Premium
Nitrate, Phosphate, and Ammonium Loads at Subsurface Drains: Agroecosystems and Nitrogen Management
Author(s) -
HernandezRamirez Guillermo,
Brouder Sylvie M.,
Ruark Matthew D.,
Turco Ronald F.
Publication year - 2011
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2010.0195
Subject(s) - lysimeter , nutrient , agronomy , agroecosystem , nitrate , nitrogen , nutrient management , ammonium , soil water , environmental science , chemistry , zoology , ammonium nitrate , drainage , manure , ecology , biology , soil science , organic chemistry , agriculture
Artificial subsurface drainage in cropland creates pathways for nutrient movement into surface water; quantification of the relative impacts of common and theoretically improved management systems on these nutrient losses remains incomplete. This study was conducted to assess diverse management effects on long‐term patterns (1998–2006) of NO 3 − , NH 4 + , and PO 4 3− loads ( L ). We monitored water flow and nutrient concentrations at subsurface drains in lysimeter plots planted to continuous corn ( Zea mays L.) (CC), both phases of corn–soybean [ Glycine max (L.) Merr.] rotations (corn, CS; soybean, SC), and restored prairie grass (PG). Corn plots were fertilized with preplant or sidedress urea–NH 4 NO 3 (UAN) or liquid swine manure injected in the fall (FM) or spring (SM). Restored PG reduced L NO 3 − eightfold compared with fields receiving UAN (2.5 vs. 19.9 kg N ha −1 yr −1 ; P < 0.001), yet varying UAN application rates and timings did not affect L NO 3 − across all CCUANs and CSUANs. The L NO 3 − from CCFM (33.3 kg N ha −1 yr −1 ) were substantially higher than for all other cropped fields including CCSM (average 19.8 kg N ha −1 yr −1 , P < 0.001). With respect to NH 4 + and PO 4 3− , only manured soils recorded high but episodic losses in certain years. Compared with the average of all other treatments, CCSM increased L NH 4 + in the spring of 1999 (217 vs. 680 g N ha −1 yr −1 ), while CCFM raised L PO 4 3− in the winter of 2005 (23 vs. 441 g P ha −1 yr −1 ). Our results demonstrate that fall manuring increased nutrient losses in subsurface‐drained cropland, and hence this practice should be redesigned for improvement or discouraged.