Malt barley (Hordeum vulgare L.) yield and quality have been evaluated using various cultivars and N rates but little is known about the eff ects of tillage and cropping sequence. We evaluated the eff ects of tillage, cropping sequence, and N fertilization on dryland malt barley yield, grain characteristics, N uptake, and N use-effi ciency from 2006 to 2011 in eastern Montana. Treatments were no-till continuous malt barley (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), with split application of N rates (0,40, 80, and 120 kg N ha-1 ) in randomized complete block with three replications. As N rates increased, malt barley grain yield, protein concentration, and N uptake increased in NTB-F, NTB-P, and NTCB, but test weight, plumpness, and N-use effi ciency decreased in all tillage and cropping sequence treatments. Similarly, plant stand, biomass (stems and leaves) yield, and N uptake increased with increased N rates. Grain and biomass yields, N uptake, and N-use effi ciency were greater in CTB-F than in NTB-P and NTCB but tillage had no eff ect on these parameters. Malt barley yield and N uptake varied with cropping sequences and N rates among years. Although grain yield increased with increased N rates, NTB-P with N rates between 40 and 80 kg N ha -1 may be used to sustain dryland malt barley yield and quality (protein concentration < 135 g kg -1 , plumpness > 800 g kg -1 ), thereby helping to reduce the potentials for soil erosion and N leaching and increase soil organic matter in the northern Great Plains.

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Sheep (Ovis aries L.) grazing is an inexpensive method of weed control in dryland cropping systems, but little is known about its effect on net greenhouse gas (GHG) emissions. We evaluated the effect of sheep grazing compared with herbicide application for weed control on GHG (CO2, N2O, and CH4) emissions from May to October 2010 and 2011, net global warming potential (GWP), and greenhouse gas intensity (GHGI) in a silt loam under dryland cropping systems in western Montana. Treatments were two fallow management practices (sheep grazing [GRAZ] and herbicide application [CHEM]) and three cropping sequences (continuous alfalfa [Medicago sativa L.] [CA], continuous spring wheat [Triticum aestivum L.] [CSW], and spring wheat–pea [Pisum sativum L.]/barley [Hordeum vulgaris L.] hay–fallow [W‐P/B‐F]). Gas fluxes were measured at 3‐ to 14‐d intervals with a vented, static chamber. Regardless of treatments, GHG fluxes peaked immediately following substantial precipitation (>12 mm) and N fertilization mostly from May to August. Total CO2 flux from May to October was greater under GRAZ with CA, but total N2O flux was greater under CHEM and GRAZ with CSW than other treatments. Total CH4 flux was greater with CA than W‐P/B‐F. Net GWP and GHGI were greater under GRAZ with W‐P/B‐F than most other treatments. Greater CH4 flux due to increased enteric fermentation as a result of longer duration of grazing during fallow, followed by reduced crop residue returned to the soil and/or C sequestration rate probably increased net GHG flux under GRAZ with W‐P/B‐F. Sheep grazing on a cropping sequence containing fallow may not reduce net GHG emissions compared with herbicide application for weed control on continuous crops.

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Sheep (Ovis aries L.) grazing, a cost-effective method of controlling weeds compared to herbicide application and tillage, may influence soil C and N levels by consuming plant residue and returning feces and urine to the soil, but little is known about the practice on soil C and N storage under dryland cropping systems in the northern Great Plains, USA. Three weed control practices [sheep grazing (GRAZ), herbicide application (CHEM), and tillage (MECH)] and three cropping sequences [continuous alfalfa (Medicago sativaL.) (CA), continuous spring wheat (Triticum aestivum L.) (CSW), and spring wheat-pea (Pisum sativumL.)/barley (Hordeum vulgaris L.) hay mixture-fallow (W-P/B-F)] were evaluated on a Blackmore silt loam from 2009 to 2011 in southwestern Montana, USA. Crop yields and soil organic C (SOC), total N (STN), NH 4 -N, and NO 3 -N contents at the 0-120 cm depth were quantified. Annualized spring wheat grain and biomass (stems + leaves) yields and C and N contents were greater with CSW than with W-P/B-F, but hay biomass and C content were similar between CA and W-P/B-F. While C and N in aboveground biomass after spring wheat and hay harvest were removed through haying in CHEM and MECH, sheep grazing removed about 99% of these elements in GRAZ. The SOC and STN at 5-15 cm were greater with CSW or W-P/B-F than with CA in GRAZ and MECH, but SOC at 30-60 cm was greater with CA than with CSW in MECH. The NH 4 -N content at most depths varied among treatments and years, but NO 3 -N content at 5-120 cm was greater with CSW and W-P/B-F than with CA. Longer duration of sheep grazing during fallow periods due to increased return of C and N through feces and urine or residue incorporation to a greater depth probably increased soil C and N storage at the surface layer with CSW and W-P/B-F in GRAZ and MECH, but increased root biomass likely increased C storage at the subsurface layer with CA in MECH. Absence of N fertilization and/ or greater N uptake probably reduced soil NO 3 -N level with CA than with other cropping sequences. Regardless of treatments, SOC and STN declined from 2009 to 2011, probably due to residue removal from haying and grazing. Moderate sheep grazing during fallow periods can be used to increase soil C and N storage, obtain farm C credit, and sustain dryland crop yields compared to herbicide application for weed control in the semiarid regions.