The publication of this Handbook was supported by the Russian Federation


P.S. Truskavetsky and V.P. Tkach (Ukraine)



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P.S. Truskavetsky and V.P. Tkach (Ukraine)
A soil phytomelioration system is a combination of  measures for rapidly improving salt-affected soils 
by including certain ameliorative crops into crop rotations. Phytomelioration is the most profitable 
biological measure for sustaining and increasing soil fertility in both agroecological and economic 
senses. The costs of  phytomelioration are 5-10 times lower than those of  chemical amelioration.
The efficiency of  phytomeliorative measures is determined by the natural influence of  plants that 
is one of  the key factors of  soil formation (biological factor). The efficiency of  phytomeliorators 
increases in the following order: annual leguminous crops – perennial cereal crops – perennial 
leguminous crops – grass mixtures in crop rotations – long-term perennial grass mixtures.
A lesser, but still significant positive effect on soils is achieved by growing winter cereals, because of  
their dense and uniformly spread root systems. The phytomeliorative effectiveness of  winter cereals 
is quite close to that of  perennial grasses due to their their ability to suppress weed growth and the 
large volume of  root residues. The soil-protective efficiency of  agricultural crops increases in the 
following order: summer cereals – pulses – winter crops – annual grasses – biannual leguminous 
crops – perennial grasses.
Planting and sowing salt-resistant plants on saline and alkaline soils encourages their gradual 
desalinization and a gradual improvement of  their properties. It is advisable to use phytomelioration 
in combination with agrotechnical and engineering measures for improving the ameliorative state 
of  salt-affected soils.
As a result of  the selection of  plant species through breeding and crossing, some promising species 
and ecotypes of  plants have been obtained, which can be used as bio-ameliorators on soils that 
have undergone secondary salinization and soils irrigated by saline water. Promising plant species 
include the following: Suaeda arcuata, Suaeda acuminata, Atriplex cana, Atriplex canescens, Climacoptera 
crassa, Bassia hyssopifolia, Salicornia herbacea, Kochia scoparia, Glycyrrhiza glabra, Artemisia halodendron, etc.
Some sun-tolerant crops (e.g., Melilotus albus) have deep root systems that can loosen a dense saline B 
horizon. The decomposition of  plant litter on the surface supplies the organic matter and nutrients 
(nitrogen, potassium, calcium, etc.) to soil. Moreover, carbon dioxide produced by the process of  
decomposition reacts with soda and converts it into less toxic sodium bicarbonate.
Biological methods of  soil desalinization are recommended for use on moderately and strongly 
saline loamy sands and loams with a chloride salinity of  less than 0.6. The effect of  planting salt- 
tolerant and sun-tolerant crops is most pronounced on improved pastures on poor soils in the south- 
east of  Russia, Kazakhstan, India and Argentina, in particular, on salt-affected floodplain soils. 
Phytomelioration is an ecologically harmless primary or secondary measure for the improvement 
of  alkaline soils [11].
Almost all tree species of  temperate regions are unable to grow on salt-affected soils that contain 
toxic soluble salts. Such tree species are unable to naturally colonize such soils and fail to survive if  
artificially planted. This is explained by the fact that tree species need large root zone that is free 


49
Chapter 4.The rational use of saline and alkaline soils (with examples from Ukraine) 
from salts. Planted trees die even if  soluble salts occur at a depth of  1.5-2 m. Therefore, sustainable 
forestry is a particularly difficult challenge of  salt-affected soils.
A distinct relationship between the type and degree of  soil salinization and the growth and survival 
rates of  different tree and shrub species has been demonstrated by studies conducted in the G. M. 
Vysotsky Ukrainian Research Institute of  Forestry and Forest Amelioration.
Analysis and synthesis of  data on the growth of  tree and shrub species on soils containing different 
salt concentrations allow species to be grouped according to their tolerance to excessive salt 
concentrations as follows:
•  Salt-tolerant species: Tamarix ramosissima, T. tetrandra and T. pallasii;
•  Strongly salt-resistant species: tree - Elaeagnus angustifolia, shrubs - Lonicera tatarica, Ribes aureum 
and Cornus sanguinea;
•  Salt-resistant species: in forest-steppe and true steppe, trees – Quercus robur, Pyrus pyraster, Acer 
campestre, A. tataricum and Ulmus laevis; shrubs – Crataegus spp. and Rhamnus cathartica; in dry 
steppe - Robinia pseudoacacia, Gleditsia sp., Ailanthus sp., Styphnolobium japonicum, Fraxinus angustifolia 
and Thuja sp.; under favourable soil moisture conditions - Populus alba and P. bolleana; to a 
lesser degree fruit trees such as Prunus armeniaca, Morus alba, Cydonia oblonga and Prunus cerasifera; 
shrubs - Amorpha fruticosa, Ligustrum sp. and Caragana arborescens.
•  Weakly salt-resistant species: Fraxinus excelsior, Pinus spp. (including P. nigra subsp. pallasiana, 
P. pinaster and to lesser degree P. sylvestris), Juniperus spp. (J. virginiana and J. sabina), Populus spp. 
(P. nigra and P. deltoides) and Acer negundo.
•  Salt-intolerant species: all other species.
The presence of  carbonates (MgCO
3
) and chlorides in soil solution presents the most serious threat 
to tree health. It has been statistically proven that the growth of  different tree and shrub species is 
only significantly correlated with the depth of  occurrence of  toxic salts, while the influences of  all 
other properties of  saline soils are insignificant.
Earlier studies have shown that the water of  soil solutions containing toxic concentrations of  
soluble salts is unavailable for trees. The water availability for trees also decreases with an increase 
in soil alkalinity and total mineralization (salinity) of  the groundwater. Therefore, soils that are 
well-moistened by salt-containing waters remain physiologically dry.
Soils are subdivided by their respective salt concentrations and moisture contents into the following 
categories of  suitability for agroforestry (agro-sylviculture): fully suitable, partially suitable, 
conditionally suitable, suitable for salt-resistant shrub species and totally unsuitable.
The  main  agrotechnical  and  ameliorative  measures  practiced  in  agroforestry  on  salt-affected 
soils include the following: deep ploughing, wide spacing, using salt-tolerant species and careful 
management of  soils and plantations. The sylvicultural quality of  soils within dry regions cannot 
be significantly improved by applications of  gypsum, mulch, organic and mineral fertilizers [12, 
18].


50
Soil salinity manаgement manual | Part I.Soil salinity management in the Eurasian Region 
4.6. Synergetic amelioration complexes

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