Livestock production systems in Chokwe, southern Mozambique

Jonathan Timberlake

UNDP/FAO Project MOZ/81/015
Land and Water Department
National Agronomic Research Institute (INIA)
C.P. 3658, Maputo, Mozambique

Introduction
Study area
Methodology
Results
Discussion
Conclusions and future lines for investigation
Acknowledgements
References

Abstract

The livestock components of the mixed crop-livestock system of Chokwe District are described. This system has been undergoing changes in recent years due to an influx of people and cattle and redistribution of land in the irrigation scheme, leading to severe localised overgrazing, cattle deaths and an increased demand for animal draft power.

A pasture/soil/dry season water points survey of the area is described and the livestock carrying capacity of the various pasture types was calculated using a livestock carrying capacity model. Total livestock capacity of rangeland areas was calculated as 50340 animal units (AU) and the feed resources of the irrigation area (fallow fields and maize stover) sufficient for a further 15700 AU. Actual livestock population is 37400 AU. The problem of the area is shown to be distribution of cattle not absolute numbers, with excessive concentrations of animals around the villages on the edge of the irrigation scheme.

The utilisation of rice straw and the introduction of appropriate forage legumes into the existing farming systems are given as ways of intensifying the production system, and these require some applied research and testing.

Introduction

Out of a total cattle population in Mozambique of 1.4 million in 1981 some 72% were found in the southern three provinces of Gaza, Inhambane and Maputo, which account for about 20% of the total area of the country. Of these cattle 86% (881,000) were in the traditional family (or communal) sector, raised on extensive grazing with some use of crop residues. The major reason for the concentration of cattle in the south is the presence of tsetse north of 22°S, a line running through the north of Gaza and Inhambane provinces.

The southern three provinces can be roughly divided into three livestock zones based on rainfall, which shows a steep gradient from the coast to the interior. The area is also bisected by three major rivers: the Limpopo (including the Elefantes and Changane rivers), the Incomati and the Maputo. Most of the family sector cattle are found along these rivers especially in:

(a) the drier interior parts (under 600 mm rainfall/year) where crop cultivation is very risky and cattle raising becomes the more important economic activity, in areas where human population densities are quite low;

(b) the area between 600 and 800 mm rainfall/year which is principally an area of mixed farming, especially on slightly heavier soils. The major activity of the family sector is crop production (principally maize and cowpeas) but cattle are kept to provide draft power, milk for family consumption, meat, economic security in bad harvest years, and as a means of investment in years of surplus: and

(c) the wetter coastal areas with their higher and more reliable rainfall (800 to 1100 mm/year), sandy soils and dense human populations. Crop production (cashew, maize, cassava and groundnuts) is very important and livestock much less so although cattle are frequently used for ploughing.

The mixed crop-livestock farming system is a very important one, involving not only a sizable portion of the national cattle herd but also a large portion of the rural population of the southern provinces.

The district of Chokwe lies in the mixed farming zone on the southern side of the Limpopo river. There has been recent immigration of cattle and people into this relatively safe district from surrounding areas affected by the war, and concentration of a previously more scattered population into villages on the edge of a large irrigation scheme. This has caused many cattle to die of hunger in the dry season. The pasture and animal feed potentials of the district are large, and there has been a big increase in demand for draft oxen for use in the irrigation scheme. The need for intensification of livestock production is clear. Because of this situation a study was carried out (Timberlake et al, 1986) into the carrying capacity of the pastures and the distribution of dry season watering points in the area. This would assist in a more rational use of existing feed resources and provide a basis for land use planning for livestock production.

This paper is in two parts. The first part describes the recent survey mentioned above, while the second part discusses these results, and results from other surveys in the area, from a farming systems perspective and gives some suggestions as- to future lines of investigation.

Study area

Chokwe District in Gaza Province, in which the study area of 1830 km² is located, is primarily an agricultural district situated on the south side of the Limpopo river some 100 km from its mouth. It is characterised by a low and variable rainfall (averaging 623 mm/year, mostly falling from November to March) and high evapotranspiration (1413 mm/year) leading to high agricultural risk in dryland farming areas. A large irrigation scheme of approximately 37,000 ha, mostly for rice, maize and vegetables, is the major feature of the district. Since 1983 some 13,000 families have been granted plots of 0.5 to 1 ha in 9,000 ha of the scheme. Surrounding this are dryland grazing areas, some of which are cultivated in the form of small family plots. Maize and cowpeas are the major crops, but cassava, groundnut and sweet potato are also grown. Cattle are an important component of the farming systems of the region, principally providing draft power. Goats are common but not numerous.

The area is flat to gently undulating and consists basically of marine deposits overlain in places by more recent colluvial and alluvial deposits. Soils close to the river are sandy but fertile, while the rest are sandy loam in texture. These latter areas are dissected by large shallow depressions of clay soils which form water-courses for a few weeks of the year. In the southeast of the study area, rising above the rest, are interior dunes of reddish sands.

Methodology

The study was in three parts: a soil survey, a pastures/vegetation survey and a dry season water points survey.

Soil Survey

The soil survey was at a reconnaissance level. A photo-interpretation map was prepared based on aerial photographs at a scale of 1:40,000 flown in 1973. On this map the main physiographic/soil units were distinguished. Fieldwork consisted of 89 soil auger observations to a depth of 1.2 m in locations thought to be representative of the various physiographic units. The following characteristics were recorded: physiography, slope, drainage class, actual land use, soil texture, soil colour and mottling, soil consistency, presence of calcium carbonate, salinity and depth of groundwater table. Some 76 soil samples were also taken for laboratory analysis including pH and mineral content. On the basis of the fieldwork the preliminary photo-interpretation map was adjusted and a final soil map prepared at a scale of 1:75,000.

Pasture/Vegetation Survey

The pasture/vegetation survey was done at the same reconnaissance level. Using the same aerial photographs, 100 observation points were chosen, representative of the varying physiographic and vegetation units distinguished. At each observation point the tree, shrub and grass species present were noted with an indication of their cover/abundance. The observation points covered an average of 0.5 ha each and were not sited in heavily disturbed areas or inside the irrigation scheme.

A matrix was later made of observation points along one axis and species along the other. This matrix was rearranged repeatedly on a micro-computer so that species which tend to be associated, and observations of similar species composition, were placed together. After various rearrangements clear groupings of observation points emerge and these form the basis of the vegetation units. The pasture/vegetation map was made using a modified version of the physiographic/soil map.

From the map the areas of each pasture/vegetation type were determined. Potential livestock carrying capacities of each type were determined using the potential pasture productivity and livestock carrying capacity model of Timberlake and Reddy (1986). The assumptions used are given in Tables 1 and 2.

Table 1. Livestock carrying capacity calculations for vegetation units in Chokwe^1/.

Vegetation unit		Estimated potential primary productivity (t DM/ha/year)²/	tree and ha/head³/
			shrub cover (%)
Broad-leaved woodland		6.0	10	1.0
Broad-leaved woodland
	- light bush	2.2	20	3.6
	- heavy bush	2.2	40	7.1
Acacia savanna
	- light bush	2.5	20	3.2
	- heavy bush	2.5	40	6.3
	- very heavy bush	2.5	50	8.8
Open grassland
	- Themeda	3.0	0	1.8
	- Dactyloctenium	2.0	0	2.7
	- wet area	6.0	0	0.9

^1/ Using the model of Timberlake and Reddy (1986) and assuming 50% use factor and an animal feed intake of 2740 kg DM/head/year for a 350-kg animal with 100 gm/day LWG.

²^/ 75% probability value.

³^/ 1 head = 1 adult 350-kg animal.

Source: Timberlake et al. (1986).

Water Point Survey

In determining dry season water points all points where water appeared to accumulate were noted on aerial photographs. Local information was used in locating those points (less than half) which still had water during September-October (dry season), and this proved quite reliable. A questionnaire was filled in at each point concerning the presence of water, type, present condition, age, size and depth, where the cattle came from which use it, overgrazing/erosion, and whether it sometimes dries up. The system of canals inside and on the edge of the irrigation scheme were not included as access by cattle is possible along most of their length.

Table 2. Areas of vegetation types and livestock carrying capacities in Chokwe.

Vegetation/land type	Area (km²)	Carrying capacity (ha/head)	Total Livestock capacity ('000 head)
Riverine woodland	61.0	3.0a	2.03
Broad-leaved woodland	226.9	6.0	3.78
Acacia savanna	849.9b	5.0	15.10
open grassland	294.3	1.0	29.43
SUB TOTAL	1423.1		50.34
Irrigation scheme	370.7	-	15.70c
Plantation forest	12.4	-	-
Open water	6.8	-	-
Urban areas	8.3	-	-
TOTAL	1830.3		66.04

^a Assuming that only half of the area can be grazed; rest is cultivated.

^b. Assuming 0.5 ha cultivated in this unit per family and 19,000 families, leaving 754.9 km² available for livestock.

^c. Uncultivated and saline areas, and maize stover from Table 3

Source: Timberlake et al. (1986).

Results

Soil Survey

The description of the soil units is based partly on data collected during the study, but also on the descriptions of Touber and Noort (1985) who carried out a detailed survey of the irrigation scheme. The 14 soil units determined can be divided into four major groups:

- soils of the interior dunes
- soils of the marine Pleistocene sediments on elevated areas
- soils of the marine Pleistocene sediments in the broad depressions
- soils of the recent fluvial sediments of the Limpopo river.

In general, the soils are quite fertile (except those of the interior dunes), but the soils from marine sediments in the broad depressions often show rooting limitations due to the heavy clay and to periodic inundation. A good correlation was seen in the field between soil type and pasture type, although the length of inundation was also an important factor.

Pastures/Vegetation

Four major pasture/vegetation units were determined and described:

1. Open Riverine Woodland. Characterised by large spreading trees of Ficus sycamorus, Trichilia emetica, Acacia albida and Sclerocarya caffra. Grass cover is mostly composed of Urochloa mosambicensis, Panicum maximum and Cynodon dactylon, with Setaria incrassata and Ishaemum afrum on the black clay soils. Most of the area is of light alluvial, well-drained soils, nearly all used for traditional cultivation.

2. Broad-leaved Woodland. A woodland or bushland type with Terminalia sericea, Sclerocarya caffra, Albizzia versicolor, Strychnos spinosa, S. madagascariensis, Tabernaemontana elegans and occasionally Hyphaene natalensis. Grass cover is mostly of Panicum maximum, Cynodon dactylon and Digitaria eriantha. Soils are sandy, and much is used for traditional cultivation. Burning is frequent.

3. Acacia Savanna or Woodland. A woodland to tree/bush savanna with Acacia welwitschli, Euclea undulate, A. senegal, A. nilotica, Omocarpum trichocarpum and Albizzia petersiana. A. xanthophloea is found in wetter areas. In the far northwest of the study area mopane (Colophosperum mopane) woodland occurs. Grass cover varies from Dactyloctenium geminatum and Sporobolus nitens to Themeda triandra depending on soil type. Termitaria sp. are often present. Soils are mostly sandy loams and cultivation is limited to the edges of the broad depressions.

4. Open Grassland. An open grassland with very few trees or shrubs of Acacia xanthophloea and A. nilotica. Grass cover is of Echinochloa colona, Eriochloa stapfiana, Panicum coloratum, Eragrostis cf. inamoena and Cyperus spp. Termitaria sp. are generally absent. These areas are flooded for varying lengths of time; soils are heavy black clays. There is no cultivation and the grasslands are only used for grazing.

Results from the livestock carrying capacity calculations are shown in Table 1, and total livestock carrying capacities of the different pasture/vegetation types are shown in Table 2. Gross estimates were also made of feed resources inside the irrigation scheme and are shown in Table 3.

Water Points

Excluding irrigation canals and the Limpopo river, 70 water points were found with water in the dry season. An additional 90 points which appear to contain water in the early dry season were noted from aerial photographs. The 70 points with water were divided into nine types: lakes, rivers, irrigation canals, small dams, small reservoirs, road excavations, boreholes, wells and natural depressions. Twenty major water points were noted and it was seen that the irrigation system, directly or indirectly (through raised groundwater levels filling excavations), is by far the most important source of water. There are 40 small reservoirs specifically made for use by cattle, but only 14 now contain water through the dry season due to silting up and lack of maintenance. The Mazimuchopes river dries up to a few pools in the dry season.

Table 3. Estimated feed resources inside the Chokwe irrigation area.

	Area (ha)	DM production/ ha/year	Feed available ('000 tons DM/yr)	Use factor	Cattlea supporting capacity ('000 head)
Uncultivated areas	5000	25000	12.5	0.7	3.2
Saline areas	2000	1000	2	0.3	0.2
Maize residue	7000	6000b	42	0.8	12.3c
Rice straw	n/a	3700d	43e	0.8	11.5f
Total	-	-	99.5	-	27.2

a. Assuming 2740 kg DM/year animal intake for a 350 kg animal.

b. ILACO (1981, p.476). Actual recorded grain yields are 1.8 t/ha with 13% moisture in the cool season, and 0.6 t/ha in the hot season (Woodhouse et al., 1986).

c. Assuming 6% protein.

d. Assuming 1:1 ratio of grain:rice. State farm production data averages 4 t/ha grain if a 50:50 ratio of the two varieties grown is used, however var. C4-63 has less vegetative growth (Woodhouse et al., 1986).

e. Assuming 1:1 grain:rice ratio and commercialised rice production data.

f. Assuming full urea treatment and 3 t DM/year animal intake. In practice urea-treated rice straw would be used as a supplement.

Source: Timberlake et al. (1986).

A notable feature of the distribution of water points is that most of them are situated on or near the edge of the irrigation scheme. Between the irrigation scheme and the Mazimuchopes rivers some 13 to 30 km distant, there is virtually no source of water, so cattle are overgrazing some areas and underutilising other good pasture areas 8 to 15 km away.

Discussion

Importance of Draft Power and Other Livestock Practices

The number and class of cattle in the area is reliably recorded every year on the basis of the dip tanks. It is probably an underestimate due to immigration of unregistered cattle and the possibility that owners with one or two head do not bring their animals to be dipped. Table 4 gives the numbers and classes of animals and shows the high percentage of oxen in the family sector herds compared to commercial herds. These cattle, however, are not evenly distributed, and great concentrations are found associated with villages bordering the northwest edge of the irrigation scheme. Average herd sizes have been calculated from livestock census data for different localities. They are very variable, ranging from 4.4 to 38.7 head/family, with a mean of 9 head (Vet. Fac., 1986).

Table 4. Cattle population, Chokwe district, 1986.

Sector	Oxen		Cows		Calves <1 yr		Total
	No.	% of sector	No.	% of sector	No.	% of sector	No.	% of total
Family	9179	18.9	16316	33.5	7362	15.1	48650	84.5
Private	156	1.8	3081	35.7	2842	32.9	8636	15.0
State	-	-	158	49.7	50	15.7	318	0.5
TOTAL	9335		19555		10254		57604

A recent study by Rocha (report in preparation) on traditional livestock practices carried out in three villages in the southwest of the study area and away from any major influence of the irrigation scheme, shows that only 2.1% of livestock owners interviewed did not have oxen, although 100% had a plough. The strong positive relationship between number of draught animals and area cultivated noted in this study is shown in Table 5. A Veterinary Faculty study (1986) into livestock practices in Chokwe District, also carried out by questionnaire, found that 27% of family sector animals were used for ploughing and/or transport, of which only 76% were oxen. The other 24% were principally cows but also included bulls and steers. Within the irrigation scheme a study into agronomic practices of families with small plots (Woodhouse et al., 1986) showed the great importance of animal draught power there, which varied with the cropping system and averaged 83% (Table 6).

Subsistence production of milk is widespread, although previously not fully recognised. Rocha's study found that 10.6% of livestock owners in Mazimuchopes do not have cows, but of those that do 93% milk in the wet season. Data on yields are still not available, but it can be assumed that yields are around 1 to 1.5 litres/day/producing cow. Milking is much less practiced in the dry season: questioned in July (dry season), only 26.5% of cattle owners said they milked their animals (Vet. Fac., 1986), but it is not clear if they were speaking generally or referring to that month in particular.

Table 5. Relationship between draught animal ownership and area cultivated around Mazimuchopes.

Number of draft animals per family	Mean area cultivated (ha)
1-2	1.1
3-5	1.9
6-9	3.6
9+	2.6

Source: Rocha (unpublished data).

Table 6. Ownership and importance of oxen in two major cropping systems in the Chokwe irrigation scheme.

		Maize	Rice	Mean
Plots ploughed with oxen (%)		92	65	83
Ownership of:
oxen	rainfed plot (%)
+	+	34	25	31
+	-	24	9	19
-	+	16	10	14
-	-	25	55	35

Source: Woodhouse et al. (1986).

Supplementary feeding appears to be an important practice of traditional livestock owners. In the Mazimuchopes study Rocha found that 32% of livestock owners gave maize stover and/or failed maize crops, 9% gave cut grass in addition to maize stover, and 2% make hay for dry season use. In the Chokwe irrigation scheme in 1987 farmers were selling maize stover at 1000 meticais (around 25% of the minimum monthly agricultural wage) per cart load (approximately 200-300 kg) at the farm, i.e. transport is not included. This however was at a time when grazing was poor because of a mid-season dry spell.

A measure of the sophistication of a farming system is its use of salaried labour. It is therefore interesting to note that 32% of livestock owners employ salaried labour for herding (Rocha, unpublished data), although the influence of receipts from migrant labour in South Africa probably plays an important role.

Carrying Capacity of Natural Pastures and Grazing Limitations

The calculated carrying capacities given in Table 1 show the good grazing potentials of the area. The importance of the open grassy depressions is very clear, although for some months of the year they are inundated and not utilised. This however is in the wet season when sufficient grazing is available in the Acacia savanna pasture type. Actual primary production data from these areas are not available and it is important to collect some.

If grazing were evenly distributed the livestock carrying capacity of the natural pastures in the study area is 50,340 adult head, perhaps 64,000 head with the existing herd structure. The number of animals in the study area (which does not cover the whole of Chokwe District) is estimated at around 47,500 head, giving a theoretical possibility of increase of 16,500 head. The problem of course is that grazing is not consistent with the distribution of grazing resources for three major reasons:

1. owners are afraid to graze the relatively unpopulated areas away from the irrigation scheme because of cattle thieving and the civil war situation;

2. most of the cattle are associated with the villages along the edge of the irrigation scheme and kraaled there at night: and

3. the great lack of dry season water points away from the irrigation scheme and the resulting long distances from grazing to water.

Overgrazing around the major villages is severe and some hundreds of animals die from hunger near water points in the late dry season. The two most practical ways of overcoming the problem are (a) to intensify livestock production with the use of forages or treatment of crop residues, or (b) provide water in the dry season in presently underutilized areas where this, rather than security or distance to the night kraal, is the limiting factor. The pasture study has made recommendations on some suitable locations for water points, which make use of runoff water that can be captured and stored in a small (approximately 100 x 50 x 3 m) reservoir. These reservoirs, many of which were constructed in the past but have not been maintained, only require re-excavation every two or three years and otherwise have no running costs.

Bush encroachment is found in the Acacia savanna and broad-leaved woodland vegetation types, particularly the former. Here it seems to be more acute in areas that are or were commercial ranches. However, some of the species causing bush encroachment in the Acacia savanna type are suitable for browsing.

Feed Resources in the Irrigation Scheme

The irrigation scheme is the centre of nearly all agricultural activity in the district, and thus produces large quantities of crop residues, principally rice straw and maize stover. There are, in addition, large areas of fallowland; estimates are as high as 13,000 ha, but 5,000 ha would seem a safer figure, and perhaps a further 2,000 ha of abandoned saline areas. In theory cattle are not allowed to enter the irrigation scheme except working animals because of the damage they cause to the canal banks and crops they might eat. But this is not enforced and large numbers of cattle can be seen inside feeding on maize stover at the end of the season, in fallow fields, and grazing on weeds and regrowth in the rice fields after harvest. It is rather difficult to quantify these feed resources, but estimates were made (Table 3). The theoretical carrying capacity was calculated assuming that the animals would be living entirely off these feed resources, which is far from the real situation as they are not available year round. However, their importance can be seen, not only at present when fallow areas and much of the maize stover is utilised, but also the potentials of the large quantities of rice straw which are now normally burnt. This requires an applied research programme into the best and most cost-effective methods of treatment to increase its acceptability and feed value at the level of small-scale livestock producers.

Cereals are not the only crops grown in the irrigation scheme. Cowpea (Vigna unguiculata), common bean (Phaseolus vulgaris), Lablab purpureus and pigeon pea (Cajanus cajan) are frequently found grown with maize. These increase the protein value of crop residues when grazed together, but foliage productivity data are not available. Lablab in particular shows promise as a dual-purpose crop-grain for human consumption and foliage for cattle. It is normally planted with maize under dryland conditions at the end of the main rains (March/April), but the plants are small. If planted one month earlier foliage production is much higher (Heemskerk, pers. com.). Some trials were carried out on Melilotus alba under irrigation as a cool-season crop after rice (Woodhouse et al., 1986). Forage dry-matter yields averaged 3.6 t/ha. Lucerne (Medicago saliva) has been grown commercially inside the scheme.

Outside of the irrigation scheme Cajanus, Lablab and Leucaena spp. would appear, from personal observation, to offer the best prospects as forages or dual-purpose crops that could be utilised as animal fodder by traditional farmers.

Conclusions and future lines for investigation

Chokwe District is undergoing a challenge as regards livestock production. It is an area with a strong livestock tradition in which the provision of draft power is of the greatest importance, and an area with a large agricultural potential due to fertile soils and a large irrigation scheme. The challenge is due to an unstable and rapidly changing situation caused by various factors:

(a) the civil war situation, resulting in a large influx of cattle and people from less-secure surrounding areas and a fear of grazing animals far from the villages;

(b) the recent concentration of villages, and therefore cattle, along the periphery of the irrigation scheme leading to localised but severe overgrazing;

(c) the impending return of much of the migrant labour force from South Africa which provides much of the cash and goods to the family economies of the area;

(d) land use conflicts between livestock and dryland arable farming concentrated around the villages;

(e) the conflict between livestock and the management of the irrigation scheme which severely limits grazing of cattle within its limits (before a major dry-season grazing area) due to damage caused to canals and crops;

(f) the insufficient quantity and quality of feed during the dry season for the draught animals which carry out an important part of the agricultural work inside and outside the irrigation scheme; and

(g) the poor distribution of dry-season water points away from the irrigation scheme which limits accessibility to pastures because of excessive distances from grazing to water points and finally to the night kraal.

With increasing land use pressure there is now a need for a more rational use of available resources (grazing, water, crop residues, etc.), and the need for intensification of traditional livestock production is clear. In the foreseeable future most agriculture will continue to be carried out by draft animals and will be in or close to the irrigation scheme. These animals need good feeding to maintain their strength, and the scheme will have a big role in providing their feed. Forages grown within the existing smallholder farming systems and better utilisation of crop residues are the main ways to achieve this.

Recent studies discussed in this paper give a general idea of traditional livestock practices in the area, the principal problems and the feed resources available. Some future lines for investigation regarding animal feeding can be drawn from this:

(a) Two or three detailed village-level studies need to be carried out in environmentally different zones in the region to determine and quantify livestock practices and constraints to production. These should include size and composition of individual herds, grazing practices, use of crop residues and quantification of weight losses (especially cows and oxen). This will ensure that future interventions by the extension service are appropriate and have a good impact.

(b) The relative importance and problems of goats which should be better adapted to shortage of grass and water.

(c) Determination of the relationship between cultivation in the irrigated areas and cultivation under dryland conditions as most smallholders in the irrigation scheme also have a plot outside and animal draught power is used in both.

(d) Determination of pasture and animal productivity from both natural pastures and crop residues and the determination of carrying capacities on a more detailed level.

(e) Determination and testing of appropriate methods of improving acceptability of rice straw, i.e. urea treatment or treatment with molasses. This testing should preferably be done through farmer-managed trials.

(f) Suitable methods of storing maize stover and rice straw for use later on in the season without losses in nutritive value.

(g) Intercropping of maize with Lablab, cowpeas and other suitable dual-purpose legumes with a view to improving the protein levels of crop residues. Some of the leafier legume varieties available from ICRISAT, IITA and other institutions presently available in the country can be used.

(h) The use of Cajanus as forage including selection of leafier varieties, its place in the cropping pattern and management techniques.

(i) The use of Leucaena as a forage reserve in dryland areas and around the village. Any limitations to its use (e.g. productive losses due to mimosine) should be investigated also.

(j) Economics and production effects of supplementation with urea/molasses and phosphate blocks.

The area of Chokwe is somewhat unique due to the influence of the irrigation scheme, but many of the traditional agricultural practices there are found over a large and important area of southern Mozambique. The impact of livestock or forage-related research, and good extension packages, on this farming system would be large. It would also greatly improve crop production in the area through a more efficient use of animal draught power, thus the rural family economies would become more stable.

The problems are now reasonably clear but still require some further quantification. Solutions have been suggested, but work has not really commenced on their viability. Given the limited resources in research a cooperative approach is required, with soil surveyors, land use planners, pasture agronomists, crop agronomists and animal production specialists working in coordination.

Acknowledgements

I am very grateful to Dr. Antonio Rocha for permission to use his unpublished data. Thanks are due to Drs. Celia Jordao and Wilhem Heemskerk for comments on the draft.

References

ILACO. 1981. Agricultural compendium for rural development in the tropics and sub-tropics. Elsevier, Amsterdam.

Timberlake, J., Jordao, C. and Serno, G. 1986. Pasture and soil survey of Chokwe. Comunicacao 50 (Serie Terra e Auga), INIA, Maputo.

Timberlake, J. and Reddy, S.J. 1986. Potential pasture productivity and livestock carrying capacity over Mozambique. Comunicacao 49 (Serie Terra e Agua). INIA, Maputo.

Touber, L. and Noort, L. 1985. Avaliacao de terra para agricultura regada na area do "SIREMO", Vale do Limpopo. Vols I, II. Comunicacao 26 (Serie Terra e Agua). INIA, Maputo.

Veterinary Faculty. 1986. Relatorio final das actividades de Julho de Brigada 7 - Chokwe. Veterinary Faculty, Eduardo Mondlane University, Maputo.

Woodhouse, P., Jimenez, H., Heemskerk, W., Spittel, M. and Slobbe, W. 1986. Smallholder farming systems research in the Chokwe irrigation area. Field Document 4, UNDP/FAO project MOZ/81/014. INIA, Maputo.