• Authors:
    • Schumacher, R.
    • Schroeder, K.
    • Li, C.
    • Okubara, P.
    • Lawrence, N.
  • Source: Canadian Journal of Plant Pathology
  • Volume: 29
  • Issue: 3
  • Year: 2007
  • Summary: Soilborne pathogens are important biotic factors in yield reduction in the dryland cereal production region of the Pacific Northwest. Rhizoctonia solani AG-8, Rhizoctonia oryzae, and Pythium spp. are causal agents of root rot, bare patch, and damping-off of wheat ( Triticum aestivum) and barley ( Hordeum vulgare). Although these pathogens can be rapidly and specifically quantified using quantitative real-time PCR, the extraction of Rhizoctonia DNA from agricultural samples is often inconsistent, especially at low pathogen population densities. Using a novel extraction system that uses pressure cycling technology (PCT), we improved the extraction of R. solani AG-8 DNA up to 16-fold and of P. abappressorium DNA up to 2-fold from three types of agricultural soils compared with a bead beating extraction method. PCT also yielded quantifiable amounts of R. solani AG-8 and R. oryzae DNA from lyophilized wheat roots that were otherwise recalcitrant to homogenization. Furthermore, the extractions were so consistent that pathogen quantification generally could be derived from two rather than three or four replicated extracts. Because PCT is performed in a closed system and minimizes sample shearing and heating, it confers a substantial advantage over conventional extraction systems. Here, we report for the first time the application of PCT in a laboratory setting for the improved extraction and quantification of three types of soilborne pathogens in soil samples. The effectiveness of PCT for three soils suggests that it will be beneficial for other hard-to-extract pathogen samples.
  • Authors:
    • Rice, C. W.
    • Boyles, S. B.
    • Williams, J. R.
    • Pendell, D. L.
    • Nelson, R. G.
  • Source: Review of Agricultural Economics
  • Volume: 29
  • Issue: 2
  • Year: 2007
  • Summary: This study examines the economic potential of using either no-tillage or conventional tillage with either commercial nitrogen or cattle manure to sequester soil in continuous corn production. This research uses stochastic efficiency with respect to a function to determine the preferred production systems under various risk preferences and utility-weighted certainty equivalent risk premiums to determine the carbon credit values needed to motivate adoption of systems, which sequester higher levels of carbon. The results indicate that no-tillage and cattle manure increase carbon sequestration. Carbon credits or government program incentives are not required to entice risk-averse managers to use no-tillage, but are required to encourage manure use as a means of sequestering additional carbon even at historically high nitrogen prices. New environmental rules for confined animal feeding operations may increase the demand for land to apply manure as a primary nutrient source and participation in the Environmental Quality Incentives Program, Conservation Security Program, and a carbon credit market to obtain payments to offset some or all of the costs of manure application.
  • Authors:
    • Yang, C. H.
    • Han, S. M.
    • Zhu, R. X.
    • Xue, S. P.
    • Yang, Q.
  • Source: Transactions of the Chinese Society of Agricultural Engineering
  • Volume: 23
  • Issue: 1
  • Year: 2007
  • Summary: The objective of this study was to determine conservation tillage techniques suitable for semiarid regions in North China. Ten different mechanized patterns of no-till or reduced-tillage for two crops (winter wheat and summer maize) within one year were set up at the Experiment and Demonstration Site for Mechanized New Techniques and Machinery at Yangling, Shaanxi Province, China, and these conservation tillage patterns were compared with conventional tillage. Results showed that wheat yield increased by 53% and summer maize yield increased by 25%, average soil water storage increased from 1% to 1.2% at different depths, and average organic matter increased by 1.03 g/kg relatively for the conservation tillage system with wheat residue cover and no-till seeding of maize immediately after wheat harvest, compared with conventional bare soil ploughing. Moreover, the efficiency of yield increase and water storage for deep soil loosening was higher than that for deep ploughing. No-till seeding of maize on high stubble mulching was better than seeding on low stubble. Finally, cost-benefit analysis results showed that conservation tillage resulted in great economic returns than convention tillage due to greater yields and lower production costs resulting from reduced tillage.
  • Authors:
    • Emel'yanov, A. M.
  • Source: Kormoproizvodstvo
  • Issue: 3
  • Year: 2007
  • Summary: Increasing fodder crop productivity is a research priority due to the cattle raising type of agriculture practised in Buryatia. Productivity of oats in different crop rotation schemes in the dry steppe zone during 2001-05 is tabulated. The highest oat grain-haylage yield (11.3 t/ha) was achieved in the following scheme: naked fallow - wheat + oats - oat for grain-haylage. Usage of multispecies cropping system for increasing hay cutting yield is described. Melilotus, oil radish and spring rape are highly recommended for cultivation in single and mixed forage sowing. Fodder crops productivity and additional yield depending on sowing time and fertilization in 5-years period are summarised in 2 tables. Optimum sowing time for using June-August precipitation is the last ten-day period of June. Nutritional quality of oat and barley hay according to degree of their ripeness is discussed.
  • Authors:
    • Liebig, M. A.
    • Merrill, S. D.
    • Krupinsky, J. M.
    • Tanaka, D. L.
    • Hanson, J. D.
  • Source: Agronomy Journal
  • Volume: 99
  • Issue: 4
  • Year: 2007
  • Summary: Producers need to know how to sequence crops to develop sustainable dynamic cropping systems that take advantage of inherent internal resources, such as crop synergism, nutrient cycling, and soil water, and capitalize on external resources, such as weather, markets, and government programs. The objective of our research was to determine influences of previous crop and crop residues (crop sequence) on relative seed and residue yield and precipitation-use efficiency (PUE) for the no-till production of buckwheat ( Fagopyrum esculentum Moench), canola ( Brassica napus L.), chickpea ( Cicer arietinum L.), corn ( Zea mays L.), dry pea ( Pisum sativum L.), grain sorghum ( Sorghum bicolor L.), lentil ( Lens culinaris Medik.), proso millet ( Panicum miliaceum L.), sunflower ( Helianthus annus L.), and spring wheat ( Triticum aestivum L.) grown in the northern Great Plains. Relative seed yield in 2003 for eight of the 10 crops resulted in synergistic effects when the previous crop was dry pea or lentil, compared with each crop grown on its own residue. Buckwheat, corn, and sunflower residues were antagonistic to chickpea relative seed yield. In 2004, highest relative seed yield for eight of the 10 crops occurred when dry pea was the previous crop. Relative residue yield followed a pattern similar to relative seed yield. The PUE overall means fluctuated for seven of the 10 crops both years, but those of dry pea, sunflower, and spring wheat remained somewhat constant, suggesting these crops may have mechanisms for consistent PUE and were not as dependent on growing season precipitation distribution as the other seven crops. Sustainable cropping systems in the northern Great Plains will approach an optimal scheme of crop sequencing by taking advantage of synergisms and avoiding antagonisms that occur among crops and previous crop residues.
  • Authors:
    • Vigil, M. F.
    • Nielsen, D. C.
    • Mikha, M.
    • Benjamin, J. G.
    • Calderon, F.
    • Henry, W. B.
  • Source: Soil Science Society of America Journal
  • Volume: 71
  • Issue: 4
  • Year: 2007
  • Summary: No-till cropping systems in the semiarid West have the potential to improve soil physical properties by increasing cropping intensity and crop diversity. An investigation at Akron, Colorado, USA, compared soil conditions in winter wheat ( Triticum aestivum)-summer fallow (WF) plots with soil conditions in wheat-maize ( Zea mays)-fallow (WCF), wheat-maize-sunflower ( Helianthus annuus)-fallow (WCSF), wheat-maize-millet ( Panicum miliaceum) (WCM), and a perennial grass/legume mix. The study began in 1990. Bulk density, pore size distribution, and saturated hydraulic conductivity were measured 7, 11, and 15 years after inception. Bulk density in the grass plots decreased from 1.39 to 1.25 Mg m -3 in 15 years. Bulk density in the annually cropped plots decreased from 1.38 to 1.30 Mg m -3 during the same time period. The pore size distribution became more uniform among the cropped treatments 15 years after the start of the experiment. Saturated hydraulic conductivity increased in the grass plots from 27 to 98 mm h -1 in 15 years. Saturated hydraulic conductivity in the annually cropped plots increased from approximately 14 to approximately 35 mm h -1 during the same period. The results show that improving soil physical properties by cropping system alone may take many years. Perennial vegetation may be more effective than annually cropped systems at improving soil physical conditions because of less surface compaction from planting operations and the apparent ability of perennial root systems to create a more stable, continuous pore network.
  • Authors:
    • Kahlown, M. A.
    • Azam, M.
    • Kemper, W. D.
  • Source: Journal of Soil and Water Conservation
  • Volume: 61
  • Issue: 1
  • Year: 2006
  • Summary: Conventional management practices for the rice-wheat rotation in Pakistan's Punjab have failed to improve crop yield, increase water and fertilizer use efficiencies, and decrease production costs enough to meet an ever-increasing food demand. New technologies such as no-till, laser leveling, and bed and furrow irrigation are being rapidly adopted by the farming community, but without adequate scientific information. Therefore, those practices were evaluated on 71 farms within four representative sites. Land preparation/sowing costs, water savings, use of fertilizers, soil salinity, and crop yield were evaluated. Land preparation and sowing cost on no-till fields was significantly less than on tilled fields. Highest yields were obtained on laser-leveled fields, followed by no-till, bed and furrow fields. Water and nitrogen use efficiencies were much higher on fields with bed and furrow irrigation as compared to the conventional fields. Although the new technologies were economically feasible, we conclude that no-till was the best option for the farmers.
  • Authors:
    • Sharma, R. K.
    • Sharma, S. K.
    • Jain, P. M.
    • Laddha, K. C.
  • Source: Indian Journal of Dryland Agricultural Research and Development
  • Volume: 21
  • Issue: 2
  • Year: 2006
  • Summary: A field experiment was conducted in Bhilwara, Rajasthan, India, during 1998 to 2004 to study the effect of compost, green leaf manure (subabul ( Leucaena leucocephala) loppings) and chemical fertilizer alone or in combination with organic residues on yield of maize and black gram cultivated in rotation in two blocks as well as in strip and change in soil properties under dryland conditions. Results revealed that application of 15 kg N through compost with 10 kg N through chemical fertilizer (urea) gave the highest yield of maize and subsequent yield in black gram in blocks as well in strips. The treatments where compost and green leaf of subabul were applied for supply of nitrogen along with chemical fertilizers were found at par in a maize block system. Organic carbon and available phosphorus content of the soil increased by the continuous application of compost and fresh green leaf of subabul and there was an indication of lowering of pH as well as electrical conductivity. The bulk density of soil decreased under treatments where compost and green leaf of subabul were used. Maximum infiltration rate of soil was observed with the application of green leaf of subabul along with 10 or 20 kg N through inorganic fertilizer in both block and strip systems.
  • Authors:
    • Nielsen, D. C.
    • Vigil, M. F.
    • Benjamin, J. G.
  • Source: Agronomy Journal
  • Volume: 98
  • Issue: 4
  • Year: 2006
  • Summary: Forages, with greater water use efficiency (WUE) than grain and seed crops, could be used to diversify reduced and no-till dryland cropping systems from the traditional wheat ( Triticum aestivum L.)-fallow system in the semiarid central Great Plains. However, farmers need a simple tool to evaluate forage productivity under widely varying precipitation conditions. The objectives of this study were to (i) quantify the relationship between crop water use and dry matter (DM) yield for corn ( Zea mays L.), foxtail millet ( Setaria italica L. Beauv.), and winter triticale ( X Triticosecale Wittmack); and (ii) determine the range and distribution of expected DM yields for these three crops in the central Great Plains based on historical precipitation records. The three crops were grown in a dryland no-till corn-millet-triticale sequence from 1998 through 2004 at Akron, CO. Dry matter production was linearly correlated with water use for all three crops, with regression slopes ranging from 24.2 (corn) to 33.0 kg ha -1 mm -1 (millet). Water use efficiency varied widely from year to year (0-32.2 kg ha -1 mm -1) for the three crops, as influenced by growing season precipitation and time of year in which the crops were grown. Millet and triticale produced similar amounts of DM for a given water use, while corn produced less. Precipitation use efficiency for the millet-triticale-corn forage system was 8.7 kg ha -1 mm -1, suggesting this as an efficient forage system for the region.
  • Authors:
    • Paulitz, T. C.
  • Source: European Journal of Plant Pathology
  • Volume: 115
  • Issue: 3
  • Year: 2006
  • Summary: Direct-seeding or no-till is defined as planting directly into residue of the previous crop without tillage that mixes or stirs soil prior to planting. No-till reduces soil erosion, improves soil structure and organic matter, and reduces fuel inputs. No-till is widely used in cereal production in Australia, Canada, Argentina, and Brazil, but has not been widely adopted in Europe and the Pacific Northwest of the U.S. One of the limitations is that root diseases may increase with a reduction in tillage. This paper discusses the importance and management of take-all, Fusarium dryland foot rot, Rhizoctonia bare patch and root rot, and Pythium root rot in dryland cereal production systems, and how they are influenced by changes in tillage practices. To address this challenge, specifically with Rhizoctonia and Pythium, our research group has (1) developed classical and molecular techniques to detect and quantify Rhizoctonia and Pythium spp. from the soil to assess disease risk; (2) studied the disease dynamics of root disease during the transition from conventional to no-till; (3) developed greenhouse methods to screen germplasm for tolerance or resistance to Pythium and Rhizoctonia, and (4) using GPS and geostatistics, has examined the spatial distribution of R. solani and R. oryzae at a field scale up to 36 ha, across a number of crop rotations and years. By a combination of ecological, epidemiological, field, and laboratory studies, we hope to provide growers with a set of disease management tools to permit the economical and sustainable production of dryland cereals without degradation of the soil resource.