Book contents
- Frontmatter
- Contents
- List of figures
- List of tables
- Preface
- List of abbreviations
- Conversions of selected units of hydrologic measurement
- 1 Water and Life
- 2 Challenge and opportunity
- 3 Unfolding recognition of ecosystem change
- 4 Natural waters
- 5 Plant–soil–water–ecosystem relationships
- 6 Groundwater
- 7 Lakes and wetlands
- 8 River channels and floodplains
- 9 Impounded rivers and reservoirs
- 10 Domestic and industrial water management
- 11 Decision processes
- 12 Integrative approaches
- Appendix: Guide to Internet resources on water and environment
- References
- Index
5 - Plant–soil–water–ecosystem relationships
Published online by Cambridge University Press: 05 October 2013
- Frontmatter
- Contents
- List of figures
- List of tables
- Preface
- List of abbreviations
- Conversions of selected units of hydrologic measurement
- 1 Water and Life
- 2 Challenge and opportunity
- 3 Unfolding recognition of ecosystem change
- 4 Natural waters
- 5 Plant–soil–water–ecosystem relationships
- 6 Groundwater
- 7 Lakes and wetlands
- 8 River channels and floodplains
- 9 Impounded rivers and reservoirs
- 10 Domestic and industrial water management
- 11 Decision processes
- 12 Integrative approaches
- Appendix: Guide to Internet resources on water and environment
- References
- Index
Summary
INTRODUCTION
The previous chapter on natural waters concluded with a discussion of natural ecosystem changes on the earth's surface. This chapter extends that analysis to encompass both intentional and inadvertent modifications of evapotranspiration, plant–soil moisture relations, and related ecosystem processes for human ends. These human ends range from use of forest, grass, and shrubland watersheds to irrigation and drainage schemes in large river basins, to stormwater management and non-point-source pollution control in urbanizing environments.
Every human activity affecting land use and land cover not only affects the hydrologic processes of interception, infiltration, evapotranspiration, aquifer storage, and runoff discussed in the previous chapter, but by altering water quality it also modifies plant–soil–water relationships. In addition to their feedback effects on land use productivity, these hydrologic processes affect natural ecosystems through erosion, sedimentation, and changes in soil organisms and habitats. A cubic meter of soil contains millions of bacteria and fungi, as well as hundreds of springtails, nematodes, and earthworms, all of which are directly affected by everyday soil–water management. In addition to these local effects, this chapter discusses recent research on effects of atmosphere–land surface fluxes on the global hydrologic cycle.
Table 5.1 indicates the extraordinary diversity and plenitude of life in the soil. While algae are primary producers that photosynthesize on wet soil surfaces, most soil organisms are secondary and tertiary consumers, converting dead plants and animals to humus. Through these processes and their movement through the soil, they also affect the porosity and moisture holding capacity.
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- Water for LifeWater Management and Environmental Policy, pp. 65 - 91Publisher: Cambridge University PressPrint publication year: 2003