• Authors:
    • Kremer, R. J.
    • Sudduth, K. A.
    • Kitchen, N. R.
    • Jung, W. K.
  • Source: Soil Science and Plant Nutrition
  • Volume: 54
  • Issue: 6
  • Year: 2008
  • Summary: Crop management has the potential to either enhance or degrade soil quality, which in turn impacts on crop production and the environment. Few studies have investigated how crop management affects soil quality over different landscape positions. The objective of the present study was to investigate how 12 years of annual cropping system (ACS) and conservation reserve program (CRP) practices impacted soil quality indicators at summit, backslope and footslope landscape positions of a claypan soil in north-central Missouri. Claypan soils are particularly poorly drained because of a restrictive high-clay subsoil layer and are vulnerable to high water erosion. Three replicates of four management systems were established in 1991 in a randomized complete block design, with landscape position as a split-block treatment. The management systems were investigated: (1) annual cropping system 1 (ACS1) was a mulch tillage (typically >= 30% of soil covered with residue after tillage operations) corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation system, (2) annual cropping system 2 (ACS2) was a no-till corn-soybean rotation system, (3) annual cropping system 3 (ACS3) was a no-till corn-soybean-wheat (Triticum aestivum L.) rotation system, with a cover crop following wheat, (4) CRP was a continuous cool-season grass and legume system. In 2002, soil cores (at depths of 0-7.5, 7.5-15 and 15-30 cm) were collected by landscape position and analyzed for physical, chemical and biological soil quality properties. No interactions were observed between landscape and crop management. Relative to management effects, soil organic carbon (SOC) significantly increased with 12 years of CRP management, but not with the other management systems. At the 0-7.5-cm soil depth in the CRP system, SOC increased over this period by 33% and soil total nitrogen storage increased by 34%. Soil aggregate stability was approximately 40% higher in the no-till management systems (ACS2 and ACS3) than in the tilled system (ACS1). Soil aggregation under CRP management was more than double that of the three grain-cropping systems. Soil bulk density at the shallow sampling depth was greater in ACS3 than in ACS1 and ACS2. In contrast to studies on other soil types, these results indicate only minor changes to claypan soil quality after 12 years of no-till management. The landscape had minor effects on the soil properties. Of note, SOC was significantly lower in the 7.5-15-cm soil depth at the footslope compared with the other landscape positions. We attribute this to wetter and more humid conditions at this position and extended periods of high microbial activity and SOC mineralization. We conclude that claypan soils degraded by historical cropping practices will benefit most from the adoption of CRP or CRP-like management.
  • Authors:
    • Fletcher, P. S.
    • Kennedy, A. C.
    • Pannkuk, C. D.
    • McCool, D. K.
  • Source: Soil & Tillage Research
  • Volume: 101
  • Issue: 1-2
  • Year: 2008
  • Summary: Burn/low-till management of winter wheat (Triticum aestivum) is being practiced by some growers in the higher rainfall areas of the Pacific Northwestern Winter Wheat Region of the US. Residue burning eliminates the numerous seedbed tillage operations that are normally required to reduce residues and control weeds and diseases in continuous winter wheat production. The detrimental effects of burn and till systems on soil erosion are well documented. However, there is little or no data on the effects of burning with no-till or low-till annual cropping on either erosion or soil quality. A 3-year field study comparing winter season erosion resulting from burn/low-till (BLT) seeded winter wheat following winter wheat and conventionally managed (CM) winter wheat following various crops was completed in 1997. Results indicate soil loss from the BLT fields was not significantly different from that of the CM fields with various crops preceding winter wheat. For the BLT fields, soil loss was as closely related to soil disturbance (number of tillage operations) as to the amount of surface residue. When residue and crop cover did not differ with the number of tillage operations, an increased number of tillage operations after burning loosened the soil and resulted in greater soil loss. No adverse effects on soil loss or soil quality from using the BLT with one or two-pass seeding of winter wheat following winter wheat were found in this study. The results have implications for harvesting wheat stubble as a source of biomass, or as an alternative technique for initiating conversion from a conventional tillage to a no-till seeding system, without high initial investment in new seeding equipment.
  • 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:
    • 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:
    • 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.
  • Authors:
    • Zhu, D. W.
    • Jin, Z. Q.
  • Source: Acta Agronomica Sinica
  • Volume: 34
  • Issue: 9
  • Year: 2008
  • Summary: Nine scenarios of climatic change and climatic variability were generated in 19 sites in 3 agroecological zones in northeast China using the WGEN as a tool and based on the output of three general circulation models (GISS, GFDL, and UKMO GCMs), the local current daily weather data from 1961 to 2000 at each site, as well as on the three hypotheses on the increase in climatic variability in future. Four crop models (SOYGRO, CERES-Maize, CERES-Wheat, and CERES-Rice) were selected as the effect models and their parameter modification, validation and sensitivity analyses were carried out using the baseline weather, statistical yield data of the 4 crops and the local typical soil data. Finally, the potential impacts of changes in both climate and its variability on the food production in this regions with a doubling of CO 2 concentration doubled were assessed by running the effect models under both baseline and various (climatic change+climatic change variability) scenarios, and by comparing the outputs simulated. The results showed that the four effect models were available in the studied regions and can be used as a tool in climate impact study. Climate change would be favorable for soyabean and rice production in the region, especially in the northern cold zone and eastern wet zone, but unfavorable for both maize and spring wheat, where the simulated yields particularly maize yield, were significantly reduced under all the scenarios. With increasing of climatic variability, not only the yields were reduced compared with the control, but also the yield stabilities also decreased for the rainfed crops, such as soyabean, maize and spring wheat. However, there was no influence for the irrigated rice.
  • Authors:
    • Egli, D. B.
  • Source: Field Crops Research
  • Volume: 106
  • Issue: 1
  • Year: 2008
  • Summary: The increases in crop yield that played an important role in maintaining adequate food supplies in the past may not continue in the future. Soybean ( Glycine max L. Merrill) county yield trends (1972-2003) were examined for evidence of plateaus using data (National Agricultural Statistics Service) for 162 counties (215 data sets) in six production systems [Iowa, Nebraska (irrigated and non-irrigated), Kentucky and Arkansas (irrigated and non-irrigated)] representing a range in yield potential. Average yield (1999-2003) was highest in irrigated production in Nebraska (3403 kg ha -1) and lowest in non-irrigated areas in Arkansas (1482 kg ha -1). Average yield in the highest yielding county in each system was 31-88% higher than the lowest. Linear regression of yield versus time was significant ( P=0.05) in 169 data sets and a linear-plateau model reached convergence (with the intersection point in the mid-1990s) in 35 of these data sets, but it was significantly ( P=0.10) better in only three data sets (
  • 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:
    • Barbottin, A.
    • Colbach, N.
    • Gruber, S.
    • Pekrun, C.
  • Source: CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources
  • Volume: 3
  • Issue: 015
  • Year: 2008
  • Summary: Data about gene escape by seeds and volunteers were compiled for the first time in one study for several crops, i.e. wheat ( Triticum aestivum), sugar beet ( Beta vulgaris), oilseed rape/canola ( Brassica napus) and maize ( Zea mays). These species represent important genetically modified (GM) crops with herbicide tolerance (HT) or insect resistance (Bt), show different levels of autogamy and allogamy and are grown in different climatic zones of the world. Post-harvest measures and strategies were identified for minimizing gene escape from these crops. All species were found to cause problems in terms of gene escape by seed and volunteers though there are important differences between species and climatic zones. Post-harvest tillage was identified as a key factor for reducing the soil seed bank and volunteers. Timing and intensity of tillage has to be specifically adapted to the dormancy characteristics of each species. Furthermore, there is a close interaction between gene escape and the cropping system. Rotations should avoid the same crop or other critical crops in temporal vicinity to the GM crop in order to keep volunteer populations below a critical density. In no-till systems with use of HT varieties, HT volunteers can reduce the efficiency of the whole system if additional herbicides have to be applied. Seed impurities and admixtures during seed production are another major source of gene escape. Since seed lots of certified growers present less adventitious presence of other varieties, these should be preferred to farm-saved seeds. Education of farmers, cleaning of equipment, control measures and separate production and supply chains are additionally important to minimize gene escape.