Author
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Delgado, Jorge |
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Follett, Ronald |
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Submitted to: Journal of Soil and Water Conservation
Publication Type: Abstract Only Publication Acceptance Date: 12/10/2010 Publication Date: 1/20/2011 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. Interpretive Summary: 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 a |
