Management and feeding systems of crop residues: the experience of East Shoa Zone, Ethiopia

A Tesfaye and P Chairatanayuth^*

Adami Ttullu Agricultural Research Center, P.O. Box 35, Zeway, Ethiopia
feven563@yahoo.com
*Department of Animal Science, Kasetsart University, Bangkok 10900, Thailand

Abstract

The management (collection, storage and processing) and feeding systems of crop residues in 3 Agro Ecological Zones (AEZs), namely, sub-moist (SM2), sub-humid (SH2) and semiarid (SA2) of East Shoa Zone, Oromiya Regional State, Ethiopia were assessed by interviewing a total of 300 households proportionally selected from the three AEZs. The results indicated that with the exception of stovers, especially sorghum stover, other crop residues are collected and stored in open by more than 90% of the respondents. Thirty to 40% of the respondents indicated that some of their crop residues are wasted mainly because of improper storage and inability to collect. With regard to feeding systems, in most cases, the residues are fed either alone or in combination and without much attention to improve their feeding values, either through supplementation or any form of processing. The respondents stated that the major constraints they had to undertake these practices were shortage of labour and capital and lack of awareness and access.

For any beneficial practice to be appealing to farmers, it must be as economical as possible. Therefore, farmers need to be trained and advised as to how best and economical they can manage and feed their residues. Extension workers need to teach the farmers and demonstrate to them as to how to implement the already known simple, feeding-value-improvement techniques such as physical processing (chopping or threshing), supplementation and urea utilization. Research should also be directed towards investigating the resource requirements of different crop residue management and nutritive value improvement techniques, both on station and at farm levels, to justify feasibility of the same.

Key words: Agro-ecological zones, constraints, crop residue collection and storage, crop residue processing and treatment, feeding system

Introduction

In small scale farming systems, animal production is integrated with crop production. The animals provide draught power, manure and meat and milk products for human consumption. However, as the expansion of crop land increases, the availability of grazing land decreases thus limiting the scope for increased livestock production. Under such circumstances crop residue play an important role in supplying feed to ruminant animals.

Crop residues are the fibrous parts of crops that remain after the parts edible by human beings are removed. These feed resources are used as livestock feeds since time immemorial. In arid and semi arid tropics where natural pastures are only seasonally available because of the shortage of moisture, crop residues assume great importance in decreasing the level of feed deficit. As Smith (1993) indicated, these fibrous agricultural by-products constitute an important and often the major fed resources available and utilized by smallholder farmers in tropical livestock feeding systems. Depending on the type of crop, crop residues may be left on the field either as grazing for ruminants or as mulch, or they may be transported to the homestead for stall feeding or other alternative uses such as fencing, building and roofing materials or as fuel.

The fact that the nutritional value of these cheaply and readily available feed resources is poor has been well documented (Preston and Leng 1984; Owen and Aboud 1988; McDowell 1988). Simultaneously, various strategies such as chemical pre-treatments, use of different supplements and physical processing were identified to be of considerable advantage in improving the feeding value of these fibrous feeds. However, the application of these improvement strategies either in the form of managing the crop residues themselves or by seeking for suitable forms of feeding systems that complement deficiencies of the residues is still unsatisfactory, especially in developing countries (Timothy et al 1997) and under the small scale farmer's condition (Owen and Jayasuriya 1989; Devendra 1991).

The major crop residues in East Shoa Zone are tef, wheat and barley straws, maize and sorghum stovers and haricot bean haulms. With an annual average production of 0.67 to 1.01 tons per TLU of a household, these crop residues were found to contribute significantly to the feed requirements of animals in the three Agro Ecological Zones (AEZs) of East Shoa Zone covering as high as 26 to 40% of the total annual maintenance feed requirement of ruminants. (Tesfaye et al 2006 in press). However, other than day to day observation that farmers feed these residues to their animals, there are no documented evidences as to how the farmers manage their crop residues before feeding and what feeding system they employ. It is not as well known whether or not the farmers practise some of the nutritive value improvement measures. Therefore, this survey study was designed to assess the crop residue management (collection, storage, processing, etc.) and feeding systems applied and to identify the constraints and opportunities for the better and efficient utilization of crop residues in three AEZs of East Shoa Zone, Ethiopia.

Materials and methods

The study area

This survey was designed to address three AEZs, namely, sub-moist (SM2), sub-humid (SH2) and semi-arid (SA2) of the East Shoa Zone, Oromiya Regional State, Ethiopia. According to the AEZ classification by MOA (1998), SM2 refers to tepid to cool sub-moist mid highland areas with an altitude range of 1000 to 3000 m above sea level and an annual rainfall of 300 to 1600 mm. These areas have a mean annual temperature of 16 to 27.5⁰C. SH2 encompasses tepid to cool sub-humid mid highlands whose altitude ranges from 1000 to 3200 m. above sea level and receiving 700 to 2200 mm rainfall annually. Their mean annual temperature varies from 11 to 21⁰C. SA2 represents areas with tepid to cool semi-arid mid altitude (1600 to 2200 m above sea level) and that receive annual rainfall of 400 to 800 mm. Their mean annual temperature ranges from 16 to 21⁰C.

Sampling techniques

Multistage purposive sampling technique was used in this survey. The three AEZs were selected based on the criterion that they cover more than 75% (46.3, 21.1 and 7.9% by SM2, SH2 and SA2, respectively) of the total area of the zone (EARO GIS unit, personal communication). Districts from each AEZ and, peasant associations (PAs) from each district were identified based on their accessibility. Households from each PA were selected according to systematic random sampling using lists of households available with the development agents. Generally, in proportion to the area the three AEZs cover, 3 districts from SM2, 1 district from SH2 and 1 district from SA2 agro-ecologies were considered. Then 3, 4 and 2 PAs from each of the selected districts of SM2, SH2 and SA2, respectively were selected. Finally 20 households were included per PA thus forming a total sample size of 300 respondents (180, 80 and 40 from SM2, SH2 and SA2, respectively).

Data collection

Information on management (Collection, storage and processing) and feeding of crop residues and constraints to undertake such practices were obtained from primary source in the year 2005 using structured questionnaire.

Statistical analysis

Descriptive statistics and frequencies were conducted using the statistical package for social sciences (SPSS 1999).

Result and discussions

Crop residue collection and storage

Distribution of households according to the crop residue collection and storage practices they undertake is shown in Table 1. In SM2 and SH2, almost all interviewed households stated that they collect and then store all their tef, wheat and barley straws in open air (without shelter) to use it later in the year. More than 77% of the households in each of the three AEZs also indicated that they collect and store their haricot bean haulms in similar way. In case of stovers, the largest proportion is left on the crop field as is the case for sorghum stover in both SH2 and SA2. Relative to sorghum stover, a large proportion of maize stover is collected and stored in all the three AEZs.

Crop residues collection and storage practices were observed to depend on the mechanism of harvesting grain from the crops. With tef, wheat, barley and haricot bean, collection of grains from the crops necessarily demands the harvesting and transporting of the crops to homesteads where they are threshed and their grain and straws are separated. Finally the straws are stacked near homesteads and, in some cases, fenced with locally available wood. In case of maize and sorghum, the maize ears and sorghum grain heads are usually removed from the stalk right in the field leaving the rest for in situ grazing. This condition is further complemented with the status of farmers in having suitable conditions that enable them to collect these residues, the severity of feed problem the farmers have and the importance of none-feed purposes for which the stovers are required. In situations where farmers have no means of transportation, or where they have sufficient feeds from other sources, or where they need the stovers for other non-feed purposes, less stovers are collected and stored for animal feeding. Owen and Aboud (1988) also found the bulky nature of crop residues and lack of means of transportation to be among the factors that constrain the collection and hence greater use of straws and stovers as feed.

If the practice of residue collection and storage is considered for the entire study area (Table 2), more than 90% of the respondents collect and store their straws and 53% do the same for maize stover. In the case of sorghum stover about 67% of the respondents indicated that they leave it on the crop field.

Major constraints to crop residue collection in the study area were assessed by asking the respondents to identify, in order of importance, three major reasons for not collecting crop residues. The orders were then converted to scores in such a way that score 3 was given for the most important reason and score 1 for the least important reason. Then the percentage score for each reason was calculated as its total weighted score divided by the total scores given for all the reasons. Calculated accordingly, the percentage scores for possible reasons of not collecting crop residues by the respondents are given in Table 3.

The relative importance of the possible reasons varied from one AEZ to the other. In SM2, lack of means of transportation, followed by use of the residues for mulching purposes did not encourage the farmers to collect and store their residues for future use. This is similar to the finding of Mlay (1986) who observed lack of transportation to be the main constraint to collection of crop residues under Tanzanian condition. In SH2, other factors (which include lack of know-how and time and un-palatability of the residues, especially the stovers) followed by lack of means of transportation and use of the residues for mulching constitutes the major reasons of not collecting residues. For more than 60% of the respondents in SA2, the reasons were either their fields were too far from homesteads, or the crop residues were of such a small quantity that they did not deserve collection, or there were no means of transportation. With regard to means of transportation, more than 90% of the respondents in all the AEZs stated that they use donkeys either of their own or by begging or hiring from others.

Regarding crop residue storage problems, 65.0, 78.8 and 66.7% of the respondents in SM2, SH2 and SA2, respectively indicated that they have no storage problems as they take maximum care at storage places. The problems mentioned by the rest of the respondents are summarized in Table 4.

Percentage score for the problems was calculated in similar way the percentage score for reasons of not collecting crop residues was calculated. Mould formation due to rain fall followed by termite attack has been the principal storage problem in all the three AEZs. The possible effect of moulding is a reduction in quality of the stover followed by rejection by animals. In this regard, Devendra (1982) observed a decrease in nutritive value of rice straw due to exposure to weather. In this study, it was observed that most of the respondents stack their crop residues in open air with out any top cover with materials such as plastic sheets. On the other hand, some respondents cover the top of their crop residue stacks by tef straw as they knew that this, to some extent, has the ability to protect the percolation of rainfall through the stack, provided that the stacking is well performed. Other storage problems listed by the households include rodents, birds, wind and fire.

Crop residue processing and treatment

Various earlier works mentioned in the preceding sections have depicted that some sort of processing or treatment of crop residues have positive effects on improving, to a variable degree, the intake and/or digestibility of crop residues. Percentage of respondents who use some kind of processing methods is given in Table 5. Most of the respondents in all the AEZs physically process their stoves by means of chopping manually or threshing by animals. All households in the three AEZs are not using chemical treatment and more than 90% do not get their residues bailed. Other than what are indicated in the table, there were no other crop residue processing methods practiced by the respondents.

From summary of constraints to the use of residue processing methods given in Table 6, it can be seen that the major bottle-neck for the application these methods was the farmers' lack of knowledge about the uses and advantages of the methods. In SM2, relatively more households know the advantage of balling as some government and private organizations bale the residues, especially tef straw, themselves and pay the farmers on per bale basis. However, the farmers were constrained by lack of finance and access to machineries to undertake the practice themselves and get more benefit. Summarized for the entire study area, shortage of labor, lack of know-how and shortage of finance have, respectively been the major constraints to undertake physical processing, chemical treatment and bailing of crop residues.

Crop residue feeding systems

From questions posed to know when do farmers use their main livestock feed resources, namely, natural pasture, weeds and crop thinnings, road side grazing and crop residues, 76 and 99% of the respondents, respectively stated that they use their natural pasture and road side grazing only during wet seasons, whereas all respondents indicated that they use weeds and crop thinnings during the wet seasons as these feeds are available only during such seasons. With regard to crop residues, 50% of the respondents replied that they use these feeds only during the dry seasons, and the remaining 50% stated that they use their residues during both wet and dry seasons.

Distribution of households according to how they feed straws and stovers to their animals is shown in Table 7.

About two thirds of the interviewed households in SM2 and SH2 AEZs stack their tef, wheat, barley and haricot bean straws together and feed the mixture to animals. According to what the respondents replied, mix-stacking has the advantage of resisting, to some degree, the damages by rain as residues like tef straws are put on top of the stack. Moreover, providing the mixed straws to animals increases palatability of the straws more than when they are fed alone. In case of stovers, there was variation among the households in the three AEZs in the way they feed these residues to their animals. In SA2, about 80% of the respondents collect the stovers and feed them alone to their animals, whereas half of the households in SH2  allow their animals to graze the stovers in situ. The disparity between these two AEZs is attributed to their difference in having other feed resources. Households in SH2 AEZ had, relatively, more alternative feeds than households in SA2 AEZ as a result of which they did not bother to collect the stovers as households in SA2 AEZ did.  In Zimbabwe, Sibanda (1986) noted that most stovers were fed to animals in situ, while only some farmers harvested and stored the residues for later use. In the current survey, more than 40% of the respondents in the entire study area (Table 7) were found to exercise the practice of collecting and feeding stovers alone to their animals. The respondents indicated that, while feeding stovers, there was no much advantage in mixing them with other residues such as straws as animals tend to select the fine straws leaving the stovers behind.

From the point of view of using crop residues efficiently in feeding to different ruminants, it is important to know whether or not the farmers prefer one type of crop residue for one animal species than for the other. In all the three AEZs, more than 80% of the interviewed households revealed that they do prefer one type of residue for one species of animal than for the other species. Preference scores for the types of straw or stover the respondents in the whole study area prefer for their cattle, goats, sheep and equines are shown in Figure 1. Significant observation from the figure is that, by virtue of being soft and fine, tef straw was the most preferred residue for all species of animals with the exception of small ruminants for which the respondents preferred haricot bean haulms the most. For any type of ruminant, sorghum stover was the least preferred type of residue. This is in agreement with the findings of this survey in which the respondents stated that this stover is used more for construction and fuel purposes than for livestock feeding.

Summary of the interview as to whether or not the respondents use any supplementary feed, in addition to grazing and crop residues indicated that in SM2, more than 80% of the respondents use one or more of some supplementary feeds. On the other hand, the same proportion of respondents in both SH2 and SA2 stated that they do not use any supplementary feed for their animals. As can be observed from the percentage score of different supplementary feeds indicated in Figure 2, the most used supplementary feeds in SM2 were oil seed cakes (linseed cake, noug seed cake and cotton seed cake). This was likely to be due to the existence of relatively more oil extraction plants within the vicinity of this AEZ. In the other two AEZs, milling by-products (wheat bran and wheat middling) followed by oil seed cakes were the most used types of supplementary feeds.

Some constraints to the use of concentrates (oil seed cakes and milling by-products) and forage legumes by households in the study area are summarized in Table 8. In all the three AEZs, the major bottleneck for the use of concentrate supplements was found to be lack of finance.

However, there were also a large number of respondents who do not know the use of such feeds because of being very far from urban centers where such feeds are available. Legume supplementation in the form of either browse plants or forages was either not known to the farmers or was not easily obtainable. The latter case , as indicated by the respondents, is in cases where some government and non-government organizations tried to demonstrate the uses of forage legumes and browse such as leucaena and sesbania to some farmers but many other farmers were not provided with seeds and necessary advices so that they use the legumes. In some cases where farmers have both the access and the know-how of using legumes, shortage of land was cited as a factor which constrain the use of these forages.

Conclusions and recommendations

• The major crop residues available in the study areas were found to be tef, wheat and barley straws, maize and sorghum stovers and haricot bean haulms. As the effects of collection and storage systems on the quantity and quality of crop residues are well known, more than 90% the respondents in this survey were found to collect and store their residues, with the exception of stovers, especially the sorghum stovers. For the rest of the respondents, lack of means of transportation has been the major constraint to collect their residues. Thirty to 40% of the respondents indicated that some of their crop residues are wasted mainly because of improper storage and inability to collect. Mould formation followed by termite attack was the major storage problem identified. With regard to feeding systems, nearly two thirds of the respondents in each of the three AEZs stated that they feed their straws to animals by mixing them together rather than alone. Stovers are either grazed in situ or are fed alone.

• While there is a great potential for improving the feeding value of crop residues through supplementation and/or simple treatment or processing methods, the residues in the study area were fed without much attention to improving their feeding values. The only processing method undertaken by appreciable number of respondents (more than 75%) was physical processing (chopping and threshing), and except in SM2, more than 80% of the respondents in each of the other two AEZs did not use any supplement to enhance the feeding value of crop residues Shortage of labour and capital, lack of awareness and access are the major constraints the respondents had to undertake these practices.

• For any beneficial practice to be appealing to farmers, it must be as economical as possible. Therefore, farmers need to be trained and advised as to how best and economical they can manage and feed their residues. Extension workers need to teach the farmers and demonstrate to them as to how to implement the already known simple, feeding-value-improvement techniques such as physical processing (chopping or threshing), supplementation and urea utilization. Research should also be directed towards investigating the resource requirements of different crop residue management and nutritive value improvement techniques, both on station and at farm levels, to justify feasibility of the same. Moreover, some important practices which are being undertaken by some farmers (eg. mix stacking and hence feeding the mixed residues) should be appreciated and extended to other farmers with sufficient explanation about the advantages of the practices.

Acknowledgements

We acknowledge the Oromiya Agricultural Research Institute for funding this research through the Agricultural Research and Training Project. The Agriculture and Rural Development Office of the Boset, Adama, Lume, Dogdabora and Adamitulu Jidokombolcha districts where this survey was conducted are highly appreciated for their cooperation in selecting representative peasant associations and households.

References

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Received 9 March 2006; Accepted 19 January 2007; Published 1 March 2007

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