Anthropogenic Inputs of Nitrogen and Phosphorus and Riverine Export for Illinois, USA

Abstract

Agricultural nonpoint sources are important contributors of N and P to surface waters. We determined N and P net anthropogenic inputs for Illinois, examining changes during the last 50 yr and linkages to surface water export of N and P. Inputs (fertilizer, atmospheric deposition, and N2 fixation) were compared to exports (grain export, after accounting for animal and human consumption, plus animal product export) from 1945 through 1998 using state‐reported data on fertilizer sales, crop production, and human and animal populations. Large inputs of N were found beginning about 1965, coinciding with increased N fertilizer applications (about 800 000 Mg N yr−1). The N input (about 400 000 Mg N yr−1) was 8.6 million Mg N for the 1979 to 1996 crop years, with a corresponding riverine flux of 4.4 million Mg N (51% of net anthropogenic inputs discharged by rivers). Using literature estimates of field and in‐stream denitrification, we could account for nearly all of the missing N in a mass balance. For P, a different paflern was found for state net anthropogenic inputs with a large input from 1965 to 1990, and on average no net inputs since 1990. For rivers, we estimated that 16% of the total N load and 47% of the total P load was from sewage effluent. We estimate that Illinois contributed 15 and 10% of the annual total N and P loads of the Mississippi River, respectively, and that any reduction strategy in Illinois must address agricultural sources.

Factors controlling phosphorus export from agricultural/forest and residential systems to rivers in eastern China, 1980–2011

“…Calculation of net anthropogenic phosphorus input (NAPI) is a P budgeting approach that sums annual P contributions from atmospheric deposition, fertilizer application, non-food input (i.e., detergent P), seed input, and net import/export in animal feed and human food supplies (Han et al, 2013). The NAPI approach has been successfully applied to many watersheds across Asia (Han et al, 2011b(Han et al, , 2013Chen et al, 2015a), the Americas (David and Gentry, 2000;Borbor-Cordova et al, 2006;Han et al, 2011a;Russell et al, 2008;Sobota et al, 2011), and Europe (Hong et al, 2012). It is a simple yet powerful approach to evaluate net P inputs from anthropogenic sources to terrestrial ecosystems, as well as an effective tool to explain among-watershed or among-year variations in riverine P exports.…”

Manure and sorbent fertilisers increase on-going nutrient availability relative to conventional fertilisers

“…Despite decades of agricultural research, applications of conventional fertiliser products, such as urea and superphosphate, result in only 40 to 60% plant uptake of the target nutrients (Bolland and Gilkes, 1998;David and Gentry, 2000;Drinkwater and Snapp, 2007;Galloway and Cowling, 2002;Van der Molen et al, 1998). For P and N, losses take different forms via different paths.…”

Polyacrylamide preparations for protection of water quality threatened by agricultural runoff contaminants

“…Most aquatic ecosystems develop in conditions limited by N and P. In the past few decades, intensive fertilization has contributed to the accumulation of these elements in aquatic environments (David and Gentry, 2000;Edwards et al, 2000;Sharpley et al, 2000;Vitousek et al, 1997;Koch and Reddy, 1992;Lebo and Sharp, 1993). Changes in flora and fauna have been attributed to increased input of nutrients (Stevenson et al, 1993;Cooper and Brush, 1993;Koch and Reddy, 1992;Davis, 1991).…”