Barbu (Cleianu), Roxana –Mihaela (2025), „The Sahara of Romania” – The Southern Romanian Plain, Cunoașterea Științifică, 4:1, 44-57, https://www.cunoasterea.ro/the-sahara-of-romania-the-southern-romanian-plain/

 

Abstract

One of the most sensitive regions of the country – the south of the Romanian Plain – is starting to be renowned for the onset of desertification. The intensification of land degradation in this area was the result of both direct and indirect factors such as weather conditions, the fauna and flora, and last but not least the features of the relief. The augmentation of the processes that stimulate the degradation of the pedological resources and of life-supporting attributes are due to anthropogenic factors as well, which leads to unsustainable land exploitation by regional users on the precarious background created by global climate change. These factors are poverty, government policies, industrial activities, incorrect management of land use, deforestation, overgrazing, unsuitable farming and irrigation practices, misuse of chemical fertilisers.

At the same time, chemical and biological degradation processes take complex forms (pollution, the reduction of the biodiversity in certain ecosystems), which form the base of the onset of morphological and functional imbalances in the soil.

The methodology I used was the expert type, which relies on a qualitative approach and the analysis of the data, in which the research topic is correlated with on-site verified information.

Keywords: desertification, soil degradation, contaminated soil, climate change, Southern Romanian Plain

„Sahara României” – Câmpia Română de sud

Rezumat

Una dintre cele mai sensibile regiuni ale țării – sudul Câmpiei Române – începe să fie renumită pentru debutul deșertificării. Intensificarea degradării terenurilor în această zonă a fost rezultatul atât a factorilor direcți, cât și indirecți precum condițiile meteorologice, fauna și flora și nu în ultimul rând caracteristicile reliefului. Creșterea proceselor care stimulează degradarea resurselor pedologice și a atributelor de susținere a vieții se datorează și factorilor antropici, ceea ce duce la exploatarea nesustenabilă a terenurilor de către utilizatorii regionali pe fondul precar creat de schimbările climatice globale. Acești factori sunt sărăcia, politicile guvernamentale, activitățile industriale, gestionarea incorectă a utilizării terenurilor, defrișările, pășunatul excesiv, practicile agricole și de irigare necorespunzătoare, utilizarea greșită a îngrășămintelor chimice.

În același timp, procesele de degradare chimică și biologică iau forme complexe (poluare, reducerea biodiversității în anumite ecosisteme), care stau la baza apariției dezechilibrelor morfologice și funcționale în sol.

Metodologia pe care am folosit-o a fost de tip expert, care se bazează pe o abordare calitativă și pe analiza datelor, în care tema de cercetare este corelată cu informații verificate la fața locului.

Cuvinte cheie: deșertificare, degradare a solului, sol contaminat, schimbări climatice, Câmpia Română de sud

 

CUNOAȘTEREA ȘTIINȚIFICĂ, Volumul 4, Numărul 1, Martie 2025, pp. 44-57
ISSN 2821 – 8086, ISSN – L 2821 – 8086
URL: https://www.cunoasterea.ro/the-sahara-of-romania-the-southern-romanian-plain/
© 2025 Roxana–Mihaela BARBU (CLEIANU). Responsabilitatea conținutului, interpretărilor și opiniilor exprimate revine exclusiv autorilor.

 

„The Sahara of Romania” – The Southern Romanian Plain

Roxana–Mihaela BARBU (CLEIANU)[1]
roxanibarbu@gmail.com

[1] PhD student, University of Bucharest, Romania

 

Introduction

Climate change both globally and locally is a major concern with great impact on the geographical environment of all land masses and with major influence on the socio-economic activities including aspects of everyday life. In 1979 UN and WMO (World Meteorological Organization) created the International Council for Science (ICSU) which organized the first World Climate Conference. On this occasion the World Climate Research Programme – WCRP was launched. Later, in 1988, the Intergovernmental Panel on Climate Change – IPCC – began its activity. IPCC’s reports confirm the importance and scale of climate change, especially in connection to global warming. Starting with 2001 greater importance was given to sustainable development, a concept which had been the main topic of UN’s Conference on Environment and Development (Rio de Janeiro June 1992) where the Local Agenda 21 was adopted. The agenda, among other things, specified the duties of the National Meteorological or Hydrometeorological Services. These duties mainly referred to supplying data about climate change, issuing warnings about potential weather phenomena, evaluating fresh water resources and monitoring environmental pollution.

In recent times we have faced extreme natural phenomena. Some of these were natural, causing damages, casualties and modification to the geographical environment. Two examples are the flooding in Central and Eastern Europe in 2002 and 2005.

Most researchers state that we are in a climatic crisis due to global climate change. UN and WMO support this research in order to produce predictions to combat the negative effects of extreme natural phenomena. As such 1991-2000 was declared the International Decade for Natural Disaster Reduction. The International Strategy for Disaster Prevention and Reduction program was inaugurated in 2001. Since 2002 its main objectives has been to reduce the effects of natural disasters in mountain areas, raising concern for the need to reduce the effects of natural disasters and incorporatw said concerns in a sustainable development platform. WMO prioritizes, through its programs, meteorological and hydrological phenomena which are risk factors. Some of these programs are: World Meteorological Monitoring, Atmospheric Research and Environment Programme, World Climate Programme.

UNCCD – United Nations Convention to Combat Desertification was written and forwarded for approval to the UN in 1994. Romania became a signatory in 1997 through the National Law no. 629, which stated that Romania is forced to approach issues related to the prevention and combating of soil degradation, avoiding the effects of droughts and opposing the desertification process. In many classifications of risky natural phenomena, desertification is defined as a phenomenon of ecological vulnerability to degradation which is strongly related to other natural and anthropic factors. Desertification cannot be separated form climatic conditions which are its major contributors. It, however, cannot be reduced to the increase of pluviometric deficits combined with higher temperatures. Desertification is a complex process with complex factors driving it. It is however possible to say that longer drought periods are the main factors for its intensification in a semiarid climate.  The notion of desertification started to be used in the 1980s, when the term was given the meaning of loss of the ecosystems’ capacity to regenerate in semi-arid regions, being replaced by proper deserts.  More recently it is recognized that desertification is more complex. It involves the high variation of rainfall, reduction of the vegetation cover, increased drought periods, and disappearance of plant species, top soil erosion. UNCCD and WMO show that annually about 40000 km² additional lands are being exposed to desertification.

Soil degradation processes, and more precisely their intensity and extent originate in the migration inland from the shore of Mediterranean people in search of new land suitable for agricultural and pastoral activities to meet the demands of the increasing human population. The onset of the desertification phenomenon occurs gradually and in variable geographic conditions, the causes can also vary in terms of their importance, as well as the factors that determine the manifestation of this phenomenon, but the result is always the same in any scenario: the emergence of desertification and the transformation of bioproductive terrestrial ecosystems into ones that are weakly productive, since desertification is rather an extensive phenomenon and not a profound event. Extensive desertification is a rather rare phenomenon. In order to identify the factors that lead to the onset of degradation processes and of the desertification phenomenon, it is important to start from the fact that they appear as a consequence of complex combinations of factors which directly and indirectly conjugated influence climatic natural and anthropogenic factors. The main processes that precede desertification are deterioration of the physical, chemical and biological soil, deterioration or destruction of the vegetation cover concomitantly with an added significant reduction of available water resources.

The dynamics of the main processes of soil degradation that amplify the risk of desertification in the Southern Romanian Plain is given by the specificity of natural factors (increase in frequency and intensity of drought periods due to global warming)  represented by the elements of the natural environment, the concrete climatic conditions under which it takes place, the fauna and flora and also by the direct or indirect influence of anthropogenic factors on the characteristics of the soil, industrial activities, land use, inadequate agricultural practices, overgrazing, deforestation and, last but not least, poverty. Depending on the synergistic relationship between natural and anthropogenic factors in conjunction with the soil and lad degradation processes there are differences in vulnerability to desertification between different areas. Droughts that last a long time intensify soil degradation processes, which in turn create water deficit.

Given that the soil cover of this field is made up of a small number of genetic types of soil, in the future the use of pedological resources should take into account a sustainable agricultural exploitation, and particularly the extension of new areas into forestry. More importantly, lands should be dedicated to reforestation. An alternative to reforestation could be the erection of protective forest curtains especially around very vulnerable lands. Considering the characteristics of the landshaft in this area it is clear that the management of this national resource should focus on the intrinsic characteristics of the pedological units which constitute it. Such an approach would guarantee its conservation and sustainable exploitation. A matter of great importance would be the establishment of a complex monitoring system, inside of a pilot project, for the Southern Romanian Plain which tracks climate, soil conditions, vegetation, biodiversity and demographic pressure.

The manifestation of desertification (which is also found in the south of the Romanian Plain, where the aridity index (R) has a precipitation /evapotranspiration ratio (P/ETP) between 0.05-0.65) associated with physical, chemical, biological processes of soil degradation (direct or indirect processes caused by human beings, including anthropogenic climate change, expressed as long-term decrease or loss of at least one of the following: biological productivity, ecological integrity, value for people) is present in historical evidence from the last centuries that indicate three main epicentres due to the fragility of the environmental conditions: around the entire Mediterranean basin, the Mesopotamian region and the loess plateau of China, with serious and extensive damage to land and land use. Desertification is currently considered a major global problem affecting 2/5 of the land area and 20% of the Earth’s population.

The identification, classification and research of soil conditions in connection with the forms of degradation to which it is exposed and the risk of occurrence and spread of the complex phenomenon of drought – aridification – desertification in the southern part of the Romanian Plain – the Romanaţiului Plain, one of the areas at risk of complex degradation due both the climatic, edaphic and human factor, is one of the major issues to be addressed.

Fіgure 1. Map from the national strategy on desertification, 2008. Source: National strategy on limiting the effects of drought, online: http://оld.madr.rо/pagеѕ/ѕtratеgіе/ѕtratеgіе_antіѕесеta_updatе_09.05.2008.pdf

Climate variability and anthropogenic climate change, especially as a result of the increase of air temperature at the Earth’s surface as well as the evaporation process and the decrease of rainfall, must have played a role together with human activities, in causing the desertification of certain areas of land, such as the Southern Romanian Plain. The main human factors of desertification which interact with climate change are the expansion of arable land, unsustainable land management practices and increased pressure on land due to population and income growth. Poverty limits both the ability to adapt to climate change and the availability of financial resources to invest in sustainable land management.

Material and Method

The effects of climate change may be seen and felt clearly in the Southern Romanian Plain. Where once green grassland and forests lined the banks of the Danube, today strips of sand spread along the river. The affected area covers today more than 800 square kilometres and the 100,000 hectares between the cities of Craiova, Calafat and Corabia is called „The Sahara of Oltenia.” Before 1989, an irrigation system was put in place between Sadova and Corabia, to be used during dry spells, but after the revolution it was destroyed and the aridity increased.

In the south of the country, the driest area in Romania, temperatures reach 29 degrees Celsius in September – a full two or three degrees hotter than half a century ago. There are regions that do not see a drop of rain for months, and when the rain does come, it is a lot, but never enough to make its way deep down the soil. The air is dry. In spring, the wind carries away roofs, destroys trees and causes electric cuts, leaving entire city sections in darkness. The wind blows sand on crops, in villages, in the gardens and inside people’s lungs and even as far as the capital city, Bucharest, which is over 200 km away. It is the result of a combination of global warming and irresponsible agricultural policies.

In the 1970s and 1980s, the dictator Nicolae Сеaușеѕсu cut down forests and drained lakes, trying to promote large-scale farming. Ecologists, entrepreneurs and local politicians are now trying to stop the devastation currently in progress in the south of the country. Hardly anything can be cultivated in the sandy soil. Even unsolicited cereals like corn can hardly find any nutrients there.

In Romania, complex agricultural drought is a phenomenon of climate peril which determines the most serious consequences in agriculture. In their sixth national communication on climate change and their first biennial report (December 2013), the Romanian authorities estimated that the area subjected to desertification, characterised by dry, semi-dry or sub-humid dry climate, is around 30% of the total surface of the country and is mainly situated in Dobrogea, Moldova, the Southern Romanian Plain and the Western Plain. Founded in January 2019 to ensure a better observation of the vegetation in agricultural areas in Romania, the National Administration of Meteorology (ANM) uses Соpеrnісuѕ Glоbal Land Ѕеrvісе products.

The 2014-2020 Romanian rural development programme contains an agri-environmental package whose main target is desertification in Romania and is open to farmers in areas at high risk of desertification. The value of the subsidy is 125 EUR per hectare. In order to receive it, farmers have to commit to plant crops that are highly resistant to drought, to practice crop rotation, and maintain the farming to a minimum. Only farmers with less than 10 hectares of arable farmland are eligible.

It would be easy to dismiss the expansion of the desert in the south of the country as “natural”, but such an evaluation would be wrong. Leaving aside all the ample and complex causes of the climate crisis, the desertification in the south of the Romanian Plain has very well known causes, all of them connected to the political economy of transition. The irrigation system was dismantled during the process of privatisation, landowners then cut down forests to extend their farmland, which they used extensively so as to yield the maximum harvest, in an attempt to maximise profits.

Deforestation was done mostly illegally and it has gradually become an increasingly pressing problem in Romania in the last decades. This attitude to land has led to its progressive degradation, as it has absorbed excessive quantities of pesticides used in farming. The drought only exacerbated the existing problems in the agricultural sector which has been made dependent on the interests of big landowners eager for monoculture farming for reasons connected with exports.

The scientific community defines the soil as a living tri-dimensional natural body, with definable boundaries, which habitually interacts with the atmosphere, the lithosphere and the hydrosphere simultaneously, which, due to its organic and mineral constituents, determines the formation of horizons containing living matter that can sustain vegetation.

The important cause for the occurrence of the various negative processes of physical soil degradation is the long-term use of conventional technological systems which determined the degeneration of their physical, chemical and biological properties and ultimately of their productivity.

Soil acidification represents a process of chemical degradation that consists in changing the reaction of the soil (the pH) which records lower values ​​than normal. The natural washing (leaching) of the soils of the Earth’s wetland, in which there is not only a washing of the salts from the soil, but also of the bases of the adsorption complex, cannot be classified as a degradation process, their place being taken by H ions, which cause its acidification.

The causes of acidification are linked to unbalanced fertilization with physiologically acidic mineral fertilizers based on nitrogen, respectively ammonium nitrate and/or urea, which, through the absorption of cations rather than anions by plants, intensifies a process that naturally exists in the soil as a result of oxidation.

Another cause of the soil acidification (less widely spread in area, but increasingly more intense in conjunction with the increase of steelmaking activities, the processing of non-ferrous, petrochemical and electro-thermal metals that discharge emissions of SO2, SO3, SH2, NOx into the atmosphere) is acid rain (there are also cases of acid fog and acid snow), a name given by their very low pH value, which is around 2.4-3.

The decrease on the soil reactivity due to acidification may lead to the accumulation, the concentration and the mobilization of Al ions, with toxic effects on most plants in the spontaneous and the cultivated flora. The vulnerability of soils to acidification is generally determined by their buffering capacity. Soils with sandy texture, a low level of humus, reduced cationic exchange capacity, low base saturation, etc., are more vulnerable to this phenomenon. Its effects upon the soil and biodiversity are multiple: a reduction in the biological activity of the soil, altered chemical composition through the loss of K, Ca, Mg, Na etc. cations, and an accumulation of Al ions adverse to plant growth, the reduction of humus mineralisation, etc.

Soil contamination with pesticides has become an extremely sensitive matter due to on the one hand the expansion of intensive use of farmland, but also the increase in their range to total forms, with a view to eliminating weeds, diseases or pests, therefore endangering biodiversity to a great extent. Pesticides are usually substances made up of organic compounds with different water solubility, which start decomposing through various specific processes (hydrolysis, oxidoreduction, volatilisation, biodegradation, etc.), after having played their role. Organochlorine pesticides of the HCH and DDT type (whose use is currently banned) are difficult to decompose, their action in the soil being permanent.

The use of urban mud-based pesticides and irrigation with waste water from sewage treatment plants represent important in-puts through contamination mostly with heavy metals (Cu, Ni, Cr, Pb, Zn, Cd, Hg, Fe etc.) and various pathogens (Salmonella, Anthrax spores, etc.), and can have negative effects on the general condition of the soil as well as further implication along the trophic links of the ecosystems of life, acting as a pollutant [5].

The contamination of the soil with hydrocarbons (usually petroleum, oil produce and oil waste, natural gas, etc.) is a complex problem, resulting from the composition and the properties of the organic and inorganic compounds as well as quantity. Usually contamination is recorded in the top soil, as the soil acts like a chromatography column, where there is a stratigraphic redistribution of the components of the contaminating hydrocarbon.

In the case of petroleum, research shows the life of plants begins to be affected when there is more than 1 kg/m² in the soil, microbiological activity is intensified as a result of the development of specific microbial populations (nitrogen-fixing, denitrifying and sulfate-reducing bacteria) and in the case of natural gas leaks we can notice a lack of vegetation due to the absence of oxygen in the gaseous phase of soil, as it is used by the microflora in methane oxidation [8].

Through the release in the atmosphere of solid mineral particles and chemical compounds (sulphates, phosphates, iron oxides, ash, carbonates, etc.), as well as gaseous compounds (hydrocarbons, nitric oxide, carbon, sulphur, etc.), industrial activities may cause accumulation of heavy metals in the upper layers of the soil, a change in the reactivity of the soil and the level of base saturation (V).

Soil contamination with toxic elements/substances is the process by which chemical elements and/or substances as a result of anthropogenic activities. Their concentration determines a change in the proportion of the various chemical elements that can have a negative impact on the life of plants and the microbiological activity of the soil [5].

The premise of this process can usually be found in the extensive use of mineral fertiliser in modern intensive agriculture, its contribution being extremely important, but the problem is that together with it we may introduce into the soil chemical elements resulting from the production process in the form of heavy metals, cadmium being the most frequent.

N fertilisers are being used extensively in great quantities in agriculture as support for production growth, risking that the some of the administered quantity be levigated as nitrates and/or nitrites in underground water or lakes and thus creating the phenomenon called eutrophication; alternatively, they can be reduced and enter atmosphere as nitrogen or nitric oxide.

P fertilisers, frequently used to increase plant resistance to extreme drought and frost, based on natural phosphates (phosphorite flour), neuter or activated phosphates, etc., may in time cause important accumulation of fluorine (F), which, together with Cl and SO4, originate in the extensive use of K fertilisers (potassium chloride, potassium salt, potassium sulphate), which poses a significant ecological threat.

Biological degradation occurs at soil level as an indirect result of all the other processes and causes the degradation of terrestrial geosystems, especially of agroecosystems (the functional unit of the biosphere, created and controlled by man with a view to obtaining agricultural produce).

Biological degradation processes are best reflected in the decrease of organic matter in the soil and are mainly determined by the reduction in the soil microorganism activity and population, to which we can also add the drop in C biomass, the decrease of specific mesofauna, the increase in the intensity and the rate of mineralisation due to environmental factors and conditions (mainly the climate, namely the soil and air temperature) [2,4].

The decrease of organic matter in the soil is the main process that defines the overall soil fertility, the management and the degree in which the pedological resource is used as a terrestrial patrimonial property. It is the result of a reduction in soil microbial synthesis simultaneous with a negative change of the humidity and the temperature of the edaphic environment and the decrease of vegetal (roots and aerial plant organs) and also fauna waste input.

The factors that determine the decrease of organic matter in the soil are numerous and are closely interconnected through continuous interaction: climate conditions, the characteristics of the soil determined by the composition of the parental material (the soil reaction, the presence of hydrocarbons, the percentage of the fine-clay fraction, etc.), the characteristics of the relief, mainly the topography, the fauna and the flora.

Organic matter represents an especially important soil component with a double role: biochemically, it is the main resource of nutrients (through mineralisation, mainly N, P, K) for the production of biomass in natural terrestrial ecosystems and support for the stimulation and intensification of microorganism activity; biophysically, through its input in the formation of stable aggregates, lending the soil resistance to erosion, destruction – crusting and compaction. At the same time, it helps increase the capacity of the soil to retain water and nutrients, its total porosity, etc.

The massive decline in the organic matter in the soil (under 1%) leads to a diminished capacity of the soil as provider for the vegetation cover of cultivated plants, fertility of the soil decreases gradually as a result the intensification the phenomenon of desertification, biological and chemical degradation [7].

The reduction of the microorganism population is given by the dynamics of the biological communities of the soil, the microflora and microfauna, which are specific to a certain bio-pedo-climatic area. It is given by the alteration of the soil’s capacity to act as a habitat because of the intensive use of substances with a wide-spectrum action (especially pesticides), the contamination with different toxic elements/substances and the change in soil and farmland management practices. As a result of these actions, microorganisms decrease in number, often resulting in a less valuable microflora which decomposes the humus, the fungi and other organisms that may produce toxins therefore leading to changes in reaction, such as the decrease of the oxidoreduction capacity (the redox potential), the change in the C:N ration, etc.

The degradation of the vegetation cover – Desertification is the degradation of land in arid, semi-arid and dry sub-humid areas, as a result of an accumulation of factors which include climate change as well as the pressure of anthropogenic activities. At the level of terrestrial ecosystems, desertification includes two main processes, namely: the degradation of soil characteristics; and the decline of the vegetation cover [3].

The decline of the vegetation cover (or of vegetation) is caused by a close association between the bio-geo-physical characteristics (the composition of the flora, the bio-geographic area and the characteristics of the natural environment) and climate, more precisely extreme phenomena caused by prolonged draughts and the climate’s tendency towards aridification. Drought represents a dangerous, mainly, meteorological phenomenon which affects on a long term relatively big land areas causing material damages, environmental degradation [6].

Fіgure 2. The main processes of soil degradation that favour desertification. Source: Lal, 1989

This process refers to the almost complete change of the vegetal composition as a result of breaking up natural grassland, removing or destroying the pre-existing vegetation (even through spontaneous or intentional fires, overgrazing, agro-technical methods, etc.), this form of degradation being considered the main biotic component which undergoes changes as desertification settles.

The development of the vegetation is a good indicator to ascertain the functional state of terrestrial ecosystems. Deterioration in time of the flora may cause a change in microbial activity which usually establishes itself in the rhizosphere and the soil in general. That is why the degradation of the vegetation cover will alter significantly the percentage of organic carbon, nitrogen and phosphorus, as a consequence of the decline of organic matter coming from organ plant decomposition (root, stem, leaf and fruit), affecting three of the five functions (ecological, economic and energetic) of the soil [1].

Along its functional implications, vegetation has an important role in protecting against erosion, both areolar and also wind erosion, helping the soil to maintain its structure through its composition and the degree of coverage – mechanical effects; controling the water input al the level of the topsoil, by intercepting it and controlling its flow to the plant, respectively the infiltration rate – hydrophysical effects.

Fіgure 3. The arrangement of the soil aggregates which are subject to crustification in the south of the Romanian Plain

Conclusion

We tried to identify, group together and describe the factors, the processes and their influence on the physical, chemical and biological characteristics; it is vital that we substantiate the place, the role and the importance of the soil within terrestrial ecosystems or agrosystems, because its place at the interface between the atmosphere, the lithosphere, the hydrosphere and the biosphere generates intense processes of transformation that affect all the other components of the environment.

Due to its structure, the soil may form an element of life support fully integrated in the environment, defined by the huge fund of biodiversity whose habitat or support it is; or an anthropogenic element, as the main means of agricultural production, characterised by its main characteristic – fertility, which permits the production of biomass (more precisely, the crop).

That is the reason why we must understand all connections and feedback mechanisms which the soil/land has in relation to the factors that lead to the occurrence, the intensification and the evolution of the degradation processes associated with desertification, with a view to protecting and capitalising as rationally as possible the existing pedological resource.

Fіgure 4. Areas affected by drought in the south of the Romanian Plain

References

[1] Andrieş. S.,  Protecţia solului, Lucrările Conferinţei republicane ştiinţifico-practice. Starea de calitate a solului: Măsuri de protecţie, ameliorare şi sporirea fertilităţii, Chişinău, Republica Moldova, 2005 pp.47-48;

[2] Blum W.E.H., 1998 – Basic concepts: Degradation, resilience, and rehabilitation, In: Lal, R., Blum, W.E.H., Valentine, C. & Stewart, B.A. (eds.). Methods for Assessment of Soil Degradation. CRC Press, Boca Raton, New York: 1-16;

[3] Dumitru. M., Convenţia Naţiunilor Unite privind combaterea deşertificării şi implementarea acesteia în  Romania, 2005;

Online on http://natura2000.ro/wpcontent/uploads/2014/10/Presentation.UNCCD.Ro.pdf

[4] Florea N., Degradarea protecţia şi ameliorarea solurilor şi terenurilor, Bucureşti, Romania, 2003;

[5] Răuţă C., Cârstea S., Prevenirea şi Combaterea Poluării Solului, Ed. Ceres, Bucureşti, Romania, pp 44-147, 1983;

[6] Sabau, N.C. Man, T.E., Armas, A. Balaj, C., Giru, M. Characterization of agricultural droughts using standardized precipitation index (SPI) and BHALME-MOOLEY drought index (BDMI). Environmental Engineering and Management Journal, Vol. 14, No.6, pp:1441-1454, 2015;

[7] Ursu A., Degradarea solurilor şi deşertificarea, Ed. Stiinţa, Chişinău, Republica Moldova, pp.110, 2000;

[8] Zwerman P.J., DeHann F.A.M, Signifiance of the soil in environmental quality improvment a review. The Science of Total Environment, 2, Elsevier Scientific Publishing Company, Amsterdam, 1973;