Abstract

In hot arid zones of India the farmers often practice mixed crop-livestock and mixed livestock-crop farming. However land productivity is low and arable crops permit no more than a subsistence living in most of the years. Assets and cash reserves of rural population is negligible, and farm employment is seasonal and very limited. The overall environmental conditions are very inhospitable and in such situation jujube (Ziziphus mauritiana Lam.) cultivation offers many solutions to the multiple problems of arid and semi-arid tropical parts of the country. Central Arid Zone Research Institute (CAZRI), Jodhpur, India is engaged in jujube R & D programmes since last three decades and has selected more than 50 delicious and highly productive cultivars of jujube and perfected a package of practices of its cultivation. At the moment 90,000 ha area in the country is under jujube cultivation, generating employment to the tune of 1.08 million man-days/year. The present paper deals with various aspects of jujube cultivation which proves it a multipurpose tree crop of arid lands.

1.Introduction

Arable farming is by large the dominant pursuit of densely populated hot arid regions of India. Through experience over the generations, the farmers have evolved some mixed crop - livestock and mixed livestock - crop farming systems. However, land productivity is low and permits no more than a subsistence living in most years, and severe shortages of food and fodder occur in subnormal rainfall years. For example, in a good rainfall year, a hectare of land produces 0.5 t of Grains and 1.2 t of fodder; a poor rainfall year gives hardly any grain and just 0.2 - 0.3 t of fodder (Sen and Kar 1993). Assets and cash reserves of the rural population are negligible. Serious indebtedness follows and despite governmental support, under - nourishment of human population and livestock mortality are common features. Besides on-farm employment is seasonal and highly limited (Tewari et. al. 1989). In such a setting, where annual crops cannot provide food and fodder in excess, even at the best times, there is obvious solution - perennial multipurpose drought - resistant crops.

A good perennial crops for the arid lands is Ziziphus mauritiana trees, commonly known in India as ber and jujube elsewhere. In fact, genus Ziziphus contains about 135 species of which nearly 90 are found in the old world and 45 are confined to the new world (Bhansali 1975). Twenty eight species of the genus are reported from various regions of India. As most extensive research efforts on jujube have been done in India, therefore, the present paper attempts to discuss the utility and importance of jujube as a perennial fruit tree crop for arid lands.

2. Distribution

The original abode of Z. jujuba Lamarck according to de Condolle (1886) is British India and Z. vulgarisLam is the native of north China. Cultivation and use of jujube have been reported both in India and China since ancient times (Hayes 1945). Mehra (1967) has given a detailed account of the use of jujube in ancient India, where it had been in use for almost 4000 years. In other parts of world jujube has been introduced. The Ziziphus species are distributed throughout the tropical, sub-tropical and temperate regions of both the hemispheres (Rendle 1959). In India, at present, jujube cultivation is practised all over the country and in hot arid zones it is the prominent fruit crop. About 90,000 ha area under cultivation of improved jujube cultivars in form of well-managed orchards exist in India at the moment, which are spread over from extreme north-west part to southern states.

3. Cultivars of jujube

A large number of cultivars are available in India. These have presumably developed because of selection made by local people in different regions (Singh et. al. 1973). The nomenclature of the cultivars has been done alone very loosely based on individual fancy, and choice on local liking. Quite often, even the well-known name of a cultivar changed after its migration from its original locality. For example, it seems that cultivar 'Umran ', believed to have originally come from Alwar (Chadha et. al. 1972), is, in fact same as 'Katha ', 'Kotho ' of Maharastra and 'Ajmeri ', 'Chameli ' and 'Madhuri ' of Gujrat. The whole cultivar situation, therefore, seems to be very much confusing. However , there are some delicious specific cultivars, which are very popular in the arid land situation of different states of India on the basis of their fruit ripening period (Table 1).

Among the cultivars which have good productivity, a single factor which makes some of them more popular for commercial production than others, is the ability of the cultivar to stand transport and storage. Such cultivars in general, have hard flesh, tough skin and high T.S.S. Earliness is desirable, particularly in arid land situation for growing cultivars.

Unfortunately, under rainfed condition, early maturing cultivars, in general have poor storage life. jujube has major problem of insect pest like fruit fly and frost susceptibility.

4. Requirement of Climate and Soils

Jujube requires a hot and dry climate. It can survive temperatures of up to 50^o C, and with such a tolerance for heat it is of little surprise that it doesn't do well when temperatures approach freezing. In areas with moderate climates, with temperatures ranging from 20 to 35^oC, Ziziphus behaves like an evergreen and does not drop its leaves. The best temperatures for fruit set are these moderate ones, with not less than 50 % humidity. Fruit set is adversely affected when temperatures climb above 38^oC during the flowering. For rainfed cultivation of the minimum annual precipitation should be 150-200 mm. However, limited irrigation at the critical period increases fruit yields (Prasad and Vashistha 1998). Jujube can thrive in any type of soil, including saline ones (e.c.< 10 ds m-1 and wastelands). When planted in depressions where rainwater collects, it can withstand water-logging for 1-2 months during vegetative growth. The hardy taproots of the rootstock can penetrate semi-hard calcium carbonate or murram layers. Even the poorest patch of land can be used for planting jujube.

5. Propagation in Nursery

Vegetative propagation is required for multiplication of improved cultivars, budding being the easiest methods. For large scale multiplication of plants, nursery raising is the only answer. The technique developed at Central Arid Zone Research Institute (CAZRI), Jodhpur, India has revolutionised jujube cultivation in the country. The budded plants which earlier took one year in the nursery before they were ready for planting out, now become ready in four months (Vashistha 1993). In the containers, root stock is raised from the seeds of local Ziziphus species, most commonly Z. rotundifolias. Such root stock seedlings are ready for budding in 90 days. Budding of improved cultivars of Z. mauritiana is done on the root stock seedlings. Within one month after budding, such budded plants are ready for planting out. When these budded plants are planted out, they need to be watered until they are well established. The popularity of this technique is such that about 50 jujube nurseries are operating at and around Jodhpur producing nearly one million budded jujube plants per year. These budded jujube plants are transplanted to north Indian state Punjab and Haryana to Tamil Nadu in down south. Such a massive utilization of the technique by the farmers has made Jodhpur, the jujube capital of India.

6. Raising Plants Directly on the Field and In-Situ Budding

For raising improved cultivars of jujube directly in the field, at first seeds of local varieties are sown in the pits. The seedlings that emerge from these seeds are allowed to grow for one year. Once the plants are one year old, they are budded with improved cultivars. The survival rate in this practice is often very high (> 90 per cent ) and plants are more drought-tolerant because the tap root is not disturbed at all, as it is in planting out nursery-raised stock (Prasad and Vashistha 1998). In fact, this is the most workable method if the improved jujube cultivars are to be raised in rain-fed situation.

Existing Ziziphus species on farmers' fields such asZ. rotundifolia and Z. nummulariain the Indian hot arid zone, can also be converted into improved cultivars by top working. The trees of existing Ziziphus species are cut back. After some time, new shoots emerge and budding is done on such new shoots. The technique is generally referred to as in-situ budding. Such top worked trees start bearing fruits from the second year onward.

The desirable density of planting relates directly to canopy development, which in turn is affected by the climatic conditions of the given location. In rainfall zone > 800 mm a year, planting distance is kept at 8 x 8 m and even some times10 x 10. The same is true for irrigated conditions. However in arid regions and semi - arid regions when rainfall is between 250 mm to 550 mm a year, the planting density is reduced to 6 x 6 m. In arid regions, through in situ rain water harvesting, the yield of jujube can be increased substantially (Gupta and Sharma 1997).

7. Management Strategies

The budded Ziziphus or jujube plants are trained at least for the first three years. The branches arising from the point of budding are kept at an appropriate distance to keep the plant balanced. Two branches are not allowed to grow from a single point. Any shoots arising from the root stock portion should be cut just 3 to 5 cm above the base and its bark is removed. This operation is done quite frequently.

For fruit production, yearly pruning of plants must be carried out as flowering and fruiting occur on current year's growth. Pruning is carried out when the plant is in dormant stage. For example, in hot arid regions of India 50-70 percent biomass (branches + twigs) are removed during mid May, when the summer season is at its peak. After pruning, the cut ends are painted with copper fungicides or paste of Neem seeds to avoid infection.

The major problem with improved cultivars of jujube is insect attack on early stages of fruit formation. The most common insect which severely damages jujube fruits is fruit flies (Carpomyia spp.) (Batra 1953; Pareek 1983). The flies infest the fruits at pea stage, so at this time it is very essential to spray a systemic insecticide. The spray is again repeated after three weeks.

The fruits of early cultivars are ready by mid December and the fruits of mid- season cultivars are ready by the end of January. In the late cultivars, fruits mature by mid February to late February. If cultivars of different fruiting period are grown systematically in a jujube orchard, a farmer can get fruits for sale regularly from mid- December to Mid March i.e., for 3 months.

8. Production Potential

Jujube starts producing fruits in the third year. Under rainfed situation, fruit yield varies from 30-40 kg/tree. In severe drought conditions, when arable crops fail, jujube can provide subsistance income to poor farmers of arid lands with 10-15 Kg of fruits, 5-8 Kg of leaf fodder and 8.0-12.0 Kg of dry fuel wood. With irrigation, a tree of >5 year age can yield 100-120 Kg fruits.

9. Jujube as a Woody Component of Arid and Semi-Arid Land Silvi-Pastoral Systems

This is a very useful tree for agroforestry, particularly for silvipastures (Hocking 1993). The leaves make excellent fodder; crude protein 13-17 percent and fiber 15 percent. Leaves are also food for tussar silkworm. The branches and twigs are excellent fuelwood having calorific value 4878 K cal/kg. Root bark and leaves have 7 percent and 2 percent tannin, respectively and are sometimes used mixed with other sources for tannin lather. The fruits provided by all the improved cultivars are delicious.

In an on-farm investigation, carried out on a farmer's field in rainfed condition, buffel grass (Cenchrus ciliaris) was introduced between the rows of improved cultivars of jujube (10 years old), established at 6 x 6 m spacing. The experiment was carried out for six years absolutely on the farmer's management practices. The area immediately around ajujube plant, its basin, was kept free. On an average, across the six years, the dry grass fodder production was 1.55 t/ha. The fruit, leaf fodder and fuel wood production from jujube trees (cultivar 'Gola ') was 2.77, 1.87 and 2.64 t/ha, respectively. Thus, such jujube based silvi-pastoral system is definitely ecologically sound and productivity sustainable for hot arid environment, where arable crop production is a gamble, if not impossible (Shankarnarayan et. al 1981). Though a combined productive - proactive system like the present one is biologically more complex either than a pure arable farming/ gram farming or forestry system, however, evidences from different studies (Tewari et. al. 1999) suggest that if compatible tree and crop/ grass species are carefully incorporated on farm lands in arid regions, the over-all level of production can increase even under unfavourable climatic and edaphic conditions.

* Tree spacing = 6 x 6 m

10. Important Issues Related to jujube Cultivation
10.1 Landuse and Economic Issues

From arable crop farming, especially rainfed ones, in hot arid zone of India, the net income ranged from Indian Rs. 3000 (US $ 66) to 5000 (US $ 111) per ha per year. The same land , if brought under jujube based arid horticulture, returns (net income) Indian Rs. 25,000 (US $ 555) to 45,000 (US $ 1000) depending upon the management and locality. The over-all benefit : cost ratio is 5.5 : 1, which is economically quite sound. The leaf fodder and fuel wood production is not included here. The excellent cultivers of jujube and technology of orchard establishment developed at CAZRI, Jodhpur resulted in rapid expansion of jujube cultivation in arid and semi-arid tropics. At the moment 90,000 ha area from extreme north-west part of the country to southern states is under jujube cultivation. It is estimated that jujube plantation in the country are generating employment in order of 1.08 million men-days/year in the country. The technological package is very simple and acceptable to the farmers with various level of family economies i.e., from poor to rich ones.

10.2 Social Capital

A very high order of adoption of jujube cultivation in arid and semi-arid tropics of the country has changed the economies of many poor farmers. The lands which have previously been very poor or of no value, are now being considered worth thousands of Indian rupees. This has a direct impact on the social status of farmers in the traditionally complex socio-economic-cultural web of rural life in India, who have successfully adopted jujube cultivation.

11. Epilogue

Conventionally, jujube is considered as a poor man's fruit. But it is a rich source of vitamin C, A and B-complex. Jujube fruit is richer than apple in protein, phosphorus, calcium, carotene and vitamin C (Bakshi and Singh 1974). Fully ripe fruits have a food value of 20.9 calories (Singh et. al. 1973). Jujube fruits can be processed as candy, diced fruits, jam and pulp. Thus cultivation of improved jujube cultivars offer solutions to many problems, especially that of arid land where water is a scarce commodity. In a country like India, especially in the rural sector of arid areas, where a huge labour force faces acute unemployment problems, the employment generation through jujube orchard plantation could play a vital role in rural economy. The integrated land use having jujube fruit tree plantation protected by wind breaks of MPTs like Acacia tortilis, Prosopis juliflora, etc. coupled with utilization of interspace by planting other drought hardy plant species of economic value appeared to be the best proposition for arid lands as it will not only provide sustainable production but will also lead to soil conservation and improvement in soil fertility level.

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