Author
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DAO, THANH |
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Submitted to: Environmental Remediation Conference Proceedings
Publication Type: Proceedings Publication Acceptance Date: 10/25/2005 Publication Date: 10/25/2005 Citation: Dao, T.H. 2005. Remediation of nutrient-enriched soils following repeated applications of animal manure. In: Proceedings of the Environmental Remediation Approaches to Municipal and Industrial Pollution in Vietnam Conference, October 25-26, 2005, Ho Chi Minh City, Vietnam. pp. 136-147. Interpretive Summary: Sediment-associated and dissolved nutrients in runoff water from manure nutrient-enriched fields can impair water quality in watersheds with high density of confined animal feeding operations. Available technologies to remediate soils containing high levels of manure nutrients include (i) techniques and strategies to lower nutrient levels in the soil, and (ii) methods and technologies to reduce edge of field losses of sediments and nutrient in runoff water. Many of the environmental concerns faced by the US producers are also facing the producers and the communities around the globe. Many of the pollution prevention and remediation technologies can be adapted to agricultural production systems in Vietnam. In the US, the use of high dry matter yielding forage crops can provide an immediate means to lower nutrient concentrations in manure-amended soils. Municipal and industrial by-products such as water-treatment residuals, non-hazardous aluminum-, iron-, or calcium-rich industrial by-products can be used to tie up excess nutrients, by forming insoluble metals or phosphates. Nutrient-immobilizing agents and reduced tillage offer another means to improve soil aggregation and thereby reduce losses of sediment-associated nutrients. Residue management and conservation tillage systems reduce raindrop impact, soil particle detachment, and runoff water velocity to minimize particulate nutrient discharges in runoff from nutrient-enriched soils. Dilution by deep tillage is a short-term solution to nutrient-enriched soils. Supplemental conservation practices should be considered along with deep tillage to control the greater potential for soil erosion losses. Conservation buffers such as riparian strips, grass waterways, living vegetative fences can effectively modify runoff water velocity to control particulate offsite losses when strategically placed in the hot spots of the watershed with impaired water quality. Technical Abstract: Sediment-associated and dissolved nutrients in runoff water from nutrient-enriched fields can impair water quality in watersheds with high density of confined animal feeding operations. Available technologies to remediate soils containing high levels of manure nutrients include (i) techniques and strategies to lower nutrient levels in the soil, and (ii) methods and technologies to reduce edge of field losses of sediments and nutrient in runoff water. The use of high dry matter yielding forage crops provides an immediate means to lower nutrient concentrations in problem field soils. Municipal and industrial by-products such as water-treatment residuals, coal-combustion by-products can be used to tie up excess nutrients, by forming insoluble metals or phosphates. Organic polymers in combination with P-immobilizing agents and reduced tillage offer another means to improve soil aggregation and thereby reduce losses of particulate nutrients. Residue management and conservation tillage systems reduce raindrop impact, soil detachment, and runoff water velocity to minimize particulate nutrient discharges in runoff. Dilution by deep mixing or profile modification is a short-term solution to nutrient-enriched soils. Supplemental conservation practices should be considered concurrently to deep tillage to control the greatest potential for soil erosion. Conservation buffers, riparian strips, grass waterways, living vegetative fences can effectively modify runoff water velocity to control particulate offsite losses when strategically placed in the hydrological active locations of the impaired watershed. |
