Quantitative results

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C O Na Mg Al Si S Cl K Ca

The study was supported by the Russian Foundation for Basic Research (no. 18-016-00129)

The salinization and land degradation processes in recretohalophyte(Tamarix sp.) plant communities 1V.V. Dokuchaev Soil Science Institute, Moscow, Russia

2K.A. Timiryazev Institute of Plant Physiology RAS, Russia3International Center for Biosaline Agriculture (ICBA) for Central Asia

and Caucasus, Uzbekistan

QRV.V. DokuchaevSoil Science Institute

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Soil and plant samples were sampled in the south of Aral-Caspian region

The aim of the study-Determine the chemical composition of soils under Tamarix in different plant communities- Characterize the specific features of excreted salts and their accumulation in Tamarix- Evaluate the effect of Tamarix as the habitat-forming factor

Methods

-Macromorphological and micromorphological studies (with an opticalmicroscope Olympus BX51).- The submicroscopic method with the use of scanning electron microscopeSEM JSC-6610LV with an X-ray microanalyzer INCAx-act to determine theelemental composition of pedofeatures and minerals of different sizes.- The chemical and physicochemical analyses were performed in the AnalyticalLaboratory of the Dokuchaev Soil Science Institute according to the routinemethods accepted in Russia (Vorob'eva 1998).- The analysis of water extracts from soils (1:5); from Tamarix (1:10)

Marina Lebedeva1, Elena Shuyskaya2, Kristina Toderich3, Tatiana Romanis1

Tamarix species are widespread in deserts, semi-deserts and steppes ofEurope, Asia and North Africa. Drought tolerance, ability to grow in saline soilsand high decorativeness make Tamarix species very promising for greening thedesert and semi-desert areas. Tamarix species grow on marginal lands withvarious salt content (19.29 - 58.97% in 5-10 cm soil horizons) and withstand adifferent content of toxic salts.

X 10 SEM X 100

Mosaic pattern of soil crust in desert soils related to it’s biogenic salinization under the canopy of Tamarix

The compacted desert crust with

rounded pores under the canopy of

Tamarix.

Salts in the biopores (thin

section, X N) in crust.

Quantitative results

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Na Cl

Quantitative results

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Na Cl

Chemical and mineralogical compositionof salt exreted by Tamarix (SEM)

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O Na S Cl Ca

Glauberite[4Na2Ca(SO4)2]

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C O Na Cl

Quantitative results

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Astrakhanite

(bloedite)

Na2Mg(SO4)2x4H2O

Сomparing the chemical composition of salts excretedby Tamarix and the composition of the soil salts, wewere obtained the following patterns: 1) Tamarixgrows in soils with different salt content and chemicalcomposition of salts (soda, chloride, sulfate-chloride orchloride-sulfate). 2) The content of salts excreted byTamarix is higher than that accumulated inside theplant; sodium chloride (halite) is predominant. 3)Whatever the chemical composition of solonchaks, theexcretion of chloride in Tamarix is higher than that ofsulphate. 4) Tamarix has a habitat-forming role indesert areas - it can salinize non-saline soils. That is,promote land degradation.

The chemical composition of salts in typical soils

Gleyic Solonchaks (pit 4)

Depth,

cm

Sum of

salts, %

Toxic

salts, %

Alkalinity,

meq/100 g soil

Cl- SO42- Ca2+ Mg2+ Na+ K+

СО32- НСО3 meq/100 g soil

0 – 5 32.703 32.41 20.24 29.76 204.94 256 3.75 3.70 485 1.32

5 – 9 2.347 2.32 3.04 3.80 21.36 10.6 0.42 0.50 34.9 0.81

45-60 0.513 0.53 0.45 1.83 2.58 2.88 0.48 0.16 6.77 0.13

Depth,

cm

Sum of

salts, %

Toxic

salts, %

Alkalinity,

meq/100 g soil

Cl- SO42- Ca2+ Mg2+ Na+ K+

СО32- НСО3 meq/100 g soil

0 - 2 0.045 0.12 no 0.31 0.03 0.20 0.22 0.13 0.11 0.15

2-7(10) 0.114 0.07 no 0.49 0.39 0.64 0.52 0.23 0.52 0.36

47-69 0.183 0.10 no 0.34 0.90 1.44 1.16 0.31 1.10 0.23

Arenosols (pit 7)

Tamarix grows in soils with different saltcontent and chemical composition of salts

Toxic salts in crust 0,1% – 58,9%

Depth,

cm

Sum of

salts, %

Toxic

salts, %

Alkalinity,

meq/100 g soil

Cl- SO42- Ca2+ Mg2+ Na+ K+

СО32-

НСО3- meq/100 g soil

0 - 0,1 58.971 57.61 2.2 3.20 205.80 665.6 19.50 143.50 755.4 0.88

0,1-

17(18) 1.735 1.07 no 0.31 9.67 16.72 9.37 1.93 15.18 0.28

30-49(50) 0.222 0.19 no 0.38 1.25 1.72 0.32 0.20 2.74 0.02

Mollic Gleyic Solonchaks (pit 6)

Tamarix ramosissima - crinohalophyte

Name and coordinate of research sites:1 - Kegeyli - N 42°46′13″ E 59°53′52″2 – Farm, 40-years Karakalspakan - N 42° 45′ 39,2″ E 059° 55′ 57,3″ 3 – Shortanbai - N 42° 36′ 44″ E 059° 28′ 15,4″ 4 - Shorkull – N 41° 28′ 17,8″

E 060° 09′ 00 ″5 – Zhanibek – N 49° 23′ 57,67″ E 04648′ 33,74 ″

Ions content in the topsoils, in photosynthetic shoots of crinohalophyte (Tamarix) and on their surface

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secreted salt plant

mg

/g D

W

K(+)

Na(+)

Ca(+)

Mg(+)

Cl(-)

SO4(2-)

The amount of excreted salts in Tamarix is higher than that inside the plant’s shoots. The ratio

between anions and cations in decreasing order: Cl > SO4 and Na > K > Ca > Mg

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Pit 4 Pit 6

Cl/S

O4

soil 0-5cm

soil 5-15cm

plant

secreted salt

The ratio of Cl / SO4 in solonchaks (pits 4 and 6)