- iron is one of the 13 essential elements for plant growth, and is considered a micronutrient based on the concentration required for plant growth
- principle form of uptake: ionic forms (Fe2+, Fe3+)
- amount required for healthy plant growth: 100 ppm, dry soil matter
- soil conditions related to iron deficiencies:
- calcareous soils with low soluble iron
- waterlogged soil
- acid soil with excessive levels of manganese, zinc, copper and nitrogen
- sandy soils low in total iron
- peat & muck soils
- iron moves through soil primarily by diffusion
- soil factors that affect iron uptake by plants:
- soil test levels (available iron in soil)
- decomposition of organic matter
- low pH (acidic) increases plant uptake of iron
- high pH (basic) decreases plant uptake
- plant factors that affect iron uptake by plant:
- hybrid or variety of plant
- stage of growth
- interactions with other elements
- Zinc: excess zinc can induce an iron deficiency, particularly in those plants sensitive to iron
Roles of Iron in Plant Functions
- important component of many enzyme systems
- required component for NO3 (nitrate) and SO4 (sulfate) reduction
- required component for N2 assimilation and energy (NADP) production
- functions as a catalyst for chlorophyll production
- thought to be involved in root-tip meristem growth
- the plant and soil chemistry that involves iron is very complex and is still under intensive study