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.

No abstract

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.

No abstract

The traditional winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) using conventional tillage (CT), the predominant cropping system in eastern Oregon, has been shown increase soil erosion and to deplete soil organic carbon (SOC). This research evaluates alternative no-tillage (NT) cropping systems designed to reduce these negative impacts on the soil and environment. In this long-term experiment (2004-05 to 2009-10 crop-years), WW-SF using CT was compared with annual winter wheat (WW-WW), annual spring wheat (SW-SW), annual spring barley (Hordeum vulgare L.) (SB-SB), winter wheat-chemical fallow (WW-CF), winter wheat-winter pea (Pisum sativum L.) (WW-WP), and winter wheat-spring barleychemical fallow rotation (WW-SB-CF), all using NT. Measurements included, phenology, plant population, plant height, yield components, grain yield, crop residues, SOC, soil moisture, and precipitation. Water-use efficiency (WUE) was derived from precipitation, phenology, and grain yield data. In annual cropping, grain yield under WW-WP and SB-SB was greater than under WW-WW and SW-SW. Grain yields among crop rotations with fallow (WW-SF, WW-CF, and WW-SB-CF) were not significantly different. On an annual basis, SB-SB rotation produced the highest yield and WW-WP rotation produced the lowest yield. The WUEs of all fallow rotations, SB-SB, and SW-SW were not different but were all higher than WUEs of WW-WP and WW-WW. Residue cover and SOC were highest under annual cropping systems and lowest following peas in WW-WP and SF in WW-SF system. Based on results from the six year study rotations with fallow using NT (WW-CF, and WW-SB-CF) can replace the traditional WW-SF system without yield penalty.