• Authors:
    • Reddy, K. N.
    • Zablotowicz, R. M.
    • Locke, M. A.
  • Source: Pest Management Science
  • Volume: 64
  • Issue: 4
  • Year: 2008
  • Summary: BACKGROUND: Conservation practices often associated with glyphosate-resistant crops, e.g. limited tillage and crop cover, improve soil conditions, but only limited research has evaluated their effects on soil in combination with glyphosate-resistant crops. It is assumed that conservation practices have similar benefits to soil whether or not glyphosate-resistant crops are used. This paper reviews the impact on soil of conservation practices and glyphosate-resistant crops, and presents data from a Mississippi field trial comparing glyphosate-resistant and non-glyphosate-resistant maize (Zea mays L.) and cotton (Gossypium hirsutum L.) under limited tillage management. RESULTS: Results from the reduced-tillage study indicate differences in soil biological and chemical properties owing to glyphosate-resistant crops. Under continuous glyphosate-resistant maize, soils maintained greater soil organic carbon and nitrogen as compared with continuous non-glyphosate-resistant maize, but no differences were measured in continuous cotton or in cotton rotated with maize. Soil microbial community structure based on total fatty acid methyl ester analysis indicated a significant effect of glyphosate-resistant crop following 5 years of continuous glyphosate-resistant crop as compared with the non-glyphosate-resistant crop system. Results from this study, as well as the literature review, indicate differences attributable to the interaction of conservation practices and glyphosate-resistant crop, but many are transient and benign for the soil ecosystem. CONCLUSIONS: Glyphosate use may result in minor effects on soil biological/chemical properties. However, enhanced organic carbon and plant residues in surface soils under conservation practices may buffer potential effects of glyphosate. Long-term field research established under various cropping systems and ecological regions is needed for critical assessment of glyphosate-resistant crop and conservation practice interactions. Published in 2008 by John Wiley & Sons, Ltd.
  • Authors:
    • Kessel, B.
    • Korzun, V.
    • Ebmeyer, E.
    • Schweizer, P.
    • Risser, P.
    • Loffler, M.
    • Miedaner, T.
    • Ouzunova, M.
  • Source: Abwehrstrategien gegen biotische Schaderreger Züchtung von Hackfrüchten und Sonderkulturen. Tagungsband der 59. Jahrestagung der Vereinigung der Pflanzenzüchter und Saatgutkaufleute Österreichs, 25.-27. November 2008, Raumberg-Gumpenstein, Austria
  • Year: 2008
  • Summary: Wheat and maize are the most important and profitable crops in Europe. They are grown with high proportions in crop rotations, often in no-till systems to reduce production costs and soil erosion. This practice favours infections by Fusarium head blight (FHB, Fusarium graminearum) and Septoria leaf blotch (STB, Septoria tritici) in wheat, and Fusarium ear rot (FER, F. graminearum, F. verticillioides) in maize. For comprehensively understanding these three pathosystems the diversity within host and pathogen populations and their interaction should be analysed as well as the responsible genome regions by QTL mapping, and candidate genes by expression profiling should be searched. An ultimate goal is to reveal broad-spectrum resistance QTL and common gene expression data for resistance to FHB and STB in wheat and FER in maize by meta-analysis. QTL with the highest effects can directly be applied in practical breeding programs and are the starting point for further functional genome analysis.
  • Authors:
    • Balkcom, K. S.
    • Delaney, D. P.
    • Mitchell, C. C.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 5
  • Year: 2008
  • Summary: After more than 110 yr, the Old Rotation experiment on the campus of Auburn University in Alabama continues to document the long-term effects of crop rotation and winter legume cover crops on sustainable cotton (Gossypium hirsutum L.) production in the southeastern United States. Long-term yields indicate that winter legumes are as effective as fertilizer N in producing maximum cotton yields and increasing soil organic carbon (SOC). Higher SOC resulted in higher crop yields. However, rotating cotton with corn (Zea mays L.) in a 2-yr rotation or with corn, winter wheat (Triticum aestivum L.), and soybean [Glycine max. (L.) Merr.] in a 3-yr rotation produced little long-term cotton yield advantage beyond that associated with SOC. Cotton yields without winter legumes nor fertilizer N are only slightly higher than they were 110 yr ago. Nonirrigated corn grain yields in rotation with cotton are typically low for central Alabama and appear limited by N. Yields of all crops on the Old Rotation increased with increasing rates of P and K through the 1950s. Since adoption of in-row subsoiling, high-residue, conservation tillage, and genetically modified cultivars; in 1997, all crops have produced their highest, nonirrigated, recorded yields since the experiment began: 1910 kg cotton lint ha(-1) in 2006, 14.8 Mg corn grain ha(-1) in 1999, 6.34 Mg wheat ha-1 in 2001, and 4.50 Mg soybean ha(-1) in 2004.
  • Authors:
    • Humburg, D. S.
    • Schumacher, T. E.
    • Osborne, S. L.
  • Source: Agricultural Journal
  • Volume: 3
  • Issue: 5
  • Year: 2008
  • Summary: Although no-till soil management has many benefits, including protecting the soil from erosion, improving soil organic matter and improving soil moisture storage, depending on environmental conditions there could be a number of potential problems. Implementation of no-till soil management in eastern South Dakota can lead to wet and cold soils at the time of planting. Cover crops have the potential to utilize excess soil moisture and improve soil conditions at planting. A field experiment was established to evaluate the impact of 14 different cover crop species as well as no cover crop and conventional tillage on soil conditions prior to corn planting and the impact on corn yield and quality. The experimental design was a randomized complete block design with 4 replications. Cover crops evaluated include a mixture of grass, legumes, cool and warm season crops. All cover crops were planted in early August (following spring wheat harvest) at recommended seeding rates. The following spring all plots were planted to corn ( Zea mays L.). The experiment was conducted in a 3 year crop rotation (soybean [ Glycine max (L.) Merrill]/spring wheat ( Triticum aestivum L.)-cover crop/corn). Cover crop species that survived the winter included hairy vetch, red clover, sweet clover, Alsike clover, slender wheatgrass and winter ryegrass. The presence of these species increased soil strength and reduced soil moisture. Corn grown following hairy vetch was the only treatment that exhibited a significant reduction in plant population. Corn yield for plots grown under red clover, winter ryegrass and no cover crop had yield significantly higher than corn grown after conventional tillage, hairy vetch and slender wheatgrass. This experiment illustrated the ability of cover crops to utilize excess soil moisture and increase soil strength compared to conventional tillage or no cover crop.
  • Authors:
    • Miller, P. S.
    • Karthikeyan, K. G.
    • Panuska, J. C.
  • Source: Geoderma
  • Volume: 145
  • Issue: 3-4
  • Year: 2008
  • Summary: The impact of field surface conditions and erosion processes on runoff volume, soil loss and sediment particle size during the rainfall runoff period was investigated. Results are reported for multiple events and from within individual events (intra-event) for sites with different corn (Zea mays L.) management systems (i.e., grain (CG), silage (CS), and silage-manure (CSM)). The multi-event bulk runoff volume and soil loss for CG were less than that for CS and CSM due to higher residue levels increasing surface roughness, ponding and infiltration. The aggregate stability for CG treatment was greater than that for CS and CSM and aggregate size peaks were identified at 5.4, 32,160 and 570 pm. Size peaks at 32 and 570 pm had the highest combined frequency (64%). Intra-event continuous monitoring covered silage plots with crop-rows oriented up-and-down the slope (CS) and along the contour (CScont). The crop-row orientation significantly influenced both runoff and sediment loss (concentration, load, size-distribution) patterns. The runoff volume and sediment concentration for CS was twice that of CScont. While no treatment difference attributable to residue coverage was evident for particle-size dynamics, crop-row orientation had a significant effect with finer-sized particles exported from the contoured site. Surface sealing, more pronounced at the silage sites, occurred after the 1st major storm in a season for all monitoring periods, types, and treatments, and it significantly influenced runoff generation, sediment load, and size distribution characteristics. Under crusted conditions, a storm with slightly higher rainfall depth but significant lower erosive potential, generated 53% more runoff and twice as much sediment compared to an early-season event. During crust development finer particles dominated sediment composition, later shifting to larger particles due to rill erosion once a stable crust was established. These results are expected to improve our understanding and, hence, predictive capability for transport of particulate-bound contaminants from row-crop systems, especially under conditions promoting surface crust formation. (c) 2008 Elsevier B.V. All rights reserved.
  • Authors:
    • Pedersen, J. B.
  • Source: Oversigt over Landsfors<o>gene. Fors<o>g og unders<o>gelser i de land<o>konomiske foreninger, 2008
  • Year: 2008
  • Summary: Following a general account of the weather, land use, application of fertilizers and pest and disease control products, and an overview of the crops grown and their yields, most of the review is devoted to reports on individual crops. These were winter barley, winter rye, triticale, winter wheat, spring barley, oats, spring wheat, peas, grasses, spinach, rape, potatoes, sugarbeet and maize. Other sections cover alternative crops (for bioenergy production), manuring and fertilizers, cultural methods, organic methods, advisory work on plant breeding, tables of approved species and varieties of crop plants, lists of relevant organizations, a list of authors of the sections, and a comprehensive subject index.
  • Authors:
    • Chikte, P.
    • Bhalkare, S. K.
    • Thakare, S. M.
    • Lande, G. K.
  • Source: Journal Of Cotton Research And Development
  • Volume: 22
  • Issue: 2
  • Year: 2008
  • Summary: The experiment was conducted during the kharif season of 2004-05 at Dr. PDKV, Akola to evaluate the effect of different possible intercrops on bollworm complex on cotton crop. The intercrops viz., cotton+greengram, cotton+blackgram, cotton+cowpea, cotton+sorghum, cotton+maize, cotton+marigold, cotton+soybean in 1:1 ratio alongwith a treatment of sole cotton crop were sown. The intercrop cotton+cowpea proved to be the best recording least population of spotted bollworm, American bollworm and pink bollworm as against the treatment of sole cotton crop. The highest seed cotton yield of 251 kg/ha was recorded in cotton+cowpea-intercropping system as against 160 kg/ha recorded in the sole cotton crop.
  • Authors:
    • Reddy, K. C.
    • Tazisong, I. A.
    • Nyakatawa, E. Z.
    • Senwo, Z. N.
    • Sainju, U. M.
  • Source: Journal of Environmental Quality
  • Volume: 37
  • Issue: 3
  • Year: 2008
  • Summary: Quantification of soil carbon (C) cycling as influenced by management practices is needed for C sequestration and soil quality improvement. We evaluated the 10-yr effects of tillage, cropping system, and N source on crop residue and soil C fractions at 0-to 20-cm depth in Decatur silt loam (clayey, kaolinitic, thermic, Typic Paleudults) in northern Alabama, USA. Treatments were incomplete factorial combinations of three tillage practices (no-till [NT], mulch till [MT], and conventional till [CT]), two cropping systems (cotton [Gossypium hirsutum L.]-cotton-corn [Zea mays L.] and rye [Secale cereale L.]/cotton-rye/cotton-corn), and two N fertilization sources and rates (0 and 100 kg N ha(-1) from NH4NO3 and 100 and 200 kg N ha(-1) from poultry litter). Carbon fractions weresoil organic C (SOC), particulate organic C (POC), microbial biomass C (MBC), and potential C mineralization (PCM). Crop residue varied among treatments and years and total residue from 1997 to 2005 was greater in rye/cottoil-rye/cotton-corn than in cotton-cotton-corn and greater with NH4NO3 than with poultry litter at 100 kg N ha(-1). The SOC content at 0 to 20 cm, after 10 yr was greater with poultry litter than with NH4NO3 in NT and CT, resulting in a C sequestration rate of 510 kg C ha(-1) yr(-1) with poultry litter compared with -120 to 147 kg C ha(-1) yr(-1) with NH4NO3. Poultry litter also increased PCM and MBC compared with NH4NO3. Cropping increased SOC, POC, and PCM compared with fallow in NT Long-term poultry litter application or continuous cropping increased soil C storage and microbial biomass and activity compared with inorganic N fertilization or fallow, indicating that these management practices can sequester C, offset atmospheric CO2 levels, and improve soil and environmental quality.
  • Authors:
    • Schlindwein, J. A.
    • Gianello, C.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 32
  • Issue: 5
  • Year: 2008
  • Summary: The change of cultivation systems from conventional to no-tillage, the change in soil sampling depth and the higher crop yields over time can influence the critical P content, fertility ranges and fertilizer doses recommended for crops. This study calibrated the soil P tests, Mehlich-1, Mehlich-3 and anion-exchange (AER) resin for soyabean, wheat and maize plants cultivated under no-tillage system, and to estimate the P fertilizer amounts for a maximum economic yield. Soil samples and yield results from several experiments under no-till and different P doses, conducted by institutions of education, research and extension of the state of Rio Grande do Sul, Brazil, were used. The calibration curves were fitted using non-linear model functions, and the levels of soil fertility and fertilizer doses for a maximum economic yield were inferred. Results indicated that the average increases in maize, wheat and soyabean yields were 47.1, 12.4 and 7.2 kg/ha per kg of P 2O 5, respectively; the determination coefficients between the relative yield and soil P concentrations were higher when the soils were separated by texture classes and were highest in the 0-10 cm than the 0-20 cm layer; the critical values of P, based on Mehlich-1 were 7.5, 15.0 and 21.0 mg/kg in the 0-20 cm layer, and of 16.0, 28.0 and 40.0 mg/kg in the 0-10 cm layer in the clay classes 1, 2 and 3, respectively. Phosphorus fertility ranges were wider by Mehlich-3 and AER as compared to Mehlich-1. The quantities of P fertilizer were higher for soyabean and maize when compared to the currently recommended quantities. The critical P concentrations are higher in soils under no-tillage with soyabean, wheat and maize in the 0-20 as well as the 0-10 cm layer. The fertility ranges by resin and Mehlich-3 were wider than by Mehlich-1. The fertilizer P quantities are higher for soyabean and maize grown under no-tillage.
  • 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.