ABSTRACT

The research was conducted in Obi Local Government Area of Benue State, Nigeria to evaluate the potentials of the soils for Cassava and Rice cultivation using the requirements for Cassava and Rice as adapted by Sys. (1985) method. The characters used were classified under climatic, physicochemical, topographic, soil wetness and fertility factors.

The soil samples were collected from six (6) different locations and in each location six (6) bulked soil samples were prepared and analyzed. The soils were placed in their suitability class of highly suitable (S1), moderately suitable (S2), marginally suitable (S3), and not suitable (N) by matching the properties of land to the requirements of the concerned crops.

The results of the study show that the rainfall amount, length of dry season, drainage qualities and mean annual temperature are sub-optimal for cassava and rice cultivation, while base saturation and soil depths are less optimal for the cultivation of the concerned crops. The optimal limitations to the cultivation of cassava and rice in the study area are organic matter content, available P, total N and CEC. Thus, the study area has become moderately suitable to marginally suitable for the cultivation of the concerned crops. Proper soil conservation/management practices like incorporation of organic manure and residue should be adopted in order to raise the suitability status of the study area to high suitability.

Table of Content

1.0 INTRODUCTION ---------------------------------------------------------------- 1

2.0 LITERAURE REVIEW ----------------------------------------------------------- 3

2.1 Soil Productivity ---------------------------------------------------------------- 3

2.2 Indicators of Soil Productivity ----------------------------------------------- 3

2.2.1 Chemical Indicators ----------------------------------------------------------4

2.2.2 Physical Indicators ----------------------------------------------------------- 4

2.3 Soil Erosion --------------------------------------------------------------------- 4

2.3.1 Effect of Soil Erosion on Productivity ------------------------------------------5

2.3.2 Effect of Soil Degradation on Productivity -------------------------------------6

2.4 Soil Quality ----------------------------------------------------------------------8

2.4.1 The MDS for different Eco-regions --------------------------------------------9

2.4.2 Indicators of Soil Condition ---------------------------------------------------11

2.5 Land use and Management Practices -------------------------------------------12

2.5.1 Agricultural Management Practices -------------------------------------------13

2.5.2 Tropic Soils --------------------------------------------------------------------14

2.5.3 Factors that influence Soil Productivity ----------------------------------------16

2.5.3.1 Topsoil depth ----------------------------------------------------------------16

2.5.3.2 Subsoil Consistence Class ----------------------------------------------------17

2.5.3.3 Soil Texture ------------------------------------------------------------------- 17

2.5.3.4 Internal Drainage --------------------------------------------------------------17

2.5.3.5 Limiting Layers -------------------------------------------------------------- 17

2.5.3.6 Soil Structure ---------------------------------------------------------------- 17

2.5.3.7 Soil Depth -------------------------------------------------------------------- 18

2.5.3.8 Soil Slope --------------------------------------------------------------------- 18

2.5.3.9 Soil Fertility ------------------------------------------------------------------ 18

2.6 Production of Cassava and Rice --------------------------------------------- 18

2.6.1 Cassava (Manihot escullenta) --------------------------------------------- 18

2.6.2 Environmental Requirements of Cassava ------------------------------ 19

2.6.3 Rice (Oryza sitva) ------------------------------------------------------------- 20

2.6.4 Environmental Requirements of Rice ----------------------------------- 21

3.0 MATERIALS AND METHODS ------------------------------------------------ 22

3.1 Study Area ----------------------------------------------------------------------- 22

3.2 Field method -------------------------------------------------------------------- 22

3.2.1 Sample Preparation --------------------------------------------------------- 23

3.2.2 Soil Physical Analysis ------------------------------------------------------- 24

3.2.2.1 Particle size Distribution ------------------------------------------------ 24

3.2.3 Soil Chemical Properties -------------------------------------------------- 24

3.2.3.1 Soil pH ---------------------------------------------------------------------- 24

3.2.3.2 Cation Exchange Capacity (CEC) -------------------------------------- 24

3.2.3.3 Percentage Base Saturation (BS) ------------------------------------- 24

3.2.3.4 Available Phosphorus (P) ----------------------------------------------- 24

3.2.3.5 Organic Carbon (O.C) ---------------------------------------------------- 25

3.2.3.6 Total Nitrogen (N) -------------------------------------------------------- 25

3.2.3.7 Exchange Bases ----------------------------------------------------------- 25

3.2.3.8 Sodium (Na) and Potassium (K) Extracts --------------------------- 25

3.3 Land Evaluation --------------------------------------------------------------- 25

3.3.1 Some Valuables Used ----------------------------------------------------- 27

3.3.2 Land Suitability evaluation Procedure -------------------------------- 27

4.0 RESULTS AND DISCUSSION ------------------------------------------------ 28

4.1 Soil Properties of the Study Sites ----------------------------------------- 28

4.2 The Quality and Characteristics of the Soils of the Study Area ---- 35

4.3 The Major Limitation to Land Suitability for

Cassava and Rice Cultivation -------------------------------------------------- 44

5.0 CONCLUSION AND RECOMMENDATION ----------------------------- 45

5.1 Conclusion -------------------------------------------------------------------- 46

5.2 Recommendation ----------------------------------------------------------- 47

       References -------------------------------------------------------------------- 52