Physical Quality of an Alfisol as Influenced by Cultivation of Jatropha curcas l. at Samaru, Northern Nigeria

Physical Quality of an Alfisol as Influenced by Cultivation of Jatropha curcas l. at Samaru, Northern Nigeria.

ABSTRACT

The decline in soil quality is increasingly seen as a form of soil degradation and is often related to land use and soil/crop management practices.

The research was conducted at the Research and Experimental Farm of the Institute for Agricultural Research (IAR) Samaru, Zaria with the aim of evaluating the influence of Jatropha curcas L. (JCL) plantation and varied management practices under JCL on soil physical quality.

To achieve this aim the research was divided into two trials. The first trial involved five adjacent land uses: Arable Land (AL), Fallow Land (FL), One Year JCL plantation (OYJ), Two Years JCL plantation (TYJ) and Three Years JCL plantation (RYJ).

The second trial comprised of three JCL spacing rates (1.5 m x 1.0 m, 1.5 m x 2.0 m and 1.5 m x 3.0 m) and four nitrogen levels (0 kg/ha, 60 kg/ha, 120 kg/ha and 180 kg/ha).

Soil samples were collected at four depths (0-5 cm, 5-10 cm, 10-15 cm and 15-20 cm) from the various treatments under study and subjected to field and laboratory investigations for soil physical quality indicators such as infiltration, organic carbon, bulk density, aggregate stability, moisture retention, S-index etc.

Result revealed that most of the parameters were significantly affected by land use.

Cultivation of JCL averagely increased total nitrogen, infiltration, dry large macro- aggregates (>2 mm), dry macro-aggregates (2-0.25 mm), dry mean weight diameter (MWD) and dry geometric mean diameter (GMD) by 47%, 26.1%, 28.3%, 13.4%, 18.8% and 12.2% respectively relative to land under continuous arable cultivation (AL).

Fallow soils (FL) recorded high organic carbon, high soil water retention between -2 to -1500kPa and, high total residual pores.

Infiltration model evaluation showed Kostiakov’s model was more efficient and proved to be an excellent predictor of infiltration over Philip’s model.

This was manifested as Kostiakov’s model gave value closed to unity for coefficient of determination-r² (0.96), Nash-Sutcliffe Efficiency-E (0.94) and lower value for Root Mean Square Error-RSME (22.37) and Coefficient of Variability-CV (6.76%).

Applications of different spacing and nitrogen rates to JCL did not significantly influence most soil  physical parameters within the three years of plantation establishment.

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TABLE OF CONTENT

TITLE PAGE………… i

DECLARATION………… ii

CERTIFICATION……….. iii

DEDICATION……. iv

AKNOWLEDGEMENTS……………… v

ABSTRACT…….. vii

TABLE OF CONTENT………………… ix

LIST OF TABLES…. xiii

LIST OF FIGURES…………. xv

LIST OF PLATES…… xvi

LIST OF APPENDICES………………… xvii

CHAPTER ONE: INTRODUCTION

• JUSTIFICATION………. 3
• OBJECTIVES……………………………. 4

CHAPTER TWO: LITERATURE REVIEW

• CONCEPT OF SOIL QUALITY……………………. 6
• SOIL PHYSICAL QUALITY INDICATORS……………………… 7
  • Infiltration……………. 8
    • Measurement of Infiltration……………………. 9
    • Factors Affecting Infiltration……. 13
  • Bulk Density………………………….. 15
  • Soil Porosity and Pore Size Distribution……….. 18
  • Soil Water Retention and Transmission Characteristics………………. 22
  • Aggregation and Aggregate Stability………………. 23
• S-INDEX OF SOIL PHYSICAL QUALITY……………………. 25
• JATROPHA CURCAS AND SOIL QUALITY……….. 26

CHAPTER THREE: MATERIALS AND METHODS

• PHYSICAL SETTING OF THE STUDY AREA…………… 29
  • Location…………………… 29
  • Geology and Soil……………….. 29
• RESEARCH DESCRIPTION AND SOIL SAMPLING……………. 33
  • Trial One: Land use effect on soil physical quality….. 33
  • Trial Two: Effect of spacing and nitrogen rates under Jatropha curcas on soil physical quality 33
• MEASUREMENT OF SOIL PARAMETERS……. 38
  • Infiltration…………….. 38
  • Infiltration Models Fitting……………… 40
  • Particle Size Distribution……………. 41
  • Total Organic Carbon………. 42
  • Total Nitrogen………………. 43
  • Soil Water Retention Characteristics……. 44
  • Bulk Density…………………. 44
  • Total Porosity…………… 44
  • Particle Density………………… 45
  • Effective Pore Sizes………… 45
  • Soil Physical Quality Index…………… 46
  • Aggregate Stability……………….. 46

3.4 DATA ANALYSIS……………………….. 49

CHAPTER FOUR: RESULTS AND DISCUSSION

• INFLUENCE OF LAND USE AND SOIL DEPTH ON SOIL ORGANIC CARBON, NITROGEN AND PARTICLE SIZE DISTRIBUTION………………………………………………………. 50
  • Organic Carbon………………… 50
  • Total Nitrogen………………………………. 53
  • Particle Size Distribution………………… 53
• INFLUENCE OF LAND USE AND SOIL DEPTH ON SOIL BULK DENSITY, PARTICLE DENSITY AND TOTAL POROSITY……………………………. 54
  • Bulk Density and Particle Density………………. 54
  • Total Porosity………………………………………………. 56
• INFLUENCE OF LAND USE AND SOIL DEPTH ON DRY AGGREGATE CHARACTERISTICS……… 56
  • Dry Aggregate Distribution………………………….. 56
  • Dry Mean Weight Diameter and Geometric Mean Diameter…………….. 60
  • Relationship between Dry Aggregates and Clay…………….. 60
• INFLUENCE OF LAND USE AND SOIL DEPTH ON WET AGGREGATE CHARACTERISTICS 65
  • Wet Aggregate Distribution…………….. 65
  • Wet Mean Weight Diameter and Geometric Mean Diameter………………….. 65
• INFLUENCE OF LAND USE AND SOIL DEPTH ON SOIL WATER INPUT CHARACTERISTICS……………………….. 69
  • Infiltration……………….. 69
  • Infiltration Models Fitting……………… 69
  • Water Retention Characteristics…………. 72
• INFLUENCE OF LAND USE AND SOIL DEPTH ON PORE SIZE DISTRIBUTION AND SOIL PHYSICAL QUALITY INDEX (S-INDEX)……… 76
  • Pore Size Distribution……………………. 76
  • Soil Physical Quality Index (S-index)………….. 79
• INFLUENCE OF SPACING AND NITROGEN APPLICATION TO JATROPHA CURCAS ON SOIL ORGANIC CARBON, NITROGEN AND PARTICLE SIZE DISTRIBUTION… 83
  • Soil Organic Carbon and Nitrogen……………… 83
  • Particle Size Distribution…………………. 84
• INFLUENCE OF SPACING AND NITROGEN APPLICATION TO JATROPHA CURCAS ON SOIL DRY AGGREGATE CHARACTERISTICS………… 88
• INFLUENCE OF SPACING AND NITROGEN APPLICATION TO JATROPHA CURCAS ON SOIL WATER STABLE AGGREGATES……. 88

CHAPTER FIVE: SUMMARY, CONCLUSION AND RECOMMENDATION

• SUMMARY………….. 91
• CONCLUSION………………… 93
• RECOMMENDATIONS……… 93

REFERENCES…………. 94

APPENDICES……. 108

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INTRODUCTION

Soil is a living and dynamic natural reservoir and source of plant nutrients that play numerous key roles in terrestrial ecosystems.

For most agrarian settlements, the primary function of soil has been production of food, fodder, timber, fiber and fuel (Lal and Shukla, 2004).

Plant roots penetrate and explore soil in order to acquire water, oxygen, nutrients and gain structural support for above-ground growth.

Demographic pressure with its attendant increase in food demand has resulted in the expansion and intensification of land use systems in the Nigerian Savanna.

The intensification of land use systems in the Nigerian Savanna is facing increased abiotic pressure of which soil quality is among the most important.

Shorter duration or absence of fallow, unsuitable crop rotation and inappropriate management practices have resulted in degradation of soil quality (Lal, 1993a).

Soil quality degradation, which can be defined as increasing inability of a soil to perform its ecosystem functions, is manifested in persisting problems of erosion, compaction, acidification, organic matter losses, nutrient losses, desertification and chemical contaminations which reduce agricultural production capacity and food security (Larson and Pierce, 1991).

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REFERENCES

Abugre, S., Oti-Boateng, C. and Yeboah, M.F. (2011). Litter fall and decomposition trend of Jatropha curcas L. leaves mulches under two environmental conditions. Agriculture and Biology Journal of North America, 2(3):462-470.
Achten, W. (2010). Sustainability evaluation of bio-diesel from Jatropha curcas L., PhD Thesis (Unpublished), Katholieke Universiteit, Belgie. PP. 8-9.
Adebowale, K.O. and Adedire, C.O. (2006). Chemical composition and insecticidal properties of the underutilized Jatropha curcas L. seed oil. African Journal of Biotechnology, 10:901- 906.
Adeoye, K.B. (1984). Influence of grass mulch on soils temperature, soil moisture and yield of maize and Gero millet in a Savanna zone soil. Samaru Journal of Agricultural Research, 2:87-98.
Adeoye, K.B. (1986). Physical changes induced by rainfall in the surface layer of an Alfisol, Northern Nigeria. Geoderma, 39:59-66.