The impact of drought on sorghum production, and farmer's varietal and trait preferences, in the north eastern Ethiopia: implications for breeding

ABSTRACT

Purpose: Sorghum [Sorghum bicolor (L.) Moench] has been cultivated for centuries as a staple food crop for millions of people in sub-Saharan Africa and Asia. In Ethiopia a total of 4.34 million tons of sorghum is being produced per annum, predominantly in the arid and semi-arid areas. However, the yield and quality of sorghum is affected by a wide array of production constraints, notably severe and recurrent drought stress. The aim of this study were to determine the impact of drought on sorghum production and productivity over time and space, and to identify farmers’ trait preferences, production constraints and coping strategies when dealing with drought in north eastern Ethiopia.

Materials and methods: Participatory rural appraisal (PRA) was employed in three administrative zones of north eastern Ethiopia. One Woreda from each Zone and two Kebeles from each Woreda were selected on the basis of sorghum area coverage, production, consumption and prior information on the intensity, duration and spatial coverage of drought. In each kebele, 30 respondents were selected for interview and 12 key informants were selected for group discussions and transect walk personal observations. Data collected from 180 respondents was subjected to statistical analysis and the information gathered from 72 key informants through focus group discussions and transect walk observations were used in discussing the results.

Results and discussion: The present study found that productivity of sorghum was challenged by recurrent droughts, Striga infestation, insects, birds, diseases, a lack of varieties with farmers-preferred traits and high yield potential, limited policy support, a lack of improved seed system, poor sorghum production practices and application of crop input and poor soil fertility, in a decreasing order of importance. Among the listed sorghum production constraints, severe drought in the post-flowering stage was identified by most interviewed farmers as the leading constraint across the three study zones. Focus group discussions and transect walk observations held in each Kebele revealed that farmers’ had lost numerous valuable local landrace varieties due to extreme drought conditions over the years. A significant number of interviewed farmers preferred to grow high grain and biomass yielder medium-maturing sorghum varieties which can be sown at the normal planting time but which would escape post-flowering drought.

Conclusion: Overall, sorghum breeding programme should be directed at developing farmers’ ideal sorghum varieties with high grain and biomass yield, adequate level of drought and Striga tolerance. In addition, development of farmer preferred medium-maturing sorghum varieties suitable for April planting should be strengthen to boost its productivity and to increase varietal adoption rate in the area.

KEYWORDS:

• Drought
• sorghum
• participatory rural appraisal
• medium-maturity
• grain yield

Introduction

Sorghum [Sorghum bicolor (L.) Moench] is the fifth most important cereal grain after maize, rice, wheat and barley in the world (FAOSTAT 2017). It has been cultivated for centuries as a staple food crop in much of sub-Saharan Africa and Asia. It has remarkably wide adaptation and tolerates high temperatures and drought stress. It grows under high radiation, inadequate and erratic rainfall and in soils of poor structure, low fertility and low water holding capacity.

Sorghum is an important source of food and feed, particularly in the arid and semi-arid regions where other cereal crops such as maize and wheat fail to grow (Duodu et al. 2003; Reddy et al. 2004). Considering recent climate changes, sorghum production could reduce the expected food shortages (Abdalla and Gamar 2011). In developing countries, including Ethiopia, more than 500 million people consume sorghum as their principal food source (Burke et al. 2013). Sorghum is a gluten-free cereal used as a whole grain or processed into flour to provide essential nutrients including carbohydrates, protein, vitamins and minerals, and nutraceuticals such as antioxidants, phenolics and cholesterol-lowering waxes (Taylor et al. 2006; Perazzo et al. 2014).

In Ethiopia a total of 4.34 million tons of sorghum is being produced per annum. The mean yield level in the country is estimated at 2.4 t ha⁻¹. The crop is the major food cereal after maize and tef in terms of number of growers, area coverage and grain production in the country (FAOSTAT 2017). It is utilised in various forms, such as for making the local bread, ‘Injera’, and for the preparation of local beverages such as, ‘tela’ and ‘areki’. Grain from some sorghum varieties is cooked as a roasted or boiled grain. Sorghum stalks are used as feed for animals, and as housing and fencing material. The crop is highly adapted to the lowland and drier parts of Ethiopia owing to its considerable drought resilience.

Despite its ability to grow in the arid and semi-arid areas of sub-Saharan Africa including in Ethiopia, the yield and quality of sorghum is affected by a wide array of production constraints such as the use of low yielding traditional varieties, which keep its productivity low. Drought, infestations by Striga hermonthica and soil salinity are the major stresses that limit sorghum production and productivity in the world (Zhu-Salzman et al. 2004). Among these, drought stress and Striga damages are the most important production constraints to sorghum production in Ethiopia (Gebretsadik et al. 2014). Drought is a major constraint in sorghum production worldwide and is considered as the most important cause of yield reduction in crop plants (Sabadin et al. 2012; Besufekad and Bantte 2013), especially in water-limited areas of the world including parts of eastern and southern Africa. Striga infestation is often linked with poor soil fertility, resulting in poor harvests and consequently of hunger (Ejeta 2007). The impact of Striga is more pronounced in areas under moisture and nutrient stresses.

In sorghum, there are two primary types of drought responses including pre-flowering and post-flowering, which are under the control of two different sets of genetic mechanisms. Pre-flowering refers to the stage from panicle differentiation to flowering, while post-flowering refers to the stage between flowering to grain development (GS-3) (Burke et al. 2010). Pre-flowering drought tolerance responses of sorghum includes reductions in panicle size, seed number, and grain yield. Post-flowering drought tolerance encompasses rapid premature senescence, which leads to reductions in seed size, yield loss and stalk lodging (Sanchez et al. 2002; Burke et al. 2010).

Much research effort has been spent trying to understand drought tolerance mechanisms in sorghum in order to breed for drought tolerant genotypes that will tolerate the frequent moisture deficit events in Ethiopia. These studies have recommended a number of soil and moisture conservation practices, which include tillage operations, tie-ridging and mulching to reduce the effects of drought (Teshome et al. 1995). Efforts have also been made to develop early maturing sorghum varieties that are adapted to areas where regular moisture scarcity is detrimental to sorghum production. In Ethiopia, more than 51 early maturing sorghum varieties are currently available for use in such environments (ABoA 2017; SARC 2017).

Despite the long-term efforts made to breeding for tolerance to drought in sorghum, advances made in developing improved varieties with adequate levels of drought tolerance using indigenous landraces combined with farmers’ and market-preferred grain, and above ground biomass traits have been limited. Farmers still prefer to plant local sorghum landraces rather than introduced varieties because local landraces produce larger volumes of biomass for animal fodder, fuel, and construction material in good cropping seasons. Therefore, sorghum breeding programmes should ensure that the new varieties satisfy the preferences of the farmers through participatory variety selection to create sustainable adaptation of the released varieties and their production packages. Therefore, there is need for a diagnostic survey using a structured questionnaire to collect information on impact of drought, and on farmer's varietal and trait preferences of sorghum in north eastern Ethiopia. This information was gathered through participatory rural appraisal (PRA).

Participatory rural appraisal is one of the most effective and popular way to gather information in rural areas. The basic concept of PRA is to learn from rural communities. It is a bottom-up approach developed in the early 1990s and stands on the principle that local communities are creative, capable and can do their own investigations, analysis and planning (Chambers 1992). Therefore, the objectives of this study were to determine the impact of drought on sorghum production and productivity over time and space, and to identify farmers’ production constraints and coping strategies when dealing with drought in north eastern Ethiopia.

Materials and methods

Description of the study areas

The study was carried out in the north-eastern Amhara Regional State of Ethiopia in three selected major sorghum growing administrative zones namely, North Wello, South Wello and Oromia Special Zones. The study areas represent semi-arid to arid lowland agro-ecologies known for their sorghum production. The geographical descriptions of the study zones are shown in Figure 1 and their typical agro-ecological characteristics are summarised in Table 1.

Figure 1. Map of Ethiopia showing the study zones.

Table 1. Major agro-ecological characteristics of the study zones.

Study zone	Agro-ecology	Altitude (masl)	Geographic position	Annual rainfall (mm)	Temperature (°C)
					Min	Max
North Wollo	Semi-arid	1450–2400	11°49′50.49′′N 39°35′39.94′′E	700–1000	19	34
South Wollo	Semi-arid	1600–2700	11°08′00.36′′N 39°37′58.32′′E	800–1250	16	31
Oromia Special	Semi-arid	1400–2100	10°42′58.64′′N 39°52′04.61′′E	750–1300	21	33

Key: masl = meters above sea level.

The priority objective of farmers in the study areas is to secure an adequate family food supply throughout the year. Therefore, farmers in these areas practice mixed crop and livestock farming, which is the predominant source of farmers’ livelihoods. Sorghum and tef are the major food crops in terms of the area they are planted and volume of production obtained (CSA 2015). The second priority is to earn cash incomes for household expenditures such as farm inputs, school fees, taxes and medical costs. This is also achieved through the production of cash crops such as sesame, noug, soybean, pepper, and in years of crop failure through the sale of livestock. The study sites are the major production and diversity belt for sorghum in the country. Sorghum, the main food source, is made into ‘injera’, which is the preferred dish in the area. Sometimes sorghum is prepared in the form of porridge, roasted ‘kolo’, cooked ‘nifro’ or locally brewed ‘tella’.

In the study site, tef is the preferred food crop. However, farmers give greater importance to sorghum and expect to harvest more grain and biomass than from tef. Sorghum is also harvested for its green-head as a food source in the immature stage, for roasted grains when tef is still in its vegetative stage, and the food supply is short.

Sampling method

Purposive sampling was employed to include the major sorghum growing agro-ecologies and zones for the study. According to the Ethiopian administrative classification a zone is a large administrative unit below region. From each administrative zone one woreda was selected. A zone is composed of a number of woredas, while a woreda is an administrative level that is equivalent to a district and composed of a number of kebeles. A kebele or neighbourhood association is the smallest unit of local government. From each woreda two kebeles known for experiencing recurrent droughts were purposely selected. The target woredas and kebeles were chosen on the basis of sorghum area coverage, production, consumption and prior information on the intensity, duration and spatial coverage of drought with the assistance of zone and woreda agriculture office. Overall, the survey was conducted in six kebeles selected from three woredas. A total of 180 farmers that cultivated sorghum during 2014/15 cropping season participated in the study. In each kebele, 30 sorghum growing men and women farmers were selected and interviewed with the participation of kebele level developmental agents and three researchers (a Socio-Economist, an Agronomist and a Plant Breeder) drawn from Sirinka Agricultural Research Center. The survey was conducted between December 2014 and January 2015 when farmers were harvesting their sorghum. In each Kebele, focus group discussions were held involving a group of 12 key informants (7 male and 5 female farmers) and the proceedings were documented. Similar group was used in each Kebele to record complementary information through personal observations in a transect walk through each of the sampled Kebeles.

Data collection and analysis

Data were collected through individual interviews, observations made by transect walks across selected kebeles, and focus group discussions with farmers. Semi-structured questionnaires were used to collect information on cropping systems, the impact of drought and other production constraints, drought coping mechanisms, farmer's varietal and trait preferences, sorghum utilisation, seed sources and planting periods. Drought tolerant sorghum landraces widely used by farmers were identified and collected with their local names.

In each kebele, focus group discussions were held among key informants chosen among elders and farmers well-known within the community and their experiences and interests were recorded. Focus group discussions were done at Adisalem and Gedemeyu village for North Wello Zone, Ancharo and Bosena for South Wello Zone and Jewuha and Mutifecha for Oromia Special Zone in December 2014. The discussion points were impact of drought, sorghum production constraints, sorghum varietal diversity, varietal food making quality, importance of sorghum, farmers’ varietal and trait preferences and drought copping mechanisms. Additional information was recorded through personal observations made during transect walks through each of the sampled kebeles. During the transect walk observations were made on sorghum fields to assess impacts of recurrent drought, maturity period, uses of sorghum, landrace diversity, cultural practices such as weeding and row planting, current crop stand, farmers’ varietal and trait preferences and drought coping mechanisms.

Both qualitative and quantitative data were collected through questionnaires. Data were coded and subjected to analysis using the SPSS statistical package version 16.0. The processes of qualitative data analysis included identifying common observations, concepts, ideas, and issues related to cropping systems, as well as elements and indicators of drought. Quantitative data that was collected from primary sources were subjected to statistical summaries such as means and chi-square analysis. Sorghum productivity data was subjected to a one tailed t-test using the SAS statistical software package version 9.3 (SAS 2011). A one tailed t-test was conducted using the mean grain yield of surveyed zones during the 2015 cropping season.

Results and discussion

Demographic descriptions and socioeconomic aspects

A total of 180 smallholder farmers (60 per administrative zone) who had planted sorghum during the 2014 main cropping season were interviewed. In addition, a total of 72 participant farmers were involved for focus group discussions and transect walk observations. Of the total 72 key informants 30 of them were female farmers. Interviewed participants’ gender, family size, age, education background and number of farm animals owned are summarised in Table 2. The percentage of male farmers was higher than female farmers in the surveyed zones except in the South Wello Zone. The Oromia Special Zone had a higher percentage (80%) of interviewed male farmers than the North Wello Zone. The South Wello Zone had the lowest percentage (46.7%) of interviewed male farmers. The South Wello Zone had the highest percentage of female sorghum growers (53.3%) while Oromia Special Zone had the lowest percentage (20%) followed by North Wello Zone (28.3%). Despite the above gender imbalance during the interview, female farmers were purposely included in the focus group discussion to collect reliable information on the food making quality of sorghum varieties.

Table 2. Proportion of respondents aggregated by sex, family size, age, education level and farm animals owned across the three study zones (N = 180) in the north eastern Ethiopia.

Variables	Zone			Total
	North Wello	South Wello	Oromiya Special
Sex
Male	71.7	46.7	80.0	66.11
Female	28.3	53.3	20.0	33.89
Family size (number of individuals)
<5	58.3	45.0	53.3	52.2
5–6	33.3	45.0	35.0	37.0
>7	8.3	10.0	11.7	10.0
Significance	df = 4	X^2  = 2.641^a		P-value = 0.620
Age (years)
<45	46.7	36.7	45.0	42.8
45–65	30.0	58.3	45.0	44.4
>65	23.3	5.0	10.0	12.8
Significance	df = 4	X^2  = 14.665^a		P-value = 0.005
Education level
Illiterate	33.3	35.0	31.7	33.30
Read and write	25.0	33.3	31.7	30.00
Grade 3–6	20.0	10.0	25.0	18.30
Grade 7–8	13.3	16.7	8.3	12.8
Grade 10 or 12 complete	8.3	5.0	3.3	5.60
Significance	df = 8	X^2  =  7.748^a,		P-value = 0.458
Number of farm animals owned
<8	16.7	35.0	18.3	23.30
9–11	30.0	45.0	23.3	32.80
>12	53.3	20.0	58.3	43.90
Significance	df = 4	X^2  =  21.668^a		P-value = 0.000

In all the surveyed zones except the South Wello Zone most of the interviewed sorghum growers had family sizes of less than five. The North Wello Zone had the most interviewed farmers with a family sizes of less than five (58.3%) followed by Oromia Special Zone (53.3%). Of all the respondents, 37.0% had a family size between 5 and 6. Only a limited number of interviewee had a family size greater than seven, with the most (11.7%) being in the Oromia Special Zone. Focus group discussions revealed that family size has a vital role in the rural farming systems of the three surveyed zones. Adult males not too old to work provide the bulk of family labour, together with boys of > 9 years old, who often help with field activities. Married women, particularly those with children > 9 years old, are mostly responsible in house work, to fetch water, to nurture children, to collect firewood and to sell grain in small quantities in the local markets. In addition, women actively participate during sorghum planting and harvesting activities which are the most labour intensive activities. Sorghum planting periods are very critical in the three surveyed zones of north eastern Amhara. The time of planting should be carefully scheduled due to: 1) unpredicted falls of first rain; 2) the necessity of planting as large area as shortly as possible with the onset of rain; and 3) to escape seeding late rains for drought management. The farming system forces farmers to undertake intensive field activities with whole family working from sunrise to sunset. In female headed households, it is normal to see women working in the fields. Relatively large farmland owners mobilise extra labour through working groups (teams) of neighbours, commonly known as ‘Debo’ or ‘Wonfel’. At the critical stages of a busy agricultural season, team work helps to keep the morale of the farmers. It is also an effective means in time management. A Debo is a team of people working together to support family relatives or intimate friends who have a labour shortage at the stages of planting, weeding or harvesting. A Wonfel is a relatively a small group of people working cooperatively at a village level to complete the tasks of planting, weeding, harvesting and threshing. Each Wonfel member receives these services in rotation on a scheduled timeframe.

The North Wello Zone had the highest percentage (46.7%) of respondents aged less than 45 years, while South Wello had the lowest percentage (36.7%) preceded by Oromia Special Zone (45%). South Wello had the highest percentage (58.3%) of respondents aged between 45 and 65 years. More (23.3%) respondents aged above 65 years old were interviewed in North Wello with fewer interviewed in Oromia Special Zone (10%) and the least in South Wello (5%). A majority (44.4%) of respondents were between 45 and 65 years of age. Inclusion of 12.8% of respondents aged more than 65 years accessed their long term knowledge of sorghum diversity and sorghum cultivation trends.

The South Wello Zone had the most illiterate farmers (45%). In the same zone 31.7% of the respondents are able to read and write. The Oromia Special Zone had fewest illiterate farmers (36.7%) followed by the North Wello Zone (38.3%). Education has an indispensable effect on the lives of rural farming community. The focus group discussion revealed that farmers who are able to read and write acted as positive role models for others around them. A more highly educated community may also lead to more active participation in all developmental activities, and in particular in resource management.

Livestock rearing is an integral part of the farming systems of the north eastern Amhara. Local breeds of cattle, sheep, goat, donkey, camel and chicken are reared by households. Cattle graze in community pastures and farm borders while goats and sheep range freely over domestic sites and scrublands. The Oromia Special Zone had the highest percentage (38.3%) of respondents who had less than 4 farm animals, while South Wello had the lowest percentage (28.4%) followed by the North Wello Zone (31.7%). The South Wello Zone had the highest percentage (48.4%) of respondents who kept between 4 and 7 farm animals per household while the North Wello Zone had the lowest percentage (35%), followed by Oromia Special Zone (38.3%). The North Wello Zone had the highest percentage (33.3%) of respondents who had more than 8 farm animals per household while in South Wello and Oromia Special Zones this was 23.3% of respondents. Experienced farmers in the focus group discussions pointed out that the ownership of cattle was directly related to the availability of forage for them. The commonly used animal feed residues were tef straw, weeds collected from farm fields and sorghum stalks. Farm animals, particularly oxen, are the main source of draft power in the lowland sorghum growing agro-ecologies of north eastern Amhara. From focus group discussions, it was learned that traditional plowing with oxen is the most common way of land preparation, therefore most of the surveyed farmers owned at least a pair of oxen. A few farmers across the three zones had one ox. These farmers pair with another single ox owner in the village (locally referred to as ‘mekenajo’) to cultivate their lands based on mutual agreements.

A survey previously conducted in South Wello, North Shewa and Metekel administrative zones in 2011 the mean farm size of each interviewed household was 2.34 ha⁻¹ (Gebretsadik et al. 2014). This finding concurs with the present study, where in the South Wello Zone the mean farm size was 1.44 ha (Beyene et al. 2016). Similarly, the mean farm size in the Oromia Special Zone was 2.0 ha⁻¹.

Cropping system

Crop production was the leading livelihood activities of all households in the surveyed areas. The predominant cropping practice was sole cropping. Transect walks across the six selected kebeles showed that crop rotation is only limited to few crops. Almost all agricultural fields were predominantly covered by sorghum and tef. The main crop production period occurs during summer (‘meher’) season during the months of April to December. In some areas double cropping is a common farming practice as a result of effective rainfall in the months of January, February and March, which is commonly known as the spring (‘belg’) season. Overall, in the study areas farmers relay on their sorghum and tef crops. They are not practicing crop rotation much due to unpredictable rainfall conditions which are inadequate to support other crops. Crop rotation enhances efficient resource utilisation, minimises weather risks, and reduces insect pest and disease prevalence (Cothern etal. 2000). It is reported that a sorghum crop yields 6 tons per hectare by taking up about 105 kg nitrogen, 15 kg each potassium and phosphorus from the soil (Hulse 1980). In the north eastern Amhara recurrent drought conditions minimise farmers’ crop choice option.

The mean area cultivated per crop depended on the total land holding, and the priority that each farmer attaches to a crop, the number of crops cultivated per household and the agro-climatic conditions of the area. Annual crops are grown for household subsistence. Sorghum and tef are the staple foods grown during the main cropping season. These two crops constituted 54.6%, 61.8% and 94.1% of the total area devoted to cereal production in South Wello, North Wello and Oromia Special Zones, respectively (CSA 2015). In addition, chickpea, barley, haricot bean, soybean, mung bean, sesame and maize were also grown with smaller land allocations. Sorghum is known to have a relatively long growing period. Consequently, it was usually the first to be planted as a main season crop in the north eastern part of Amhara. It was planted between mid-April to the first week of May annually for a harvest during November and December. During the main cropping season, time of sorghum planting varied from place to place, with most planting done in April, depending on the start of the main rains in a given location. The method of planting of all crops was hand broadcasting and often a given field was planted at one time. Farmers have their own experience of seed rate that may be adjusted based on soil fertility, moisture content of the soil, planting time and variety used. Focus group discussions indicated that the onset of ‘belg’ rain appeared to be shifting towards the ‘meher’ season, perhaps due to climate change. This has left the farmers to grow only one crop of sorghum reducing production and productivity.

Crop weeds are not a major problem in the study areas, given that most farmers owned smaller landholdings and weeds were removed by family labour. However, the parasitic weed Striga hermonthica was reported to be a production constraint. Households in the surveyed zones have excess labour relative to the land they have. As such, weeding was done at least twice. Farmers weeded until resemble no weeds left, or the numbers of weeds were trivial. In some cases farmers left weeds with the current crop so that it could be used as animal feed using a cut and carry method.

Importance of sorghum

The three surveyed zones are drought prone areas characterised by semi-arid and arid environmental conditions. The areas experienced erratic rainfall with poor distribution. Early cessations of rainfall and high temperatures were common scenarios across the three zones. This made sorghum the best potential crop across the study areas. Sorghum is a C₄ plant predominantly grown in environments subjected to high temperatures and water limitation (Edwards et al. 2004).

In Ethiopia sorghum remains a subsistence crop with limited industrial value. It is the third most important cereal next to tef and maize on the basis of area cultivated and production amount (CSA 2016). In the Oromia Special and North Wello Zones, sorghum is the first major cereal crop in terms of area coverage and amount produced whereas it is the second next to tef in area coverage in the South Wollo Zone (CSA 2015). Because of its drought tolerance, high biomass production for cattle feed, relatively better productivity during good rainy seasons, and its provision of continuous supply of food starting from mid-September, farmers rely heavily on sorghum cultivation yearly.

In the study zones, April is the ideal sorghum planting time. Farmers start to harvest green heads for food around September or in the ‘Meskel’ season (coinciding with the celebration of the Finding of the True Cross. At this time sweet stem sorghum varieties reaches the middle of the grain filling stage, at this point the stems can be chewed as an important food source (‘Gulbet’). Farmers often grew a mixture of varieties (locally referred to as ‘Wajera’) so that in some areas medium maturing local landraces of grain and sweet sorghum could be ready for family consumption before September 11. It was believed that eating sweet sorghum stalks before September 11 would increase the likelihood of catching malaria. Some stands of the sweet sorghum varieties were left in sorghum fields up to grain physiological maturity to be used for porridge preparation and as a seed source in the coming production year. Heads of sorghum at grain filling are roasted and eaten, which is locally termed as ‘mashella eshet’, ‘tibese’ or ‘lemete’. These are the most common food types around September and October when sorghum reaches the soft dough stage. Depending on the maturity period farmers have access to ‘mashela eshet’ until harvest.

Respondents were asked to estimate their sorghum yields per unit area during the 2015 cropping season. Table 3 summarises their responses, showing the significant differences (P ≤ 0.05) of sorghum productivity across zones. The mean yield reported in Oromia Special Zone was 4.5 t ha⁻¹, which was the best performance than the overall mean of 3.6 t ha⁻¹. In the North Wollo Zone the mean sorghum yield was the lowest (2.8 t ha⁻¹) (Table 3). The national mean yield of sorghum is 2.4 t ha⁻¹ (FAOSTAT 2017). In general sorghum productivity assessed in the three administrative zones were positive relative to the zonal and country yield levels.

Table 3. Significance tests of surveyed sorghum productivity across the study zones and mean sorghum reference productivity ASRP of the year 2015, N = North Wello Zone, S = South Wello, O = Oromia Special Zone and E = Ethiopia.

Zone	Respondents	Mean	Std. Deviation	Std. Error	Min.	Max.	ASRP
North Wello	60	2.83	1.3308	0.1718	0.7	5.6	1.8 ^N
Significance	df = 59	t-value = 6.00		P-value = 0.0001
South Wello	60	3.55	1.6500	0.2130	0.9	6.3	2.3 ^S
Significance	df = 59	t-value = 5.85		P-value = 0.0001
Oromia Special	60	4.4867	1.73.3	0.2234	1.2	6.8	2.4 ^O
Significance	df = 59	t-value = 9.34		P-value = 0.0001
All zones	180	3.6211	1.7119	0.1276	0.7	6.8	2.4 ^E
Significance	df = 179	t-value = 9.57		P-value = 0.0001

After harvest, sorghum grain was usually used to make of injera (flat bread), qollo (roasted grain), nifro (boiled), chibeto (kitta or chapatti mixed with noug or sesame), kitta (chapatti), porridge, soup and tella (local beer). Women farmers who participated in the focus group discussion explained that they made sorghum injera daily to increase its palatability. Typically, sorghum injera has a dry texture with a lower palatability one or two days after cooking than tef injera. Eating of sorghum as chapatti with milk was common in the lowlands of the north eastern Amhara.

A highly significant number (68.3%) of interviewed farmers indicated that they mixed their sorghum landraces during planting to improve the food making quality of sorghum (data not shown). Further, farmers planted mixtures of different maturity groups to reduce resource competition because the reproductive stage of sorghum, in the flowering, heading and grain filling stages, the crop enters into a high resource intake situation for its source-sink balance. Farmers also practiced mixing of different sorghum maturity groups to have food access for an extended period of time. They grew also different sorghum landraces in one season on a single farm for the preparation of different foods from sorghum. During focus group discussion women farmers explained that sorghum landraces such as Chobye, Jameyo, Degalete and Zengada are very good for the preparation of porridge, injera, tela and soup, respectively.

Sorghum had a special economic, cultural and psychological significance in the livelihoods of rural households of the surveyed zones. In these areas maize does not perform well due to regular drought conditions. The three most important uses of sorghum were to prepare pure sorghum injera, sorghum chapattis and mixed sorghum and tef injera, which were reported by 38.3%, 35% and 26.1% of respondents, respectively (Table 4). Table 4 shows the various uses of sorghum grain for food. Injera with wot (local stew) was the most common food made from sorghum grain in the north eastern Amhara.

Table 4. A summary of cross tabulation analysis on sorghum utilisation by farmers across the three study zones.

Utilisation	1st	2nd	3rd	4th	5th	Total
Injera (pure sorghum)	38.3	51.1	10.6	0.0	0.0	100.0
Injera mixed with Tef	26.1	26.1	45.0	2.8	0.0	100.0
Porridge	0.0	0.0	9.4	47.8	42.8	100.0
Alcoholic drink	0.6	0.0	5.6	37.2	56.7	100.0
Chapatti	35.0	24.4	28.3	11.7	0.6	100.0
Total	20.0	20.3	19.8	19.9	20.0	100.0
Significance	df = 16		X^2  = 825.546^a		P-value = 0.000

Sorghum was indicted as a crop that provides food needs at time when the majority of households had exhausted their previous year grain stores. A farmer growing tef has to wait until the crop is harvested and threshed at ground before it can be consumed. Sorghum also provides feed for cattle starting from early in June (a stage of early cultivation to reduce the plant population, locally referred as ‘shilshalo’) until harvest. Leaves, chaffs, and unproductive tillers are the main animal feed sourced from sorghum.

Table 5 summarises the main reasons why farmers grew to grow sorghum year after year. The main reasons were the availability of rainfall in April, and the drought tolerance of the crop. These were ranked first and second (57.8%) and (41.7%), respectively. Limited crop options ranked third (42.8%) followed by the good productivity of the crop (38.9%). The good productivity of sorghum also ranked fourth (55%) followed by limited crop option (42.8%) in area cultivated (Table 5). Good biomass productivity and extended family size ranked fifth with 55% and 41.7%, respectively.

Table 5. Farmers reason of why they would like to grow sorghum year after year in the three study zones.

Reason for cultivating sorghum	Rank of reasons						Total
Rank	1st	2nd	3rd	4th	5th	6th
Drought tolerance	41.7	45.6	12.8	0.0	0.0	0.0	100.0
Good gain yield	0.6	0.6	38.9	55.0	1.1	3.9	100.0
Good harvestable biomass	0.0	0.6	0.0	1.1	55.0	43.3	100.0
Availability of rainfall in April	57.8	41.7	0.6	0.0	0.0	0.0	100.0
Extended family size	0.0	0.0	8.9	2.2	41.7	47.2	100.0
Limited crop option	0.0	7.8	42.8	45.6	1.7	2.2	100.0
Total	16.7	16.0	17.3	17.3	16.6	16.1	100.0
Significance	df = 25		X^2  = 1785.433^a			P-value = 0.000

Other crops grown in the study zones

Table 6 summarises other crops grown next to sorghum in the surveyed zones. These included tef, maize, chickpea, sesame, soybean, mung bean and barley in decreasing order of importance. Tef (33.3%), maize (25.6–27.8%) and chickpea (15.6–20%) were cultivated widely in the three zones. Barley production was not widely practiced in the North Wello and Oromia Special Zones because of the high temperatures and low altitude being unsuitable for the crop. Due to limited farm size and low productivity, the amount of sorghum grain available to sell was small. However, sesame, mung bean and chickpea were cultivated largely to sell. Farmers sell their produce in local markets after they meet the family needs. Focus group discussions revealed that grain and oil crops (e.g. noug) were sold in December–February to buy clothing, to pay debts, school fees and transport fees, and to purchase house supplies (e.g. pepper, coffee and spices) and for payments for various social events. The South Wello Zone had the highest percentage (27.8%) of respondents who had grown maize, while the North Wello Zone had the lowest percentage (25.6%) of respondents next to Oromia Special Zone (26.7%). There was statistical significant difference among crops grown across the three administrative zones.

Table 6. Other crops grown in the three study zones during 2014/2015.

Zone		Sesame	Tef	Soybean	Chickpea	Maize	Barley	Mung bean	Total
North Wello		11.1	33.3	7.8	18.3	25.6	0.0	3.9	100.0
Oromia Special		11.1	33.3	6.7	20.0	26.7	0.0	2.2	100.0
South Wello		2.8	33.3	7.2	15.6	27.8	7.8	5.6	100.0
Total	Count	45	180	39	97	144	14	21	540
	%	8.3	33.3	7.2	18.0	26.7	2.6	3.9	100.0
Significance		df = 12			X^2  = 41.902^a			P-value = 0.000

Trend of sorghum cultivation

East African countries including Ethiopia, Kenya, Burundi, Rwanda and Tanzania experienced about 15% rainfall variability from 1979 to 2005, resulting in followed by drastic losses in food production and increased food insecurity (Funk et al. 2008; Lobell et al. 2008). In north eastern Ethiopia, the erratic rainfall impacted on traditional sorghum farming, although drought is a common challenge for the lowland farming communities of Ethiopia. The region experienced a severe drought during 2015, which caused major social and economic impacts. As a result of increased climatic changes, areas that previously cultivated faba bean, lentil and barley are shifting to sorghum, mung bean, soybean and lowland oil crops. In Ethiopia from 2013 to 2014, sorghum total production and area coverage increased from 3.83 to 4.34 million tons and from 1.68 to 1.83 million hectares, in that order (FAOSTAT, 2017). Sorghum has become the most important crop because of its ability to grow under arid and semi-arid conditions. Among farmers interviewed, 78.3% in the North Wello Zone, 73.3% in South Wello and 71.7% in Oromia Special Zone explained that cultivation of sorghum was increasing despite its variable productivity. Respondents from Oromia Special Zone (28.3%), North Wello (21.7%) and south Wello (26.7%) perceived that the state of sorghum cultivation was constant (Table 7).

Table 7. Farmers perceptions of changes in sorghum production.

Zone		Constant	Increasing	Total
North Wello		21.7	78.3	100.0
Oromia Special		28.3	71.7	100.0
South Wello		26.7	73.3	100.0
Total	Count	46	134	180
	%	25.6	74.4	100.0%
Significance		df = 2	X^2  = 0.759^a	P-value = 0.684

Sorghum cultivation increased from time to time in the study areas (data not shown). This increment has been attained mainly by increasing sorghum area coverage while replacing the area allotted to other crops such as tef, chickpea, maize, soybean, mung bean and sesame in north Wello and Oromia Special Zones in the order of decrease of replacement percentage. The highest percentage (33.3%) of respondents across the three zones perceived that sorghum cultivation increased through minimised farm size allocated to tef. It was noted that sorghum has been largely grown under higher altitude areas such as in south Wello Zone of Ancharo Kebele. Chickpea, maize and mung bean were replaced by sorghum almost in a similar fashion across the three zones. A greater number of interviewed farmers allocated their plots for sorghum production instead of tef, soybean, chickpea, and maize crops.

Constraints to sorghum production

In Ethiopia about 1.9 million hectares of land is devoted to sorghum production every year. About 4.34 million tons of grain is produced with mean productivity of 2.4 t ha⁻¹ per annum exclusively by about 5 million smallholder farmers (CSA 2015). During the past two decades production area and total production of sorghum have increased considerably. However, productivity per unit area stagnated due to biotic and abiotic production stresses and socio-economic factors. Table 8 summarises the most important constraints that affected sorghum production in the study areas. Sorghum production is challenged by various constraints associated with the harsh growing environment where other crops are unable to perform well and other socio-economic aspects (Wortmann et al. 2006).

Table 8. Farmers’ ratings of the severity of the primary abiotic and biotic sorghum production constraints across the three study zones of the north eastern Amhara, Ethiopia during 2014/2015.

Abiotic and biotic constraints		Highly severe	Moderately severe	Less severe	Total
Drought		44.8	29.1	0.0	34.4
Striga		23.0	0.0	0.0	11.1
Lack of farmer-preferred improved varieties		12.6	5.1	0.0	8.3
Low yield potential of local landraces		5.7	11.4	0.0	7.8
Lack of policy attention to sorghum production and commercialisation		4.6	3.8	7.1	4.4
Lack of improved seed system		3.4	8.9	0.0	5.6
Insect pests		2.3	5.1	35.7	6.1
Birds		2.3	3.8	28.6	5.0
Diseases		1.1	6.3	0.0	3.3
Limited access and affordability of sorghum production packages		0.0	11.4	28.6	7.2
Poor soil fertility		0.0	10.1	0.0	4.4
Poor stand establishment		0.0	5.1	0.0	2.2
Total	Count	87	79	14	180
	%	100.0	100.0	100.0	100.0
Significance	df = 22	X^2  = 115.452^a		P-value = 0.000

The most important production constraints affecting sorghum production include poor stand establishment, drought stress, unavailability and unaffordability of improved production packages, low yield potential of local landraces, a lack of an improved seed system, a lack of farmer preferred improved varieties, poor soil fertility and a lack of attention by policy makers. The most important biotic stresses of sorghum include insect pests such as stalk borer (Chilo partellus), sorghum shoot fly (Atherigona soccata) and sorghum chaffers (Pachnoda spp.), diseases such as anthracnose (Colletotricum graminicola), red billed quelea (Quelea quelea), Striga (Striga hermonthica), leaf blight (Exserohilum tiorcicum), and sorghum panicle diseases especially head smut (Sphacelotheca peiliana) and grain mold (Aspergillus Sp.) (Wortmann et al. 2006; Gebretsadik et al. 2014; Beyene et al. 2016).

In the present study the most important production constraints described by interviewed farmers were drought, Striga and a lack of improved cultivars with farmers-preferred traits, followed by the cost of production inputs (fertilisers etc), poor stand establishment and poor soil fertility. These were rated as moderate to severe production constraints (Table 8). Most of farmers (71.4%) considered that insects, birds, limited use of production packages and lack of attention by policy makers were relatively less severe sorghum production constraints. Focus group discussants in the North Wello Zone of Kobo Woreda revealed that the effect of head smut disease was severe, whereas stalk borer was the main challenge of farmers in Oromia Special Zone, occurring after the May rainfall, i.e. before the sorghum plants reached knee height. These production stresses, coupled with high temperatures and drought, hamper growth, development and final yields of sorghum (Prasad et al. 2008; Hammer et al. 2010; Nguyen et al. 2013; Singh et al. 2015). Overall, farmers rated drought as the most challenging sorghum production constraint reported by 44.8% and 29.1% of respondents as being a very severe and moderately severe constraint, respectively. Striga infestation was reported by 23% of interviewed farmers in the study areas. Gebretsadik et al. (2014) reported that in North Wello and Metekel Zones Striga was the first biotic constraint to sorghum production.

Impact of drought

Drought is a constant problem of crop and livestock production in Ethiopia. It is especially important in the lowland and mid-altitude regions of the country. Severe droughts now occur frequently. In the north eastern Amhara Region of Ethiopia, crop production is mainly rainfall dependent. Use of irrigation is confined to small areas which are adjacent to main rivers. Where irrigation is available, farmers grow high value crops such as tomato, onion, green maize, cabbage, carrot, lettuce and tropical fruit to earn cash.

In the north eastern Amhara region drought has historically caused multidimensional economic, social, and environmental disruption. Poor crop production and productivity, the absence of agriculture based industries, reduced employment in agriculture, increased costs of transport for water and food, and strains on financial institutions are typically among the major drought induced economic problems. Drought causes negative social impacts leading to shifting settlements, disintegration of extended families, social losses, change in social values, disruption of sociocultural institutions, disturbance of inter-caste relations, and conflicts are water and other resources among communities. The most severe socio-economic impacts of drought have been the loss of crop and livestock genetic resources, increased prevalence of diseases and insect pests, poor crop performance, high levels of livestock mortality, forced sale of land and sale of household and personal assets and water insecurity. During severe drought conditions, loss of crop diversity, removal of vegetation, overgrazing, wind erosion, increased areas of abandoned and barren lands, and over-exploitation of ground water are among the most negative bio-physical impacts of drought.

Some crops that were common in the past have become rare as a result of high temperatures coupled with regular severe droughts. Focus group discussions revealed that farmers’ crop choices were thus apparently made on the basis of ecological potential, historical antecedents, and the relative economic and social pay-off of different options. Farmers in the study area indicated that sorghum diversity had been drastically affected by drought. The farmers reported that several replanting (two to three times) in the year of drought exhausted their seed stock of valuable local sorghum varieties. Drought also had highly significant effects on the composition of natural vegetation, structure and function (Allen et al. 2010). It also adversely affects photosynthesis and increases species mortality by creating conditions conducive to the increase of plant insect pests and diseases, leading extensive plant mortality, endangering the survival of plant species and accelerating the loss of biodiversity (Wang et al. 2010). In the three surveyed zones in North eastern Amhara Region farmers were able to identify local sorghum landraces lost as a result of the adverse effect of drought (Table 9). According to Lanta et al. (2012) extreme conditions of drought and high temperatures aggravate the extinction of species.

Table 9. Names of farmers’ sorghum varieties lost as a result of severe drought conditions in the north eastern Amhara Region of Ethiopia.

Zone	Name of local sorghum varieties lost due to drought
North Wello	Abola, Kuchibeye Jameyo, Arate Afa Chibete
	Tekureta, Chobye, Workeye Zengada, Kolebo
	Rayo, Melete Degalet, Tati, Jeru, Marute
South Wello	Keteto, Gorade, Marute, Gurendo, Achier jamo
	Nech jeru, Keye Wogene, Tengele, Marute
Oromia Special	Jarse, Marchuke

Drought adaptation and mitigation mechanisms

There were highly significant differences (P ≤ 0.05) on the ranking of major drought adaption and mitigation practices used by farmers in the lowland sorghum agro-ecologies of north eastern Amhara Region (data not shown). To reduce the effects of drought, farmers apply various drought mitigation and adaptation strategies. Most interviewed farmers (69.2%) indicated that planting of medium-maturing sorghum landraces such as Jameyo, Jegurete and Cherekit was their first way of avoiding drought stress. Growing medium maturity sorghum varieties was considered to be the most successful drought coping strategy in the study areas. The listed sorghum landraces have the capability of adapting to late planting with relatively early maturity when compared to long cycle sorghum landraces that are usually affected by both pre-flowering and post-flowering drought stress. All interviewed farmers indicated that they cultivated a mixture of sorghum landraces with different maturity periods in a single field as a second option in order to achieve a reasonable yield. Repeated field ploughing before sorghum planting to increase water holding capacity of the soil and diversion of flood waters into sorghum fields time of heavy rainfall events were the most important drought mitigation mechanisms reported by 64.3% and 58.9% of interviewed farmers, respectively (data not shown). These methods increase moisture in the soil to cope with the uneven rainfall rates in the season planting early maturing sorghum varieties is the fourth drought mitigation option reported by 82.2% of respondent farmers while crop rotation, particularly alternate cultivation of sorghum with tef was regarded a fifth option that was practiced by a significant percentage of respondent farmers (79.2%). Growing sorghum with a reduced plant population during periods of moisture stress was among the drought mitigation mechanisms adopted to ensure maximum productivity of the remaining plants with compensatory yield gains per unit area. Reduced plant population is perceived to be associated with big panicle size and consequently providing better yield in drought prone areas of the north eastern Amhara Region.

Farmers-preferred traits in sorghum varieties

Knowledge of farmers preferred traits in sorghum varieties and the prevailing climatic conditions of the growing areas are among the overriding prerequisites for launching a breeding programme, and to ensure the adoption of these improved varieties. In the study areas, sorghum traits preferred by farmers included high grain and biomass yields, good food making quality, medium-maturity, drought tolerance, Striga tolerance, good market price for the grain and adaptability. All respondent farmers preferred high yielding local sorghum landraces as their first choice. During the study period, 49.7% and 44.3% of respondent farmers chose to grow drought tolerant and medium-maturing sorghum landraces, next to high yielding varieties. Farmers perceived that medium-maturity period helped the crop to withstand post-flowering drought problems. The second farmers preferred traits included food making quality, medium-maturity and drought resistance as expressed by 100%, 55.7% and 42.3% respondents, in that order (data not shown). Other farmers preferred traits included adaptability, good biomass yield and tolerant to Striga which were rated as their third choice with 100%, 53.9% and 47%, respectively. Respondents listed some traits like good market price, tolerant to Striga and good biomass as their fourth preferred traits showing statistically significant difference among traits chosen under the fourth category (Table 10).

Table 10. Farmers preferred traits in sorghum in north eastern Amhara, Ethiopia.

Farmers-preferred traits		Percentage of respondents who ranked a preferred-trait
		1st	2nd	3rd	4th	Total
Drought tolerance		49.7	42.3	8.1	0.0	100.0
Good food making quality		0.0	100.0	0.0	0.0	100.0
Medium- maturity		44.3	55.7	0.0	0.0	100.0
High yield		100.0	0.0	0.0	0.0	100.0
Tolerant to Striga		0.0	2.0	47.0	51.0	100.0
Good market price		0.0	0.0	0.0	100.0	100.0
Best adaptability		0.0	0.0	100.0	0.0	100.0
Good biomass		5.1	0.0	53.9	41.0	100.0
Total	Count	180	180	180	180	720
	%	25.0	25.0	25.0	25.0	100.0
Significance		df = 21	X^2  = 834.822^a			P-value = 0.000

Sorghum planting time and farmers preferred maturity groups

In the North Wello Zone 71.7% of interviewees preferred medium-maturing sorghum varieties followed by early maturity and long maturity types with 18.3% and 10.0%, respectively. Number of farmers who preferred long maturing sorghum varieties was the highest in the South Wello Zone (35%) and lowest in the North Wello Zone (10%). North Wello Zone had the most of farmers (18.3%) who preferred early maturity types, while the South Wello Zone had the least farmers (10%) next to Oromia Special Zone (16.7%). In general, the result showed statistically significant differences among the maturity groups preferred by farmers across the three study zones.

The South Wello Zone had the most farmers (90%) who usually planted sorghum from April to the first week of May, depending on the onset of rain fall. Similarly focus group discussion and transect walk observations indicated that most of early maturing sorghum varieties were not readily adopted by farmers for varied reasons. Firstly, planting dates for these varieties are mismatched with what the farmers are currently using; mid-April to mid-May is the normal sorghum planting time, particularly in north eastern Amhara Region. Secondly, farmers highly expect two most important benefits at the same time from sorghum crop, i.e. grain yield and above ground biomass to their livestock. Thirdly, farmers believe that post-flowering drought recovery capacity of long and medium-maturing sorghum landraces is better than early maturing ones. The Oromia Special Zone had the most farmers (21.7%) planting from the third week of June to July. This showed that the rainfall from April to May every year was not sufficient to support sorghum crop in the Oromia Special Zone. There was non-statistical difference (P ≤ 0.05) in percentage of farmers practicing sorghum planting among the three study zones but there were a slight variation of sorghum planting times among the three zones (Table 11).

Table 11. A summary of farmers- preferences (%) on maturity group and planting dates across the three study zones of the north eastern Amhara Region of Ethiopia.

Administrative Zone		Maturity group				Planting time
		Early maturity	Medium maturity	Long maturity	Total	April to first week of May	End of June to July	Total
North Wello		18.3	71.7	10.0	100.0	81.7	18.3	100.0
South Wello		10.0	55.0	35.0	100.0	90.0	10.0	100.0
Oromia Special		16.7	50.0	33.3	100.0	78.3	21.7	100.0
Total	Count	27	106	47	180	150	30	180
	%	15.0	58.9	26.1	100.0%	83.3	16.7	100.0
Significance		df = 4	X^2  = 13.157^a	P-value = 0.011		df = 2	X^2  = 3.120^a	P-value = 0.625

Acknowledgements

The Alliance for a Green Revolution in Africa (AGRA) is gratefully acknowledged for financial support of the study through the African Centre for Crop Improvement (ACCI). Thanks are due to the Amhara Agricultural Research Institute, Sirinka Agricultural Research Center, for giving study leave to the first author.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Solomon Assefa Derese is a PhD Student at University of KwaZulu-Natal, African Centre for Crop Improvement (PhD – Plant Breeding) Sorghum Breeder, Sirinka Agricultural Research Center, SARC, Ethiopia.

Hussein Shimelis is Professor of Plant Breeding at University of KwaZulu-Natal, African Centre for Crop Improvement, and is the Deputy Director of African Centre for Crop Improvement.

Mark Laing is Professor of Plant Pathology at University of KwaZulu-Natal, African Centre for Crop Improvement, and is the Director of African Centre for Crop Improvement.

Fentahun Mengistu is the Director General of Ethiopian Institute of Agricultural Research, Addis Ababa, Ethiopia.

Additional information

Funding

The study was funded by the Alliance for Green Revolution in Africa (AGRA) (PASS 030) through the African Centre for Crop Improvement of University of KwaZulu-Natal.