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Evaluating Management and Soil and Weather Contributions to Potential Nitrate Leaching from a Pennsylvania Dairy Farm using NLEAP
Author(s) -
Saporito L. S.,
Lanyon L. E.
Publication year - 1998
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/jeq1998.00472425002700060013x
Subject(s) - leaching (pedology) , environmental science , agronomy , nitrate , soil water , hydrology (agriculture) , soil science , ecology , biology , geotechnical engineering , engineering
Developing approaches to reduce nitrate‐N (NO 3 ‐N) leaching from farms requires an understanding of the factors influencing the potential for NO 3 ‐N leaching. An annual screening analysis, NLEAP, was used to determine NO 3 ‐N leaching potential (NL) from a 110‐ha mixed crop and dairy farm in a central Pennsylvania limestone valley for each of 9 yr. The farmer management goal was to meet the animal and crop needs as much as posssible with internal farm resources. Nitrate‐N leaching potential was estimated from annual field N balances (NAL) and a yearly soil and weather factor (SWF) based on winter and summer rainfall, soil bulk density, rooting depth, and soil hydrologic group. Primary crops grown were corn ( Zea mays L) and alfalfa‐timothy ( Medicago sativa L.‐ Phleum pratense L.). A geographic information system was used to calculate and map SWF, NAL, and NL The magnitutude and aerial distribution of field SWF was significantly different (Kolomogorov‐Smirnov, D‐max, p = 0.05) for most year‐to‐year comparisons. The excess of N inputs over outputs (field NAL) was low for all fields and did not vary significantly during the 9‐yr period. The NL was <25 kg ha −1 for 75% of the farm and <50 kg ha −1 for 85% of the farm for all years of the study. The careful and conservative N management strategy by the farmer, reflected in the consistently low NAL, had an overriding impact on potential NO 3 ‐N leaching from the farm.