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Systems of Dura production and Buda infestation

The system of aura production varies from one region to another. However, there are some features common to all regions. First of all, a large labour force is engaged in aura production, because most of the agricultural operations, even under mechanized cultivation, are done by manual labour using primitive tools. This is especially true in the weeding operation, which is directly related to the question of buda. Secondly, neither fertilizers nor manures are usually applied. A third feature is that in most cases animals play a role in the income of the farmers.

The System of Dura Production in Western Sudan

It may be more appropriate to refer to systems rather than one system in western Sudan. However, throughout western Sudan, except in the Nuba Mountains, cultivation is mainly confined to the sand soils of the qoz. Here dukhn tends to replace aura as the dominant subsistence crop, under rainfed cultivation. Here also cultivation is essentially a family affair for each family's own requirements, and animal raising plays a more important role in the domestic economy of the region than in the other regions under study.

Western Sudan is a land of cultivators and pastoralists. The northern part is occupied by camel nomads (rearing camels and sheep), the southern part by cattle nomads (rearing cattle and sheep), with settled cultivators in the zone between the two (Davies 1966). Both the camel and cattle nomads regularly graze their animals in the middle zone; and some nomads, especially from among the cattle nomads, have settled and taken up cultivation in addition to animal raising. (One of the villages in the survey, Gallabi, is occupied by settled nomads from the Misseiriya Zurg tribe.) Cultivation as practiced in this zone follows a system of land rotation or bush fallowing with the villages permanent and compact. Cultivation is usually practiced around the village. Normally each family has two types of cultivation: a small plot of a few metros square in the immediate vicinity of the house, and the main cultivation some distance further away and much larger.

TABLE 4. Dura production in Sudan by region and mode of production (thousands of feddans)

Source: Sudan Government 1979* No figures are given for traditional rain-fed production in Kassala Province; the data may have been included here.

TABLE 5. Areas under aura in Sudan in selected years (thousands of feddans)

Sources: Sudan Government (various years, to 1938), 1961,1979

Near the houses quick maturing crops, including some cereals and vegetables, are grown. These small farms are cultivated almost every year, but, being close to the house, they receive manure from the village animals.

The main cultivation is carried on away from the village. In May before the start of the rainy season, the farmer clears a plot of land, usually between 8 and 15 feddans (1 feddan = 0.42 hectare), but the size of the farm will depend on the family labour supply. A few rich individuals may hire labour and are able to cultivate areas of 40 to 50 feddans. As the rain starts, the farmer sows the land using simple tools. Weeding is done once or twice depending on the intensity of the rainfall and weed growth, and on the labour supply available. Soon after the end of the rainy season the crops are harvested; subsistence crops are stored and the cash crops are taken to the nearest market.

A plot of land is cultivated for from four to six years, until it loses its fertility, and then another plot is cleared and cultivated. The first plot reverts to bush, and through selection during the clearing of the vegetation Acacia Senegal (hashab) is left to dominate in more or less pure stands. The farmer may return to this land after 10 to 25 years depending on the pressure of population. The hashab is a nitrogen fixer and thus gives fertility to the land. At the same time gum arabic is tapped from it as a supplementary source of income to the farmer. Tapping is done between November and February after the crop harvests.

In the El Obeid area of Northern Kordofan three main crops-dura, dukhn, and sesame-sesame - areare cultivated in the rati' of 5:3:7 and are rotated. In the past only aura and dukhn were important, and sesame, if cultivated at all, occupied a subsidiary place. But this began to change in the El Obeid area with the building of the railway in 1912. Later factors included the introduction of lorry transport, initiation of market places, and improvement of rural water supplies. However, in recent years the most important incentive to sesame production has been the high prices for oil seeds during the 1970s. The result has been that areas under sesame for cash have expanded dramatically to surpass the subsistence cultivation of both aura and dukhn. The farmers are helped in their decision to increase the area under sesame by the availability of comparatively cheap aura brought in from Gedaref and the southern Gezira region of Blue Nile Province to supplement their own production.

TABLE 6. Sudan production, consumption, and trade in dura (thousands of metric tons,

Source: Sudan Government 1979

One farmer who cultivated 17 feddans in 1980 (10 under sesame, 4 under aura, and 3 under dukhn) explained his rationale as follows: One feddan yields four sacks of sesame, worth £S 17 per sack, or one to three sacks of aura of dukhn, worth £S 10 or £S 15 per sack.

With these prices it is plainly advantageous to grow sesame, provided aura is readily available. However, the farmers cannot risk giving up their aura and dukhn cultivation, because if they did so they could be faced with a shortage of aura or very high prices for supplies brought in from other parts of Sudan.

Buda is plainly present in the area within the survey, but its intensity is light. Of the farmers interviewed - 5 per cent reported no buda infestation; - 51 per cent reported light infestation; - 44 per cent reported medium infestation; - none reported severe infestation. This low intensity is related to the agricultural practices and in particular to (a) the type of land rotation practiced, with the land under cultivation for about four to six years and then abandoned for a long period, during which hashab trees establish themselves (b) the rotation of crops, as sesame is not affected by buda, and dukhn appears to be affected here only to a small degree and certainly less than aura; and (c) the increase of the sesame area at the expense of aura and dukhn.

The System of Dura Production in the Irrigated Gezira

The Gezira Scheme is representative of agriculture in the large gravity-and pump-irrigated schemes of the White and Blue Niles as it was the blueprint for them.

The Gezira started to come under gravity irrigation in 1925, when 300,000 feddans were cultivated. It now totals nearly 2 million feddans. Annually some 400,000 feddans are put under cotton, 380,000 under aura, 500,000 under wheat, and 250,000 under ground-nuts. (The areas fluctuate somewhat from year to year; these figures are for 1978/79.) The main crop in the Gezira is cotton, modern Sudan's traditional commercial crop. Dura is also cultivated for subsistence to ensure the supplies for the feeding of the tenant, his family and his cotton pickers. In the past an eight-course rotation was practiced: cotton, resting, aura, resting or lubia (hyacinth bean}, resting, cotton, resting, resting. This system was considered an extremely lavish use of land. As returns from cotton decreased with falling world prices, the government wished both to maintain the earnings of the tenant and to grow more wheat for the increasing urban population. The old system of rotation was replaced by a more intensive and diversified land use. In the two villages in this survey the rotation on a 30-feddan tenancy now is 10 feddans under cotton, 10 under wheat, and 5 under each of aura and groundnuts. There is no fallow. This is the general rotation throughout the Gezira Scheme, although in certain areas some small plots of land are put under rice or vegetables. Animals are not catered for in the Gezira, though most of the tenants' own livestock are sent to distant grazing areas during the cultivation season from June to March. These animals and some of those owned by cotton pickers are allowed into the fields in March to graze the crop residues after cotton picking is completed.

The cash earnings of a tenant from cultivation in the Gezira Scheme may be estimated at £S 660, of which over half comes from ground-nuts and a further £S 60 comes from the sale of gassab (aura stubble).

Originally it was thought that the tenants and their families could provide the needed labour except for picking cotton, for which hired pickers would be employed on a seasonal basis. This theory did not work out in practice, as females were reluctant to work in the fields and children began to go to school. This in turn meant that educated children and their parents developed off-scheme interests, and so hired labourers came to be used on a wide scale on either a wage or a crop-sharing basis. Furthermore, the existence of off scheme interests led to neglect of some of the agricultural operations, in particular the weeding of aura.

The old eight-course rotation, extravagant in the use of land as it may have been, gave little chance for bud a to appear, but with the intensification of cultivation the buda problem began to increase. Hardly a tenancy is totally free from buda. Eighty-six tenants were interviewed; of these

- none reported no infestation;
- 9 per cent reported occasional infestation;
- 61 per cent reported light infestation;
- 21 per cent reported medium infestation;
- 9 per cent reported severe infestation.

Two factors may have contributed to saving the situation so far: firstly, the crop rotation and use of fertilizers in connection with cotton has prevented the soil from reaching the stage of exhaustion; and secondly, the cultivation of ground-nuts, a nitrogen-fixing crop, helps to maintain soil fertility.

The Mechanized and the Traditional Rain-fed Systems of Dura Cultivation on the Central Clay Plain

The central clay plain of Sudan extends eastwards from the White Nile to the foothills of the Ethiopian plateau. It includes much of the Gezira and Blue Nile provinces as well as the Gedaref region of Kassala Province. The striking physical characteristics of this plain are its flatness to the naked eye except where occasional hills rise out of it, the lack of drainage lines of any importance over extensive areas, and the dominance of cracking clay which is suitable for cultivation of many crops such as cotton, aura, wheat, and sesame. Since the last century the plain has had the reputation of being the "granary of Sudan," and this has been reinforced since the 1940s with the introduction of extensive semi-mechanized cultivation. Today this region accounts for over 55 per cent of the area devoted to aura cultivation in Sudan. If the irrigated aura areas of the Gezira and the Blue and White Niles are added, then the central clay plain accounts for about 65 per cent of all areas under aura in the Sudan (table 4).

The rain-fed aura cultivation can be divided into traditional and mechanized. As these have some important common features as well as the main implied difference in the methods of production, they have been brought together here.

The main difference between the mechanized and traditional cultivation is in scale of operation due to the use of modern agricultural machines in some but not all the field operations in the former type. The traditional type, long established in the region, uses simple tools and depends on family labour; it is undertaken mainly for subsistence purposes. As the cracking clay is not easy to cultivate, the size of a normal traditional farm is small, between 15 and 50 feddans. Some of the betteroff families may hire some labour and/or tractors and may be able to cultivate up to 250 feddans. Mechanized cultivation, on the other hand, creates large farms, usually between 1,000 and 1,500 feddans, though the actual cultivated area may range from 600 to 1,200 feddans. These began to expand rapidly in number from the late 1950s. Machinery is used mainly for ploughing and sowing, and a large manual labour force is still required for many operations, including weeding and harvesting, as preferred varieties of aura cannot so far be harvested by combine. It has been estimated that a 1,000feddan scheme requires about 300 labourers and that on the Simsim Mechanized Farming Project labour amounted to 48 per cent of the production costs of sorghum and 63 per cent of sesame in 1969/70, compared to 64 per cent and 71 per cent respectively in 1974/75 (Thimm 1979). Mechanized cultivation therefore requires heavy investment not only to buy the necessary machines and to run them but also to pay the labour force. Thus this type of cultivation is fully commercialized and has attracted wealthy people, often from outside the region and with no previous experience in cultivation.

The common characteristics of cultivation in the region are the dominance of aura, the impermanence of cultivation, and the low yields.

When the idea of mechanized cultivation was first conceived in the late 1940s (Davies 1964), it was thought that sesame could be producted to contribute towards solving the world shortage of edible oils at that time. Sesame proved to be a difficult crop for extensive mechanized cultivation. Firstly, the crop requires very rapid harvesting; otherwise on reaching maturity the crop bursts and the seeds spread over the ground and cannot be collected. Secondly, it cannot be harvested by machinery. And, thirdly, sesame needs more rain than aura and thus it was not very suitable for the northern part of the Gedaref region around Ghadambaliya, where mechanized cultivation was first attempted. Cotton was also considered, but it needs a large labour force during the picking time, which would coincide with cotton picking elsewhere. Dura proved to be the best crop from both the physical and the human aspect. It is not as demanding in its water requirements as sesame; it is easy to cultivate; and the expanding population of the Sudan provides a ready market for the crop. Thus aura became the dominant crop, although sesame and cotton are also grown to some extent (table 7).

In the surveyed villages of the Gedaref region, only a few individuals cultivated aura and sesame, and aura clearly dominated. At Abu Na'ama in Blue Nile Province most of those interviewed stated that they cultivated both aura and sesame, but 65 per cent of the area cultivated was given to aura. In both regions cotton plays but a very minor role and most of the farmers do not cultivate it. So one can safely describe aura cultivation in this region as a mono-cuture.

As in western Sudan rain-fed cultivation in the central plain is carried out on a shifting basis, but in this context there is a significant difference between traditional and mechanized cultivation.

TABLE 7. Areas by main crop under rain-fed cultivation in Gedaref (Kassala Province) and Blue Nile Province

Source: Sudan Government 1979

Traditional cultivation is practiced over small areas near permanent villages, where accessibility by donkey or on foot is important. Thus, the cultivated fields rotate around the village. This gives the natural vegetation, usually composed of an Acacia seyal-Balanites aegyptiaca scrub with appropriate grasses, a chance to regenerate itself and restore fertility to the soil. After 10 to 25 years, depending on the population pressure, cultivation is resumed. By then there is plenty of dry grass and dying bushes to make possible the clearance of vegetation, old and new, by merely setting fire to it-hence the name harip cultivation. This system has the advantage of adding potash to the soil, but the disadvantage of burning some of the humus in the topsoil. Seeds of weeds, including those of buda, may also be neutralized, but this needs to be investigated. With the expansion of the cultivated area due to rising population, the fallow period has certainly been shortened over recent years, which suggests that soil fertility is being continuously reduced.

Mechanized cultivation on the other hand may or may not be located near villages. A person is given a plot of land on lease. After three to four years it loses its fertility and is abandoned, and another piece of land is allotted as a replacement. In some areas, e.g. in the Simsim Mechanized Farming Project, the size of each farm exceeds 1,000 feddans, with the idea that at least 25 per cent should be left fallow at any one time. Because of a lack of supervision by the administration, this system of fallow is not practiced. With the increased number of mechanized schemes it is no longer possible to allot new land as replacement for old which has lost its fertility. The difficulties of developing sound management practice have been aggravated by the desire of all farm owners to have their holdings near the road, and their preference for old schemes with this advantage even if the soil is less fertile rather than new schemes more remotely situated. Furthermore, much of the land under cultivation has been acquired in an illegal way; the "owners" continue cultivation as long as the land is productive, and the illegal cultivation is not detected.

The monoculture of aura coupled with shortening of the fallow period or even its disappearance has led to soil deterioration and severe invasion by weeds, including buda. Loss of fertility is in practice difficult to measure. Decline in yield could be taken as evidence of loss of fertility, but there are also other factors responsible for decline in yields. Low rainfall or abundance of rainfall leading to sheet floods, shortage of essential inputs such as fuel oil or money to pay for labour, and mismanagement of the farms are also important factors. Tables 8 and 9 indicate that the aura yield is fluctuating, with a tendency to decline.

Buda is also one of the important factors in the low yield, but it is difficult to separate it from the others. In the Blue Nile villages, where some sort of crop rotation is generally used, there was less of a aura monoculture; and the buda infestation reported, though very serious, was less than in Gedaref. Of the farmers interviewed in Blue Nile

- none reported no infestation;
- 21 per cent reported light infestation;
- 24 per cent reported medium infestation;
- 55 per cent reported severe infestation; whereas in Gedaref 100 per cent reported severe infestation.

Both the Blue Nile and Gedaref areas use their animal wealth, though not to such an extent as western Sudan. Almost all the small farmers in Gedaref and Abu Na'ama own some cattle, sheep, and goats, and these are allowed into the fields at the end of the harvest season. In addition both the mechanized and traditional areas of aura cultivation are regularly visited by nomadic groups-first at the beginning of the cultivation season, when they move northwards, and again just before the harvest season, when they move southwards. On both journeys the nomadic animals may enter the fields and damage the crop. The nomads claim that they have a right in the land under mechanized cultivation since these were their tribal lands. The important point is that the movement of livestock owned by settler and nomad alike is one of the factors assisting the spread of buda.

TABLE 8. Yields of aura and sesame for Simsim MCPS and Agadi State Farm, 1974/75 (kilograms per feddan)

Source: Thimm 1979

TABLE 9. Yields of aura and sesame for mechanized and traditional cultivation in Blue Nile Province and Gedaref (kilograms per feddan)

Source: Sudan Government 1979

Combating Buda

There is a very considerable lack of knowledge in the Sudan about buda, how it is spread, and how it may be combated. There is little evidence of effective extension work among farmers on the subject, partly because the Ministry of Agriculture cannot make up its own mind what to recommend on the subject.

Most of the farmers stated that they do not know of any method of combating buda, and they also complained that they found no help from the agricultural extension service. However, a small number from the Gedaref region had tried fallowing as a possible means of reducing buda infestation but found it ineffectual. Three of the respondents left part of their lands fallow for periods of from 10 to 15 years, but when they cultivated it again, the buda showed up once more. Four respondents stated that they had been told that, if they delayed sowing for two to three weeks, the buda infestation would be reduced. Two of them tried this method and found it successful, but they did not know why. Here it could be that buda grew with the other weeds including adar, which is a wild veriety of sorghum, and when the farmers cleared the weeds, they cleared the buda with them. This is an aspect of the trap-crop method of possible buda control. In doing this farmers know that they are taking a great risk, for if the rainy season ends early, as often happens, then their harvest will be in jeopardy. The seasonality and unreliability of rainfall in central Sudan represents a real problem to aura cultivation in general and makes the problem of buda control here even more difficult. Rainfall, even in much of Blue Nile, is marginal, with a coefficient of variation at Gedaref of 22. Maldistribution during the rainy season exacerbates the problem still further.

The farmers do not use fertilizers except in the Gezira, where fertilizers are used for cotton, nor do they manure most of their fields. The re-establishment of soil fertility depends on natural processes. Pesticides and weed-killers are not used. Most of the farmers are suspicious of imported chemicals, perhaps with good reason. Furthermore, the traditional cultivators are too poor to buy them, and mechanized cultivation, although sometimes very re - warding financially, is still seen as a gamble with the elements. The farmers concerned, even if they had the know-how, would not be willing to increase their financial risk by using inputs of expensive chemicals. The pulling of buda plants is not tried in either the traditional or the mechanized sector because of the additional labour required.

In conclusion, buda is experienced everywhere in central Sudan as a parasite on aura. It is more serious in the central and eastern areas than in the west. It is more serious when systems of production do not include proper crop rotation or an organized system of fallowing. The problem is getting worse because of increasing pressure on available lands, as buda appears to thrive best on heavily used soils of less fertility. It is generally less serious on hariq lands, but whether this is because the burning reduces germination or because hariq cultivation usually represents land in good heart and left fallow for long periods is not clear.

The problems standing in the way of adopting measures for buda control include ignorance on the part of the farmers and the lack of a coherent programme of recommendations from the Ministry of Agriculture. However, even if they could be overcome, there remains the problem of a restricted growing season which militates against any trapcrop system of control. There is little tradition of using animal manures and no tradition (even a distrust) of using artificial fertilizers and other imported chemicals. The financial risks involved in cultivation on these semi-arid lands make even those otherwise capable of taking up control methods unwilling to do so, as the possibly improved yields cannot be guaranteed.

Another unresolved question relates to livestock and the extent to which they are involved in the spread of buda. If there is little buda, as in western Sudan, and the pressure on land is low, there is room for cultivation and animals without the two coming into conflict, and the role that livestock may play in its diffusion will be reduced. However, where the reverse applies, animals may well play a significant role in its dispersal.

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