Intensive cultivation of native grassland for dryland agriculture continuously depleted soil organic carbon (SOC) and nutrients. In 2010, we evaluated the infl uence of 80 yr of crop residue and nutrient management practices on SOC and N in 0-to 60-cm soil depth profi les in conventionally tilled winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) system. Residue and N treatments, no N addition with fall burning (FB0), spring burning (SB0), and no burning (NB0), 45 kg N ha -1 with SB (SB45) and NB (NB45), 90 kg N ha -1 with SB (SB90) and NB (NB90), manure (MN, 5.32 Mg dry mass ha -1 yr -1 ), and pea vines (PV, 0.99 Mg dry mass ha -1 yr -1 ), were in ordered arrangement, and an undisturbed grassland (GP) was used as a reference. All WW-SF treatments had less SOC and N stocks than GP. Th e SOC stocks were lowest under FB0 with 50% less SOC than GP. Th e WW-SF treatments have depleted up to 63 and 26% of SOC and N from surface soil since 1931. Fall burning and MN treatments depleted SOC at rates of 0.64 and 0.17 Mg ha -1 yr -1 . Nitrogen stocks decreased at a rate of 0.02 Mg ha -1 yr -1 in FB, SB, and NB treatments, and 0.01 Mg ha -1 yr -1 in PV treatment. Reduction in tillage, application of low C/N ratio residues, and elimination of burning can improve sustainability of winter wheat production in the summer fallow region of the Pacifi c Northwest (PNW).

Grain β‐glucan content is the most important attribute for barley (Hordeum vulgare L.) varieties destined for the human food market. This trait is important because of the blood glucose and cholesterol‐reducing properties of β‐glucans. High levels of grain protein content, test weight, and seed size and endosperm color may also add value. Seed yield potential, in part, determines the economic feasibility of producing human food varieties. To determine the potential of food barley production in the dryland production areas of the Pacific Northwest of the United States, 33 cultivars and advanced lines reported to vary in β‐glucan content were grown in 2006 and 2007 at two locations in northeastern Oregon under dryland cropping conditions. Seed yield, test weight, percentage of plump kernels, grain β‐glucan, and grain protein were measured on replicated samples from the four environments, allowing for assessment of average performance as well as genotype × environment interaction. Estimates of variance components showed that ∼66% of the variability in β‐glucan content was attributable to genotype. Cultivars and lines with waxy starch had an average β‐glucan value of 55 g kg−1 compared with 35 g kg−1 for cultivars and lines with nonwaxy starch. We found significant two‐ and three‐way interactions, but these accounted for much less of the total variation in the measured phenotypes than the main effects of variety, year, and location. Hulless accessions produced an average of 3580 kg grain ha−1 compared with 4260 kg grain ha−1 for the hulled accessions. Hulled, waxy‐starch varieties appear to have the greatest agronomic potential for dryland production, as they combine high yield potential and grain β‐glucan percentage.

Soil organic carbon (SOC) has beneficial effects on soil quality and productivity. Cropping systems that maintain and/or improve levels of SOC may lead to sustainable crop production. This study evaluated the effects of long-term cropping systems on C sequestration. Soil samples were taken at 0- to 10-, 10- to 20-, 20- to 30-, and 30- to 40-cm soil depth profiles from grass pasture (GP), conventional tillage (CT) winter wheat (Triticum aestivum L.)-fallow (CTWF), and fertilized and unfertilized plots of continuous winter wheat (WW), spring wheat (SW), and spring barley (Hordeum vulgare L.) (SB) monocultures under CT and no-till (NT). The samples were analyzed for soil organic matter (SOM) and SOC was derived. Ages of experiments ranged from 6 to 73 yr. Compared to 1931 SOC levels (initial year), CTWF reduced SOC by 9 to 12 Mg ha(-1) in the 0- to 30-cm zone. Grass pasture increased SOC by 6 Mg ha(-1) in the 0- to 10-cm zone but decreased SOC by 3 Mg ha(-1) in the 20- to 30-cm zone. Continuous CT monocultures depleted SOC in the top 0- to 10-cm zone and the bottom 20- to 40-cm zone but maintained SOC levels close to 1931 SOC levels in the 10- to 20-cm layer. Continuous NT monocultures accumulated more SOC in the 0- to 10-cm zone than in deeper zones. Total SOC (0- to 40-cm zone) was highest under GP and continuous cropping and lowest under CTWF. Fertilizer increased total SOC only under CTWW and CTSB by 13 and 7 Mg ha(-1) in 13 yr, respectively. Practicing NT for only 6 yr had started to reverse the effect of 73 yr of CTWF. Compared to CTWF, NTWW and NTSW sequestered C at rates of 2.6 and 1.7 Mg ha(-1) yr(-1), respectively, in the 0- to 40-cm zone. This study showed that the potential to sequester C can be enhanced by increasing cropping frequency and eliminating tillage.

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Winter malting barley (Hordeum vulgare L.) is a potential alternative crop for the dryland region of the Pacific Northwest. Nitrogen fertilization can increase grain yield but may also increase lodging and grain protein and reduce test weight. The objectives of this research were to determine the effect of N application rate and timing on grain yield and quality of winter feed and malting barley varieties. Field trials were conducted at Pendleton, OR (17 inches annual precipitation) and Moro, OR (12 inches annual precipitation). Nitrogen was applied at 0, 50, 100, or 150 lb N per acre in the fall and at 0 or 50 lb N per acre in the spring at Pendleton and at 0, 30, 60, or 90 lb N per acre in the fall and at 0 or 30 lb N per acre in the spring at Moro. Nitrogen fertilization increased grain yields at Pendleton to a maximum of 5,800 lb/acre in 2001 and 5,200 lb/acre in 2002 and at Moro to a maximum of 3,000 lb/acre. Nitrogen fertilization increased grain protein and reduced test weights. Yields of the advanced lines of malting barley were about 90% of the yields of feed type barley varieties. Spring N applications did not increase grain yield or protein more than fall N applications.