Agriculture in arid and hyper-arid regions

In the MENA region, Agriculture in arid and hyper-arid regions is a primary concern. Potentialities, constraints, and the capitalisation of experiences preoccupy every country official and/or involved farmer.

The above image is for illustration credit: Interesting Engineering

 

Agriculture in arid and hyper-arid regions: Between potentialities, constraints and the capitalisation of experiences

Published in El Watan-DZ 29/12/2024

 

As we know, agriculture is based on several bioclimatic levels. For Algeria, from the Mediterranean climate to the arid and hyper-arid environment, including the semi-arid with a diversity of agricultural and agri-food vocations, terroirs, possibilities for rational and remunerative crops, production systems, multiple farming activities and farming sectors from the coast to the Great South, via the mountains and the Highlands.

It turns out that agriculture is a particularly strategic sector where many issues intersect, such as food, land use planning, preserving the environment and biodiversity, maintaining agro-systems and landscapes, and developing economic activity in rural areas.

Algeria has significant potential to meet its needs, diversify production systems, contribute to regional food security throughout the year, and become a major player in the international market for the agri-food and agro-industrial sectors.

My contribution to this article, which is intended to be vital, is to transmit my knowledge and share my rich experience accumulated over more than 40 years in the agriculture of arid and hyper-arid areas. It will help guide agricultural development in the various Saharan regions and promote local and regional agriculture.

It should be remembered that these Saharan natural regions are very different and that territorial foresight, or the exploration of possible futures, must be approached separately for each.

This foresight will allow us to define a long-term strategy.

But as a first step, we need to understand and master the potentialities, assets, strengths, and favourable factors of the 14 Saharan natural regions identified during the zoning of the Algerian Sahara, and the division increases according to indicators (Study of the General Master Plan for the Development of the Saharan Regions—PDGDRS 1996 – 2000, a tool for general orientation of agricultural development and decision-making support in planning).

The development of agriculture and agricultural production in Saharan natural regions such as Touat, Gourara, Tidikelt, M’zab, Ouargla, Oued Righ, Souf and Zibans is now paramount in the country’s economy.

The Sahara’s natural regions appear to have a significant asset: the sun. Unfortunately, this asset is not being used optimally. The oases only operate for a few months of the year, while three or four rotations with irrigation water savings are possible.

Let’s not forget this asset: the coolness in winter and the duration of the sunshine, which is 3200 to 3800 hours per year, compared to less than half in other countries. The soil’s potential is much greater than the available water resources.

We also need to know the main constraints. Before listing them, it is interesting to know that climatic aridity differs from drought and that aridity is a permanent feature of the climate. On the other hand, drought is a meteorological phenomenon that can extend over several seasons or even years, as in many regions and countries.

For the developer, planner, scientist, producer, investor, professional, student, and decision-maker, the constraints that have affected and continue to affect the development of agriculture in the various Saharan natural regions must be identified, analysed, and found at all costs, along with the necessary ways and means to remove them, for any study of possible futures or prospective vision.

Different constraints exist and do not affect all the Saharan natural regions identified in the PDGDRS study similarly. The areas have been grouped into four groups corresponding to the significant morphological groups of the Algerian Sahara.

1—the constraints related to the Saharan climate, including extreme temperatures, high temperatures over several months, significant potential evapotranspiration, the temperature range day and night, and winds and sand winds, are key features of the climate. It should be remembered that evapotranspiration is restrictive and presents interregional variations ranging from 1500 mm in the country of the Dayas to more than 2500 mm in the regions of Touat, Gourara, and Tidikelt.

Over 50% of the total annual ETP or evapotranspiration is recorded between April and September or until October.

ETP, or evapotranspiration as a climatic factor, is of the utmost importance in estimating the irrigation requirements of crops in a given region (the rate and importance of irrigation).

2—Pedological constraints, i.e., Saharan soils are sandy mineral substrates devoid of organic matter and have a low water retention capacity. 3—Constraints caused by the management of water resources, such as the rise of the water table due to the lack of drainage in natural regions such as Souf and Ouargla, which impacts the suitability of soils for agricultural development, increases the risk of salinisation of water and soil, and asphyxiation of crops. Other constraints are added, such as groundwater pollution and water waste.

The origin of water resources in the Saharan regions is diversified:

• The intercalary continental aquifer
• The terminal complex aquifer
• The other aquifers
• Surface waters

We must remember that water resources in the Saharan regions vary significantly from one area to another. Large aquifers have constraints on salinity, temperature, and depth, while others have low salinity.

1 – Very uncertain for surface resources such as flood spreading.

Water is the first limiting factor in agriculture; it must become the best-controlled factor. We must consider the non-renewable nature of the water resource and the high cost of dewatering.

2 – Water is still very poorly valued since yields are still low.

3 – Significant water savings can be achieved while increasing production.

4 – constraints related to the size of the territory, distances, trade in goods, supply and cost of inputs, the sale of production, and the mobility of people.

5 – Agronomic constraints prevent achieving the best production performance and affect crop and animal production.
6 – the economic constraints that affect the microeconomy, i.e. the operation of farms, their economic profitability and sustainability.

7 – the constraints related to the organisation of the agricultural profession, the structuring and development of efficient agricultural and agri-food sectors, agricultural research, agricultural training and extension, the technical supervision of producers in the field,  and support for marketing, bank lending and macroeconomics.

I would also like to point out that grain production requires occupying much longer plots of land, which increases water consumption and production costs. One kilogram of maise, wheat, or rice grains requires transferring 1 to 3 tons of water through the plant’s tissues. However, the amount of water a crop transfers is not proportional to its production.

Saudi Arabia’s example favoured irrigated wheat cultivation on an industrial scale with enormous financial and technological resources in the 1990s, to the detriment of water reserves. Despite obtaining excellent yields, the Saudi authorities have realised that the ecological price is very high and have become aware of certain limitations.

We are currently witnessing a dualism between ancient or traditional oases and new or modern oases within the framework of the APFA. These oases are characterised by their plot or cadastral plans, the alignment and density of date palms, the irrigation and drainage network in some cases, and crops distributed particularly over three different height levels or large strata. In addition, agricultural perimeters aim to increase the productivity of strategic sectors by promoting investment.

It is interesting to remember that the presence of a tree ensures the sustainability and resilience of agrosystems or oasis agricultural landscapes. The date palm is known for its remarkable resilience and adaptation to the climatic conditions of hot, arid regions with crops.

Why not promote productive green belts around the various Saharan cities, with the date palm, the king tree of the oases, representing the monopoly for these natural regions? This would preserve the genetic diversity of the Phoenix cultural heritage and enhance this appreciable varietal diversity.

These different cultivars or local varieties, resulting from a lengthy selection of oases, would be equivalent to, if not superior to, the Deglet Nour regarding earliness, conservation methods, susceptibility, and resistance to diseases and water stress.

They are highly valued for their dual use, fresh or preserved, their digestibility, the production of offshoots, marketing, prices, and the characteristics of fruits, stones, palms, spadix, or inflorescence. It is essential to know that there are varieties that are by-products, raw materials for animal feed, or the production of expensive derivatives that are currently imported.

Date by-products or scraps can be used as concentrates alone or crushed, incorporated at different rates, and mixed with other feeds such as bran, barley, oilcake, and dehydrated alfalfa. In 1985, as director of agriculture and head of the agricultural and hydraulic development division, I led and followed this initiative and experience at the level of the young wilaya of El Oued.

They are substitute foods with a high energy value that contribute to the recovery of waste, the evaluation of which gives us a significant tonnage as a raw material and also reduces imports. Date scraps are a perfect feed for fattening young sheep. The development of livestock farming in oasis environments is conditioned by the fodder supply in the palm grove, i.e. a combination of fodder represented by 0.25 ha of barley and 0.75 ha of alfalfa, with good yields of green fodder and average dry matter rates.

Since a sheep zootechnical unit needs 700 UF, livestock farming in oasis environments should be promoted, particularly small ruminants with a load of around 10 sheep per hectare.

Biochar or ecological carbon has another significant benefit: it improves soil and crop productivity, its ability to hold water and nutrients and the sequestration of the carbon that plants incorporate as CO2 during their growth.

It is used as an additive in livestock feed containing carbonaceous forages or mixtures with usual forages and concentrated feeds in compliance with rations and management boards.

The benefits of animal production and health are remarkable, not to mention its effects on the environment, namely the reduction of methane emissions produced by ruminants with a very powerful greenhouse effect. We must attach great importance to rural development, agricultural hydraulics and the development of agriculture in the Saharan regions. I insist a lot on water resources as a factor of development and limiting by recalling, according to hydrogeological studies, for example, for the continental interlayer (IC), that the depth of boreholes, the depth of pumping, salinity and temperature vary between:

• The west of the M’zab, the Gourara, the Touat, the Tidikelt and the north-east of the Tassili: 300 to 1000 m – pumping between 50 and 300 m – possibility of outcrop in the Touat – Between 2 and 3 g/l in In Salah – 0.5 and 1 g/l between Adrar and Timimoun – less than 0.5 g/l in El Goléa – temperature between 25 and 40°C.
• The north of Tassili, Ouargla, the south of Oued Righ and Souf, the east of M’zab: 1000 to 1500 m – artesian – greater than 5 g/l south of Hassi Messaoud – between 3 and 5 g/l in El Borma – between 1 and 2 g/l north of Hassi Messaoud and towards Zelfana – Temperature of 40 to 60°C. • The south-west of the Zibans, the north of the Oued Righ and the centre of the Souf: 1500 to 2500 m – strongly artesian – Between 2 and 3 g/l – 60 to 70°C. • The northern limit of the RNS du Souf: 2500 to 3000m – Strongly artesian – Between 2 and 3 g/l (few data) – 70 to 80°C.

For the terminal complex, we must monitor and control the regions and areas affected by piezometric drawdowns, current and future withdrawals, and their impacts on the most sensitive areas.

We can measure the additional withdrawals and analyse the effects by testing this aquifer with different exploratory scenarios.

The salinity of the waters of the terminal complex varies between 2 and more than 5 g/l in the Oued Righ region.

Other groundwater tables are distributed between aquifers, including the Mio-Pliocene aquifer, groundwater, and Wadi interflows. Some have potential, and others’ water resources are random, depending on rainfall.

Surface water or surface water resources are grouped into five major regional groups, of which only the hydrographic network of the foothills of the Atlas ranges and on the slopes of the Hoggar massif is active with significant and lasting flows.

Among the crucial actions to be undertaken are updating the water resources maps, updating the database and mathematical modelling, updating the inventories of water points and surveying extracted flows, the frequency of pumping, operating flows, technical monitoring of borehole drilling, and monitoring soil and water salinity for groundwater.

Let us not forget that one of my initiatives, among others, has been retained, namely the organisation of the first National Seminar on Access to Agricultural Land Ownership through Development and Saharan Agronomy in El Oued on 5 and 6 May 1985, by the local authorities of the wilaya and under the high patronage of the Ministers of Agriculture, Fisheries, Hydraulics, Environment, and Forestry.

The commission in charge of water and soil resources, the production system, sanitation and drainage, structures and means, and research and development made a necessary synthesis with several recommendations.

In conclusion, priority attention must be paid to developing specific studies or technical and economic feasibility studies for each natural region. New zoning based on the new Saharan and pre-Saharan provinces and the General Master Plan for developing the Saharan Regions must also be considered.

The updating of the PDGDRS study and the specific studies with the various exploratory simulations will allow us to identify the reality of the present context as closely as possible, assess the current situation of agricultural resources, and develop a plan for the scope of agricultural production, future oasis, and Saharan tourism.

They will also allow us to identify better regions of high water resource sensitivity, particularly given the decline in aquifer levels, and visualise the consequences of water resource withdrawals since 2000.

This update’s challenges will help us better understand each natural region, with a new regional monograph for each from a socio-economic and environmental point of view. This will give us a modernised and dynamic vision of water resources, a new conception of the development of agriculture and tourism in the Saharan regions, and an integration of climate change.

Finally, the replacement of Saharan agriculture by agriculture in arid and hyper-arid areas seems to me to be more judicious and logical. Think of more rational water management, improved irrigation efficiency, water recovery and encouragement of water recycling.

 

Dr. M. Bouchentouf , Engineer-doctor in agronomy

PhD in Environment and Sustainable Development Adaptation of Agriculture to Climate Change Former Executive at the Ministry of Agriculture and Rural Development Specialist in the Agroecology of Arid and Semi-Arid Regions Management Consultant and development of international projects Researcher in innovation and agricultural foresightPresident of the association Europe Afrique resilience agroecological and climate Paris Director of the ecological and innovative micro-farm “La Clé des oasis” in Timimoun, Algeria

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