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Nitrate Leaching from Continuous Corn, Perennial Grasses, and Poplar in the US Midwest
Author(s) -
Hussain Mir Zaman,
Bhardwaj Ajay K.,
Basso Bruno,
Robertson G. Philip,
Hamilton Stephen K.
Publication year - 2019
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/jeq2019.04.0156
Subject(s) - miscanthus , perennial plant , panicum virgatum , agronomy , leaching (pedology) , environmental science , poaceae , lysimeter , soil water , bioenergy , biology , biofuel , ecology , soil science
Leaching from annual corn ( Zea mays L.) crops is a primary source of nitrate (NO 3 − ) pollution of ground and surface waters. Here, we compare NO 3 − losses from no‐till corn with losses from various alternative perennial cropping systems (switchgrass [ Panicum virgatum L.], miscanthus [ Miscanthus × giganteus J.M. Greef & Deuter ex Hodkinson & Renvoiz], a native grass mixture, and restored prairie), as well as hybrid poplar ( Populus nigra L. × P. maximowiczii A. Henry ‘NM6’), all grown on a well‐drained soil in Michigan. Soil water was sampled from below the root zone using suction cup samplers during nonfrozen periods (March–November) between 2009 and 2016. Leaching was estimated from NO 3 − concentrations in soil water and modeled drainage (percolation) rates. Drainage rates were not significantly different among crops, constituting ∼30% of total annual precipitation. Aboveground net primary production (Mg ha −1 yr −1 ) averaged across the 7 yr was highest in poplar (30.8 ± 1.9 [SE]) followed by miscanthus (23.9 ± 2.4) and corn (20.4 ± 0.9). Volume‐weighted mean NO 3 − concentrations (mg N L −1 ) and NO 3 − leaching (kg ha −1 yr −1 ) averaged across the 7 yr were 9.2 and 34.1, 2.3 and 5.9, and 3.0 and 7.2, respectively, for corn, perennial grasses and poplar. Approximately 10 to 32% of applied N was lost as NO 3 − from these crops, with the highest percent losses from poplar (32%) followed by corn (20%). Perennial cropping systems leached considerably more NO 3 − in first few years after planting, but over 7 yr they lost much less NO 3 − than corn. Perennial crops may therefore help ameliorate NO 3 − pollution in agricultural landscapes even if they receive modest N fertilization. Core Ideas Over 7 yr, perennial grasses and poplar trees leached much less nitrate than corn Nitrate leaching from grasses and poplar was comparable with corn for 1–2 yr after planting. Perennial crops can ameliorate nitrate pollution in agricultural landscapes.