Land Use and Management Practices in Arid Zones | India

After reading this article you will learn about the land use and management practices in arid zones of India.

Indian arid zone occupies about 3.17 lakhs km² of hot desert of north-western India and about 0.7 lakh km² of cold desert. Thus, the area in the hot desert in north-western India constitutes about 93% of the total arid zone in the country, and the cold desert account for 7% of the total arid zone in India. More than three-fifth of the Indian hot desert is located in Rajasthan and about one-fifth area lies in Gujarat state.

Besides, there are small pockets of hot desert in Punjab, Haryana, Maharashtra, Andhra Pradesh and Karnataka. The climatic classification of India and the delineation of the arid zone, based on the mois­ture index of less than or equal to – 40, has been given in Table 9.1.

In Rajasthan, the districts falling wholly in the arid zone are Ganganagar, Bikaner, Jaisalmer, Barmer, Jodhpur and Churu. The districts falling partly in arid zone are Nagpur, Jalore, Jhunjhunu, Sikar, Pali and Ajmer having 96, 88, 69, 65, 48 and 9% of their area under arid zone.

To the north of Rajasthan the demarcation line of the arid zone intersects Mahendragarh and Hissar districts of Haryana and Sangrur, Bhatinda, and Ferozepur districts of Punjab State. The percentage of arid zone in the above mentioned districts are 77, 88, 8, 90 and 9% in Ferozepur, Bhatinda, Sangrur, Hissar and Mahendragarh, respec­tively.

The various districts of Gujarat state falling under arid zone are Banaskantha, Mehsana, Ahmedabad, Surendranagar, Rajkot, Jamnagar and Junagarh with their arid area percentage as 18,7,6,29,6,80 and 20, respective­ly. Kutch is the only district which wholly falls in arid zone.

Land and Water Resources:

The great Indian desert, also called the arid zone of north-western India, ex­tends between 22° 30’N and 32° 05’N latitude and from 68° 05’E to 75° 45’E longitude. The landforms comprise of barren rocky stretches, shifting dunes and sandy plains, saline flats, alluvial plains, dead streams, barren gravelly stretches and undulating topography.

Physiographically the entire arid zone is characterised by vast tracks, almost covered by thick blanket of dune sand ex­cept a few places which are rocky desert. Nearly 70% of the desert region is covered by wind-worked sandy soils-sands, loamy sands and sand dunes.

The remaining area is under medium textured, old and recent alluvium, sandy, rocky and gravelly soils. Indian coastal desert is concentrated along the gulf of kutch and extends into the interior of Gujarat. In Gujarat, three types of deserts are identified. They are salt, clay and stone deserts whereas in Pun­jab and Haryana, only the sand desert is the most common one.

The Indian arid zones are characterised by low and erratic precipitation, frequent occurrence of drought, hot summers, large annual diurnal tempera­ture ranges and low humidity. Of the total rainfall 78 to 96% is received during the monsoon season, especially by the south-west monsoon. Only in the south arid zone, south-eastern monsoon contributes 21 to 32% of the annual rainfall.

The mean annual precipitation varies from 100 to 450 mm in Rajasthan, 300 to 500 mm in Gujarat, and 200 to 450 mm in Punjab and Haryana. It is about 500 mm in the southern arid zone. The annual potential evapotranspiration varies from 1411 to 1700 mm (Table 9.1).

A study of the rainfall map of the north­western Indian arid zone indicated that the region has 3 rainfall belts, viz.,

(a) 500 to 300 mm from the foot hills of Aravallis in the east to the desert plains in the west;

(b) 300 to 100 mm, the hot sandy desert, and

(c) Below 100 mm, the extremely sandy desert with dunes.

This area (Rajasthan) is devoid of well-defined drainage system. The general slope is towards south­west. The drainage lines of the arid zone of Gujarat are having their own local base levels. The drainage line of Punjab and Haryana are in south-east.

Mann and Dhir (1982) and Mann (1982) reported that in Rajasthan, except in Bikaner and Jaisalmer districts which are more desertic, the cultivated and cropped area constitutes, 69 to 90% and 45 to 75%, respectively. The cul­tivated and cropped area for Bikaner are 39.5 and 28.9% and for Jaisalmer 6.4 and 5.4%.

In arid zone of Haryana, the net cultivated area ranges from 71 to more than 85%. Similar is the situation in Punjab. In Jamnagar district of arid zones of Gujarat, the cultivated area is about 50%. In Kutch district cultivated area is only 14% whereas in southern arid zone about 47 to 60% of the area is cultivated.

The human population in the Rajasthan desert increased from 3.42 million in 1901 to 8.84 million in 1971, representing a growth rate of 158%. In fact, the Indian desert is possibly the most thickly populated in the world. It has an average density of 61 persons to a sq/km as against 3 persons/km² in the other deserts of the world.

In spite of the low productivity of the arid lands, Rajas­than sustains a fairly high population of livestock. The livestock population in Rajasthan has registered an alarming increase, almost doubling, from 9.4 mil­lion in 1951 to 15.5 million in 1972.

The livestock density/100 ha rose from 72 in 1951 to 175 in 1971 in the desert districts. Cattle, buffaloes, sheep, goat, camels and other livestock constitute 7.30,2.65,6.86,5.07,0.65 and 0.19 million, respectively, of the total 23 million livestock population in the arid zone of India. The livestock population exceeds the human population.

Problems of Arid Zones of India:

The high pressure of livestock on grazing lands, especially in view of its carrying capacity (animals), results in the over use of land and depletion of vegetational resources. The man to land ratio is fast decreasing and as a consequence more and more marginal land is being brought under plough resulting into substan­tial increase in sown area at the expense of grazing land.

At the same time the population explosion in livestock has led to an over-exploitation of the shrink­ing grazing lands. Due to increased population of both human and livestock, the trees and shrubs even their roots are indiscriminately cut by rural popula­tion for fuel, top feed, thorn fencing and for construction of thatched hutments.

Another important consequence of overgrazing is the interference in natural regeneration and succession of vegetation, especially the grass species.

Wind erosion is the major problem in the Thar Desert. It is doubly harmful to both the areas from where the soil blows and where it is deposited are lost to crop production. The phenomenon of desert spread has, for long, been ap­prehended as one of the most potent dangers to the overall growth of Rajasthan and adjoining states.

According to the report of the Planning Commission of India (1952), “The great Indian desert of Rajasthan” is spreading towards the non-desert areas of Haryana, Delhi and Uttar Pradesh at the rate of 0.8 km per year and is encroaching upon approximately 128 km² of fertile land every year.

The increase and decrease in wind-blown surfaces have been illustrated by a comparison of old and recent survey maps which indicated an extension of the desert towards east.

Recently, a study based on socio-economic parameter revealed that there may not be any scientific basis of the view that Rajasthan desert has been spreading in the north-easterly direction (Mann et al., 1974). However, there is no reason to be complacent in this regard.

Realising the serious consequences, a committee set up by Govt., of India in 1950-51 to advise on the measures for controlling deserts within its limit and to improve condi­tions for better development of vegetation and for inhabitants of the area, recommended setting up of a Desertification Station at Jodhpur.

Besides work on of afforestation, this station conducted investigations on grassland and agronomy. In 1958, the Central Arid Zones Research Institute was set up to tackle the problems of arid zones.

Causes of the Problems in Arid Zone:

The land management practices developed over the years are not conclusive for long term soil productivity. The ploughing of land during winter and sum­mer is a common practice for preparing the land for growing of crops. This practice, without adequate soil conservation measures leads to soil instability and promotes wind erosion.

Open grazing lands are in a serious state of degradation. The vegetative cover is thin and dominated by low-yielding an­nuals or unpalatable species. Therefore, an important undesirable conse­quence of the land management of both open grazing and ploughing increases the loose sand in the landscape. Wind speed during summer may reach as high as 20-27 km/hr in areas like Jaisalmer in Rajasthan.

The threshold velocity of wind for initiating the soil movement is 14 km/hr for desert conditions. The causes of wind erosion in the desert region are low rainfall, high wind velocity and sandy soils with loose single grained structure, faulty methods of land use, over grazing and deforestation.

Control Measures:

Arid zone research has considerably increased our knowledge about the struc­ture and functioning of arid zone ecosystem. It has provided with a number of measures for upgrading the production on farms and grazing lands.

These measures can broadly be classified under two heads:

(i) Sheltering the soil from wind action, and

(ii) Creating a soil condition resistant to wind erosion.

Land Use Adjustment:

The limitations, which primarily determine the land use capability classes in arid zone are the arid climate, the coarse sandy texture of soil with very low water retentive capacity, proneness to severe wind erosion, duny physiography, effective soil depth and a high salinity hazard.

There are, hardly any class I and class II lands in arid regions. Class III lands occupy 27% of the area, class IV 16%, class V about 1.2%.Class VI lands predominate and account for 45% of the area and they are highly susceptible to erosion, particularly in less than 200 mm rainfall regions. Only 45 to 60% of the area in arid zone of Rajasthan is suitable for arable farming.

The rest 21 to 24% of the area is made up of dunes highly susceptible to wind erosion. This area should be put under permanent pasture for sustained production and soil conservation. Rocky pediments con­stituting 5.6 to 8.8% should also be brought under permanent silvi-pastural cover with light grazing intensity.

Raheja (1964) suggested that crop cultiva­tion in arid zone be limited to areas receiving rainfall more than 275 mm that too with rigorous measures for wind erosion control. Though this will shorten the cultivated area, the gap in production can be made good by adoption of improved cultivation practices developed for this region.

Crops and Cropping System:

Bajra is the chief crop in the arid zones of north-western India and occupies about 75% of the total cultivated area under food grains. It is followed by pul­ses (10-30%), cluster bean and sesame. In more desertic western part of Rajas­than it is the sole crop. In the northern part of the arid zone, which is characterised by winter rainfall, besides millets and clusterbean there is large area under gram and oilseeds in rabi season.

In the coastal desert of Gujarat bajra, jowar and maize are the major cereals produced. Bajra represents more than 80% of the total cropped area. During kharif season tur, moth and mung are grown as mixed crop with bajra.

Gram and peas are generally grown in winter season as a second crop after pearl millet. In Gujarat with medium tex­tured soils and higher rainfall, groundnut, sorghum and cotton assume sig­nificance. Wherever irrigation facilities exist wheat-cotton and a variety of fodder crops constitute the cropping pattern.

Mixed cropping of pearlmillet with mungbean, moth-bean or clusterbean and sesame is recommended for soil and water-conservation and to minimise the risk due to erratic rainfall by exploiting the behavioural difference between these crops.

Bajra should be replaced by pulses (mung, moth and clusterbean) if monsoon is delayed beyond July 20. Field strip cropping in grass strip of legumes, mungbean and moth in a ratio of 6 : 1 has been found useful for con­trol of wind erosion and higher production in arid zones.

Development and Management of Grass Land:

Seven potential grass land types have been identified:

(i) Sehima nervosum type for hills and piedmont regions;

(ii) Dichanthium annulatnm type on older alluvial flats with sandy clay loam to clay soils;

(iii) Cenchrus type for well drained alluvial soils;

(iv) Lasiurus sindicus type on loose sandy soils;

(v) Demostachya bipinnata type on young alluvium;

(vi) Sporobolus-Dichanthium annulatum type on low lying heavy soils; and

(vii) Panicum turgidum type on sand dunes.

Following points may be con­sidered while planning for the management of such lands:

(i) Cultivation on Marginal and Sub-Marginal Lands:

Cultivation on marginal and sub-marginal lands should be stopped and brought under grass land to curb erosion. Lands falling under capability classes V to VIII are unfit for crop cultivation and those under class IV are subject to wind and water erosion hazards. It will be desirable if long grass production is followed on class IV land to reduce erosion hazards and improve soil fertility and vegetative production.

(ii) Grubbing of Unwanted Bushes:

Unwanted thorny bushes like Lycium barbarian, Belanites aegyptiaca, Acacia leucophloea, Mimosa hamata hinder the growth of grass species and are troublesome to grazing animals. These should be grubbed out mechanically.

(iii) Maintenance of Top Feed-Cum-Shade Trees on Grass Land:

On a good grass land there should be about 30 trees/ha of useful species like Prosopis cineraria, Azadirachta indica, Salvadora spp., Albizzia lebbek, Acacia nilotica, etc. suitable for different tracts to provide shade, timber, top feed, and fuel.

(iv) Reseeding the Rangeland:

High yielding and palatable perennial grass species like Cenchrus ciliaris, C. setigems, Lasiurus sindicus in north­western Rajasthan and Dichanthium annulatum, Panicum antidotale, Sehima nervosum and Chrysopogon sp. for southern part of Rajasthan should be grown.

Dichanthium annulatum gives high yield on heavy soils with an annual rainfall of above 380 mm while Cenchrus ciliaris and C. setigerus produce high forage yield on well drained soils under medium to low rainfall conditions.

Lasiums sindicus gives high forage yield on sandy soils under low precipitation conditions. Panicum an­tidotale performs well on medium textured soils with an annual rainfall of 250 mm and above under protected condition.

Sehima nervosum yields good forage on hilly terrains. Contour furrowing, staggered pitting and trenching and contour trenching have been found useful for soil and water conservation. Closure or fencing is essential pre-requisite for any improvement of grass land.

The average seeding rate recommended is 2 kg/ha for Dicanthium annulatum and Panicum antidotale, 2-3 kg/ha for Cenchrus ciliaris and C. setigerus and 5 kg/ha for Lasiurus sindicus. Seeding during June-July results in maximum germination of seed in the field.

Seed should be covered with soil to a depth of 1-2 cm. The recommended row spacing is 50 cm for grass and 100 cm for grass legume mixture where annual legume crop may be grown in between the grass rows for combined forage and grain production.

Plantation of Trees as Wind Break and Shelterbelts:

Wind break is a barrier for protection from winds commonly associated with homestead garden, orchard, etc., while a shelterbelt is usually a longer barrier than a wind break consisting of a combination of shrubs and trees intended for protection of field crops and conservation of soil and water. Large scale tree planting of proven merits are based on the results obtained at Central Arid Zone Research Institute, Jodhpur.

(i) Sallow soils — Albizzia lebbak, Eucalyptus camaldulensis and Casuarina equisetifolia

(ii) Semi-rocky areas — Acacia Senegal, Prosopis juliflora, Tecomella un- dulata, Acacia nilotica, Proposis cineraria

(iii) Rocky areas — Prosopis juliflora and Acacia Senegal

(iv) Roadside avenue and windbreak planting.

(a) Prosopis juliflora, Azadirachta indica and Albizzia lebbek were found suitable for low rainfall areas (120-350 mm).

(b) Prosopis juliflora, Azadirachta indica and Albizzia lebbek were also suitable for areas having rainfall of about 350 mm.

(c) Azadirachta indica, Albizzia lebbek and Dalbergia sissoo were 80-90% successful without supplemental irrigation.

(v) Fodder trees: Prosopis cineraria is an important forage tree species which grows in cultivated fields. The trees may be 60-80/ha without affecting crop yield.

Some of the exotic species with good adap­tability in arid regions are Acacia aneura (Australia), Pittosporum phillyraeoides (Australia), Brasilettia mollis (Venezuela), Geoffroea decorticans (Chile), Prosopis alba (Argentina) and Colophospermum mopane (South Rhodesia).

Prosopis juliflora, Azadirachta indica and Albizzia lebbek have been success­fully used as three row shelterbelts along the high ways in western Rajasthan. Five row shelterbelts in pyramidal shape were found to be suitable in desert areas where wind direction changes abruptly. Acacia tortilis was found most suitable for arid zone afforestation on sand dunes.

Best results with windbreaks and shelterbelts are obtained where mixed plantation consisting of grasses, shrubs and trees are raised. While selection of species may be made according to the experience of local conditions, the fol­lowing list may be considered as guide.

First Row:

Euphorbia, royleana, E. neriifolia, Saccharum munja, Acacia rundodonax, Sesbania aegyptiaca, Lawsonea alba, Agave americana, A. sisalana, Thevetia neriifolia, Tecoma stans, Ipomoea cemua, Vitex negundo, Ziziphus nummularia, Calotropis gigantea, Tamarix articulata, Balanites roxburghii, Leucaena glauca, Gliricidia maculata, Ricinus communis, Tephrosia Candida, Casuarina equisetifolia, bamboos.

Second Row:

Ziziphus jujuba, Parkinsonia aculeata, Prosopis juliflora, P. spicigera, Acacia arabica, Azadirachta indica, Pongamia glabra, Acacia catechu, Cassia siamea, Boswellia serrata, Anacardium occidentale, Acacia mollissima, Casuarina spp., Cocos nucifera, Pionciana alata, Borassus flabellifer.

Third Row:

Acacia arabica, Albizzia lebbek, Dalbergia sissoo, Eugenia jambolana, Cedrela toona, Tectona grandis, Mangifera indica, Dalbergia latifolia, Tamarindus indica, Hardwickia binata, Terminalia spp. Eucalyptus spp., Grevillea robusta, Casuarina spp., Anacardium occidentale, Artocarpus integrifolia, and other palm, bamboos.

Windbreaks may be 80 ft. wide and consist of 8 rows depending upon the availability of land. There should be two rows of long lived broad leafy trees and four rows of hardy conifers. Such a combination affords protection all the year round.

A typed shelterbelt should be like a conical roof in cross-section. In the centre, the peak of the roof, there should be tall trees flanked by short trees, conifers and tall shrubs and grasses with low shrubs on the outside.

Protection of shelterbelts from animals is necessary since any cattle move­ment tends to destroy vegetation in lower level of the stand and this reduces its effectiveness as a wind barrier. It is, therefore, necessary to keep the belts ef­fectively fenced. Regeneration is very important. Shelterbelt should be protected from fire. Cleaning and thinning of shelterbelts should be carried out according to need of the belts.

Management of Dunes:

Dunes should be closed to grazing, cropping and other biotic interferences for at-least 15 years. Grasses should not be harvested during the first two year? From third year onwards, the grasses should be got harvested manually every year. From tenth year onward the trees should be lopped for top feed.

Tillage practices: Tillage practices for wind control in arid zones include con­touring and strip cropping, initial tillage and subsequent tillage operations. Those practices which provide rough soil surface and leave part of the crop residue on the soil surface are most effective.

Contouring and Strip Cropping:

Contouring on sloping land is most effective for moisture conservation on arid zone. Field strip cropping in grass strips of legumes (mungbean — Vigra radiata and moth-bean—Phaseolus aconitifolius) in a ratio of 6 :1 has been found use­ful for the control of wind erosion and higher total production in arid zones. Grass strips should be oriented as nearly as possible at right angle to the wind direction.

The chief advantages of strip cropping are:

(i) Physical protection against blowing provided by vegetation;

(ii) Soil erosion limited for a distance equal to the width of the strip;

(iii) Greater moisture con­servation; and

(iv) Possibility of earlier harvest.

Control of Soil Crusting:

Crusting is one of the serious problems of crop production in arid zones. Sandy soils of arid zones are reported to develop soil crusts due to reorientation of soil particles caused by impact of raindrops. Crusting, just after seeding, a con­sequence of rainfall immediately after seeding, results in poor emergence of seedlings and lead to poor crop stand and low yields.

Though seeds germinate below the crust, seedlings are not able to exert sufficient upward thrust to pierce through the crust, resulting in pre-emergence death of seedlings. Gupta and Yadav (1978) reported that increased intensity of rainfall from 15 to 21 mm/min reduced the seedling emergence of sunflower (Helianthus annuus) and mustard (Brassica juncea) from the normal 70 and 63% to 48 and 30%, respectively.

To overcome this problem of seedling emergence, the soil can be worked with a spike tooth harrow, if crust is formed within one or two days of seeding. Gupta and Yadav (1978) observed that sowing on ridges reduced the crusting hazard considerably.

Since soil crust is normally formed due to beat­ing action of rain, structural break down and rapid drying of soil, mulching the soil surface to minimise the beating action of rain reduces the problem of soil crusting.

Stubble Mulching:

Gupta and Agarwal (1980) observed that soil loss in wind erosion from fields having pearl-millets stubbles (10-15 cm) in Bikaner district of Rajasthan was 22.5 tonnes/ha against 1449 tonnes/ha from unprotected bare field. This prac­tice, however, has its limitation on a large scale adaptation. The farmers are not inclined to leave stubbles in the field, because it is a source of animal feed.

In years of scarcity of fodder, particularly in drought years, animals are left free on these lands for grazing. During summer month, there is hardly anything for grazing in the field, hence animal feed on whatever they can find in the field, thus making it difficult to maintain stubbles in the fields during summer months.

Primary and Secondary Tillage:

Excessive tillage leads to severe wind erosion in arid areas. To be most effec­tive, primary tillage (ploughing) and secondary tillage should leave the soil sur­face as rough and irregular as possible.

Water Harvesting:

Owing to low moisture storage capacity and high infiltration rates of sandy soils, the scope of water harvesting in desert soils is small. The limitation of low water storage capacity does not apply to plants having deep root system, i.e., fruit trees.

The moisture stored in murrum is well within the reach of tree roots and hence does not go waste. Singh et al. (1980) reported beneficial effect of in situ water harvesting in a ber orchard.

The moisture stored in 3 soil profile under ber trees throughout the season was 50 to 80% higher in plots having micro-catchments than those under flat planting. This practice has been recommended for orchard development in desert areas in Rajasthan.

A considerable area in the Rajasthan desert is under rocky terrain. Runoff from such areas can be collected for utilisation in adjoining soil by pond storage method or in situ depending upon the condition of soil.

Such areas are widespread in Jaisalmer and Barmer districts of Rajasthan which are normally wet during the kharif season, and hence, are cultivated in the rabi season for wheat and mustard. Such catchments need to be surveyed, and runoff needs to be collected so that the excess runoff may be diverted elsewhere for increasing production.