization, ammonification, nitrification
conversion of organic compounds to inorganic N forms
Immobilization
C/N ratio

18. Fertilizers, plants and animals
residues
denitrification
N fixation
using microorganisms
NO3-
nitrification
NH4+
( bacteria)