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Tef (Eragrostis tef) straw

Datasheet

Description
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Common names 

Tef, teff, Williams lovegrass, Abyssinian lovegrass, annual bunch grass [English]; teff, tef [French, Spanish, Portuguese, Indonesian]; mtefi [Swahili]; ጤፍ [Amharic]; 苔麸 [Chinese]; בן-חילף טף [Hebrew]; テフ [Japanese]; Теф, Тефф [Russian]

Synonyms 

Eragrostis abyssinica (Jacq.) Link; Poa abyssinica Jacq.; Poa tef Zuccagni

Description 

Tef (Eragrostis tef (Zuccagni) Trotter) is a dual purpose cereal, valued for both grain and forage production in dry areas with short rainy seasons. Tef grain is a staple food in Ethiopia. Tef straw, called ch'ed, is the main by-product of the tef grain harvest, and a basal component of livestock diets in this country. Tef is also grown as forage in other countries. See the Tef grain and Tef hay datasheets for specific information about these products.

Morphology

Tef is an annual tufted grass that reaches a height of 150-200 cm at maturity. The culms are fine, erect, simple or sparsely branched and prone to lodging. The root system is shallow and fibrous. Tef is a leafy species. Its leaves are glabrous, linear, 25-45 cm long x 0.1-0.5 cm wide. The seed head is a long panicle of 10-65 cm bearing 10-40 slender racemes, which may be either very loose or very compact. Panicles bear 30-1100 spikelets. Fruits are ellipsoid, minute (1-1.5 mm x 0.5-1 mm), yellowish-white to deep brown caryopsis (grain) (Tefera et al., 2006; Seyfu Ketema, 1997). The word "tef" is connected by folk etymology to the Ethiopian-Semitic root "ṭff", which means "lost", because of the small size of the grain.

Uses

Tef straw is the basal diet of all classes of ruminants in Ethiopia, where it is considered as a nutritious fodder comparable to good natural pasture and much preferred to the straw of other cereals, particularly during the dry season (Lulseged Gebrehiwot et al., 1989). For this reason, tef straw prices are higher than those of other cereal straws (Dejene Mengistu et al., 2012). Indeed, tef straw yield has become as important for farmers as grain yield (Dejene Mengistu et al., 2012). Tef straw is also used as mulch and is mixed with mud to build walls of houses, and of the grain storage facilities called gotera (Geremew Bultosa, 2008; Alemayehu Refera, 2001; Seyfu Ketema, 1997).

Distribution 

Tef is thought to have originated in Ethiopia, where it has been used as a food grain since sometime between 4000 and 1000 BCE. It is mainly cultivated in its native range (Ethiopia and the highlands of Eritrea) and in neighbouring Northern Kenya. It has been introduced into South Africa, the USA, Canada, Australia, the Netherlands and Yemen for small-scale production of gluten-free grain (Tefera et al., 2006). In the tropics, tef is best suited for altitudes ranging from 1300 to 2800 m, but can grow from sea level up to 3400 m. Only brown/red tef is grown above 2500 m. Tef is particularly valued for areas too cold for sorghum or maize, and it can be found where temperatures as low as -15°C occur provided the frost does not last too long (NRC, 1996). In Ethiopia, tef grows where annual rainfall ranges between 950-1500 mm with about 450-550 mm during the growing season (Tefera et al., 2006). Tef cannot withstand more than 2500 mm rainfall. However, it can adapt to growing conditions ranging from drought to waterlogging. It is able to withstand wet conditions perhaps better than any cereal other than rice. Tef is mainly grown on sandy loams, but it can grow on black, heavy clay soils (black cotton soils) provided they are well drained and have sufficient N. Neutral or slightly acidic soils are preferred (Tefera et al., 2006). Tef can withstand as much or more salinity than alfalfa (Miller, 2010). A C4 plant, tef makes efficient use of water and heat. It can grow in places prone to drought after short rains (Tefera et al., 2006).

Tef grain production accounts for 25% of total cereal production in Ethiopia, and was reported to be about 4.3 million t in 2015, up from only 1.4 million tons in 2001 (Lyddon, 2015; Alemayehu Refera, 2001). Tef straw yield is about 3 times that of the grain, at about 5-7 t DM/ha (Keftasa, 1988). It can thus be estimated that there was about 13 million t of tef straw available in Ethiopia in 2015 (Lyddon, 2015; Alemayehu Refera, 2001).

Forage management 

Tef is a basic food crop in Ethiopia due to its specific agronomic capabilities. It is possible to harvest tef after a first cereal harvest in the same year (NRC, 1996). Tef may be used as an emergency crop when harsh conditions occur. Farmers can still sow tef when their other crops are failing, and harvest grain after only two months, thereby gaining some relief from famine (NRC, 1996).

Establishment

Tef is propagated through seeds and should be used in sole cropping systems as it does not withstand intercropping (Ecocrop, 2016). Tef is commonly grown in rotation with cereals, pulses and niger (Tefera et al., 2006). It requires a weeded, well-prepared, firm seed-bed. It can be planted, broadcast or sown at 15-20 kg/ha, in rows, no deeper than 1 cm, and subsequently rolled (Ecocrop, 2016; Tefera et al., 2006). It must be regularly weeded. N fertilizer should be provided in small amounts, or tef should be sown after an N-legume in order to reduce the risk of lodging. Tef requires little care after establishment and its rapid growth outcompetes weeds. It suffers few diseases and pests attacks. In Yemen, it is considered a "lazy man's crop" as it does not require any care between sowing, after flash flooding, and harvesting (NRC, 1996).

Harvest

Tef is one of the fastest maturing cereal crops. Grain maturity occurs 2 months after sowing in very early-maturing types, 3-9 months after in early-maturing types, and 6 months after in late-maturing types. Tef maturity is indicated by the yellowing of the stalks bearing the spikelets (NRC, 1996). Harvesting after physiological maturity may result in seed shattering, especially in windy and wet conditions. In Ethiopia, harvesting is done between November and early January. Tef is hand-harvested. The plants are cut at ground level with sickles and then transported to the threshing ground (Tefera et al., 2006). Threshing is done by animal trampling or by using threshers. All grains cannot be completely removed from the straw (Seyfu Ketema, 1997; Alemayehu Refera, 2001). Tef straw is soft and fast drying (NRC, 1996).

Grain and straw yields

Tef grain yield ranges from 0.2 to 2 t/ha. Tef straw yield, which is reported be about 3 times that of the grain, should, therefore, range from 0.6 to 6 t DM/ha (Lyddon, 2015; Alemayehu Refera, 2001).

Environmental impact 

Erosion control, ground cover, green manure

Tef can serve as a temporary ground cover. Its very fast germination and fibrous root system development makes it an excellent choice for erosion control (Miller, 2010).

Nutritional aspects
Nutritional attributes 

Like other cereal straws, tef straw is a roughage with a low protein content (about 4% of DM) and high amounts of fibre (NDF 71% DM, ADF 42% DM). However, its fibre content, including its lignin content (about 6%), is about 10-15% lower than that of wheat or barley straws.

Potential constraints 

Oxalates

Tef straw may have an unbalanced oxalate:calcium ratio. There have been reports of lethal urolithiasis (stones of calcium oxalate in the urethra) in rams in Ethiopia (Tiruneh, 2004).

Ruminants 

Tef straw is highly valued in Ethiopia for feeding ruminant livestock. Farmers feed it in preference to milking cows and working oxen. The price of tef straw is higher than that of other cereals (Alemayehu Refera, 2001). However, tef straw, like other cereal straws, has low protein and energy contents. When fed as the basal diet, particularly to growing and lactating animals, it should be supplemented with an energy and/or protein source, such as oil cakes and forage legumes. Most studies about the use of tef straw in ruminants assess supplementation strategies (Seyoum Bediye, 1998).

Palatability

Tef is fine stemmed, leafy and soft which makes the straw very palatable to livestock. Cattle prefer tef straw than the straw of any other cereals (Alemayehu Refera, 2001).

Degradability and digestibility

Tef straw is of low digestibility and degradability. The in vitro DM digestibility of tef straw was 39%, and in sacco DM and OM effective degradabilities were 34% and 33%, respectively. N degradability was actually negative (El Hassan et al., 2000).

Cattle

Comparisons with other cereal straws in Ethiopia have been favourable to tef straw. In a comparison of different cereal straws for steers (supplemented with molasses, niger cake and bone meal), the tef straw-based diet resulted in the highest DM intake (6.9 kg/d) and daily weight gain (628 g/d) (IAR, 1976 cited by Lulseged Gebrehiwot et al., 1989). Bulls had a much higher intake of tef straw than of maize stover, which may have been due to its higher protein content and lower NDF content (Aredo et al., 2003). While growing cattle require supplementation, breeding bulls were fed on tef straw as a sole feed ad libitum without showing any reproductive problems (LaRey, 2002).

The following supplements have been tested for cattle fed a basal diet of tef straw:

Animal Supplement Reference
Fattening draught oxen Niger cake Mengistu, 2003
Crossbred (Friesian x Boran (zebu)) calves Cowpea (Vigna unguiculata), lablab (Lablab purpureus) Abule et al., 1995
Crossbred heifers Urea, clover hay, niger cake Olayiwole et al., 1986

Sheep and goats

In growing Horro lambs grazing natural grassland, provision of tef straw (dry or wetted) ad libitum failed to improve daily weight gain significantly (Lemma Gizachew et al., 1991). The following supplements have been tested for sheep and goats fed a basal diet of tef straw:

Animal Supplement Reference
Menz sheep Cottonseed cake, dry sesbania, dry leucaena, fresh leucaena Bonsi et al., 1995a
Menz sheep Leucaena leaves, sesbania leaves, tagasaste and vernonia Bonsi et al., 1995b
Menz sheep Sesbania or leucaena + crushed maize Bonsi et al., 1997
Tigray Highland sheep Oilseed cakes Degu et al., 2009
Sheep Sesame cake, wheat bran Fitwi et al., 2013
Sheep Cactus (Opuntia ficus-indica) Gebremariam et al., 2006
Sheep Tembien clover Mosi et al., 1985b
Highland sheep Urea, urea molasses, niger cake, legume hay Nuwanyakpa et al., 1987
Sheep Acacia spp., Sesbania sesban, niger cake, Vicia dasycarpa Reed et al., 1990
Sheep and goats Leucaena pallida, Sesbania sesban Woldemeskel et al., 2001
Sheep and goats Acacia nilotica, Acacia seyal and Sesbania sesban Ebong, 1995
Ethiopian Highland sheep and goats Leucaena, sesbania Kaitho et al., 1998
Rabbits 

No publications are available in the international literature concerning tef straw for feeding rabbits (as of 2016). Because tef straw is widely used in ruminant feeding as the main feed, it should be safe to feed to rabbits. The NDF content of tef straw is very high but the lignin content may in some cases be lower than values recommended for rabbits (Lebas, 2013). The calculated digestible energy is only 5.3 MJ/kcal DM, but this value is higher than that generally used for wheat straw (e.g. 3.5 MJ/kg). Because the crude protein content is very low for a forage, tef straw should be considered only as a potential source of fibre (Lebas, 2016).

Horses and donkeys 

Though tef hay has been reported to be a valuable source of forage for horses, no information could be found on the use of tef straw for horses or donkeys (2016).

Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 91.6 1.0 89.0 94.4 444  
Crude protein % DM 4.1 1.1 1.8 7.3 429  
Crude fibre % DM 35.8   33.2 38.4 2  
NDF % DM 70.9 3.3 68.4 83.8 418  
ADF % DM 41.7 3.2 37.9 52.2 111  
Lignin % DM 5.8 1.1 3.3 8.5 110 *
Ether extract % DM 1.9       1  
Ash % DM 7.9 1.3 3.7 12.4 228  
Gross energy MJ/kg DM 18.1   17.1 18.1 2 *
               
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 3.0 1.1 1.4 6.2 50  
Phosphorus g/kg DM 1.4 0.6 0.2 2.7 76  
Potassium g/kg DM 12.0 2.1 6.5 18.4 46  
Sodium g/kg DM 0.1 0.1 0.0 0.2 41  
Magnesium g/kg DM 1.5 0.3 0.8 2.3 45  
Manganese mg/kg DM 134 127 22 371 43  
Zinc mg/kg DM 25 10 13 67 41  
Copper mg/kg DM 10 5 3 26 41  
Iron mg/kg DM 176 83 66 320 43  
               
Ruminant nutritive values Unit Avg SD Min Max Nb  
OM digestibility, ruminants % 57.0 4.6 45.4 57.0 3 *
Energy digestibility, ruminants % 53.6         *
DE ruminants MJ/kg DM 9.7         *
ME ruminants MJ/kg DM 7.9         *
Nitrogen digestibility, ruminants % 15.6 12.7 1.0 24.3 3  
a (N) % 16.9       1  
b (N) % 37.5       1  
c (N) h-1 0.030       1  
Nitrogen degradability (effective, k=4%) % 33         *
Nitrogen degradability (effective, k=6%) % 29         *

The asterisk * indicates that the average value was obtained by an equation.

References

Abule et al., 1995; Aredo et al., 2003; Bonsi et al., 1994; Bonsi et al., 1996; CGIAR, 2009; CIRAD, 1991; Ebong, 1995; Melaku et al., 2003; Mosi et al., 1985; Nsahlai et al., 1996; Nsahlai et al., 1999; Umunna et al., 1997

Last updated on 24/09/2016 00:17:22

References
References 
Datasheet citation 

Heuzé V., Thiollet H., Tran G., Lebas F., 2017. Tef (Eragrostis tef) straw. Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. https://feedipedia.org/node/22033 Last updated on March 6, 2017, 17:55

English correction by Tim Smith (Animal Science consultant)