Amaranth (Amaranthus spp.)

Amaranth is one of the most interesting plants for soil restoration, as it combinesvery fast growth, huge biomass, powerful root system and the ability to absorb some heavy metalsUnlike alfalfa or fireweed, amaranth is not a perennial, but it can produce a large amount of green mass in a single season.

Several species of amaranth are being studied as promising plants for the phytoremediation of cadmium, lead, zinc, copper, nickel, and arsenic. However, the effectiveness varies greatly depending on the amaranth species, the soil, and the specific pollutant.mdpi.com)

Main advantages

Property	Meaning
Very fast growth	Covers the soil quickly
Large biomass	High potential for removing contaminants during harvesting
Deep root system	Improves soil structure
Drought resistance	Suitable for hot areas
Heat resistance	Grows well in summer
Large leaves	High photosynthetic activity
Rapid accumulation of organic matter	Improves the soil after the cycle is completed
Good compatibility with microorganisms	Active rhizosphere

1. Root system

Amaranth has:

powerful taproot;

many lateral roots;

a large number of root hairs.

This allows him to:

penetrate deeper than many annual crops;

use water from lower horizons;

loosen compacted soil;

create channels for the following crops.

2. High biomass

One of the main advantages of amaranth is the huge amount of green mass.

This is especially important in phytoextraction.

For example:

Plant A has accumulated 100 mg of metal/kg biomass - 1 ton = 100 g of metal.

Plant B accumulated 40 mg/kg but biomass is 8 tons = 320 g of metal.

This is why amaranth sometimes turns out to be more effective than rare hyperaccumulators.

3. What metals can it accumulate?

Pollution	Potential
Cadmium	high
Zinc	high
Copper	average
Nickel	average
Lead	limited
Chromium	limited
Arsenic	is being studied
Mercury	short

The best results are usually achieved by:

With

4. Cadmium

This is one of the most promising uses of amaranth.

He is capable of:

actively absorb cadmium;

transfer it to the above-ground mass;

form a large biomass;

tolerate moderate pollution.

This is why amaranth is often considered as an alternative to mustard.

5. Zinc

Zinc is an essential trace element.

At elevated concentrations, amaranth is capable of:

actively absorb it;

partially remove from the soil;

maintain good growth.

6. Copper

Copper is extracted worse,

but due to the huge biomass, the total copper removal can be quite high.

7. Lead

The situation here is different.

Lead:

poorly soluble;

poorly transported;

often remains in the roots.

Therefore, amaranth is not considered the best plant for Pb.

The most rational:

amaranth + biochar + phosphates + liming + turf grass.

8. Oil

Amaranth itself does not "eat" oil.

However, its root system:

saturates the soil with oxygen;

stimulates bacteria;

supports the mushroom network.

Therefore, it can be used for:

diesel;

light petroleum products;

some PAHs.

9. Radionuclides

Following the Chernobyl nuclear accident, various crops, including amaranth, were studied as potential accumulators of cesium and strontium. Results depend on the species, soil, and potassium content, so amaranth should only be used for such purposes within the framework of a specialized radiological project.

10. Soil improvement

Amaranth:

✔ improves structure

✔ increases porosity

✔ creates organic matter

✔ stimulates microorganisms

✔ protects the surface

✔ Reduces erosion

11. Drought resistance

Amaranth tolerates heat much better than:

oats;

wheat;

rye;

barley.

Therefore, it is of interest to:

Southern Europe;

Morocco;

Western Sahara (if water is available at the rooting stage);

steppe zones.

12. Restrictions

Amaranth does not like:

overwatering;

strong shading;

very acidic soils;

severe salinization.

13. Use after phytoremediation

If amaranth was grown in a contaminated area,

it cannot be used:

as food;

for oil production;

for flour;

for cereals;

for medicinal products.

All biomass is considered potentially contaminated and must be disposed of in a controlled manner.

Amaranth and other plants

Plant	The main advantage
Amaranth	Huge biomass, fast growth, Cd and Zn extraction
Alfalfa	Nitrogen fixation, deep roots, soil restoration
Fireweed	Pioneer of succession, restoration of disturbed lands
Mustard	Rapid extraction of Cd and Zn
Sunflower	Large biomass, water purification and some metals
Iva	Perennial tree crop, water interception, stabilization
Poplar	Rapid growth, dealing with contaminated groundwater
Miscanthus	Very high biomass, soil protection and stabilization
Industrial hemp	Fast growing, strong root system, being studied for extracting a range of metals and restoring soil structure

Prospects for the DREVO project

For large-scale land reclamation, a combination of plants with different functions appears particularly promising:

Amaranth— rapid accumulation of biomass and partial phytoextraction of cadmium and zinc.

Alfalfa— restoration of soil biology and the nitrogen cycle.

Industrial hemp- soil structuring, high biomass and additional phytoextraction.

Miscanthus- long-term stabilization of the surface and accumulation of organic matter.

Iva- deep root system and control of water regime.

Fireweed— restoration of natural succession and support of biodiversity.

This multi-layered approach is usually more effective and sustainable than using a single "generalist" plant, as different species perform complementary functions at different stages of ecosystem restoration.