Data from: Leaching losses of dissolved organic carbon and nitrogen from agricultural soils in the upper US Midwest

Leaching losses of dissolved organic carbon (DOC) and nitrogen (DON) from
agricultural systems are important to water quality and carbon and
nutrient balances but are rarely reported; the few available studies
suggest linkages to litter production (DOC) and nitrogen fertilization
(DON). In this study we examine the leaching of DOC, DON, NO3-, and NH4+
from no-till corn (maize) and perennial bioenergy crops (switchgrass,
miscanthus, native grasses, restored prairie, and poplar) grown between
2009 and 2016 in a replicated field experiment in the upper Midwest U.S.
Leaching was estimated from concentrations in soil water and modeled
drainage (percolation) rates. DOC leaching rates (kg ha-1 yr-1) and
volume-weighted mean concentrations (mg L-1) among cropping systems
averaged 15.4 and 4.6, respectively; N fertilization had no effect and
poplar lost the most DOC (21.8 and 6.9, respectively). DON leaching rates
(kg ha-1 yr-1) and volume-weighted mean concentrations (mg L-1) under corn
(the most heavily N-fertilized crop) averaged 4.5 and 1.0, respectively,
which was higher than perennial grasses (mean: 1.5 and 0.5, respectively)
and poplar (1.6 and 0.5, respectively). NO3- comprised the majority of
total N leaching in all systems (59-92%). Average NO3- leaching (kg N ha-1
yr-1) under corn (35.3) was higher than perennial grasses (5.9) and poplar
(7.2). NH4+ concentrations in soil water from all cropping systems were
relatively low (<0.07 mg N L-1). Perennial crops leached more NO3-
in the first few years after planting, and markedly less after. Among the
fertilized crops, the leached N represented 14-38% of the added N over the
study period; poplar lost the greatest proportion (38%) and corn was
intermediate (23%). Requiring only one third or less of the N
fertilization compared to corn, perennial bioenergy crops can
substantially reduce N leaching and consequent movement into aquifers and
surface waters.