Evaluating water quality benefits of manureshed management in the Susquehanna River Basin.

Manureshed management guides the sustainable use of manure resources by matching areas of crop demand (nutrient sinks) with areas generating livestock manure (nutrient sources). A better understanding of the impacts of manureshed management on water quality within sensitive watersheds is needed. We quantified the potential water quality benefits of manureshed-oriented management through scenario-based analyses in the Susquehanna River Basin (SRB) using the Soil and Water Assessment Tool. Five manureshed management scenarios were developed and compared with a baseline "business-as-usual" scenario. The baseline assumes manure is less transportable, which means some locations have manure application in excess of crop demand. The "watershed nutrient balance" scenarios assume excess manure from surplus locations is transportable and that manure is applied around the SRB based on crop nutrient demand. The "watershed nutrient balance avoiding runoff prone areas" scenarios assume manure is transportable but not applied in vulnerable landscapes of the SRB. Each scenario was evaluated under two application rates considering crop nitrogen demand (N-based) and phosphorus demand (P-based). Phosphorus-based manureshed management was more effective in water quality improvements than N-based management. Phosphorus-based nutrient balance scenarios simulated 3 and 25% reduction in total N (TN) and total P (TP), respectively, from the baseline scenario at the watershed outlet. The N- and P-based scenarios avoiding runoff prone areas simulated 3 and 6% reduction in TN loss and 4 and 25.2% reduction in TP loss, respectively, from the baseline. Overall, the manureshed management scenarios were more effective in improving the quality of local streams in livestock-intensive regions than at the watershed outlet.

Envisioning the manureshed: Toward comprehensive integration of modern crop and animal production.

The specialization and intensification of agriculture have produced incredible gains in productivity, quality, and availability of agricultural commodities but have resulted in the separation of crop and animal production. A by-product of this separation has been the accumulation of manure regions where animal production is concentrated. Enter the "manureshed," an organizing framework for integrating animal and crop production where budgeting of manure nutrients is used to strategically guide their recycling and reuse in agricultural production systems where manure resources are of highest value. To move beyond regional nutrient balance analyses into the transformational realm required to mitigate "wicked" manure problems, manureshed management requires recognition of the challenges to systematically reorganizing resource flows. In better integrating crop and livestock systems, manureshed management must account for the unique nature of managing manure nutrients within individual livestock industries, anticipate trade-offs in substituting manure for commercial fertilizer, promote technologies to refine manure, and engage extensive social networks across scales that range from the farmgate to nation and beyond.

Manuresheds offer a system-level strategy for recovering manure's fertilizer value. Manuresheds address nutrient imbalances and environmental and socioeconomic outcomes. Manuresheds scale from single operations to a "mega-manureshed" transecting the southeastern United States. Manureshed management supports the strategic alignment of technologies, markets, and networks.

Elevated concentrations of trace elements in soil do not necessarily reflect metals available to plants.

Bioaccumulation and entry of trace elements from soil into the food chain have made trace-elements major environmental pollutants. The main objective of this investigation was to study the impact of mixing native agricultural soil with municipal sewage sludge (SS) or SS mixed with yard waste (SS+YW) compost on total concentration of trace elements in soil, metals available to plants, and mobility of metals from soil into peppers and melon fruits. Regardless of soil treatment, the average concentrations of Ni, Cd, Pb, Cr, Cu, Zn, and Mo in melon fruits were 5.2, 0.7, 3.9, 0.9, 34.3, 96.1, and 3.5µg g(-1), respectively. Overall concentrations of Ni, Cd, Pb, and Zn in melon fruits were significantly greater (P < 0.05) than pepper fruits. No significant differences were found in Cr, Cu, and Mo concentrations between pepper and melon fruits at harvest time. Total metal concentrations and metal ions in soil available to melon and pepper plants were also determined. Total concentration of each metal in the soil was significantly greater than concentration of metal ions available to plants. Elevated Ni and Mo bioaccumulation factor (BAF > 1) of melon fruits of plants grown in SS+YW mixed soil is a characteristic that would be less favorable when plants grown on sites having high concentrations of these metals.