• DOI:10.2134/jeq2016.09.0373
• Corpus ID: 25642291

Long-term Changes in Grassland Soil Phosphorus with Fertilizer Application and Withdrawal.

@article{CadeMenun2017LongtermCI,
  title={Long-term Changes in Grassland Soil Phosphorus with Fertilizer Application and Withdrawal.},
  author={Barbara J. Cade-Menun and Donnacha G. Doody and Corey W. Liu and Catherine J. Watson},
  journal={Journal of environmental quality},
  year={2017},
  volume={46 3},
  pages={
          537-545
        }
}

• B. Cade-Menun, D. Doody, +1 author C. Watson
• Published 1 May 2017
• Chemistry, Medicine
• Journal of environmental quality

Long-term phosphorus (P) applications can increase soil P concentrations in excess of agronomic optima, posing a risk to water quality. Once fertilization stops, however, it may take time for soil P concentrations to decline. Whereas P fertilization adds orthophosphate, little is known about changes in other soil P forms during P buildup and drawdown. This study examined changes in P pools (total P, Olsen P, Mehlich P, and water-extractable P) and P forms determined by P-nuclear magnetic resonance spectroscopy (P-NMR) in grazed grassland plots from Northern Ireland. Between 1994 and 1999, all plots received 8.3 kg P ha yr with variable rates of nitrogen (100-500 kg N ha yr). From 2000 to 2005, plots received 0, 20, 40, or 80 kg P ha yr and 250 kg N ha yr; from 2005 to 2010, no P fertilizer was applied to any plots. In 2005, soil P pool concentrations at the highest P fertilization rates were significantly elevated compared with those in 2000 but had decreased to 2000 concentrations by 2010. In soils receiving no P, soil P pool concentrations were significantly lower than those in 1994 only in 2010. There were few changes in P forms determined by P-NMR. Orthophosphate followed the same trend observed for the soil P pools; total organic P, total inositol phosphates, and total orthophosphate monoesters and diesters were highest in 2010 in the soil receiving no P fertilizer for 10 yr. For these soils, fertilizer application and cessation influenced inorganic P more than organic P.