specific consolidation works have been done, samplings will be planted. From the
assortment of species recommended, one species will be chosen, obviously most
suitable for stationary conditions. In particular, nitrogen-fixing species such as
acacia and alder are used in these cases (Mishra et al. 2017).
Very rarely, to achieve landscape effects, two-species combinations are used. The
density of the crops will be 0.3–1 m  2–3 m; the lowest density will be for acacia
plantations (0.8–1 m  2–2.5 m), and the highest for the plantations in the white
buckthorn (0.3–0.5 m  2–2.5 m). Preplanting or concomitant planting is highly
recommended for the prevention of erosion, especially by using perennial lump for
greening the slopes.
Fertilization and finishing are just as important for trees as for grasses and
legumes. If deficiencies and pH are not corrected at the beginning and maintained
at normal levels, tree growth will be poor. After many years, the trees will root deep
enough to provide nutrients in the necessary quantities, but poor initial growth can
lead to tree death through vandalism, due to animals or competition with the
surrounding vegetation. If the stock of fertile soil from planting is well fertilized
and yields nutrients for the first year, the main care will be given for the second and
third years. The limiting nutrients will be, as in the case of herbs, nitrogen and
phosphorus.
The Accompanying Vegetation Since trees are planted at low density, much of the
land remains unprotected and then a vegetal carpet can be important. This is not
necessary if the terrain is flat, but in slopes exposed to erosion, the vegetal mat
becomes essential. It can be made from a mixture of grasses with legumes or only
legumes; the latter are also valuable by fixing the nitrogen. But the vegetable mat
will compete for nutrients and water with young trees and even for light if the trees
are very small. Thus, the grass species must be carefully chosen, and the seed rate
should be very small, much lower than in the meadows.
Even so, it may be necessary for vegetation to be combated around the trees by
cutting or herbicide in the second and third years. Such works are common for forest
plantations on eroded land, and other specific maintenance works will be added
depending on the characteristics of the landfill (Rana and Maiti 2018).
4.11 Biological Reclamation of the Mining Waste Deposits From
the Exploitation of Nonferrous and Precious Metal Ores
Mining, nonferrous and precious metal mining, underground or underground,
produces two main types of waste: tailings mines and tailings ponds, to which the
(sterile) materials can be added for quarries. From a physical point of view, mine
tailings and flotation tailings are different. Mining waste is a complex mixture of
coarse parts, mostly over 5 cm in diameter. They are stable, but, unless they have a
high proportion of fine material, they will be extremely permeable and dry, with a
very low water retention capacity.
4 Advanced Technologies for Ecological Reconstruction and Bioremediation of. . .
117
assortment of species recommended, one species will be chosen, obviously most
suitable for stationary conditions. In particular, nitrogen-fixing species such as
acacia and alder are used in these cases (Mishra et al. 2017).
Very rarely, to achieve landscape effects, two-species combinations are used. The
density of the crops will be 0.3–1 m  2–3 m; the lowest density will be for acacia
plantations (0.8–1 m  2–2.5 m), and the highest for the plantations in the white
buckthorn (0.3–0.5 m  2–2.5 m). Preplanting or concomitant planting is highly
recommended for the prevention of erosion, especially by using perennial lump for
greening the slopes.
Fertilization and finishing are just as important for trees as for grasses and
legumes. If deficiencies and pH are not corrected at the beginning and maintained
at normal levels, tree growth will be poor. After many years, the trees will root deep
enough to provide nutrients in the necessary quantities, but poor initial growth can
lead to tree death through vandalism, due to animals or competition with the
surrounding vegetation. If the stock of fertile soil from planting is well fertilized
and yields nutrients for the first year, the main care will be given for the second and
third years. The limiting nutrients will be, as in the case of herbs, nitrogen and
phosphorus.
The Accompanying Vegetation Since trees are planted at low density, much of the
land remains unprotected and then a vegetal carpet can be important. This is not
necessary if the terrain is flat, but in slopes exposed to erosion, the vegetal mat
becomes essential. It can be made from a mixture of grasses with legumes or only
legumes; the latter are also valuable by fixing the nitrogen. But the vegetable mat
will compete for nutrients and water with young trees and even for light if the trees
are very small. Thus, the grass species must be carefully chosen, and the seed rate
should be very small, much lower than in the meadows.
Even so, it may be necessary for vegetation to be combated around the trees by
cutting or herbicide in the second and third years. Such works are common for forest
plantations on eroded land, and other specific maintenance works will be added
depending on the characteristics of the landfill (Rana and Maiti 2018).
4.11 Biological Reclamation of the Mining Waste Deposits From
the Exploitation of Nonferrous and Precious Metal Ores
Mining, nonferrous and precious metal mining, underground or underground,
produces two main types of waste: tailings mines and tailings ponds, to which the
(sterile) materials can be added for quarries. From a physical point of view, mine
tailings and flotation tailings are different. Mining waste is a complex mixture of
coarse parts, mostly over 5 cm in diameter. They are stable, but, unless they have a
high proportion of fine material, they will be extremely permeable and dry, with a
very low water retention capacity.
4 Advanced Technologies for Ecological Reconstruction and Bioremediation of. . .
117