ABSTRACT
A three year trial (2004-2006) was conducted to assess the performance of three forage legumes, Stylosanthes hamata(L) Taub. cv Verano, Chamaecrista rotundifolia (Pers) Grenne cv Wynn and Centrosema pascuorum Mart. ex Benth (Centurion) cv Cavalcade in range rehabilitation. The first phase of the trial covered a period of sixteen months when the feasibility of range improvement by strip-sowing of the selected forage legumes into natural pastures was tested. Data on legume establishment, forage dry matter yield were collected from the strip-sown legumes and the natural pastures. The first phase was followed by a second one where Bunaji bulls were introduced to graze the treatments continuously over the next 12 months. The grazing animals were weighed fortnightly to monitor liveweight changes while the body condition score were recorded on a monthly basis. In the final year, persistency and spread of the different forage legumes were assessed. In the year of establishment, S. hamata recorded the highest stand count of 117 stands/m2, with lower counts of 65 stands/m2 for C. pascuorum and 25 stands/m2 for C. rotundifolia. The S. hamata stand count was significantly higher (P<0.01) than that of either C. pascuorum or C. rotundifolia. In the second year following establishment, stand count in both S. hamata and C. pascuorum dropped while C. rotundifolia increased to 67 stands/m2. The stand counts in S. hamata and C. pascuorum further decreased in the third year while C. rotundifolia stand count increased. Regeneration from seed from the legumes tested was 100% in C. pascuorum, 99.9% in C. rotundfoilia and 87.6% in S. hamata. In the third year, C. rotundifolia was found to have spread beyond its sown strips. Dry matter yields from the strips of the sown legume at commencement of grazing was highest in S. hamata strips (1.4t DM/ha)
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than C. rotundifolia (1.1t DM/ ha) and C. pascuorum (0.9t DM/ha). The dry matter yield from the native pasture alone was 3.0 t DM/ha. In the grazing trial, paddocks were stocked at 4 Bunaji bulls /ha. The animals grazed from 9:00 am to 5:00 pm over a one year grazing cycle. Weight gain was highest in animals on S. hamata treatment than those on C. rotundifolia, with the least gain recorded in animals on C. pascuorum treatment. However, there was no significant difference due to treatment. Similarly body condition scores, which ranged between 3.30±0.09 to 3.53 ± 0.09 were not significantly different (P>0.05) in the treatments. The results of this study, therefore, indicate that C. rotundifolia has the potential for use in re-seeding degraded rangelands. It has the capacity to colonize areas faster than either S. hamata or C. pascuorum. C. pascuorum has the disadvantage of being very susceptible to attacks by various pests which prevented it from setting seed and subsequent regeneration in the open strip-sown range site. It is recommended that Chamaecrista rotundifolia be further tested in the rehabilitation of the degraded rangelands in the other Savanna ecological zones.
TABLE OF CONTENTS
Title Page………………………………………………………..………………. i
Declaration………………………………………………………………………. ii
Certification……………………………………………………………………… iii
Dedication………………………………………………………………………… iv
Acknowledgement……………………………………………………………….. v
Abstract…………………………………………………………………………… vii
Table of Contents…………………………………………………………………. ix
List of Tables……………………………………………………………………… xiv
List of Figures…………………………………………………………………….. xv
List of Appendices………………………………………………………………… xvi
Abbreviations and Symbols………………………………………………………. xvii
CHAPTER ONE
1.0 INTRODUCTION……………………………………………………… 1
1.1 Arable and livestock agriculture in Nigeria……………………. 1
1.2 Hypothesis……………………………………………………… 4
1.3 Objectives………………………………………………………. 5
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 Range Livestock Production…………………………………….. 5
2.2 Overview of Livestock Production………………………………. 12
2.3 Livestock Production Systems…………………………………… 17
2.3.1 Extensive Production System…………………………… 17
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2.3.2 The Semi Intensive Production System………………… 19
2.3.3 The Intensive Production System……………………… 20
2.4 Role of Rangelands in Livestock Production…………………………… 21
2.4.1 Effects of Grazing on Rangeland Productivity………… 22
2.4.2 Assessing Range Condition…………………………… 26
2.4.3 Range Rehabilitation Methods………………………… 29
2.4.3.1 Complete Renovation…………………………. 31
2.4.3.2 Use of Companion Crops…………………… 31
2.4.3.3 Sole Crop Seeding……………………………… 32
2.4.3.4 Grass-Legume Mixtures……………………….. 33
2.4.3.5 Grass-Legume Rotation………………………… 34
2.4.3.6 Under-sowing or Sod Seeding..………………… 35
2.4.3.7 Over-sowing…………………………………… 36
2.4.3.8 Livestock Seeding……………………………… 37
2.4.3.9 Strip Seeding…………………………………… 37
2.4.3.10 Spot Seeding…………………………………… 37
2.5 Role of Legumes in Pasture Systems…………………………………… 38
2.5.1 Soil Fertility Management……………………………………… 41
2.5.2 Tool in Pest Control and Management…………………………. 42
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2.5.3 Forage Production……………………………………………… 42
2.5.4 Nutritive or Feeding Value……………………………………… 42
2.5.5 Animal Production……………………………………………… 43
2.5.5.1 Animal Health Interactions…………………….. 44
2.5.5.2 Liveweight Changes…………………………… 45
2.5.5.3 Milk Yield……………………………………… 46
2.5.5.4 Reproduction…………………………………… 47
2.6 Legumes in Rangeland Development…………………………………… 47
2.6.1 Forage Legumes Introduction into Nigerian Savanna…………… 48
2.6.1.1 Stylosanthes hamata ( L) Taub cv Verano…………… 48
2.6.1.2 Chamaecrista rotundifolia (Pers) Greene cv Wynn… 50
2.6.1.3 Centrosema pascuorum Mart. ex Benth
cv. Cavalcade…..…………………………………….. 51
CHAPTER THREE
3.0 Materials and Methods…………………………………………….. 54
3.1 Study Area…………………………………………………………. 54
3.2 Experimental Design……………………………………………….. 58
3.3 Legumes Establishment……………………………………………. 58
3.4 Botanical Composition and Dry Matter Yields……………………. 59
3.5 Animals Performance……………………………………………… 60
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3.6 Statistical Analysis…………………………………………………. 61
CHAPTER FOUR
4.0 Results…..………………………………………………………… 62
4.1 Botanical Composition of Experimental Site ……………………. 62
4.2 Legumes’ Establishment and Regeneration………………………… 65
4.2.1 Seed Germination Test …………………………….. 65
4.2.2 Effects of Soil Depth on Legume Establishment….. 69
4.2.3 Legumes Regeneration …………………………… 72
4.3 Dry Matter Yields from Strip-sown Legumes……………….……. 77
4.4 Dry Matter Yields from the Native Pasture……………………………….. 78
4.5 Legumes’ Spread into Native Pasture……………………………… 81
4.6 Animal performance………………………………………………. 83
4.6.1 Effects of treatments on liveweights, weight changes
and body condition scores……………………………….. 83
4.6.2 Effects of Soil Depth on Animal Performance……………. 85
4.6.3 Effects of Season on Animal Performance………………… 87
4.6.4 Effects of Treatments by Season and interaction
on Animal performance……………………………………. 89
4.6.5 Animal Liveweight Changes……..…………………………. 91
CHAPTER FIVE
5.0 Discussions………………………………………………………… 94
5.1 Vegetation Composition…………………………………………… 94
5.2 Legumes Establishment……………………………………………. 96
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5.3 Effect of Soil Depth on Legumes Establishment…………………… 100
5.4 Forage Dry Matter Yield…………………………………………… 101
5.5 Animals Liveweight Changes……………………………………… 102
5.6 Legume Persistence and Spread…………………………………… 104
CHAPTER SIX
6.0 Conclusions and Recommendations………………………………… 105
6.1 Conclusion…………………………………………………… 105
6.2 Recommendations…………………………………………… 106
7.0 References…………………………………………………………… 108
8.0 APPENDICES……………………………………………………… 130
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CHAPTER ONE
1.0 INTRODUCTION
1.1 ARABLE AND LIVESTOCK AGRICULTURE IN NIGERIA
Before Nigeria attained independence in 1960, agriculture was the leading sector of the economy, accounting for more than 50% of the total GDP and more than 75% of export earnings (Aregheore, 2005). It was the nation’s bedrock for development until petroleum was discovered and exploited soon after independence from colonial Britain. The development of the petroleum industry in the late 1960s and 1970s radically transformed Nigeria from an agricultural based economy to a major oil exporter. The dramatic fall in international prices for petroleum in 1986 induced government to institute a two-year Structural Adjustment Program (SAP). The programme was aimed at expanding non-oil exports, reducing import of goods that could be manufactured locally and increasing the role of private sector participation in agriculture so as to achieve self-sufficiency in food (Aregheore, 2005).
Since the mid 1980’s, many other countries of sub-Saharan Africa have been implementing the structural adjustment programmes (SAP) aimed at rectifying severe macro-economic problems, including falling export earnings, worsening balance of payments, mounting debts and declining economic growth (Misana et al., 1996). Reductions in cereal imports and resurgence of public and private investment in agriculture resulted in a sharp recovery in production (FAO, 2001). Consequently, in countries that have implemented SAP, a major effect, among others, has been higher crop prices (Misana et al., 1996). The net results of this were upsurge in land clearance to
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open new lands for crop cultivation and reduction in surface area and habitat for animals while increasing marginalization of grazing to less productive lands. Thus, although there was steady growth in the production of both staple and cash crops since 1990, the supply of animal products has been declining over the past two decades. The demand for animal products, on the other hand, has been increasing as a result of increases in population and urbanization. Nigeria still remains a net importer of livestock and livestock products (Aregheore, 2005). The introduction of the SAP, which resulted in massive devaluation of the local currency continued to increase the expenditure on import of food and live animals as demand could not be met by local production (FMEN, 2001).
Almost all over the world rangelands are recognized as significant baseline resource in the livestock industry. This is more so on the continents of Africa, Australia, North America and South America where vast expanses of territory provide habitat and grazing for livestock and wild life. Rangelands are home to some 200 million people in the tropics and support about a billion domestic animals (Heady and Heady, 1982; ILRI, 1998). For all practical purposes, ruminant livestock production in Nigeria is in the hands of pastoralists who own over 90% of the stock holdings. The stocks are mainly reared under transhumant system of grazing over large expanses of rangelands. Under this production system the livestock rely on the natural rangeland forages with little or no supplementation for their nourishment year-round.
Despite the significant contribution of rangeland to the socio-economic lives of the inhabitants of developing countries, the resource is often abused and neglected in terms of planned utilization, development and management for sustainability (Kallah, 1999).
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Pamo and Pieper (2000) noted a number of factors and developments which are placing increasing strains on rangeland resources, prominent among which is the rapidly growing human population and its associated stresses. The greatest challenge on what is left of the rangeland is the limited vegetative cover and capabilities in biomass production that can match the increasing demand and feed requirements of the grazing animals to be sustained in a given area (Hodgson, 1975).
Although the deterioration of the Sub-Saharan rangelands is a subject of great concern and extensive study, no blueprint has been produced which can accommodate the great diversity of natural, environmental and socio-economic conditions encountered in the management of the resources (Pamo and Pieper, 2000). Models introduced from temperate regions into tropical Sub-Saharan region before and after independence from colonial control have failed to improve range productivity (Jahnke 1982; Scoones 1995). Factors militating against the success of the models were social, economic, cultural and above all lack of good understanding of the functioning process of the system (Brumby, 1987; Preston and Murgueitio 1994; Pamo and Pieper 2000).
Sub-Saharan countries need to face the challenge of increasing degradation of rangelands and effectively deal with the management of open-access resources at disequilibrium (Ellis, 1995). This is necessary if livestock production must be improved and sustained in the millennium ahead. A wealth of information and knowledge in the range sciences and experiences from other regions could be borrowed and adapted to provide basis for alleviating some of the constraints (Barnes 1985).
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The introduction of productive, nutritious, persistent plant species particularly legumes into the range had shown promise in that direction. Legumes have wide scope for restoring stability of feed resources in degraded landscape (Conner et al. 1998). Landscapes with extreme loss of soil and nutrients which could not otherwise be rejuvenated through improved grazing management alone may be restored by applying a combination of land terrain modifications and the introduction of adapted forage species to stabilize the system. Legumes introduction has been suggested as a low-cost, socially integratable restoration technology which can induce landscape alterations and allow grazed ecosystems to stabilize (Conner et al. 1998). The most suitable legume would have to be one that would withstand grazing, incessant fires and capable of high seed yield that can spread through the native range easily and colonize large areas naturally. In the final outcome, such species would be expected to improve grassland primary productivity to prevent further land degradation and increase productivity in the grazing animals especially during the dry season.
1.2 HYPOTHESIS
This study was carried out on the basis of the following hypotheses:
H0: Three legumes introduced into native range will not differ in their ability to establish, contribute substantially to the dry matter production, increase animal production, persist and colonize the native range
Ha: Three legumes introduced into native range will differ in their ability to establish, contribute substantially to dry matter production, increase animal production, persist and colonize the native rangeland
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1.3 OBJECTIVES
The broad objective of the trial was to identify suitable forage legume species for strip-sowing into the native rangeland of the Northern Guinea Savanna to improve productivity of the native rangeland, subject to open access utilization. The specific objectives were as follows:
i) To determine the ability of three introduced legumes to establish successfully in the native rangeland
ii) To evaluate the dry matter production capacity of the three legumes in the native rangeland
iii) To determine effect of the legumes on animals grazing the pastures and
iv) To assess the ability of the legumes to persist and colonize the native rangeland.
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