Management practices can reduce N losses through N leaching and N2O emissions (a greenhouse gas) by increasing soil N storage. The effects of tillage, cropping sequence, and N fertilization rate were studied on N contents in dryland crop biomass, surface residue, and soil at the 0- to 120-cm depth, and estimated N balance from 2006 to 2011 in eastern Montana. Treatments were no-till continuous malt barley (Hordeum vulgaris L.) (NTCB), no-till malt barley-pea (Pisum sativum L.) (NTB-P), no-till malt barley-fallow (NTB-F), and conventional till malt barley-fallow (CTB-F), each with 0 to 120 kg N ha(-1). Biomass and surface residue N increased with increased N rate and were greater in NTB-P or NTCB than CTB-F and NTB-F in all years, except in 2006 and 2011. Soil total nitrogen (STN) at 0 to 60 cm decreased from 2006 to 2011 at 254 kg N ha(-1) yr(-1), regardless of treatments. At most depths, soil NH4-N content varied, but NO3-N content was greater in CTB-F than other cropping sequences. Estimated N balance was greater in NTB-P with 40 kg N ha(-1) than other treatments. No-till continuous cropping increased biomass and surface residue N, but conventional till crop-fallow increased soil available N. Because of increased soil N storage and reduced N requirement to malt barley, NTB-P with 40 kg N ha(-1) may reduce N loss due to leaching, volatilization, and denitrification compared to other treatments.
