Raanan Katzir

"SACOG",Sustainable Agriculture Consulting Group,4 Efter St.Tel-Aviv,69362,Israel

1 Introduction

Agricultural production and desert conditions are usually considered to be antagonistic or at best incompatible.Since the desert is an area with adverse climate and soil conditions,and is regarded as a marginal natural resource,it is unattractive for modern agriculture,even though it also has specific characteristics which could be useful for agricultural development and production.Thus,it is necessary to identify the advantages and disadvantages of each of these characteristics and existing natural resources before deciding on a large-scale development program(Katzir,2002).

For developing modern agriculture,it is necessary to generate expertise and specific technologies needed for the utilization of desert resources.This can only be accomplished by intensive local research under desert conditions(Katzir,2000).

The success or failure of desert development depends on the human factor.Exclusively dedicated human resources are needed for desert development and the ability to use scientific and technologically advanced cultivation methods.Also,applying environment controls are needed for successfully performing under adverse desert conditions.This approach requires abundant economic resources.

The Israeli Negev Desert is characterized by wastelands,low population density,a large number of sunny days with high temperature and radiation levels and scarcity of water.Usually,the few existing limited sweet water resources are only found in oasis.However,in most deserts of the world,deep saline water aquifers exist that may be utilized when applying specific technological methods.Extreme climate conditions frequently occur,such as strong winds,sand storms and extreme temperatures.

Modern agricultural production methods,particularly for crops grown under protection in greenhouses,where specifically developed for controlling the favorable properties of the desert,such as high temperatures and intense sun radiation,in order to achieve high biomass production.Local saline water resources are advantageously used as drip irrigation method.Applying state-of-the-art technologies in greenhouses makes it possible to control almost all factors influencing plant growth,such as temperature,humidity,radiation,wind protection,growth media and plant nutrients.

One of the characteristics of desert loess soils is the structure of the superficial crust which produces a low water infiltration rate.The rapid sealing of the surface layer,once the soil becomes wet,causes almost immediate water run-off in the form of streams and flooding even after a short rainfall.This run-off can be harvested or captured and directed into the fields or reservoirs for later use.

Israel is a small country in the Middle East with a total land area of about 26,000 km2.Sixty percent of its territory is desert,with rainfall not exceeding 200 mm/a and limited to the five winter months from December to next April,which is the only rainy season of the year.Only 7% of the total population of Israel lives in this area.However,the Israeli Desert is not homogenous.It includes the Arava Valley extending from the south of the Dead Sea to the northern part of the Red Sea,which is part of the Afro-Asian Rift Valley.Part of this valley is below sea level.Dates,mangos,vegetables,flowers and milk are produced in this valley.

Another part of the desert is the central Negev High Plateau of 600 m a.s.l..This area produces flower bulbs such as irises,narcissus and gladioli,as well as olives,grapes,melons and vegetables grown in open fields and greenhouses.Also,Tilapia fish are raised in open ponds and greenhouses with thermal saline water.

The northern Negev Desert is the flat and hilly area covered by loess soils on which rain fed and irrigated wheat,vegetables,flowers,forage,apple,apricot and citrus,mainly produced lemons.

The northwestern Negev Desert,near the Mediterranean Sea predominantly consists of sand dunes.These dunes can be easily flattened and cultivated.By using drip irrigation integrated with fertilizer application,Israel's most outstanding agriculture is practiced on these once desolate sand dunes.At present,citrus,avocado,mango,vegetables and flowers are grown here.

2 Methodology

This article is based on the approach of sustainable agriculture.Under these methods,the regional natural resources are examined in order to take advantage of agricultural production.Natural resources such as soil,water,crops,animal husbandry,climate and human resource are revised and researched in order to reveal their advantages under local desert circumstances.

A special system named:Agricultural Regional Research and Development(R&D),is being applied in the Negev region and contributes mostly to solving agricultural production problems and introducing adequate innovations.This R&D system is composed of the cooperation of farmer's representatives,local agricultural researchers;extension services agents and representative regional authorities.A local R&D committee is charged with the identification of problems and prepares a short and long term local research and extension working programs.The same committee monitors procedures and is charged with the application of practical results.

In this article,we describe the characteristics of local natural resources,and the values of these natural resources after developed with adaptive technologies,research findings and local agricultural production measures in Israel,for contributing to conversion of a desert into an advanced agricultural system in the world.

3 "Desert Agriculture" and "Agriculture in the Desert"

As early as almost 3,000 years ago,an ancient agricultural system known as the Nabatean Agriculture was successfully practiced in the desert.This system is based on water harvesting from nearby bare hill slopes.The run-off water,directed to,and accumulated in cultivated plots located at lower topography levels,contributed to the increase of soil moisture.Various vegetables and fruits such as olives,almonds,figs and others were successfully grown under this system.

This system mainly fits small-scale subsistence farming and is not applicable for more advanced agricultural systems.However,the system has high potential for adoption in the Sahel region of Africa or in other desert areas in Africa,Asia and Latin America.Under this system,Eucalyptustrees can be grown for fire wood,Leucaenatrees for fodder for goats and sheep,and olive trees for oil production for human consumption.

Another type of traditional agriculture,practiced in the hilly loess-soil area,where rain-fed wheat cultivation occurs during the rainy winter season.Precipitation in this desert area is around 200 mm/a.This amount of rainfall can produce 2 t/h of wheat grain.In summer,sheep and goat herds graze on the wheat trash.This is the type of agriculture characteristically practiced by the nomad population of the desert,the Bedouins.

Under the new reality and habits of Israel,modern agriculture is developing and has established itself in the desert.This advanced agriculture,which the present article is dealing with,may be named "Modern Agriculture in the Desert."

4 Water

"Modern Agriculture in the Desert" is firstly based on the availability of irrigation water.We are distinguishing between external and local water resources.External water resources are transported by the "National Water Carrier" over a distance of more than 300 km from the Sea of Galilee in the north of the country.

Another external resource is recycled sewage water from the central urban area of Tel Aviv and its satellite cities with a total population of 1.4 million located 80 to 100 km to the north of the target area.After secondary biological treatment,the sewage water undergoes further treatment.It is filtered through sand dunes down to a depth of 80 m where it is stored for a prolonged period.After reaching a very high quality almost comparable to potable water standard,the water is pumped into the distribution system to be transferred south to the desert.

These two aforementioned water resources from the north are either immediately used by the agricultural sector in the south or stored in very large reservoirs in the target area,some of which may contain up to 1.5 million m3water.

One of the local water resources is the saline water stored in 1,000 m deep aquifers.Water is pumped from 700 m deep artesian wells.Salinity(chloride ion content)ranges from 1,000 to 2,500 mg/L,and the thermal temperature of the water is about 40 °C.The successful use of saline water requires knowledge and specific technology.

An Israeli innovation of the early 1970s,the drip irrigation method,made it possible to use saline water for crop irrigation.Using this method,relatively long and frequent irrigation applications at a very low water discharge rate provide a permanent leaching of salts from the root zone system of the plants,while other irrigation systems accumulate salt around the root system and demand strong sprinkler irrigation with sweet water once a time before starting new crop cultivation to leach the salt down to a depth of 1.2 m below the crop root zone.

Research carried out in recent years provides a long list of crops which are tolerant and resistant to saline water.Among others,they include asparagus,broccoli,beet-root,celery,cabbage,tomato,melon,lettuce,Bermuda grass,Rhodes grass,wheat,sorghum,sugar-beet and cotton,dates,olive and grapes.These crops produce commercial yields under a saline water irrigation regime.For some crops,such as tomatoes,the use of saline water for irrigation results in a plant stress response of increased sugar concentration in roots and fruits:"Sweet Desert Tomato." In vineyards,by saline water irrigation,grapes attain a high level of dry matter and then can produce high quality wine.Using saline water for irrigating olives also improves their oil quality.

By using a special sealed pipe system installed near the plants,thermal water pumped from the well is used for raising the air temperature in the greenhouse during cold nights.After cooling,the same water is reused for irrigation.

The thermal water can also be used for the cultivation of tilapia fish raised in fish ponds protected by greenhouses.

5 Introduction of new botanical species

Most of the commercial crops produced by Israel's modern agriculture were developed from species introduced from other parts of the world.

As in other agricultural fields,research is continuously searching for new species to be assimilated to our desert conditions.In the last years,new crops such as Jojoba,Opuntia and Pitaya were commercially introduced from Mexico and cultivated on a large scale.The introduction process includes various phases like quarantine,observation,demonstration plots,semicommercial and commercial plots(Katzir,2004).

6 Climate

The desert area of the Arava Valley,part of which is below sea level,is known for its warm temperature and mild climate during the winter season.Precipitation in the valley is low and erratic,usually not exceeding 100 mm/a and relative air humidity is low.

In winter,when it is cold and rainy in the north of the country,it is the best time for producing in the Arava off-season vegetables,flowers and herbs.These products obtain the highest prices on the market and are mainly destined for export.The limiting climate factors to be dealt with are wind and hail storms,and sometimes extreme temperatures.Crops grown under protection in greenhouses are the best solution to this set of problems.The agriculture growing season in this area lasts from September to next May.

7 Soils

The growth media in greenhouses usually consists of sand brought from a local sand dune resource.Other growth mediums consist of mixtures of sand,compost,rock wool,peat,and vermiculite,used as detached media.Irrigation,integrated with fertilizer application,is fully computer controlled.The amounts of water and fertilizers to be applied as well as irrigation frequency are determined by field tests for establishing water and nutrition demands.Special sensors,such as tensiometers and extractors are installed in the plots and used for monitoring soil moisture content and controlling irrigation.In the sandy desert area near the Mediterranean coast,there exists a very advanced agricultural system of citrus,avocado,mango,flowers and vegetables.The sandy dunes can be easily leveled and cultivated.Based on the drip irrigation method,high quality recycled sewage water is used for irrigation.The climate in this area is usually mild and the vicinity of the sea limits frost hazards.

8 Control of other factors

Under greenhouse conditions,air temperature,humidity,radiation and wind storms can also be automatically controlled.Furthermore,the greenhouse is protected by insect-proof nets for preventing the penetration of insects,many of which serve as vectors transmitting virus diseases and in addition causing physical damage to the plants.The plastic sheets used for covering the greenhouse possess UV(Ultra Violet)or IR(Infra Red)characteristics,thereby achieving additional advantages(Katzir,2005).The greenhouse atmosphere,enriched by CO2which is induced in early morning hours,facilitates improved photosynthesis,resulting in higher yields.

9 Plant protection

Pests and diseases,including nematodes and mites,may inflict heavy damage to the crops and indeed are the most limiting factors.Virus diseases,transmitted by vectors such as aphids,mites and white-fly,are capable of completely destroying a crop.The existence of the Mediterranean fruit fly,limits the export of fresh produce to the U.S.A.and Japan.As already mentioned,the protection of greenhouses by insect-proof netting and IR plastics is very useful for controlling insects and strongly diminished the spreading of virus diseases.A plant protection specific project running in the Arava Valley is aimed at controlling pest and disease damage.The project is based on the assumption that the valley is isolated from other agricultural areas and all the agricultural plots in the valley are also isolated from each other.The principles of the project are(Katzir,2011):

˙Cultivating in autumn,winter and spring and maintaining zero-cropping during mid-summer.

˙Removing all crop residue and trash immediately after harvesting.

˙Monitoring and applying control treatments based on threshold values.

˙Introducing beneficial insects for biological insect control.

˙Using environmental friendly,biologically un-harmful pesticides.

˙Introducing sterile males for controlling the Mediterranean fruit fly.

˙Using soil fumigant treatments for soil disinfection.This method however was replaced by solarization.

˙Solarization is a soil disinfecting method,whereby the prepared soil bed is covered during mid-summer with plastic sheets for a period of one month.The plastic cover traps sun radiation and increases soil temperatures to more than 50 °C over a prolonged period of time,thereby achieving the desired soil disinfection effect.

The project,running for the past 15 years,succeeded in drastically reducing pest and disease damage,achieved the eradication of the Mediterranean fruit fly in the whole zone,and resulted in the granting of permission for exporting agricultural produce to the U.S.A..

10 Reforestation

The northern desert area includes the southern part of the Judean Hills.In this area,precipitation amounts to 250 mm/a.During previous generations the hills were completely eroded.By using appropriate soil conservation methods like terracing,fencing with stones and bushes,rain harvesting is obtained and soil moisture is increased.Species such asEucalyptus occidentalis,E.stricklandii,E.sarangetii,Prosopis alba,P.juliflora,P.nigra,Acacia salicina,A.raddiana,Tamarix aphylla,Ceratonia siliqua,Pistacia palestina,Pinus halepensis,andParkinsonia aculeataare planted in the area and are slowly turning into forests,which are completely changing the landscape.

11 Raising Tilapia fish,Ostriches and dairy cattle in the desert

11.1 Tilapia fish

The existing deep aquifer in the desert is saline and thermal(40 °C).Tilapia can easily adapt to this type of water.The optimum temperature for harvesting commercially profitable fish(400 g)is 30 °C.Under these conditions,the life cycle is short,making it possible to obtain two cycles per year,compared with only one cycle for fish raised at normal water temperature.Fish raised in greenhouses ponds with a forced oxygen environment,has the capacity of yielding 15 ton per 1,000 m2.This is a very capital intensive but profitable agricultural branch.

11.2 Ostriches

Ostriches are well adapted to desert conditions and can survive on eroded land of very limited alternative use.They are efficiently utilizing the scarce natural vegetation produced on the pastureland,but also receive some supplementary food from other sources.The commercial ostrich products are meat,eggs for ornamental purpose,skins for the leather industry and live animals sold for reproduction purposes.All in all,this is a very profitable agricultural enterprise.

11.3 Dairy cattle raised under heat stress conditions

Under heat stress,cattle are wasting energy for body cooling instead of producing milk,resulting in reduced milk production.Technological innovations were introduced for overcoming heat stress problems.These include:

?High and well aerated structures.

?High-potential ventilators.

?Sprinklers for spreading water droplets.

?Frequent wetting of the cattle.

?Continuous supply of cool drinking water.

All these measures help reducing cattle temperatures and diminishing heat stress.Under such circumstances,milk production in the hot desert zones can be increased(Katzir,1993).

12 Human factor

Among all factors and resources influencing agricultural development in the desert,the human factor is the most important one.

The farmer who presently settles in the desert is usually of a very dedicated but also strongly economically oriented type,attempts to exploit the advantages(while overcoming the disadvantages)of the desert environment and to develop and apply relevant knowledge and technologies needed for this purpose.

Under the prevailing Israeli circumstances,the Regional Agricultural Research and Development(R&D)system has proved to be very effective.

This system is based on regional cooperation between farmers,researchers,extension workers and local regional authorities.Within the framework of such cooperation,the objectives,working plans and allocation of economic resources,are approved and implemented.The aim of this R&D system is to produce the most relevant,immediately needed solutions and practical knowledge and technologies to be used by farmers for sophisticated and modern agricultural production.

The development of agriculture in the desert requires relatively high capital investments and additional capital for the purchasing of highly sophisticated production inputs.The cost of a 1,000 m2large greenhouse alone is within a range of 100,000 US dollars.

Such high investments are justified due to the intensive,sophisticated and profitable farming developed as the result of the cooperative management and research efforts of all participating parties.Farming settlements in the desert require a well-developed regional infrastructure,resulting from physical and social regional planning and development.This infrastructure includes roads,communication systems,access to production inputs,credit and banking services,and supporting systems for grading,packing and cool-storage.Supporting technological systems and agricultural extension and research services are also essential as well as advanced leadership.

The settler in the desert needs living conditions that allow him to overcome the harsh climate conditions.At present,this can be achieved by technological innovations in desert architecture,air conditioning and other related fields.An impressive number of such innovations have been recently achieved.All in all,if intelligently managed by dedicated manpower,the desert has a very high potential for human settlement and food production.

13 Conclusions and discussion

The Negev Desert area of southern Israel is part of the Sahara Desert which extends from North Africa,through the Sinai Peninsula to the southern Israeli Negev.The winter season moderate climate condition is the main advantage of the Negev Desert area.In open fields and in various types of plastics greenhouses,vegetables,fresh herbs,flowers and fruits are grown in the winter season and exported to Europe in winter,December–April.The agricultural items are exported to a high purchase consumer's markets and as a result,a very efficient profitable agriculture is created(Katzir,1996).

The Regional Agricultural Research and Development(R&D)system is unique and very efficient in supplying to the farmers practical solutions and introduction of innovations.

This type of advance agriculture in the desert shows the efficient use of the saline marginal water resource by using the drip irrigation system which was originally(1970)developed in this region by the local R&D system.

The local R&D system also succeeded to overcome the barrier of desert marginal soils,by introducing efficient artificial growing mediums and protected agriculture in plastics greenhouses,to overcome extreme climate events.

Despite the hot summer condition,a very efficient milking dairy branch was developed due to methods developed by the local R&D system,to reduce the cattle Heat-Stress factors.

The local human resource is the key factor of success.Most of the farmers have academic degrees and idealistic motivation.The local authorities and governmental policies allow for the development of an advance regional infra-structure and support the mechanism of regional development.

The combination of all the aforementioned factors enable an advance regional development in an extreme desert area.A very advance rentable agriculture is developed,which allows for a high income and high standard of living.This example can serve other desert areas in the world.

Thanks should go to Naiman Desertification Research Station,Cold and Arid Regions Environmental and Engineering Research Institute,CAS for inviting me and funding my trip to the International Conference on Restoration and Sustainable Utilization of Desertified Lands,Tongliao,China,August 16–19,2014.

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Katzir R,2011.The Negev,Arava valley farming under extreme dry condition.Chinese Academy Science's Conference,Beijing,China.