Submitted to: National Center for Manure and Animal Waste Management
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/15/2002
Publication Date: 4/16/2002
Citation: ZHANG, H., DAO, T.H., BASTA, N.T., DAYTON, E.A., DANIEL, T.C. REMEDIATION TECHNIQUES FOR MANURE NUTRIENT LOADED SOILS. NATIONAL CENTER FOR MANURE AND ANIMAL WASTE MANAGEMENT. 2002. Interpretive Summary: Many agricultural fields in the United States are loaded with nutrients following years of manure application. The runoff and eroded soils from those fields carry soluble and particulate nutrients to water bodies even if no additional manure is applied. Available technologies to remediate manure nutrient-loaded soils were grouped in two broad categories: (i) techniques and strategies to lower soil nutrient levels, and (ii) methods and technologies to reduce edge of field losses. Although dramatic improvement in identifying superior accumulator plants is needed, use of high dry matter yielding forage crops provides an immediate means to lower nutrient content in problem fields. Mixing chemical amendments such as water-treatment residuals, coal-combustion by-products, or aluminum-, iron- , or calcium-rich municipal or industrial by-products also immobilize excess nutrients and lower soil levels. Residue management and conservation ntillage are efficient practices to reduce particulate nutrient discharges. Conservation buffers such as riparian strips and vegetative fences, when strategically placed in a problem field control particulate offsite losses. Dilution by deep profile modification is another solution. Thus, remedial techniques exist to lower the environmental risks of nutrient-loaded soils. Emerging technologies for nutrient immobilization such as vitrification are at the exploratory stages. More intense development effort and creativity to return nutrient-loaded soils to a more sustainable and productive status are anticipated. Clearly, integrated solutions are needed for managing excess nutrients found in soils that have received repeated applications of manure across very diverse physiographic and climatic zones.
Technical Abstract: Many US soils contain excessive nutrients, especially phosphorus (P) due to repeated applications of manure. Also, soils with a history of poultry or swine manure applications have been found to have elevated levels of copper, zinc, selenium, and arsenic metals. Potential remedial approaches include: (i) phytoremediation (for P, nitrate, metals) with plant species that preferentially accumulate nutrients or metals, high biomass yielding forage plants, and use of deep-rooted crops in novel rotations for subsurface N recovery. (ii) Soil amendments with P immobilization chemicals and municipal or industrial by-products to reduce dissolved P and metal availability such as water treatment residuals, aglime, coal combustion by-products. (iii) Addition of polymers to reduce sediment and particulate nutrient offsite discharges (organic matter, N, P, metals). (iv) Deep tillage to dilute near-surface zone elevated nutrient levels and reduce odor emissions. (v) Conservation buffer strips to remove dissolved reactive P from runoff and reduce edge-of-field losses of sediments and particulate nutrients. Critical areas of needs for further soil remediation research include urgent efforts to (i) develop efficient novel accumulator plants and profitable crop rotations. (ii) Develop efficient nutrient immobilizing chemicals and by-products for manure-derived P and metals. (iii) Develop soil treatment and recovery technologies to produce value-added specialty products. (iv) develop geo-reference techniques to target remediation on field and watershed-scales; and (v) develop and evaluate the effectiveness of specific BMP systems in reducing manure nutrient export to the surrounding environment.