R&D experiences of IAR in NRM and crop–livestock interactions in the highlands of Ethiopia

Alemu G/Wold, Alemu Taddese and Asgelil Dibabe

Ethiopian Agricultural Research Organization, Addis Ababa, Ethiopia

Abstract

The paper describes the research activities and achievements of the Ethiopian Institute of Agricultural Research in the areas of natural resources management, livestock feed improvement and cattle production improvement, for the highland farming systems.

Introduction

Agriculture is the dominant economic sector in the country, accounting for about 45% of the GDP and 85% of export earnings. The highlands of Ethiopia comprise 45% of the country, include 95% of the cropped area and two-thirds of the livestock. Approximately 88% of the population live in the area, at an average density of 64 persons per km² (CSO 1988). The highlands reach up to 4620 m asl in altitude which provides a wide range of environments suitable for the growth of tropical, sub-tropical and temperate crops. A wide range of farming and land use systems has thus developed over several millennia in response to this diversity.

The major environmental and developmental issues which are of concern to Ethiopia include drought, poverty and food insecurity, soil erosion, land degradation, deforestation and over-grazing.

Annual soil loss in Ethiopia is estimated at between 1.5 and 3 billion tonnes. Of this, 50% occurs in croplands where soil loss may be as high as 296 tonnes/ha per year on a steep slope (SCRP 1987). Because the Ethiopian highlands support a large livestock population, the area experiences severe deficit of animal feed. One estimate (Hurni 1988) forecasts that all pasture land will be fully utilised by 2005. The demands for crop and for grazing land are increasingly in competition.

Ethiopia has diversified topographic and climatic conditions. The human population are mainly concentrated in the highland and semi-arid zones (46% and 42%) while the cattle population distribution varies among the different agro-ecological zones. Livestock are an important component in the highland mixed farming systems. Next to the highland zone, semi-arid, subhumid and arid zones support 16, 16 and 14% of cattle population respectively (Table 1).

Table 1. Human and cattle distribution in the major agricultural systems of Ethiopia.

Source: Modified from Jhanke (1982).

Research establishment and approach

As Ethiopia is dominantly an agricultural country, the well-being of its people and the country's economic development largely depend on the efficiency and strength of its agricultural system. Agricultural research in Ethiopia was institutionalised in 1966 when the Institute of Agricultural Research (IAR), now renamed Ethiopian Agricultural Research Organization (EARO), was established as a national institute with the following objectives:

• to identify farming system constraints

• to generate appropriate technologies to increase agricultural productivity across different agro-ecological regions

• to demonstrate technological packages.

IAR commenced its research undertakings at 5 major centres, which represent five agro-ecological regions of the country. The mandate programmes vary according to the ecology (Table 2). The beneficiaries of the research results are smallholder and commercial farmers.

Table 2. Major research centres representing different mandated agro-ecological zones.

During 1966–92 the IAR/EARO research was mainly focused on three major areas—crops, natural resources and livestock. The research was discipline oriented and agro-ecology focused. However, current research approach (since 1992) is mainly commodity oriented (multi-disciplinary). At present there are 26 commodities distributed to the federal and regional research centres.

Highland farming scenario

Current situation of highland resources and farming may be summarised as

• highly utilised, developed and over populated

• small farm size due to fragmentation

• reduced land productivity

• cultivation of steep slopes and over-grazing

• wide scale soil erosion and land degradation

• food deficit endemic

• destructive deforestation common.

• Livestock farming in the highland has the following characteristics

• the climate is favourable (temperate type) for human, livestock and crop

• high human and livestock population zone

• smallholder mixed farming is the dominant mode of production

• average farm size 1–5 ha

• average herd size 4–5 heads of animals

• cattle are sources of draft power, milk, meat and manure

• high fraction of the bovine biomass are oxen (30%)

• oxen are used for draft purpose 60–70 days per year

• draft power determine crop production

• cattle productivity is very low (draft, milk and meat)

• acute feed shortage and reduced grazing land.

Research achievements in the highlands

Natural resources management

Drainage improvement

Traditional farming has developed a wide range of drainage practices (drainage furrows, ridge and furrows, hand made broadbed and furrows, soil burning) and the use of low yielding crop varieties and late planting practices to avoid water logging period in Vertisols. It has been recognised that, with the exception of hand made broadbed and furrows, the technical efficiency of the traditionally applied surface drainage techniques is not sufficient to allow full use of the potentials of Vertisols (Mesfin Abebe 1982).

The use of improved drainage techniques such as the broadbed and furrow system (BBF) on these soils to remove the excess water in the main rainy season allows the possibility of re-using the drained water for irrigating the second crop after the harvest of the early planted first crop, thereby enhancing the utilisation of these potentially productive soils. Research results indicate that camberbeds of different widths for draining excess moisture and application of N and P fertilisers highly increase the yields of crops on Vertisols (Berhanu Debele 1985).

Fertiliser efficiency was highest with wheat with improved drainage (Table 3). Data in Table 4 demonstrate that both grain and straw yields were increased by planting under enhanced surface drainage conditions compared to flat planting. Grain yield increases of 33% and 100% were obtained over flat planting by using ridge and furrow, and broadbed and furrow methods of seed bed preparation, respectively.

Table 3. Influence of drainage and fertiliser on grain yields of wheat, teff and chick-peas, Ginchi, 1975–77.

C r o p	Grain Yield (Kg ha-1)
	Undrained		Drained
	Fo	F1	Fo	F1
Wheat	360	670	720	1530
Teff	740	1140	840	1470
Chick-pea	850	900	1220	1400

F_o :No fertiliser; 
F₁ :60/20 (N/P) kg ha^-1 for wheat and teff ; 27/30 (N/P)
kg ha^-1 for chick-pea. Source: Hiruy Belayneh (1986).

Table 4. Effect of method of seedbed preparation on the grain yield of durum wheat at Debre Zeit, 1987.

Method of seedbed preparation	Yield (kg ha-1)		Increase over  flat planting (%)
	Grain	Straw	Grain	Straw
Flat	1528	3102	–	–
Ridge and furrow	2037*	3843*	33	24
Broadbed and furrow	3009*	8095**	100	161

* Significantly different from yield on flat seedbed at P = 0.05 level.
** Significantly different from yield on flat seedbed at P = 0.01 level.
Source: Tekalign Mamo et al (1993).

Nutrient management

Sustainable agricultural production can be achieved only by proper use of soil resources, which includes the maintenance for the enhancement of soil fertility. Attempts have been made to improve the productivity of Ethiopian Vertisols through N and P fertilisation. Spectacular response to N and P fertilisation have been obtained by many crops including durum wheat, teff, barley, bread wheat and faba bean, and in most cases application of as high as 90 kg N ha^-1 resulted in maximum yield (Table 5). The high response to N is understandable because total N in most Vertisols is low. The efficiency of the N fertiliser applied could be improved through the use of nitrate forms of fertiliser and deep placement of split application of the ammonium fertiliser.

Table 5. Grain yield (kg ha^-1) of crops at different levels of N fertiliser in Vertisol of Ethiopia.                                                                                             

 – = not applied.

Source: Desta Beyene (1988).

Many crops have also obtained responses to P fertilisation. At Sheno, barley reached a peak yield of 2057 kg ha^-1 with the application of 13 kg P ha^-1 (Table 6). Significant P responses were obtained for teff and bread wheat at Ginchi.

Soil conservation

Runoff and soil loss studies were conducted under different soil covers at Holetta. The experiments were conducted on land with 6% slope in 1986 and 1987 using runoff plots. The different soil cover treatments showed significant differences (P<0.01) in the amount of both runoff and soil loss (Tables 7, 8).

In the grass-covered plots soil erosion was less than 1 t ha^-1 per year and was least compared with other treatments. Bare-fallowed plots experienced the highest soil erosion, 28 t ha^-1 per year, owing to the absence of any cover to protect the soil in the earlier part of the rainy season (Asrat Abebe 1992). Runoff also had similar effect to the cover crop treatments and was positively correlated with soil loss. Runoff was higher for bare-fallowed plots followed by wheat and teff-covered plots. Natural grass cover resulted in the lowest runoff as a result of the retarding effect of the dense grass growth throughout the season.

Table 6. Grain yield (kg ha^-1) at different levels of P fertiliser in Vertisol of Ethiopia.                                                                  

 – = not applied.
Source: Desta Beyene (1988).

Table 7. Effect of different soil covers on soil erosion (t ha^-1) at Holetta.                            

Mean followed by the same letter in the column are not significantly different at P<0.05 using Duncan’s multiple range test.
Source: Asrat Abebe (1992).                        

Watershed management

A watershed is made up of the natural resources in a basin, especially the water, soil and vegetative factors. In order to make the improved practices more widely applicable and ensure that the recommended packages are environmentally safe, research has been started at watershed scale in Ginchi to develop the result of the plot based research into recommended watershed planning, because water drained from individual field plots can cause widespread land degradation elsewhere. Such improved watershed-based drainage system will enhance cropping systems options and overall production in a more sustainable way. Watershed research involves systematic development of soil conservation and water control techniques that will be appropriate to the farmer endowments.

Table 8. Effect of different soil covers on runoff (m³ ha^-1 per year) at Holetta.

 Source: Asrat Abebe (1992).

It was evident from the work in the Ginchi watershed conducted under the Joint Vertisol Project with Ministry of Agriculture, ICRISAT, ILRI and Alemaya University of Agriculture that farmers were aware of the advantages and need for improved field drainage. Ginchi farmers appreciated the need for a communal drain which will solve the problem of waterlogging.

Extension of the BBF in the Gimbichu area showed that the mean grain yield of durum wheat ranged from 2900 to 4300 kg ha^-1 for 50 farmers (Table 9). Results of bread wheat and teff demonstration at Ginchi watershed site indicated that the range in grain yield of wheat variety ET–13 was 1480–2560 kg ha^-1, whereas the grain yield of teff ranged from 1210–2200 kg ha^-1.

Table 9. Wheat grain yields from Gimbichu BBF technology transferability study, 1995.               

Livestock feed improvement

Crop residue utilisation

Crop residues represent a large amount of feed and are regularly conserved in the dry season as a sole feed for animals in the highlands of Ethiopia. About half of the animal feed in this zone comes from crop residues (straws, stubble and chaffs). Teff, wheat and barley straws are major residues used.

In addition to animal feed, crop residues are also used for other purposes like fuel, construction materials and mulching soils. According to Seyoum Bediye and Zinash Sileshi (1989), 63%, 7%, 20% and 10% of the cereal straws produced in the central Shoa zone are used for animal feed, bedding, fuel and house construction, respectively.

Crop residues in the Ethiopian highlands are usually fed to animals without supplementation. When offered as a sole diet, crop residues cannot fulfil even maintenance requirement of animals due to their low palatability, digestibility and intake (Table 10). They are also low in protein, energy and some important mineral nutrients (Seyoum Bediye and Zinash Sileshi 1989). Chemical composition, and energy values of the major crop residues used as animal feed in the highlands of Ethiopia are given in Table 11.

Table 10. Energy and protein supply from an average quality straw when fed alone to ruminants.                                                                                                                     

 Source: Seyoum Bediye and Zinash Sileshi (1989).

Table 11. Chemical composition, digestibility and energy values of some crop residues.                                                                    

 Source: Seyoum Bediye and Zinash Sileshi (1989).

Table 12. Teff straw intake, daily live weight gain and total DM intake of male Horro sheep as affected by different protein supplements.                              

Mean followed by the same letter in the column are not significantly different at0.05 using Duncan’s multiple range test.

Source: Lema Gizachew (1993).

Improved forage crops development

Malnutrition and under nutrition are the major constraints lowering the productivity of livestock in Ethiopia. Natural pastures provide more than 90% of the livestock feed but cannot fulfil more than half of the nutritional requirement of the animals mainly due to their poor management, low productivity and poor quality (Table 13). Crop residues and agro-industrial by-products are also poorly utilised. This results in over all low productivity of the animals. This situation can be improved by introduction of improved forages into the farming system.

Table 13. Yield, CP content and in vitro organic matter digestibility of different classes of feed.                                                                                    

To seek technical solutions for the indicated feed shortage problems, IAR/EARO in the past three or so decades has made considerable effort to test the adaptability and yield potential of different species of pasture and fodder crops under a range of environmental conditions to select suitable species for different agro-ecological zones of the country. As a result, six improved grasses, four herbaceous legumes and two tree legumes were selected for the highland zone. In general, the selected forage crops were found to be higher yielding than naturally occurring swards and are proven to have higher nutritional value (Table 13). The length of growing period (green stage) is also longer for improved forages than for native pastures. Among the selected grasses, Napier grass (Pennisetum purpureum), Rhodes grass (Chloris gayana) and Panicum coloratum were more productive, their annual herbage yields ranging from 10–15 t ha^-1 DM.

Inspite of all this potential, the utilisation of improved forages on farm is very minimal. Fodder production on arable land for livestock feeding is not practised by smallholder farmers except in very few areas where commercial dairy or beef fattening enterprises are undertaken by few individuals near urban centres where market outlets are available for sale of the produce.

Cereal–forage crops integration

The major constraint to plant and animal production in the highlands is deficiency of nitrogen (Jutzi et al 1987; Tothill 1987). Nitrogen deficiency can be overcome by application of fertiliser, manure or biological nitrogen fixation by leguminous plants. Application of commercial fertiliser is expensive and is often erratically available in subsistence oriented smallholder farming system. Except in very limited homestead areas, the use of manure for production of major crops is also minimal in the highlands due to its several other uses. Thus, leguminous plants such as herbaceous and tree legumes may be economical and feasible nitrogen sources of significance for such farming systems. Legumes have two major functions in mixed farming systems. They enhance soil fertility thereby improving crop and forage yields, and improve quality of forage for animal production.

Forage legumes can be integrated into the highland farming system in different ways. Growing them in rotation or inter-cropping them with cereals, alley cropping and sequential cropping are some of the approaches (Jutzi et al 1987). With these types of cropping systems, both crop and livestock derive benefits exploiting the assets of forage legumes. Higher grain yields are obtained from the crop and yield of crop residues are improved for livestock feeding (Table 14).

Table 14. Mean grain and straw yields of wheat grown in rotation and inter-cropping with forage legumes at different IAR centres.                                                                                            

Source: IAR unpublished data.

Legume plants have the ability of fixing atmospheric nitrogen as a result of symbiosis with soil bacteria. As the nodules and legume roots decay, the nitrogen they contain is mineralised and becomes available thus increasing the yield of crops growing in association or rotation with the legume.

As a result of experiments done at Holetta, some suitable annual forage legumes such as Trifolium spps and Vicia dasycarpa have been selected for cropping in rotation with barley and wheat thus increasing grain yields of the cereals. Several other studies conducted at various IAR/EARO Centres have also demonstrated the possibility of successfully producing forage legumes in association with cereal food crops without imposing much reduction on yields of the associated crops (Table 14).

Cattle production improvement

Indigenous breeds characterisation and crossbreeding

From 1966–1974, the Department of Animal Sciences concentrated its research efforts on characterising three indigenous zebu breeds at three research centres. The major findings indicated that for the local breeds, age at 1st calving on the average was 43 months, milk yield on the average was 618 kg per lactation and lactation length was 150 days.

From 1974–1988, IAR/EARO conducted crossbreeding studies crossing three indigenous breeds with three exotic dairy breeds (Friesian, Jersey and Simmental) under four varying agro-ecological conditions. Major findings are: age at 1st calving—36 months, milk yield—1792 kg, and lactation length—320 days.

Crossbred dairy cows for draft

From 1989–1992, IAR/EARO in collaboration with ILCA/ILRI conducted studies on-station focussing on power output of crossbred dairy cows, effects of draft on milk yield, feed intake, and reproduction. The major findings were:

• milk yield: 1770 kg per lactation

• work output: 269 MJ/cow per annum

• oestrus manifestation delayed by 200 days for working crossbred cows.

As a follow up of on-station results, since 1992 crossbred cows were distributed to farmers around Holetta for on-farm studies. The following results were obtained:

• milk yield (305 days): 1501 kg per lactation

• work output: 135 MJ/cow per annum

• oestrus manifestation delayed by 221 days.

Oxen traction study

The power output of the male animals from different crossbreds and local oxen were studied at Holetta. Results are summarised in Table 15.

Table 15. Working speed, power and work outputs of local oxen and its crossbreeds.    

Source: IAR unpublished data.

Summary

IAR/EARO during the past 3 decades of research services have generated technological packages to increase agricultural productivity. However, to support attainment of national goals of food self-sufficiency, poverty alleviation and environmental protection through sustainable technology packages, the research approach should focus to:

• integrate crop–livestock production systems

• strengthen research–extension linkage

• prioritise research programmes in the highlands

• increase trained manpower and research facilities.

References

Asrat Abebe. 1992. Assessment of runoff and soil losses under different cover crops and slope length. In: Natural resource management for conservation and development. Proceedings of the Second Natural Resources Conference, Addis Ababa, Ethiopia, 10–13 May 1990. pp. 50–56.

Berhanu Debele. 1985. The Vertisols of Ethiopia, their characteristics, classification and management. In: Fifth meeting of the Eastern Africa Sub-Committee for Soil Correlation and Land Evaluation. Proceedings of a workshop, held in Wad Medani, Sudan, 5–10 December 1983. World Soil Resource Reports 56. FAO (Food and Agriculture Organization of the United Nations), Rome, Italy. pp. 31–54.

CSO (Central Statistical Office). 1988. Statistical abstracts, 1968–1988. CSO, Addis Ababa, Ethiopia.

Desta Beyene. 1988. Soil fertility research on some Ethiopian Vertisols. In: Jutzi S.C., Haque I., McIntire J. and Stares J.E.S. (eds), Management of Vertisols in sub-Saharan Africa. Proceedings of a conference held at ILCA, Addis Ababa, Ethiopia, 31 August–4 September 1987. ILCA (International Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 223–231.

Hiruy Belayneh. 1986. Drainage benefits for wheat, teff and chick-pea on heavy clay soil in central Ethiopia. In: Desta Beyene (ed), Workshop on review of soil science research in Ethiopia, Addis Ababa, Ethiopia, 11–14 February 1986. IAR (Institute of Agricultural Research), Addis Ababa, Ethiopia. pp. 12–18.

Hurni H. 1988. Degradation and conservation of the resource in the Ethiopian highlands. Mountain research and development 8(2&3):123–130.

Jahnke H.E. 1982. Livestock production systems and livestock development in tropiocal Africa. Kieler Wissenschaftsverlag Vauk, Kiel, Germany. 253 pp.

Jutzi S., Haque I. and Abate Tedla. 1987. The production of animal feed in the Ethiopian highlands: Potentials and limitations. In: Proceedings of the first national livestock improvement conference, Addis Ababa, Ethiopia, 11–13 February 1987. IAR (Institute of Agricultural Research), Addis Ababa, Ethiopia. pp. 141–142.

Lema Gizachew. 1993. Comparisons of legumes hay, urea and noug cake as protein supplements to Horro sheep fed on teff straw. In: Proceedings of the fourth national livestock improvement conference, Addis Ababa, Ethiopia, 13–15 November 1991. IAR (Institute of Agricultural Research), Addis Ababa, Ethiopia. pp. 211–215.

Mesfin Abebe. 1982. Uses of improved seed bed and fertilisers as an alternative to soil burning or guie. Ethiopian journal of agricultural science 4(1):1–9.

Nsahlai I.V., Zinash Sileshi, Seyoum Bediye and Umunna N.N. 1996. Nutritional characteristics and strategies to enhance utilization of tropical feeds for low resource livestock producers. In: Proceedings of the fourth national conference of Ethiopian Society of Animal Production, Addis Ababa, Ethiopia, 18–19 April 1996. ESAP Proceedings. ESAP (Ethiopian Society of Animal Production), Addis Ababa, Ethiopia. pp. 40–56.

SCRP (Soil Conservation Research Project). 1987. Soil conservation progress report. Ministry of Agriculture, Addis Ababa, Ethiopia.

Seyoum Bediye and Zinash Sileshi. 1989. The composition of Ethiopian feeds. IAR Research Report 6. IAR (Institute of Agricultural Research), Addis Ababa, Ethiopia. 34 pp.

Tekalign Mamo, Abiye Astatke, Srivastava K.L. and Asgelil Dibabe (eds). 1993. Improved management of Vertisols for sustainable crop–livestock production in the Ethiopian highlands: Synthesis report 1986–92. Technical Committee of the Joint Vertisol Project, Addis Ababa, Ethiopia. 199 pp.

Tothill J.C. 1987. Application of agro-forestry to African crop–livestock farming system. ILCA bulletin 29:20–23. ILCA (International Livestock Centre for Africa), Addis Ababa, Ethiopia.