Residual effects of novel versus traditional organic amendments for rain-fed notill barley: Yield, nutrient uptake, and N<inf>2</inf>O emissions

Organic amendments recycle nutrients, but N2O emissions are both environmental and agronomic concerns. We conducted a 4-year field experiment to determine no-till barley (Hordeum vulgare L.) yield and nutrient uptake and soil N2O emissions following a single application of six amendment treatments: (1) no amendment (Check); (2) synthetic N fertilizer (Fert); (3) fresh beef cattle feedlot manure (ManureF); (4) beef cattle feedlot manure compost (CompostR); (5) beef cattle feedlot manure composted with cattle mortalities (CompostM); and (6) separated solids from anaerobically digested cattle feedlot manure (ADM). Barley grown in Year 1(2006), Year 2(2007), and Year 4 (2009) (with Year 3 (2008) under fallow) had higher grain yields from ManureF (4.73 Mg ha-1) in Year 2 and ADM (6.30 Mg ha-1) in Year 4 (p < 0.05) than other treatments. The grain N and P contents were not affected (p > 0.05), but N uptake over 3 years (112.8 kg N ha-1 yr-1), and P uptake in Year 1 (19.1 kg ha-1 yr-1) and Year 2 (14.3 kg ha-1 yr-1) from ManureF, were higher (p < 0.05×) than other treatments. The cumulative N2O emissions from ManureF in Year 1 (1.488 kg N ha-1) and from ADM in Year 2 (1.072 kg N ha-1) were higher (p < 0.05) than other treatments while the fraction of applied N emitted as N2O was small (0.00 to 0.79%) and not affected by treatment. However, the percentages of applied N emitted as N2O from compost and ADM were similar to synthetic fertilizer and livestock manure.