POPULARIZATION OF A NOVEL TECHNOLOGY FOR SILAGE MAKING IN WESTERN
BURKINA FASO

by
Brahim Kebe

1.0 PREAMBLE

The FAO/AGPC under PWB Entity 212A3, Major Output 004 "Strategies and Technologies for Sustainable Herbage Production Systems", funded a highly successful diffusion of a novel silage production technology in Western Burkina through the agency of PRODS/PAIA (Integrated Production Systems-Priority Area for Multi-disciplinary Action). This was achieved through the interest and encouragement of a women's co-operative group called Songd-Waoga from Tanghin Kossodo in Oubritenga Province of Central Burkina who trained interested groups in Northern and Western Burkina.

2.0 PROVENANCE OF THE TECHNOLOGY

Located in central Burkina Faso, Oubritenga Province lies in a low rainfall area where annual precipitation scarcely exceeds 500 mm and the dry season is very long and severe. [refer to the Calendar of Agricultural Activities for details] During the dry period, stock feeding is difficult, especially for small ruminants and severe weight loss during the dry period is the rule. This prolongs the period for the animals to reach maturity. In critical years animals may even die. Although cottonseed may be used to bridge this gap, this is not readily available to the smallholder, especially women. An Extension Agent therefore taught some co-operative women groups the technology of silage making with salt and through several years of practice, the technique has been perfected. Silage making has now become a regular household practice as even those without livestock employ it to generate supplementary family income.           

3.0 DESCRIPTION OF THE TECHNOLOGY

3.1 Forages Used

Herbages that are ensiled may be (i) herbages growing naturally in the grasslands e.g. Andropogon gayanus, Brachiaria ruziziensis, Digitaria ciliaris, Echinocloa colona and Pennisetum pedicillatum or (ii) green cereal crop residues such as a  crop of rice, maize, sorghum or millet which has missed the rains and is not likely to yield a worthwhile grain crop. In the study zone, the source of herbage is from an area of up to about one kilometre from the living quarters.  

Natural grassland herbage is harvested at the early flowering stage while cereals are cut as the grain is at the dough stage. At this stage, moisture content is about 30-40 %. This stage occurs from early August to mid September.

3.3 Method and Time of Harvesting

The herbage is cut at 10 cm above the ground for natural grasses and 15 cm for cereals. The forage is cut in the morning as soon as the dew has dried from the plant. This occurs about two hours after sunrise. Apart from ensuring that the herbage is free from excess moisture, this timing also prevents infestation by water loving insects that abound on  herbage that is wet with the morning dew. After harvesting, the herbage is wilted under shade for one or two hours; sometimes wilting is done in the open sun for a very brief period.

3.4 The Silage Pit

The pit or trench method is used. The pit, measuring 3 m long, 1.05 m wide and 1.1 m deep, is dug the previous day before the crop is harvested. This pit silo would carry about 3.6 to 3.9 tons of herbage which when cured, would shrink to about 3 tons of silage. Fifty kilograms of common salt is required for this.

Plate 1	Plate 2
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3.5 Filling and Sealing the Silo

The herbage is packed into the pit in layers of about 5 – 10 cm without chopping. A 200 litre drum, filled with water, is used as a roller to compact the herbage. When the herbage is well compacted, table salt, preferably ground, is sprinkled on the herbage. At the lower layers, less salt is added but as the silo fills up, the upper layers are given more salt.

Plate 3	Plate 4
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The pit is filled to a height slightly above ground, thus making a convex mound. The herbage is then covered with a heavy duty black plastic sheet measuring 3.5 m by 1.5 m. The mass is then covered with about 5 to 10 cm of earth and compacted further to ensure a watertight seal.

Plate 5	Plate 6
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The silo is inspected regularly and more earth piled over spots that may subside as the fermentation progresses. It is essential to maintain the convex shape to prevent rain water from seeping into the pit. For this reason, the silage pit should be close to the living quarters. Curing is complete after three weeks, and the silage can be fed thereafter.

Plate 9

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4.0 UTILIZATION OF THE SILAGE

4.1 Feeding the Silage

The silage is aired for 24 hours or more under shade, before feeding. This allows certain noxious gases that may be formed during the fermentation process to escape.

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4.2 Production of Salt Lick from the Silage

Experience has shown that animals love to eat the salt-laden soil from under the silage pit. Indeed, they prefer it to the usual commercial salt block. To capitalise on this, a technique has been developed for making salt lick as a by-product of the silage.

For this purpose, the pit is made 20 cm deeper and a layer of fine sand or kaolin clay is spread at the bottom of the pit to that depth. If necessary, the sand should be sieved to ensure that it is fine. Half a kilogram of common salt is spread over the sand before the herbage filling is done. During the ensilage process, some salt may leach as much as 10 cm into the soil beneath the layer of sand. As with the sand deliberately placed in the pit, this salt-impregnated earth can also be used in making the salt lick block.

Using a wooden frame, 40 x 20 x 10 cm, a compact salt lick block is made from the sand/salted earth beneath the silage. The blocks are hardened by sun-drying. This block weighs 2.5 kg and each pit can produce about 50 kg of blocks.

Plate 12

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4.3 Feeding the Salt Lick

Access to the salt lick should be restricted to about one hour per day. Beyond this, animals tend to consume excess salt leading to their drinking too much at the expense of feed. Pregnant ewes are in fact at risk of aborting when they consume an excess of the salt lick.

4.4 Impact of Silage Feeding on Animals

Ewes that were supplemented with the silage maintained their milk yield throughout the year, while those which were on rough natural grazing alone dried up during the lean season. Similarly, Azaouak cows on the silage supplement produced 10 litres of milk per head per day throughout the year. Indeed, their owner said he could have obtained more milk from them but decided not to extract too much from the cows. In contrast, cows that were on natural grazing alone, produced no milk during the dry season.

Sheep on dry season silage supplementation were sold for CFA 50,000 each, whereas those that were not supplemented fetched only CFA 22,500 per head [1US$ = 552 CFA as at 27/04/2004].

In consideration of such benefits, one female practitioner of the silage technology who made one pit of silage this year, has decided to make two pits next year. She intends to sell the silage from one pit and use the second one to feed her own sheep.

In the same vein, a man with 40 head of cattle who learnt the technique this year, has decided to make five pits of silage next year. This means he would produce 15 tonnes of silage for his animals. 

5.0 ECONOMICS OF SILAGE PRODUCTION

5.1 Equipment Required

Digging equipment: pick axes, chisels and shovels.

Herbage harvesting equipment: harvesting sickles and machetes.

Transportation: donkey and cart.

Compressor: empty 200 litre drum (to be filled with water).

Silo cover: plastic sheet.

Silage extraction: garden forks.

The direct expenditure made by the women's groups was on the cost of tools, feeding the men who dug the pit and the cost of salt sprinkled on the herbage. For the purposes of calculating the cost of production, a two year life span is assumed for the tools.

5.2 Use of Labour

A co-operative group of 50 persons may divide themselves into three groups as follows: 20 persons would harvest the forage, 10 would transport the herbage to the pit and 20 would fill the pit. Work usually starts at 0800 and is finished by 1400. Forage harvesting is completed by 1000. Haulage of herbage is generally by head porterage and starts from about 0830 to be completed by 1200. When the cutting is done and there is still herbage to transport, the first group would join the carriers to haul the material to the pit. Filling is done from about 1000 to 1400. Again, the others would assist with filling the pit, if it became necessary.  

5.3 Digging the Pit

The pit is dug by the men in the community for the women without a formal charge. The task is regarded as a social occasion and the workers are fed by the women beneficiaries. Two or three men are required to dig one pit from about 0900 to 1200. Two pits would require 4-6 men but sometimes as many as ten men may show up to dig. The cost of feeding them would typically be as is shown in Table 1. While the cost of tools and materials used would be as shown in Table 2.

Table 1: Cost of Feeding the Diggers of the Silage Pit

Item	Quantity	Unit Price (CFA)	Amount (CFA)
Rice	25 kg	210/kg	5,250
Cowpeas	4 kg	1,050	4,200
Cooking oil	2 L	1,500	3,000
Salt	Lump	Lump	100
TOTAL			12,550

Table 2: Cost of Materials and Supplies Required: (CFA)

Item	Cost	Annual Cost
Pick axe	500	250
Chisel	2,000	1,000
Shovel	1,500	750
Forage Harvesting
Sickle	2,000	1,000
Silage Trimming
Machete	300	150
Compacting the herbage
Drum	10,000	5,000
Silo Cover
Plastic Sheet	2,000	1,000
Silage Picker
Garden Fork	1,500	750
Shelter
Shed	10,000	5,000
Sub-total		14,900
FEEDING PIT DIGGERS		12,550
SALT (50 KG)		6,000
ANNUAL TOTAL		33,450

5.4 Selling Price of Silage

The price of silage varies from CFA 50 per kg to CFA 100 per kg depending on the season, the peak price being in May to June. For the purposes of this computation, an average price of CFA 70 per kg is assumed.

The 3,000 kg of silage would be worth 3,000 x CFA 70 = CFA 210,000
Less the production cost of CFA 33,450
Cash Profit Per Silage Pit = CFA 210,000 –CFA 33,450 = CFA 176,550 

The minimum daily wage for 50 persons in Burkina Faso = CFA 500 x 50 = CFA 25,000
Thus the opportunity cost of the silage is very low and the venture is very profitable with a benefit-cost ratio of over 527 %.

6.0 DISSEMINATION AND ADOPTION OF THE ENSILAGE TECHNOLOGY

The popularity of the technology can be seen in the rapid growth of the numbers of smallholder farmers who have adopted it. In 2002, only one village was involved in the training and 120 persons, mainly Telefood farmers comprising about 80 women and 40 men, participated. In 2003, the beneficiaries numbered 537 persons comprising 185 men and 352 women.

Two pathways were involved in the diffusion process: through PRODS/PAIA encouragement and by direct farmer-to-farmer dissemination.

6.1 Farmer-to-Farmer Diffusion

Farmer-to-farmer dissemination has operated primarily in Central Burkina, where the technology originated. Smallholders in villages within a radius of 10 to 20 km from Tanghin Kossodo village, hear of the novel technology and go to see it for themselves. They are given a one-day training covering every aspect of the process, from digging the pit through sealing the silo and opening it. When these new 'converts' to the technology are ready to undertake the venture, they invite the old practitioners to come and supervise the process. The only expenditure incurred by the learners is the cost of feeding their teachers. This medium has covered 17 groups from 12 villages, with each group comprising about 50-80 persons. 

6.2 PRODS/PAIA Facilitation

In 2003, formal dissemination was achieved through PRODS/PAIA and the Special Programme for Food Security (SPFS). The training programme takes four days as follows:

            Day 1: Socialisation between trainees and old practioners

            Day 2: Theory of Silage Making

            Day 3: Pit digging.

            Day 4: Herbage cutting and pit filling.

This medium has reached co-operative smallholder groups in eight villages as shown in Table 3.

Table 3: Beneficiaries Reached by Formal Dissemination in 2002 and 2003