Manage fertilizer or herbicide application
Overall effectiveness category No evidence found (no assessment)
Number of studies: 0
Background information and definitions
An excess of fertilizers and herbicides can have negative effects on vegetation. Herbicides can kill plants directly. An excess of nutrients, such as nitrogen and phosphorous, can alter the competitive balance in marshes and swamps leading to domination by single species (Tilman et al. 1999) or algal blooms (Smith et al. 2006). For many marshes and swamps, problems are related to chronic spillover of chemicals from agricultural or domestic land. Nutrient pollution is especially severe where a large proportion of the land is cultivated, e.g. in Europe, eastern North America and southeast China (Verhoeven et al. 2006). In some cases, e.g. rice paddies, excess chemical application could affect vegetation during the growing season and/or fallow periods.
Various techniques could be used to reduce these problems, without reducing the overall amount applied (although this could also be beneficial; Section 10.6). Applying fertilizers when plants are actively growing means a greater proportion of the nutrients are taken up by the plants. Within watersheds, avoiding application before heavy rain reduces the amount that is immediately washed away. Ultimately, better chemical management could be driven by legislation, financial incentives and/or education.
Related actions: Reduce fertilizer or herbicide use, without other management of its application (freshwater marshes – brackish/salt marshes – freshwater swamps – brackish/saline swamps). In practice, that action and the current one will often be used simultaneously.
Smith V.H., Joye S.B. & Howarth R.W. (2006) Eutrophication of freshwater and marine ecosystems. Limnology and Oceanography, 51, 351–355.
Tilman E.A., Tilman D., Crawley M.J. & Johnston A.E. (1999) Biological weed control via nutrient competition: potassium limitation of dandelions. Ecological Applications, 9, 103–111.
Verhoeven J.T.A., Arheimer B., Yin C. & Hefting M.M. (2006) Regional and global concerns over wetlands and water quality. Trends in Ecology and Evolution, 21, 96–103.