Causes and Effects of Watershed Degradation
USING SUITABLE EXAMPLES FROM KENYA, EXAMINE THE CAUSES AND EFFECTS OF WATERSHED DEGRADATION AND SUGGEST POSSIBLE INTERVENTION MEASURES
TABLE OF CONTENTS
CAUSES, EFFECTS AND SOLUTIONS TO WATERSHED DEGRADATION
PREAMBLE Page 4
1. INTRODUCTION Page 4 - 6
2. Causes of Watershed Degradation Page 7 2.1 Land degradation 7 - 8 2.2 Deforestation 8 2.3 Removal of vegetation 8 2.4 Shifting cultivation without adequate fallow periods 9 2.5 Overgrazing 9 2.6 Poor farming methods 9 - 10 2.7 Cultivation of marginal lands 10 - 11 2.8 Improper crop rotations 11 2.9 Unbalanced fertilizer use 11 2.10 Pests and diseases 11
3. Underlying causes of degradation Page 12 3.1 Land shortage 12 3.2 Land tenures 12 - 13 3.3 Economic pressures 13 3.4 Poverty 13 3.5 Population increase 14 3.6 Wind erosion 14 3.7 Over pumping of ground water 14
4. Effects of Watershed Degradation Page 15 4.1 Soil erosion 15 - 16 4.2 Water erosion 16 4.3 Desertification 16 4.4 Salinization and Nutrient Loss 16 - 17 4.5 Decline in soil fertility 17 4.6 Degradation of soil structure 17 - 18 4.7 Soil acidification 18 4.8 Water pollution 18 - 19 4.9 Wetland Degradation 19 20
5. Watershed Management Page 20 5.1 Terracing 20 5.2 Adding organic matter 20 5.3 Avoiding excessive tillage and soil compaction 21 5.4 Managing pests and nutrients efficiently 21 5.5 Keeping the ground covered 21 5.6 Increasing diversity 22 5.7 Combating desertification 22 - 23 5.8 Wetland protection 23
6. Conclusion Page 23 - 25
7. References Page 25
CAUSES, EFFECTS AND SOLUTIONS TO WATERSHED DEGRADATION
PREAMBLE
SOIL is one of the most vital of our natural
TABLE OF CONTENTS
CAUSES, EFFECTS AND SOLUTIONS TO WATERSHED DEGRADATION
PREAMBLE Page 4
1. INTRODUCTION Page 4 - 6
2. Causes of Watershed Degradation Page 7 2.1 Land degradation 7 - 8 2.2 Deforestation 8 2.3 Removal of vegetation 8 2.4 Shifting cultivation without adequate fallow periods 9 2.5 Overgrazing 9 2.6 Poor farming methods 9 - 10 2.7 Cultivation of marginal lands 10 - 11 2.8 Improper crop rotations 11 2.9 Unbalanced fertilizer use 11 2.10 Pests and diseases 11
3. Underlying causes of degradation Page 12 3.1 Land shortage 12 3.2 Land tenures 12 - 13 3.3 Economic pressures 13 3.4 Poverty 13 3.5 Population increase 14 3.6 Wind erosion 14 3.7 Over pumping of ground water 14
4. Effects of Watershed Degradation Page 15 4.1 Soil erosion 15 - 16 4.2 Water erosion 16 4.3 Desertification 16 4.4 Salinization and Nutrient Loss 16 - 17 4.5 Decline in soil fertility 17 4.6 Degradation of soil structure 17 - 18 4.7 Soil acidification 18 4.8 Water pollution 18 - 19 4.9 Wetland Degradation 19 20
5. Watershed Management Page 20 5.1 Terracing 20 5.2 Adding organic matter 20 5.3 Avoiding excessive tillage and soil compaction 21 5.4 Managing pests and nutrients efficiently 21 5.5 Keeping the ground covered 21 5.6 Increasing diversity 22 5.7 Combating desertification 22 - 23 5.8 Wetland protection 23
6. Conclusion Page 23 - 25
7. References Page 25
CAUSES, EFFECTS AND SOLUTIONS TO WATERSHED DEGRADATION
PREAMBLE
SOIL is one of the most vital of our natural
References: 3. The National Land Policy in Kenya: Addressing Historical Injustices. (Issues paper no. 2/2004). 7. Mwakubo, S. M. 2002. "Land Tenure and Farm Level Soil Conservation in Semiarid Areas, Kenya. 10. Tiffen, M., M. Mortimore, and F. Gichuki (1994), More People, Less Erosion, New York: Wiley, Walker. 11. World Bank (1982), World Development report 1992: Development and the Environment, World Bank, Washington D.C.