Submitted to: Journal of Soil and Water Conservation
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2010
Publication Date: January 20, 2011
Citation: Delgado, J.A., Follett, R.F. 2011. Advances in Nitrogen Management for Water Quality. Journal of Soil and Water Conservation. 66(1):25A-26A. Technical Abstract: Nitrogen (N) is an essential nutrient for crops and other plants, and is needed for many plant physiological functions. Nitrogen is critically important for global sustainability of food, and has been key to the success of the green revolution. Due to its importance as a crop nutrient, N fertilizer is of great importance for maximizing crop production. Crop uptake of N follows a sigmoid function with N-uptake necessarily preceding above-ground dry matter while early season N requirements of the root system are met. For most agricultural cropping systems, production cannot be maximized without additional N inputs. However, N inputs can also have environmental impacts because of increased losses of N losses to the environment (Cowling et al., 2002; Galloway et al., 2003). Management of this dynamic nutrient is key to lessening its potential impact on the environment. Though N management is complex in many aspects, there are basic principles that can be used to reduce N losses via leaching and/or atmospheric losses (Meisinger and Delgado 2002; Mosier et al 2002). The risk of environmental impacts is increased when recommended management practices for reducing N losses are not implemented (Meisinger and Delgado 2002; Mosier et al 2002). Scientists have previously reported on the transport of N to bodies of water and/or the potential impacts that reactive N can have on terrestrial, freshwater and marine ecosystems (Follett and Hatfield 2001, Hatfield and Follett 2008, Matson et al., 1997; Vitousek et al., 1997; Bricker et al., 2007; Follett et al. 1991; Mitsch and Day, 2006). Environmental impacts of N have been described with the Nitrogen Cascade model, which shows how the molecule of N moves in the environment once it is released (Cowling et al., 2002; Galloway et al., 2003). Impacts of N to water bodies across the United States and the world are reported in the literature. For example, a significant percentage of stream miles and groundwaters in the U.S. have been found to have high N levels (EPA 2006; Dubrovsky et al., 2010), and reports of N impacts to water bodies such as the Mississippi River Basin, Gulf of Mexico, and Chesapeake Bay, can be found throughout the literature (Rabalais et al. 2002a, 2002b; Goolsby et al. 2001; Mitsch and Day, 2006, US EPA 2006). Rupert (2008) reported increases in groundwater nitrates across the USA ranging from groundwater areas located in the west coast, irrigated mountain west, midwest, and the southeast and eastern USA. At the international scale, N has been reported to impact groundwaters including in Spain (De Paz et al, 2009) and China (Li et al. 2008). These reports agree with 15N studies and report from Delgado et al. (2010) and Randall et al. (2008) that the losses of N from agricultural systems is about 30%. Delgado et al. (2010), and Delgado (2010) have reported that management practices that take N cycling into consideration can result in significant cuts in N losses, increased N cycling, and enhanced water quality protection by lowering nitrate leaching and atmospheric N2O emissions, in agreenment with Delgado and Follett (2002). Numerous studies support the need to continue to search for viable management alternatives to increase N use efficiency and reduce N losses to the environment. Because of the great many issues related to N management, our new book, published by the Soil and Water Conservation Society, Advances of Nitrogen Management for Water Quality is a highly timely publication. A large series of management practices are included that can increase N use efficiency and decrease N losses from agriculture. We think the reader will find that the information presented in this book can provide users, conservationists, and potential nutrient managers with strategies they can consider in their efforts to improve N management practices at the farm level. Nitrogen losses are affected by water, irrigation, management and drainage systems as discussed in this book, however readers are also provided with information on new tools and concepts such as the Nitrogen Index, the Nitrogen Trading Tool, N sensors, and precision agriculture. These important advances can contribute to conservation of water quality and even the biosphere. The readers will find that the book covers practices to increase carbon sequestration and improve N use efficiency while also mitigating effects of a changing climate; such practices include use of cover crops, organic management, and precision agriculture. Other key mitigating strategies, such as good irrigation management and management of drainage systems, are also covered. The book discusses not only how these best practices can increase N use efficiency, while maintaining crop yields. The new book was a joint effort that started with the 7th annual symposium that was held by both the Soil and Water Conservation Society (SWCS) and Soil Science Society of America (SSSA) in 2006. Many N-management experts contributed to the joint symposiums also are contributors to the chapters of Advances in Nitrogen Management for Water Quality as authors or co-authors. The chapters of the book, fifteen in total, tackle a variety of topics, including the impact of reactive N on human health, N management as an integrated approach, N budgets, organic systems, precision farming, N sensors, use of cover crops and cropping systems. The book includes examples where best management practices in the USA and internationally are evaluated. The book discusses how tools can be used to best assess how management practices can help to conserve our biosphere. It looks at nutrient credit trading and its potential to improve water quality. The use of a tiered approach is presented, including information on the USDA Tier 1 Nitrogen Index and Tier 2, Nitrogen Loss and Environmental Assessment Package (NLEAP). Advances in Nitrogen Management for Water Quality addresses both new concepts and recent advances in the efforts to increase N use efficiency and demonstrates the value of their application (Delgado and Follett, 2010). It is up to N managers, conservationists, and other participatory parties to use the practices effectively— and we believe that this book can be an important reference to all those seeking to improve N management. REFERENCES Bricker, S., B. Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks, and J. Woerner. 2007. Effects of nutrient enrichment in the nation’s estuaries: A decade of change. NOAA Coastal Ocean Program Decision Analysis Series No. 26. National Centers for Coastal Ocean Science. Silver Spring, MD. Cowling, E., J. Galloway, C. Furiness, and J.W. Erisman et al. 2002. Optimizing nitrogen management and energy production and environmental protection: Report from the Second International Nitrogen Conference. Bolger Center, Potomac, MD, 14-18 Oct. 2001. Available at http://www.initrogen.org/fileadmin/user_upload/Second_N_Conf_Report.pdf. (Verified 16 Nov 2010). Delgado, J.A. 2010. Crop residue is a key for sustaining maximum food production and for conservation of our biosphere. Journal of Soil and Water Conservation 65:111A-116A. Delgado, J.A. and R.F. Follett (eds.) 2010. Advances in nitrogen management for water quality. SWCS, Ankeny, IA (in press). Delgado, J.A., and R.F. Follett. 2002. Carbon and nutrient cycles. Journal of Soil and Water Conservation 57(6):455-464. Delgado, J.A., S.J. Del Grosso, and S.M. Ogle. 2010. 15N isotopic crop residue cycling studies and modeling suggest that IPCC methodologies to assess residue contributions to N2O-N emissions should be reevaluated. Nutr. Cycl. Agroecosyst. 86:383–390. De Paz, J. M., J. A. Delgado, C. Ramos, M. J. Shaffer, and K. K. Barbarick. 2009. Use of a new Nitrogen Index-GIS assessment for evaluation of nitrate leaching across a Mediterranean region. J. Hydrol. 365:183-194. Dubrovsky, N.M., K.R. Burow, G.M. Clark, J.A.M. Gronberg, P.A. Hamilton, K.J. Hitt, D.K. Mueller, M.D. Munn, L.J. Puckett, B.T. Nolan, M.