• Authors:
    • Lawrence, R.
    • Jones, C.
    • Weist, D.
    • Schulthess, U.
    • Christensen, N.
  • Source: Proceedings of the 9th International Conference on Precision Agriculture, Denver, Colorado, USA, 20-23 July, 2008
  • Year: 2008
  • Summary: RapidEye's five satellites to be launched in the summer of 2008 will make it possible to regularly monitor the N-status of crops from space. The sensors on board of each satellite are equipped with five broad bands: blue, green, red, rededge, and NIR. This opens new avenues for red-edge based algorithms to predict the N-status of cereals. In a study conducted in Montana in 2007, we obtained the best results to predict tissue N content (TNC) of irrigated spring wheat and barley, as well as dryland barley from the following algorithm, based on light reflectance (R) of the canopy in the red, red-edge, and NIR bands: ( TNC= RNIR - Rred-edge )/( RNIR -s* Rred ) where s stands for slope of the soil line, i.e. the separately measured bare soil reflectance of the NIR band divided by the red band. Red-edge band based algorithms will open new avenues to optimize in-season N management of cereals, and for monitoring and verifying the efficacy of N fertilization.
  • Authors:
    • Easley, S.
    • Sheedy, J.
    • Smiley, R.
  • Source: Plant Disease
  • Volume: 92
  • Issue: 12
  • Year: 2008
  • Summary: Dryland field crops in the Pacific Northwest United States are commonly produced in silt loams infested by the root-lesion nematodes Pratylenchus neglectus and P. thornei. Soils at 30 sites in Oregon were sampled from 0 to 120 cm depth to examine the vertical distribution of these Pratylenchus spp. Both species were distributed through entire soil profiles of all cropping systems. Populations were generally greatest in the surface 30 cm, but sometimes high populations were detected at depths greater than 45 cm. Sampling to 30 cm depth allowed detection of more than 50% of the population in most sites, while sampling to 45 cm depth yielded more than 75% of the population in over 75% of the sites evaluated. Therefore, soil samples should be collected to 30 to 45 cm depth to accurately estimate populations of Pratylenchus spp. in dryland crops produced on silt loams in the Pacific Northwest. Populations of Pratylenchus spp. were found to be related to the most recently planted crop, with populations after barley, after wheat, and during summer fallow being detected in ascending order.
  • Authors:
    • Follett, R. F.
    • Alley, M. M.
    • Spargo, J. T.
    • Wallace, J. V.
  • Source: Soil & Tillage Research
  • Volume: 100
  • Issue: 1/2
  • Year: 2008
  • Summary: Carbon sequestration in agroecosystems represents a significant opportunity to offset a portion of anthropogenic CO 2 emissions. Climatic conditions in the Virginia coastal plain and modern production practices make it possible for high annual photosynthetic CO 2 fixation. There is potential to sequester a substantial amount of C, and concomitantly improve soil quality, with the elimination of tillage for crop production in this region. The objectives of our research were to: (1) measure C sequestration rate with continuous no-till management of grain cropping systems of the Virginia middle coastal plain; (2) determine the influence of biosolids application history on C content and its interaction with tillage management; and (3) evaluate the impact of continuous no-till C stratification as an indicator of soil quality. Samples were collected from 63 sites in production fields using a rotation of corn ( Zea mays L.)-wheat ( Triticum aestivum L.) or barley ( Hordeum vulgare L.)/soybean double-crop ( Glysine max L.) across three soil series [Bojac (coarse-loamy, mixed, semiactive, thermic Typic Hapludults), Altavista (fine-loamy, mixed semiactive, thermic Aquic Hapludults), and Kempsville (fine-loamy, siliceous, subactive, thermic Typic Hapludults)] with a history of continuous no-till management ranging from 0 to 14 years. Thirty-two of the sites had a history of biosolids application. Five soil cores were collected at each site from 0-2.5, 2.5-7.5 and 7.5-15 cm and analyzed for bulk density and soil C. Bulk density in the 0-2.5 cm layer decreased and C stratification ratio (0-2.5 cm:7.5-15 cm) increased with increasing duration of continuous no-till due to the accumulation of organic matter at the soil surface. A history of biosolids application resulted in an increase of 4.191.93 Mg C ha -1 (0-15 cm). Continuous no-till resulted in the sequestration of 0.3080.280 Mg C ha -1 yr -1 (0-15 cm). Our results provide quantitative validation of the C sequestration rate and improved soil quality with continuous no-till management in the region using on-farm observations.
  • Authors:
    • Basnyat, P.
    • Huber, D.
    • Fernandez, M. R.
    • Zentner, R. P.
  • Source: Soil & Tillage Research
  • Volume: 100
  • Issue: 1-2
  • Year: 2008
  • Summary: Fusarium head blight (FHB) is an important disease which has been causing damage to wheat and barley crops in western Canada. Because crop residues are an important source of inoculum, it is important to know the ability of Fusarium spp. to colonize and survive in different residue types, and how their populations might be affected by agronomic practices. Sampling of residue types on producers' fields for quantification of Fusarium and other fungi was conducted in 2000-2001 in eastern Saskatchewan. Fusarium spp. were isolated from most fields, whereas their mean percentage isolation (MPI) was over 50% for cereal and pulse residues, and under 30% for oilseed residues. The most common Fusarium, F. avenaceum, had a higher MPI in pulse and flax (45-48%) than in cereal or canola (10-22%) residues. This was followed by F. equiseti, F. acuminatum, F. graminearum, F. culmorum and F. poae which were isolated from all, or most, residue types. Factors affecting Fusarium abundance in residues included the current crop, cropping history, and tillage system. In cereal residues, the MPI of F. avenaceum was higher when the current crop was another cereal (24%) versus a noncereal (4-8%). When the current crop was another cereal, the lowest MPI of F. avenaceum and F. culmorum occurred when the field had been in summerfallow (SF) two years previous (F. avenaceum: 17% for SF, 28% for a crop; F. culmorum: 1% for SF, 4% for a crop); in contrast, F. equiseti and Cochliobolus sativus were most common in residues of cereal crops preceded by SF (F. equiseti: 16% for SF, 10% for a crop; C. sativus: 22% for SF, 13% for a crop). The MPI of F graminearum was higher when the crop two years previous was an oilseed (7%) versus a cereal (4%). In regards to tillage effects, when the current crop was a cereal, the MPI of F. avenaceum was higher under minimum (MT) and zero tillage (ZT) (22-37%) than conventional tillage (CT) (15%), that of F. graminearum was lowest under ZT (3% for ZT, 7-11% for CT-MT), whereas that of C. sativus was highest under CT (27% for CT, 6-11% for MT-ZT). Under ZT, previous glyphosate applications were correlated positively with F. avenaceum and negatively with F. equiseti and C. sativus. These observations generally agreed with results from previous FHB and root rot studies of wheat and barley in the same region. Percentage isolation of F avenaceum from noncereal and of F. graminearum from cereal residues were positively correlated with FHB severity and percentage Fusarium-damaged kernels of barley and wheat caused by the same fungi. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.
  • Authors:
    • Sainju, U. M.
    • Caesar-TonThat, T.
    • Lenssen, A. W.
    • Evans, R. G.
    • Kolberg, R.
  • Source: Soil Science Society of America Journal
  • Volume: 71
  • Issue: 6
  • Year: 2007
  • Summary: Long-term management practices are needed to increase dryland C storage and improve soil quality. We evaluated the 21-yr effects of combinations of tillage and cropping sequences on dryland crop biomass (stems + leaves) returned to the soil, residue C, and soil C fractions at the 0- to 20-cm depth in a Dooley sandy loam (fine-loamy, mixed, frigid, Typic Argiborolls) in eastern Montana. Treatments were no-till continuous spring wheat (Triticum aestivum L.) (NTCW), spring-tilled continuous spring wheat (STCW), fall- and spring-tilled continuous spring wheat (FSTCW), fall- and spring-tilled spring wheat-barley (Hordeum vulgare L.) (1984-1999) followed by spring wheat-pea (Pisum sativum L.) (2000-2004) (FSTW-B/P), and spring-tilled spring wheat-fallow (STW-F). Carbon fractions were soil organic C (SOC), soil inorganic C (SIC), particulate organic C (POC), microbial biomass C (MBC), and potential C mineralization (PCM). Mean crop biomass was 53 to 66% greater in NTCW, STCW, FSTCW, and FSTW-B/P than in STW-F. Soil surface residue amount and C content in 2004 were 46 to 60% greater in NTCW and FSTCW than in STW-F As a result, soil C fractions at 0 to 20 cm were 23 to 141 % greater in all other treatments than in STW-F due to increased C input. At 0 to 5 cm, SOC, SIC, POC, and PCM were greater in NTCW than in FSTW-B/P. At 5 to 20 cm, POC was greater in NTCW than in FSTW-B/P and PCM was greater in STCW than in FSTCW. Long-term reduced tillage with continuous nonlegume cropping increased dryland crop biomass, residue and soil C storage, and soil quality by increasing microbial biomass and activities compared with a conventional system such as STW-F.
  • Authors:
    • Young, D. L.
    • Schillinger, W. F.
    • Kennedy, A. C.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 120
  • Issue: 2-4
  • Year: 2007
  • Summary: The tillage-based winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) cropping system has dominated dryland farming in the Pacific Northwest USA for 125 years. We conducted a large-scale multidisciplinary 8-year study of annual (i.e., no summer fallow) no-till cropping systems as an alternative to WW-SF. Soft white and hard white classes of winter and spring wheat, spring barley (Hordeum vulgare L.), yellow mustard (Brassica hirta Moench), and safflower (Carthamus tinctorius L.) were grown in various rotation combinations. Annual precipitation was less than the long-term average of 301 mm in 7 out of 8 years. Rhizoctonia bare patch disease caused by the fungus Rhizoctonia solani AG-8 appeared in year 3 and continued through year 8 in all no-till plots. All crops were susceptible to rhizoctonia, but bare patch area in wheat was reduced, and grain yield increased, when wheat was grown in rotation with barley every other year. Remnant downy brome (Bromus tectorum L.) weed seeds remained dormant for 6 years and longer to heavily infest recrop winter wheat. There were few quantifiable changes in soil quality due to crop rotation, but soil organic carbon (SOC) increased in the surface 0-5 cm depth with no-till during the 8 years to approach that found in undisturbed native soil. Annual no-till crop rotations experienced lower average profitability and greater income variability compared to WW-SF. Yellow mustard and safflower were not economically viable. Continuous annual cropping using no-till provides excellent protection against wind erosion and shows potential to increase soil quality, but the practice involves high economic risk compared to WW-SF. This paper provides the first comprehensive multidisciplinary report of long-term alternative annual no-till cropping systems research in the low-precipitation region of the Pacific Northwest.
  • Authors:
    • Becher, R.
  • Source: Plant Breeding
  • Volume: 126
  • Issue: 3
  • Year: 2007
  • Summary: Polymerase chain reaction-based microsatellite markers are valuable tools for molecular breeding because of their co-dominant inheritance and their applicability for high-throughput analysis. Being still very limited for oats, their number has to be increased significantly to cover the entire genome. For these purposes, a set of 7031 recently published expressed sequence tags (ESTs) was screened for microsatellites with dinucleotide, trinucleotide and tetranucleotide repeat motifs. Subsequent in silico analysis resulted in the development of 216 primer pairs for Avena EST-derived microsatellite loci ( AME). Using a sample set of 12 oat lines, 107 of 195 functional primers could be assayed as polymorphic. The marker variability averaged out at three alleles per locus and a polymorphic information content (PIC) value of 0.42. This variability documents their suitability for molecular oat-breeding purposes. Finally, 51 of the AME loci could be placed within the known reference map of 'Kanota' * 'Ogle' that previously contained only 12 microsatellite loci. Thus, a remarkable enhancing of the number of mapped oat microsatellite loci could be achieved.
  • Authors:
    • Weiss, M. J.
    • Pike, K. S.
    • Buntin, G. D.
    • Webster, J. A.
  • Source: Handbook of small grain insects
  • Year: 2007
  • Summary: This handbook is designed primarily for the practitioners of integrated pest management programmes in small grains, growers, crop consultants, extension agents, and company agronomists and sales representatives. Its primary objective is to provide fundamental and useful information about managing (through cultural, plant resistance, biological and chemical methods) small grain insects throughout the United States and Canada. Although it focuses on insect pests of small grains, noninsect pests (e.g. mites) also are covered. Crops covered in this handbook are wheat, barley, oats, rye and triticale, with an emphasis on wheat. The first three sections provide information about small grains and their production, principles and practices of small grain insect management, and an overview of the pest injury to small grains by insects, weeds, and plant pathogens. The remainder of the handbook is devoted to discussions of insect and mite pests of small grains and to beneficial organisms, including insect pathogens, parasitoids and predators.
  • Authors:
    • Moravcikova, P.
    • Kuniak, L.
    • Hozova, B.
    • Gajdosova, A.
  • Source: Czech Journal of Food Sciences
  • Volume: 25
  • Issue: 6
  • Year: 2007
  • Summary: Water-insoluble beta-(1,3)-D-glucan (lichenan) was determined in 43 samples of various cereal (i.e., oats, barley, wheat, millet) and pseudocereal (i.e., buckwheat, amaranth) cultivars using a modified procedure with fungal alpha-amylase (Fermizyme P 300). The content of water-insoluble beta-glucan varied with dependence on the cereal species and cultivars. The highest content was observed in covered oat cultivars (Cyril and the new breeding cultivar PS-100), ranging from 26.7 to 28.2 g/100 g dry matter (d.m.), followed by less traditional cereals such as millet ( Panicum miliaceum), amaranth ( Amaranthus sp.), and buckwheat ( Fagopyrum) - more than 20 g/100 g d. m. A somewhat lower average content of water-insoluble beta-glucan was found in wheat - 12.7-16.2 g/100 g d. m., in spelt wheat - 8.5 g/100 g d. m., and in oats - varying between 15.3 and 18.7 g/100 g d. m.
  • Authors:
    • Dotlacil, L.
    • Kucera, L.
    • Leisova, L.
  • Source: Czech Journal of Genetics and Plant Breeding
  • Volume: 43
  • Issue: 3
  • Year: 2007
  • Summary: Barley ( Hordeum vulgare L.) and oat ( Avena sativa L.) are important crop species. 1865 accessions of winter barley, 2707 accessions of spring barley and 1998 accessions of oat are maintained in RICP Gene bank. The expert core collection is used to be established as a tool for germplasm study, conservation of genetic variability and for the identification of useful genes. The main aim of this study was to evaluate genetic diversity of barley and oat genotypes within the expert core collections. Genetic variation of 176 barley accessions was analyzed using 26 microsatellite loci, covering all 6 chromosomes. 330 oat accessions were analyzed using 26 microsatellite loci that are mapped only into linkage groups. For 26 barley microsatellite loci, 328 alleles were detected. The average number of alleles per locus was 12.6. In oat, for 26 oat microsatellite loci, 353 alleles were detected. The average number of alleles per locus was 13.6. The average DI (diversity index) was 0.11 in barley and 0.09 in oat. Dendrogram and PCA (Principal Component Analysis) based on microsatellite data showed a different influence of the place of origin, age of variety and pedigree on grouping into clusters. PCA showed that the breeding process had a negative impact on the level of genetic diversity and therefore there is a necessity of barley and oat germplasm conservation.