CHAPTER XVI TEF: Post-harvest Operations

2.1 Harvesting

2.2 Threshing

2.3 Cleaning

2.4 Utensils for measurement

2.7 Packaging

2.8 Storage

2. Post-Production Operations

2.1 Harvesting

Tef is harvested when the vegetative parts turn yellowish or straw colour. This depends on the maturity period of varieties, which varies from 60 to 120 days. Drying of the pedicel (straw colour) which holds individual spiklets is a good indicator of maturity of tef (Hailu, 1993). Harvesting before the plant gets too dry helps prevent losses owing to shattering (Seyfu, 1997). The average cutting loss is not known. The moisture content is not specifically determined for tef, but for many cereals it is around 12 percent. Tef does not need artificial drying before harvesting. The seeds are dry when the plant is harvested. Seeds can immediately germinate if moisture is absorbed.

Harvesting is carried out by grasping the tef plants in one hand and cutting them with the sickle near the base of the plant. The cut plants are placed in piles on the ground. In some parts of Ethiopia, such as in Showa province, the farmer when harvesting the tef, crouches and cuts the plants near the soil surface. This is done especially when the tef plants are short. In other parts of the country, the whole plant is pulled out. Eight to twelve people can harvest one Massa which is about 2 000-2 500m² in one working day. Farmers share their human labour and their harvesting equipment during harvesting. Rarely do farmers harvest alone on their farm. After the plant is cut and placed on the ground, other people, usually the elderly, women and young children follow the harvesters and tie the harvested plants in small bundles or sheaves called Nado. These are 14 to 18cm in diameter bundled with green tef plants: the sheaves are larger if bundled with green sorghum stalks. Other farmers, instead of tying into sheaves, leave the plants loose on the ground. The sheaves or loose plants are subsequently stacked in the field where they remain until the farmer has finished harvesting all of his crops in other fields.

There is a migration of farmers during harvesting. Farmers, whose tef crop is late for harvesting mostly in highland areas, migrate to middle and lower altitude areas for harvesting. They earn much for their services and return to harvest their own crop. Due to lodging problems and shattering of seeds during harvesting tef is not suitable for mechanized harvesting. Quality consideration during harvesting is not possible. Grass weeds could be harvested along with tef and this could lower the quality of the product. Farmers usually do their best not to harvest grass weeds along with tef during harvesting. The harvested crop is then carried on the women's backs, men's shoulders or heads and/or on a donkey to near the threshing ground in the village where a large stack or pile, called Kemmer is situated (Figure 12). Stones are usually the base for Kemmer thus eliminating access of termites to the crop.

 Figure 12:Pile of tef called Kemmer.

In areas where termites are non existent the stacks can be on bare ground. The heads are turned towards the centre of the stack so that rain will not wet them, and animals cannot feed on them. The crop remains in the stack until the farmer is ready to thresh (Taddesse 1969). According to the characterization made on 2 255 tef pure lines the harvest index ranged from 7 percent to 38 percent (Table 1). In the existing varieties mostly 24.4 percent is taken as a harvest index (Seyfu, 1997).

2.2 Threshing

Threshing is done after all crops have been gathered from the field. The threshing ground is prepared first. A threshing ground called Awdemma is made on nearly level or gently sloping ground by digging out the vegetation inside the soil and smoothing the ground.

 Figure 13:Threshing of tef.

Note that the farmers are permanently pushing tef to the centre of the threshing ground with forks that have three or four prongs.

In some parts of the country the ground is made firm by wetting the soil and then driving cattle over it. Then fresh cattle dung is collected from corrals or fields where cattle have grazed and a mixture of manure and water is prepared. This mixture is prepared in a shallow hole dug in the ground called Bola Obid, in earthenware jars, and a wooden container is prepared on the so-called Awdemma. The loose soil is removed and the bare ground is smeared with this mixture. To some extent, this reduces the mixing of the grain with soil. Pulse and other grain crops are threshed first. Tef is then threshed on the firmed Awdemma. Usually the threshing floor is re-smeared after every threshing, since the same floor is used for threshing all crops. The size of the threshing ground varies in different localities and dependent in part on the wealth of the farmer (Taddesse, 1969).

Threshing may be a festive occasion. The farmers whose fields are being worked on is expected to provide T' ella a native beer and Enjera or roasted parched grains such as barley, maize, etc. for the threshing day. Neighbouring farmers are asked to help with the threshing. In return the farmer helps them when they thresh their grain. Such cpp [eratopm is called a Debo. Males mostly do threshing. When threshing begins the farmer and his sons or friends get on the top of the tef stack with sickles and undo the stack by taking out each sheaf, cutting the tie with a sickle and throwing it onto the threshing ground. The untied bundles are spread evenly over the threshing ground with long wooden forks called Andogo or Mansh. This has two Andogo or three to four Mansh slightly curved prongs or tines. Nowadays Mansh with four prongs made of metal are distributed and widely used in many parts of the country. In many places, oxen are driven over the tef to tread out the grain. In other parts of the country, threshing is done with cows or donkeys. The working animals are driven in a circle round and round on the threshing by one or two men at a time. Sometimes the working animals. mouths are tied during threshing so that they cannot eat the grain. Men, who push it into the centre with forks, Andogo or Mansh, keep tef on the threshing floor (Figure 14). After the top part of the tef bundles is broken or trampled out, the animals are driven out and workers start turning the broken tef under, starting from one side. After they have done this several times, the straw with some grain remaining in it is drawn aside with the Mansh and put in a long row (Figure 15).

Here it is beaten or flailed with a long, slender stick, usually eucalyptus or with a long curved stick usually made from Milletia ferruginea, known locally as Birberra or Maytenus ovatus, known locally as Atat or Aule taffi meaning stick for tef. When the Aule Taffi is used two men usually stand opposite each other along the row of straw and beat it in rhythm. Then the chaff with seeds is thrown up against the wind to separate the seeds from the chaff (Figure 16). Then the straw is pulled to the lower side of the Awdemma with the Mansh are removed with bundles of a branch of shrub called Matoya or Abachara.

 Figure 14:Separation of the tef chaff from the seeds after threshing on the ground.

The grain, with a lot of chaff called Galaba is then swept to the centre or to one side of the Awdemma with dried kale heads tied into a small bunch Matragiya or with wooden shovels, Layada or Lahada.

 Figure 15:Separation of the tef chaff from the seeds using the air current.

 Figure 16:Separation of the tef chaff from the seeds using the wind.

The remaining chaff is then separated from the grain by wind. In this work a farmer will put a small amount of tef seeds together with small sized chaffs inside a Sefed. A Sefed is a kind of a fan woven from grass stems (Figure 17). This fan is used for a lot of post harvest operations. This operation is carried out by raising the fan above the farmers height and letting it drop smoothly so that the blowing wind will separate the seeds from the chaff. Winnowing (Figure 18) will then separate the chaff that cannot be removed by the above-mentioned work. The remaining inert materials are removed by fanning with an Afarssa or Maragabiya or small Sefed. The Maragabiya is a small piece of stiff skin from a wild hog or the head of oxen with semi-circular wooden handle (Taddesse, 1969).

In some areas thresher machines are used to thresh tef. However due to the incompatibility of the sieves which are specifically made for other crops, small sized tef seeds escape along the chaffs. Work to improve and evaluate the thresher for tef indicated that increasing the number of bars on the drum from six to twelve and replacing the rasp bars with 40 by 40 angle iron reduced threshing losses from 31.5 percent to 2 percent (IAR Annual Report, 1996). Hence, rethreshing tef could be avoided and threshing losses can be minimized with the right modifications and a proper workshop to assemble the drum-concave. During testing, it was observed that rethreshing was easier with the new modifications than with previous threshing units. However, economic analysis as well as economic loss due to different threshing, cost and equipment maintenance, as well as labour inputs has not been well determined.

2.3 Cleaning

Women usually separate chaff from grain. The woman usually takes a container full of grain and chaff and winnows it from a long strip. When she reaches the end of the row another person using a Maragabiya starts fanning away the chaff that is too heavy for the wind by swinging the Maragabiya to and throws over the grain. The woman then takes another container of grain and winnows it by adding another layer over the previous one. It is fanned again and again with a Maragabiya. This process is repeated until the cleaning is finished. Sieves remove the heavy particles and dirt. If sieves are not available a bundle of kale heads is tied together right at the bottom and the grain is poured over it so that the grains pass through this bundle while the dirt remain in the bundle. More cleaning work is done by women through sieving many times in their homes (Taddesse, 1969).

A farmer grades his tef into two grades while it is on the Awdemma. When winnowing, the light grains fall away from the centre of the windrows. These grains are considered to be of low quality and are called Gerd while the heavy ones fall in the centre of the windrow. These are high in quality. The Gerd that contains dirt and chaff is used for poultry and cattle feed (Taddesse, 1969).

2.4 Utensils for measurement

After cleaning, the grain is measured and stored in different types of storage facilities. There are many different kinds of measuring devices or utensils used. These differ in different communities, but the ones most commonly used are kunna and Enkeb (Figure 19), which vary slightly from one village to another. It usually has a volume of 4-5 kg and is made from wood, earthenware or grass stalks. Another measuring device is known as Enkeb. This is a basket, is equivalent in volume to 3-4 kunnas. A Dawula is the other measuring unit. There is no container to measure a Dawula but it is an imaginary container which will hold about 20 kunna or 4-6 Enkebs. Other types of measuring devices are fibre and cloth sacks and Akomada which is a sack made from goat or sheep skin. Many other measuring methods are used, but are far too many to mention here.

 Figure 19:Utensils for measurements: Kunna and Enkeb.

The farmer measures his crop to determine how much he can sell and how much he must retain for his family's use and for seed (Taddesse, 1969).

2.7 Packaging

Farmers pack their produce in different packing materials, which are either the traditional types such as Akomada or the modern packing materials such as plastic bags, sisal or plastic sacks. The traditional ones are not preferred because of the odour that could affect the quality of the produce. Modern packaging materials, especially plastic sacks, are much better since they prevent water from penetrating into the seeds. The size of packaging materials differs according to the amount of the seed to be stored or to be transported. For sale at the local market, small plastic sacks are preferred while for long distance transport, export sacks of bigger sizes which contain 100kg tef are preferred. Packing is done within the family. Mostly women put the grains in the sacks and males close the sacks by hand sewing or tying with sisal or jute fibres.

2.8 Storage

After the grain is threshed, cleaned, and measured at the threshing ground it is stored in the house or outside. Today, outside storage is not seen, unless it is in very remote areas. Farmers justify that this is due to theft occurring from time to time. The seeds are already dried at the time of harvesting and threshing. There is not as such quantified moisture content of seed for storage. The moisture content of tef during storage as for other cereals is about 12 percent. Normally seeds are dried in the open air under natural sun heat that will decrease the moisture content of the seeds. Up to now there is no artificial drying facility for tef. Since it is dried during harvesting and storage, the shelf life of tef is longer and can be stored quite safely for several years. Tef seeds are stored for seed reserve for the next cropping season, for human consumption, for trade and at the cooperative and governmental level for food reserves. The government is buying tef seeds for human consumption from different teaching institutions, hospitals, and military institutions and for food reserves. Tef as a food reserve is used during periods of famine in the country.

Usually tef is moved from a highly productive area to drought prone areas. A 3kg of tef flour, 480g of Ersho, 10 kg of water (6kg of water for dough and 4kg of water for baking) will make 18 Enjeras each Enjera weighing 450g (ENI, 1980). Accordingly, a family of three, consuming 6 Enjeras a day, needs only 190 kg of tef as a food reserve, which will last six months. Storage is in baskets, pots, Gotera and Gusgusha or Gugusi, Gota or Gumbi, in barrels (Figure 20) and Debgnt or Doggo

 Figure 20:Tef storage: Tef stored inside barrel and placed inside the store or the house.

 Figure 21:Tef storage: Tef stored inside Debgnt also called Doggo, which is placed inside the house.

There are several kinds of granaries; the most common ones are mentioned here. These containers can be made in one piece or from 2-3 or more pieces fitted together. Usually a container made in one piece is called a Gusghusha or Gugusi. It is mostly used for one kind of grain. The one made of many pieces or sections are called Gota or Gumbi. These are used for more than one type of grain. When the grain is all used from the upper section, the housewife can lift up the upper section and use the grain below. Children can get into the storage, Gota from the top and hand out the grain in small containers. The size of a Gusghusha and Gota depends on the amount of grain one has. These granaries are usually raised from the ground on pieces of stones placed at the corners. They are moveable and can be used for a number of years if well made. There is a larger type of granary referred to as Gotera(Figure 22). Richer farmers having a large amount of grain usually use them.

 Figure 22:Tef storage: Gotera built in the house with different sections inside.

The size of this sort of granary varies in size, i.e. from a larger Gota to one "that measures 3. 4 meters or more in diameter depending, of course, on the amount of grain. A Gotera is usually circular or rectangular in shape made from wickerwork and cemented with mud. It is reinforced with tef straw, both inside and outside. During the last ten to twenty years, it has been placed outside the house raised from the ground on short posts with a moveable conical thatched roof. However, nowadays it is built with the house to protect their produce from theft. Different varieties of tef (Figure 23) or other crops are stored in a Gotera by putting a layer of tef straw and chaff between the grains.

 Figure 23:Tef storage: Tef seeds stored inside Gotera.

Tef can be stored or conserved for many years in practically any kind of storage system without any appreciable change or damage from insect pests, if vermin and water are exclude from the storage bins. Some farmers store chickpea and other pulse crops along with tef. This is due to the minute size of the tef seeds, which could hamper the movement of weevils inside tef seeds and the low level of oxygen by closing air holes. Small farmers store their grain in an upright earthenware container made from mud reinforced with tef straw and sun dried during the dry period. These are placed in the house. In some areas in the vicinity of Jimma, farmers store their grain on straw (before threshing) in their granaries. In these, the sheaves are counted when they are put up. The wife takes a sheaf or more according to the size of the family and threshes it on a fine woven mat or basketry by hitting it with a small stick or by rubbing the panicles between her palms. Grains, such as sorghum and corn, are stored under ground in some parts of the country, for example in Harar, but it is unusual for tef to be stored in such pits (Taddesse, 1969).

In all of the storage facilities mentioned above, the farmers monitor and maintain the systems themselves. The major defects of these storage facilities are:

1. there cannot be observed in an in-first out system;
2. they are very liable to rodent attack;
3. water could easily penetrate into the storage container, which could deteriorate the quality of the produce.

Communal or cooperative storage facilities are very rare and farmers. cooperatives and/or Ministry of Agriculture make use of these. However, in such storage facilities, fumigation is not used. Storage facilities under government and/or traders are very large. The roofs are made from corrugated metal sheets. The walls are either made of bricks, cement blocks or wood cemented with mud. The floors are made of cement. The store can be used for different kinds of cereals. Large sacks filled with seeds are stored there (ca. 100kg). Tef is not attacked by weevils, therefore it does not need storage pest control chemicals, and can easily be stored under local storage conditions. This makes it an ideal stored food and the basis of an alternative, low-cost, low-risk Food Security Reserve System (FSRS).

In some parts of the country including the main grain store in the capital, Addis Ababa, imported modern storage bins can be seen. In these kinds of storage bins the principle of first in first out method is easily implemented. Attack by rodents and water leakage is minimal.