Open AccessDeep Soil Cores Reveal Large End‐of‐Season Residual Mineral Nitrogen Pool
Author(s) -
Hirsh Sarah M.,
Weil Ray R.
Publication year - 2019
Publication title -
agricultural and environmental letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.681
H-Index - 12
ISSN - 2471-9625
DOI - 10.2134/ael2018.10.0055
Subject(s) - leaching (pedology) , residual , agronomy , mineral , environmental science , soil water , nitrogen , chemistry , soil science , biology , mathematics , ecology , organic chemistry , algorithm
Core Ideas Residual mineral N in 0‐ to 210‐cm‐deep soil following summer crops was evaluated. Soils contained a mean of 253 kg ha −1 mineral N, 115 kg ha −1 as NO 3 –N. 55% of mineral N was 90‐ to 210‐cm deep, where it is most at risk for leaching loss. More residual NO 3 –N remained after soybean than after corn. Awareness of residual deep N levels is essential to develop N conservation practices.The amount of mineral N remaining after cash crops informs agronomic and conservation practices. Few studies investigate mineral N below 30 cm, yet deeper N is more at risk for leaching to groundwater. We found, on average, 253 kg ha −1 of mineral N, 115 kg ha −1 in the NO 3 –N form, remaining after summer cash crop growth in the mid‐Atlantic region. Of this residual mineral N, 55% was 90 to 210 cm deep. More residual NO 3 –N remained after soybean than after corn. These substantial pools of mineral N remaining deep in the soil profile after productive cash crops, even unfertilized soybean, suggest that practices should be designed to scavenge residual N from deep soil layers in the fall, before it is lost over winter.