THE EFFECTS OF LAND DEGRADATION ON FOOD CROPS YIELD IN NIGERIA :A CASE STUDY KARU LOCAL GOVERNMENT AREA, NASARAWA STATE, NIGERIA
The study assessed the effect of land degradation on food crop yield in Karu Local Government Area of Nasarawa State for 2013-2014 cropping season. The study area lies on Latitude 8º45" and 10º15"N of equator and Longitude 11º45"E and 12º30"E of Greenwich meridian. Random sampling method was used in selecting four wards and respondents to administered questionnaires to farmers. Soil samples were collected from farm lands and fallow lands from four wards ( Karu, Aso Kodape, Uke and Karshi I) with the aid of soil auger at 0-15cm and 15 – 30cm depth and were laid out in randomized blocks and replicated four times. Soil quality model by (Larson and Piece, 1999) was used to calculate soil quality and the result revealed that the land is degraded with a ΔQ/Δt of -0.02 for 0-15 depth and -0.02 for 15 – 30 cm depth of farm lands. Result of analysis of variance revealed that there is significant different in means value of soil properties across the top and sub-soil of farm land under cultivation and fallow site. Logistic regression analysis on the causes of land degradation showed that farming system and employment status had a significant contribution to land degradation and crop yield reduction in the study area. Chi-square analysis indicated both dependable(factors responsible for land degradation) and independent variable (household characteristics) such as erosion, deforestation, increase in population conversion of land to non agricultural use, over cultivation and bush burning rated as the major causes of land degradation in the study area. Inappropriate farming practice such as continuous cultivation, cutting of tree for land preparation for cultivation, excessive use of agro- chemical have been identified also as responsible for land degradation. From the adopted work done by Chindo et al (2014), from 1973 – 1986, 11% of the forest land of the study area were depleted, between 1986 – 1999, recorded 64% forest land depletion and 25% from1973 – 1986. The rated of depletion annually was 2,4043 km, 1986 – 1999, 13,774km2 and 6,8854km, between 1999 – 2009 respectively. The study revealed the effect of land degradation in the study area to include; decrease in food crop yield and high cost of farming in terms of farm inputs. Farmers adopted the following strategies; creation of land degradation awareness, avoidance of bush burning, planting of leguminous crops and preventing of indiscriminate cutting of tree to cushion the effect of land degradation. Recommendations were made in area of routine soil test to enable farmers to apply appropriate fertilizer, good farming practice, retention of crop and other plants residues on the soil after harvest in the hope to offset the decline in organic matter level and increase sensitization on sustainable land management to increase food crop yield in the study area.
Key word: Land Degradation, Erosion, Deforestation, Cultivation, Farming.
TABLE OF CONTENTS
TITLE PAGE - - - - - - - - - i
DECLARATION - - - - - - - - - ii
CERTIFICATION - - - - - - - - - iii
DEDICATION - - - - - - - - - iv
ACKNOWLEDGEMENTS - - - - - - - v
ABSTRACT - - - - - - - - - vi
TABLE OF CONTENTS - - - - - - - - vii
LIST OF TABLES - - - - - - - - - xi
LIST OF FIGURES - - - - - - - - xiii
LIST OF LIST OF PLATE - - - - - - - - xiv
LIST OF SYMBOLS - - - - - - - - xv
LIST OF ABBREVIATIONS - - - - - - - xvi
CHAPTER ONE: INTRODUCTION
1.1 Background of the study - - - - - - - - 1
1.2 Statement of the problem - - - - - - - 3
1.3 Aim and objectives of the study - - - - - - - 5
1.4 Significance of the study - - - - - - - 5
1.5 Scope and Limitation of the study - - - - - - 6
1.6 Research Hypothesis - - - - - - - - 7
2.1 Theory of land degradation - - - - - - - 8
2.2 Causes of land degradation - - - - - - - 10
2.3. Types of Land degradation - - - - - - - 12
2.4 Factors that determine plant growth and yield - - - - - 13
2.4.1 Soil quality - - - - - - - - - 14
2.4.2 Soil loss and crops yield in Sub-Saharan Africa - - - - 14
2.5 Effect of Land degradation - - - - - - - 15
2.6 Brief history of Agricultural in Nigeria - - - - - - 17
2.7 Land tenure in Nigeria - - - - - - - - 18
2.8 Review of related Literatures - - - - - - - 19
2.9 Implications of the literatures reviewed to the present study - - - 22
3.1 Location and size of the study area - - - - - - 23
3.1.2 Ethnicity, cultural background and religion of the study area - - 24
3.1.3 Economy and trade - - - - - - - - 25
3.1.4 Climate - - - - - - - - - - 26
3.1.5 Physical characteristics - - - - - - - - 26
3.1.6 Soil - - - - - - - - - - 26
3.1.7 Hydrology - - - - - - - - - 27
3.1.8 Environment - - - - - - - - - 27
3.1.9 Vegetation - - - - - - - - - 27
3.2 Research Methodology - - - - - - - - 28
3.2.1 Data source - - - - - - - - - 28
3.2.2 Sampling and sampling technique - - - - - - 28
3.2.3 Soil sampling - - - - - - - - - 28
3.2.4 Laboratory analysis - - - - - - - - 30
3.2.5 Determination of soil quality of the study area - - - - 31
22.214.171.124 Soil quality model - - - - - - - - 31
3.2.6 Study area and Household sampling - - - - - - 32
3.2.7 Questionnaire administration - - - - - - - 32
3.2.8 Validation of instrument and pilot testing of questionnaire - - - 33
3.2.9 Distribution of questionnaire - - - - - - - 33
3.2.10 Interview survey - - - - - - - - 34
126.96.36.199 Issues faced during farming communities survey - - - - 34
3.2.11 Field measurement/ observation - - - - - - 35
3.2.12 Tool for data analysis - - - - - - - - 36
188.8.131.52 Data storage and processing - - - - - - 36
184.108.40.206 House hold survey data analysis - - - - - - 36
3.2.13 Process of analysis of focus group discussion (FGD) - - - 38
220.127.116.11 Data storage and processing of focus group discussion - - - 38
18.104.22.168 Pre-analysis of farmer’s survey - - - - - - 38
4.1 profile of farmers - - - - - - - - 40
4.1.1 Discussion of result of table 4.1 and 4.2 - - - - - 41
4.1.2 Farm and farming activities - - - - - - - 42
4.1.3 Discussion of result of table 4.3 - - - - - - 43
4.2 Determination of soil quality in the study area using
Larson and Pierce model (1991) - - - - - - 43
4.2.1 Calculation of Soil Quality - - - - - - - 47
4.2.2 Discussion on the result of the analysis of soil quality - - - 49
4.3 Analysis of Variance to determine the variation in the means of analysed
Soil properties of degraded farm land and fallowed lands used as
Control sites - - - - - - - - - 49
4.3.1 Discussion on table 4 - - - - - - - - 51
4.4 Causes of land degradation - - - - - - - 51
4.4.1 Test of hypothesis - - - - - - - - 56
4.5 Farming practices in the study area - - - - - - 57
4.5.1 Discussion on farming practices - - - - - - 58
4.6 The Average number of plant per square meter of various crops
Cultivated in the study area - - - - - - - 58
4.6.1 Crop yield in the study area - - - - - - - 59
4.6.2 Discussion on crops yield in the study area - - - - - 60
4.6.3 Environmental awareness of declining yield among farmers - - - 60
4.7 Land use/cover of the study area - - - - - - 61
4.7.1 Analysis of vegetation change (deforestation) - - - - 65
4.8 Effect of land degradation - - - - - - - 66
4.9 Major strategies adopted by farmers to cushion the effect of
land degradation in the study area - - - - - - 68
4.9.1 Discussion on the major strategies adopted by farmers to cushion the
effect of land degradation the study area - - - - - 69
4.10 Focus group discussion - - - - - - - - 69
5.1 Summary of Findings - - - - - - - - 70
5.2 Conclusion - - - - - - - - - 75
5.3 Recommendations - - - - - - - - 76
References - - - - - - - - - - 77
Appendix A Responses of household on wards basis - - - - 85
Appendix B Procedures for laboratory analysis - - - - - 90
Appendix C Physic-chemical properties of the soil of the study area - - 97
Appendix D Questionnaire - - - - - - - - 101
LIST OF TABLE
TABLE TITLE PAGE Table 2.1 Diagram of conceptual framework 9
Table 2.2 shows the soil types in the ecological zones of Nigeria 14 Table 3.1 2006 Karu Local Government population according to ward’s 23
Table 3.2 shows soil properties and the method and equipments used for measurement 30 Table 3.3 shows the name of the four wards selected for the study and their
respective number of households and number of questionnaires allocated 34 Table 3.4 Logistics Regression of three variables 37
Table 3.5 Six groups of farmer’s interviewed 39
Table 4.1 Summary of the characteristics of respondents in the study area (n=235) 40
Table 4.2 Continuation of characteristics of respondents 40
Table 4.3 Farming characteristics of the respondents 42
Table 4.4 means of analysed soil properties of the study area at 0-15cm depth 44
Table 4.5 means of analysed soil properties of the study area at 15-30 cm depth 44
Table 4.6 means of analysed soil parameters of control site of the study area
at 0-15 cm depth 45
Table 4.7 means of analysed soil parameters of the control site of the study area
at 15-30 cm depth 45
Table 4.8 sustainability of farm land and control site of the study area at 0-15 cm depth 46
Table 4.9 sustainability of farm land and control site of the study area at 15-30 cm depth 48
Table 4.10 means of means of analysed soil parameters of farm lands and
control site at 0-15 cm depth 50
Table 4.11 means of means of analysed soil parameters of farm lands and
control site at 15-30 cm depth 50
Table 4.12 shows the major causes of land degradation as revealed by respondents 52
Table 4.13 Chi-square showing the relationship of dependent variables and
independent variables in land degradation in the study are 56
Table 4.14 shows major farming practices in the study area 57
Table 4.15 shows average number of plants per stand of various crops cultivated 58
Table 4.16 shows standard number of plants per stand of various crops cultivated 59
Table 4.17 shows standard crops yields of selected crops per hectare 59
Table 4.18 shows estimated crops yields of selected crops in the study area 60
Table 4.19 shows difference in crops yields in the study area 60
Table 4.20 Logistics Regression Analysis for variables predicting individual
awareness of declining yield/ land degradation problem 61
Table 4.21 shows land use/cover of the study area for (1973, 1986, 19999 and 20009) 62
Table 4.22 shows spatial change of forest land in the study area 62
Table 4.23 Logistics Regression Analysis for variables predicting land degradation 66
Table 4.24 shows the effect of land degradation as revealed by farmers 67
Table 4.25 shows strategies adopted by farmers to cushion the effect of land degradation 68
LIST OF FIGURES
Figure 3.1 Map of Nigeria showing Nasarawa State and Karu Local Government Area 24
Figure 3.2 Map of Karu Local Government showing the study area 25
Figure 4.3 shows the trend of depletion of forest land between 1970s and 2000s 63
Figure 4.4 shows annual depletion rate of forest land in the study area 63
LIST OF PLATE
Plate 4.1 Erosion activities at Ado Kassa, Karu ward 53
Plate 4.2 The effects of non biodegradable refuge dump on maize farm at Auta
Plate 4.3 Degraded land as a result of mining activities at Karshi I 55
Plate 4.4 shows remote sensing imagery of land use/ cover change of the
Study area (1973-2009) adopted from Chindo et al (2014) 64
Plate 4.5 Products of deforestation activities at Uke 65
LIST OF SYMBOS
List of symbols 113
LIST OF ABBREVATIONS
List of abbreviations 114
1.1 Background to the Study
Agriculture is the predominant and important economic sector in Nigeria. According to Omofema, (2007) agricultural sector is a major source of employment in Nigeria’s rural setting, source of income for rural dwellers and a stable supply of nutritional needs. Despite that, food insecurity is another critical issue challenging the sector. This is evidenced in the amount of staples like; rice and wheat importation in the country which caused the economy billions of naira annually (NBS, 2010).
Land degradation couples with poverty pose a serious threat on farmer’s income and food security. According to Senjobi, et al. (2010) Land, being limited in supply is pressured and competed for by several uses. The intensification of cultivation resulting in the opening up of new lands exposes the top soil to the elements of degradation and alters the natural ecological conservatory balances in the landscape. Land degradation, a decline in land quality caused by human activities, will remain high on the international agenda in the 21st century.
Eswaran & Reich, (2001) stressed that Land degradation is a broad term that can be applied differently across a wide range of scenarios. There are four main ways of looking at land degradation and its impact on the environment around it
(a) A temporary or permanent decline in the productive capacity of the land.
(b) A decline in the lands usefulness. A loss or reduction in the land capacity to provide resources for human livelihoods.
(c) Loss of biodiversity. A loss of range of species or ecosystem complexity as a decline in the environmental quality
(d) A shifting ecological risk. Increased vulnerability of the environment or people to destruction or crises.
In a study undertaken by Food and Agricultural Organization (FAO) in 1991, causes of land degradation in Nigeria have been identified. Those of particular relevance to Nasarawa State and Karu Local Government in particular are listed below;
Degradation Problem Immediate Causes
Gully Erosion poor road design, inadequate urban
Drainage, cultivation on steep sides and destruction of vegetation cover.
Sheet Erosion Inadequate on-farm conservation;
over-exposure of cultivated soil
to rain splash at critical seasons.
Intensive cultivation, leading to soil capping and compaction due to organic matters loss; overgrazing; destruction of tree cover.
Declining Soil Fertility shortened fallow periods; inadequate supply of mineral and organic fertilizer; impoverished soil; intense cultivation.
Soil Physical Deterioration Inappropriate cultivation practices;
Depletion of organic matter during cultivation.
Rangeland Degradation overstocking; bush burning, destruction of tree cover; increasing aridity.
Deforestation Clearing for agriculture; over - exploitation for timber and firewood.
Causes of land degradation include, overgrazing, improper cultivation practices, unsustainable agricultural land use, poor soil and water management, deforestation, construction of roads and houses, drought, flood, erosion, poverty, shortage of land due to increase in population, encroachment on marginal land, flash flood among others.
According to Fagbemi, (2002) Land degradation can cause human, economic, social and infrastructural losses. In an agrarian economy, it can reduce agricultural output and yield thereby precipitating starvation and poverty.
According to the report of the United Nation Convention to Combat Desertification (UNCCD) held on April, 2001 in Bonn, Germany, Stated that, the international community is losing vast amounts of agricultural production due to the effects of contingency land degradation such as desertification. The study also shows that the social cost of land degradation are even more staggering with nearly 870 million people suffering from chronic hunger globally.
Soil productivity is the capacity of soil to produce a certain yield of crops or other plant under a defined set of management practice. Soil productivity entails striking a balance among soil physical, chemical and biological fertilities, as none is of much value without other. All these soil properties are affected by top soil removal; crop yields are affected through the resulting changes in these properties. Soil chemical properties that are mostly adversely influenced by erosion or topsoil removal in south Saharan Africa and Karu inclusive include; PH, Organic matter content, total Nitrogen, available Phosphorus, exchangeable bases and Cation Exchange Capacity.( Mbagwu, 1998)
In the developing countries like Nigeria and Karu Local Government in particular where a large population of human depends almost entirely on land resources for their sustenance, there is increasing competing demand for land utilization such as grazing, agricultural activities, cutting of wood for domestic energy needs, construction, quarrying, infrastructural development, increase in population with the resultant effect on soil quality and crop yields. The study therefore is aimed at assessing the effects of land degradation on food crops yield in the study area.
1.2 Statement of Problem
There were indications that field clearing, extraction of trees for firewood and charcoal, bush fire and overgrazing in Karu lead to land degradation.
Generally, much work has been done relating to the effect of degraded land which is increased cost of input, loss of soil nutrients, low agricultural productivity, poverty and hunger,( UNCCD 2013, Eswaran &Reich, 2001, Mbagwu, 2003).
Ajayi, (1992) emphasized that, there are artificially induced hazards arising from human activities such as the disposal of domestic and industrial wastes, bush burning and poor management of agricultural land. He concluded that there are also human assisted hazards the occurrences of which are naturally inherent but which are escalated by human activities such as excessive soil erosion, soil nutrient depletion or imbalance, urban floods and dam failure.
Several scholars have established the fact that environmental problems (land degradation, bio diversity loss) are widespread in the study area. Such Scholar include; FAO (1991) Yari et al (2002), Oldemen et al (1990), UN-HABITAT (2013), Rikko(2013).
Yari, et al (2002) on their report of Karu Development Strategy(KDS),( as quoted in world bank report 2005), confirmed that rapid development resulting from very high population growth of about 40% with high rate of urbanization in Karu because of its proximity to Abuja posses the following problems:
- Loss of fertile agricultural land to urban expansion.
- Large scale indiscriminate mining and construction materials such as sand and late rite.
- Encroachment on marginal land especially flood plains for housing.
- Erosion as a result of improper environment management
Also the United Nations Human Settlements Programmed (UN-HABITAT) confirmed the environmental problems in the study area in form of; bad agricultural techniques such as in appropriate use of agro–chemicals and unrestricted harvesting of trees for domestic heating and cooking, uncontrolled excavation of sand for construction, unregulated grazing and bush burning and among others.
In Karu Local Government, there is pressure on land usage such as agricultural activities, grazing activities, cutting down of wood for domestic energy needs, frequent use of heavy machinery for construction purposes, encroachment on marginal lands, removal of natural vegetation for construction purpose, amongst others, there is no doubt that the above land usage can result to land degradation with attendant result on food crops yield.
Thus the research seeks to answer the following questions;
1. What is the status of physic- chemical soil properties and its implication on food crop yield in the study area?
2. What are the major causes of land degradation in the study area?
3. Has farming practices contributed to land degradation in the study area?
4. What is the extent of depletion of vegetation cover in the study area?
5. How has farmers been able to cope with all the attendant problems from land degradation?
1.3 Aim and Objectives of the Study
In view of the land degradation processes in Guinea Savannah belt of Nigeria due to human interference on the natural ecosystem, it then becomes pertinent to study the impact of this degradation on soil quality and their implication on soil productivity to food crops yield. To achieve the above aim, the following specific objectives have been set to:
1. Assess physic- chemical soil properties and its implication on crop yield in the study area
2. Identify the major causes of land degradation in the study Area
3. Assess the farming practices in the study area
4. To use studies by Chindo et al (2014) to detect trends and pattern of vegetation change
over the Period of three decades (1973-2009)
5. Examine the strategies adopted by the farmers in reducing the effect of land degradation
in the study area.
1.4 Significant of the Study
Sustainable development is a concept which refers to development that meets the needs of the present without compromising the ability of the future generation to meet their own needs (United Nation, 1987). This can only be achieved if the natural environment is protected. The study of the effect of land degradation on food crop yield will unveil the impact of land degradation on food crop yield and the effect on the major player (farmers) in land usage and its implication on land management, environmental conservation and agricultural production.
The result of the research apart from contributing to general knowledge on land degradation and its effects on agriculture production would also.
1. Increase national and local concern on land management practice and policies
2. Enhance the effort of agricultural/environmental department, agencies, donor nations, NGOs, research institutes and extension workers on current agricultural practices in order to improve on food production, reduce poverty and protect natural environment
3. Serve as a reference point for future study/research.
1.5 Scope and Limitation of the Study
Spatial Scope- Karu Local Government Area has 11 administrative wards. They include; Karu, Guruku kabusa, Aso Kodape, Uke, Bagagi Agada, Keffi Shanu, Karsh I, Karshi II, Panda Kare, Tattara Kondoro and Gitata.
For the purpose of this research, four wards that is Karu, Aso Kodape, Uke and Karshi I were randomly selected for the study because of the conspicuous factors responsible for land degradation such as overgrazing, cutting of wood for domestic energy needs, construction, quarrying, infrastructural developments, increase in population, frequent use of heavy machinery, removal of natural vegetation, encroachment on marginal land pollution in terms of littering of refuges dumps on agriculture land seen in these areas.
Conceptual Scope. The causes of land degradation are both natural and human induced and the most common methods used for assessment are: expert opinions, land users’ opinions, field monitoring, observations and measurement, modeling, estimates of productivity change and remote sensing. Taimi Sofia (2008)
For this study, the causes of land degradation is restricted to human induced and the tools for assessment used was land users’ opinion (socio economic), pictures and soil fertility analysis test to determine its effect on food crop yield in the study area.
Temporal Scope. The study attempts to assess the level of degradation of farm land under cultivation and fallow site for 10 years (from 2004 -2014)
1.6 Research Hypothesis
H0: There is no relationship between factors responsible for land degradation and the socio-economic characteristics of household
H1: There is relationship between factors responsible for land degradation and the socio-economic characteristics of household.
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