TY - JOUR
T1 - Cover crops and fertilization alter nitrogen loss in organic and conventional conservation agriculture systems
AU - Shelton, Rebecca E.
AU - Jacobsen, Krista L.
AU - McCulley, Rebecca L.
N1 - Publisher Copyright:
© 2018 Shelton, Jacobsen and McCulley.
PY - 2018/1/22
Y1 - 2018/1/22
N2 - Agroecosystem nitrogen (N) loss produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, conservation agricultural management practices aimed at reducing N loss are increasingly adopted. However, the ecosystem consequences of these practices have not been well-studied. We quantified N loss via leaching, NH3 volatilization, N2 O emissions, and N retention in plant and soil pools of corn conservation agroecosystems in Kentucky, USA. Three systems were evaluated: (1) an unfertilized, organic system with cover crops hairy vetch (Vicia villosa), winter wheat (Triticum aestivum), or a mix of the two (bi-culture); (2) an organic system with a hairy vetch cover crop employing three fertilization schemes (0N, organic N, or a fertilizer N-credit approach); and (3) a conventional system with a winter wheat cover crop and three fertilization schemes (0N, urea N, or organic N). In the unfertilized organic system, cover crop species affected NO3 -N leaching (vetch > bi-culture > wheat) and N2 O-N emissions and yield during corn growth (vetch, bi-culture > wheat). Fertilization increased soil inorganic N, gaseous Nloss, Nleaching, and yield in the organic vetch and conventional wheat systems. Fertilizer scheme affectedthe magnitude of growing season N2 O-N loss in the organic vetch system (organic N > fertilizer N-credit) and the timing of loss (organic N delayed N2 O-N loss vs. urea) and NO3 -N leaching (urea >> organic N) in the conventional wheat system, but had no effect on yield. Cover crop selection and N fertilization techniques can reduce N leaching and greenhouse gas emissions without sacrificing yield, thereby enhancing N conservation in both organic and conventional conservation agriculture systems.
AB - Agroecosystem nitrogen (N) loss produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, conservation agricultural management practices aimed at reducing N loss are increasingly adopted. However, the ecosystem consequences of these practices have not been well-studied. We quantified N loss via leaching, NH3 volatilization, N2 O emissions, and N retention in plant and soil pools of corn conservation agroecosystems in Kentucky, USA. Three systems were evaluated: (1) an unfertilized, organic system with cover crops hairy vetch (Vicia villosa), winter wheat (Triticum aestivum), or a mix of the two (bi-culture); (2) an organic system with a hairy vetch cover crop employing three fertilization schemes (0N, organic N, or a fertilizer N-credit approach); and (3) a conventional system with a winter wheat cover crop and three fertilization schemes (0N, urea N, or organic N). In the unfertilized organic system, cover crop species affected NO3 -N leaching (vetch > bi-culture > wheat) and N2 O-N emissions and yield during corn growth (vetch, bi-culture > wheat). Fertilization increased soil inorganic N, gaseous Nloss, Nleaching, and yield in the organic vetch and conventional wheat systems. Fertilizer scheme affectedthe magnitude of growing season N2 O-N loss in the organic vetch system (organic N > fertilizer N-credit) and the timing of loss (organic N delayed N2 O-N loss vs. urea) and NO3 -N leaching (urea >> organic N) in the conventional wheat system, but had no effect on yield. Cover crop selection and N fertilization techniques can reduce N leaching and greenhouse gas emissions without sacrificing yield, thereby enhancing N conservation in both organic and conventional conservation agriculture systems.
KW - Ammonia volatilization
KW - Conservation agriculture
KW - Cover crops
KW - Nitrate leaching
KW - Nitrous oxide emissions
UR - http://www.scopus.com/inward/record.url?scp=85041293908&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85041293908&partnerID=8YFLogxK
U2 - 10.3389/fpls.2017.02260
DO - 10.3389/fpls.2017.02260
M3 - Article
AN - SCOPUS:85041293908
SN - 1664-462X
VL - 8
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
M1 - 2260
ER -