• Authors:
    • Lenssen, A. W.
    • Sainju, U. M.
    • Jabro, J. D.
    • Evans, R. G.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 18
  • Year: 2011
  • Summary: We evaluated the effect of no tillage (NT) and conventional tillage (CT) on soil penetration resistance (PR), bulk density (BD), gravimetric moisture content (MC), and saturated hydraulic conductivity (Ks) during the fallow phase of a spring wheat-fallow rotation. The study was conducted on two soils mapped as Williams loam at the Froid and Sidney sites. Soil measurements were made on 19 May, 23 June, and 4 August 2005 at the Froid site and on 6 June and 8 July 2005 at the Sidney site. Tillage had no effect on either soil properties except on the PR at Sidney. However, soil PR, MC, and BD varied significantly with depth regardless of tillage and location. Further, soil PR and MC varied with the date of sampling at both locations, and PR generally increased with decreased MC at all soil depths. Soil Ks was slightly influenced by tillage at both locations.
  • Authors:
    • Esker, P. D.
    • Jirak-Peterson, J. C.
  • Source: Plant Disease
  • Volume: 95
  • Issue: 5
  • Year: 2011
  • Summary: Corn anthracnose (Colletotrichum graminicola) is an important disease of field coni (Zea mays). Two phases, leaf blight and stalk rot, can reduce yield through either premature leaf senescence or reduced grain harvest due to stalk lodging. Corn residue is an important source of primary inoculum and is increased through cultural practices such as no-tillage and continuous corn cropping, which are common practices in Wisconsin. Field studies conducted at the Arlington Agricultural Research Station (ARS) and the West Madison ARS showed that the incidence and severity of anthracnose leaf blight were higher in continuous-corn crop rotations than in soybean corn rotations (91% higher incidence, 24 to 78% higher severity). Anthracnose stalk rot was marginally affected by tillage in 2008 (P = 0.09), with higher incidence in chisel-plowed treatments. There was a positive association between spring residue cover and anthracnose leaf blight but no association was found between residue and stalk rot. No association was found between anthracnose leaf blight and stalk rot. There was a negative association between anthracnose leaf blight and yield but not between anthracnose stalk rot and yield. Managing residue levels through crop rotation would help to reduce anthracnose leaf blight but further work is needed to elucidate factors that lead to stalk lodging prior to harvest.
  • Authors:
    • Sarauskis, E.
    • Karayel, D.
  • Source: Žemės Ūkio Inžinerija, Mokslo Darbai
  • Volume: 43
  • Issue: 3
  • Year: 2011
  • Summary: Seed placement uniformity and failure to establish a uniform plant stand are critical problems associated with no-tillage production of maize ( Zea mays L.) following wheat ( Triticum aestivum). The objective of this research was to evaluate the effect of different downforces (680, 880, 1150 and 1400 N) on performance of disc furrow openers and determine the optimum downforce for modified precision seeder equipped with single or double disc-type openers. The study was conducted in two different field conditions (field I and field II). The soil of field I and II were clay-loam and loamy, respectively. Seed spacing uniformity, sowing depth uniformity, mean emergence time and percentage of emergence were determined. Sowing depth and seed spacing uniformity, mean emergence time and percentage of emergence of both furrow openers were increased as a result of increasing downforce for both fields. The downforce of modified conventional precision seeder should be greater than 880 N for more precise no-till sowing using with single and double disc furrow openers for clay-loam and loamy soils.
  • Authors:
    • Hernandez, R. M.
    • Bravo, C.
    • Rivero, C.
    • Lozano P.,Z.
  • Source: REVISTA DE LA FACULTAD DE AGRONOMIA DE LA UNIVERSIDAD DEL ZULIA
  • Volume: 28
  • Issue: 1
  • Year: 2011
  • Summary: Some researchers suggest the use of different SOM organic matter (SOM) fractions or compartiments like indicators of the agricultural systems sustainability. In order to evaluate the amount, composition and distribution in the profile of different SOM fractions from the soil on conservation agriculture systems, evaluations in an Ustoxic Quartzipsament soil located at Venezuelan savannahs, were carried out. Three cover crop treatments were evaluated, as improved land fallows for the establishing of maize no-tillage system and grazing with ovine cattle: Brachiaria dictyoneura (BD), Centrosema macrocarpum (CM), and spontaneous vegetation (SV), and its comparison with the natural savannah ecosystem (NS). Samples to three depths (0-5, 5-15 and 15-30 cm), and were taken at three times: initial, 286 days after the establishment (dae), and 1463 dae. At all depths and to 1463 dae were evaluated: total organic carbon (TOC), hidrosoluble carbon (HSC), and particulate organic matter carbon (POMC). At all times and in the the 0 to 5 cm layer physical and chemical fractions of the SOM, were evaluated. The results show statistical differences between cover crops types in some SOM fractions, mainly in the light fractions (HSC, and fulvic acid carbon), with the greater values in BD and the minors in SV. The cover crops introduction produced the diminution in some fractions; but after three continuous cycles under the proposed management, these fractions reached similar values or superior to those initials. The humification indexes, and the relations between the different fractions and the TOC, were the most sensible indicators.
  • Authors:
    • Ralish, R.
    • de Lima, G. P.
    • Rosa, D. M.
    • Pereira Nóbrega, L. H.
    • Mauli, M. M.
  • Source: Brazilian Archives of Biology and Technology
  • Volume: 54
  • Issue: 4
  • Year: 2011
  • Summary: This study analyzed possible interferences associated to the amount of crop residues produced by the black oats and the consortium of black oats, common vetch and forage turnip on weeds incidence and soil seed bank. It was a field trial with seven treatments and five replications. The cover crop was sown at throwing, cut at 100 days and residues were put on each respective plot, using a proportion of normal amount of produced straw, either its half and double. The heaviest weights were obtained from cover crop consortium and their application decreased weeds incidence in such area. The seeds bank and other analyzed parameters did not show statistical differences. According to these results, it was concluded that winter cover crop could be used in crops rotation with soybean.
  • Authors:
    • Risaliti, R.
    • Antichi, D.
    • Barberi, P.
    • Sapkota, T. B.
    • Mazzoncini, M.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 2
  • Year: 2011
  • Summary: No-tillage, N fertilization and cover crops are known to play an important role in conserving or increasing SOC and STN but the effects of their interactions are less known. In order to evaluate the single and combined effects of these techniques on SOC and STN content under Mediterranean climate, a long term experiment started in 1993 on a loam soil (Typic Xerofluvent) in Central Italy. The experimental variants are: conventional tillage (CT) and no-tillage (NT), four N fertilization rates (N0, N1, N2 and N3) and four soil cover crop (CC) types (C - no cover crop; NL - non-legume CC; LNL - low nitrogen supply legume CC, and HNL - high nitrogen supply legume CC). The nitrogen fertilization rates (N0, N1, N2 and N3) were: 0, 100, 200, 300 kg N ha(-1) for maize (Zea mays, L); 0, 60, 120,180 kg N a(-1) for durum wheat (Triticum durum Desf.); 0, 50, 100, 150 kg N ha(-1) for sunflower (Helianthus annuus L.). From 1993 to 2008, under the NT system the SOC and STN content in the top 30 cm soil depth increased by 0.61 and 0.04 Mg ha(-1) year(-1) respectively. In the same period, the SOC and STN content under the CT system decreased by a rate of 0.06 and 0.04 Mg ha(-1) year(-1) respectively. During the experimental period, N1, N2 and N3 increased the SOC content in the 0-30 cm soil layer at a rate of 0.14, 0.45 and 0.49 Mg ha(-1) year(-1). Only the higher N fertilization levels (N2 and N3) increased STN content, at a rate of 0.03 and 0.05 Mg ha(-1) year(-1). NL, LNL and HNL cover crops increased SOC content by 0.17, 0.41 and 0.43 Mg C ha(-1) year(-1) and -0.01, +0.01 and +0.02 Mg N ha(-1) year(-1). Significant interactions among treatments were evident only in the case of the N fertilization by tillage system interaction on SOC and STN concentration in the 0-10 cm soil depth in 2008. The observed SOC and STN variations were correlated to C returned to the soil as crop residues, aboveground cover crop biomass and weeds (C input). We conclude that, under our Mediterranean climate, it is easier to conserve or increase SOC and STN by adopting NT than CT. To reach this objective, the CT system requires higher N fertilization rates and introduction of highly productive cover crops. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Moreno, F.
    • Muñoz-Romero, V.
    • López-Bellido, L.
    • López-Bellido, R. J.
    • Melero,S.
    • Murillo, J. M.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 2
  • Year: 2011
  • Summary: Studies of the impacts of the interactions of soil agricultural practices on soil quality could assist with assessment of better management to establish sustainable crop production system. The main objective was to determine the long-term effects of tillage system, crop rotation and N fertilisation on soil total N and organic C (SOC), labile fractions of organic matter (water soluble carbon, WSC, and active carbon, AC), nitrate content, and soil enzymatic activities (dehydrogenase (DHA), beta-glucosidase (Glu) and alkaline phosphatase (AP)) at four different soil depths (0-5, 5-10, 10-30 and 30-50 cm), in a Mediterranean dryland Vertisol in SW Spain. Tillage systems were conventional tillage (CT) and no tillage (NT). Crop rotations were wheat-sunflower (WS), wheat-chickpea (WC), wheat-faba bean (WFb), wheat-fallow (WF) and continuous wheat (WW). Nitrogen fertiliser rates were 0, 50 and 150 kg N ha(-1). The different crop rotation systems had a great influence in soil C and N fractions and enzymatic activities. In general, the SOC. total N. WSC, and beta-glucosidase contents were higher in the no tillage system than in conventional tillage system in the wheat-wheat and in the wheat-faba bean rotations at upper layer (0-5 cm), while the lowest ones were obtained in the wheat-fallow rotation in both tillage systems. Carbon and N fractions, calculated by volumetric soil, showed an increase with depth in both tillage systems and in all crop rotations, which could be related to the increase of soil bulk density and soil mass with depth. The highest N fertiliser rate increased most of soil variables, especially nitrate content at deeper layers, thereby precautions should be taken with long-term N fertilisation to avoid leaching of nitrates below the tillage layer. With the exception of wheat-fallow rotation, slightly greater grain and above-ground biomass yields were obtained for wheat in NT, especially at 150 kg N ha(-1). Combination of NT with any biannual rotation except fallow could be an adequate sustainable management in order to improve soil quality of Vertisols, under our conditions. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Canaday, C. H.
    • Little, C. R.
    • Chen, P.
    • Rupe, . B.
    • Wrather, A. J.
    • Shannon, G. J.
    • Bond, J. P.
    • Arelli, P. A.
    • Mengistu, A.
    • Newman, M. A.
    • Pantalone, V. R.
  • Source: Plant Health Progress
  • Issue: September
  • Year: 2011
  • Summary: Charcoal rot, caused by Macrophomina phaseolina, significantly reduces yield in soybean more than most other diseases in the midsouthern United States. There are no commercial genotypes marketed as resistant to charcoal rot. Reactions of 27 maturity group (MG) III, 29 Early MG IV, 34 Late MG IV, and 59 MG V genotypes were evaluated for M. phaseolina between 2006 and 2008 in a non-irrigated, no-till field that had been artificially infested for three years. There was significant variation in root colonization among genotypes and years, indicating the value of screening genotypes over multiple years. Based on CFUI there was no genotype that was consistently immune to charcoal rot each year. However, there were a total of six genotypes (one genotype in MG III, one in Late MG IV, and four in MG V) that were identified as moderately resistant. Some of the commercial and public genotypes were resistant to M. phaseolina at levels equal to or greater than the standard DT97-4290, a moderately resistant cultivar. The genotypes identified as having moderate resistance across the three years could be useful as sources for developing resistant soybean genotypes.
  • Authors:
    • Nichols, K. A.
    • Toro, M.
  • Source: Soil & Tillage Research
  • Volume: 111
  • Issue: 2
  • Year: 2011
  • Summary: Soil aggregate stability is a frequently used indicator of soil quality, but there is no standard methodology for assessing this indicator. Current methods generally measure only a portion of the soil or use either dry-sieved or wet-sieved aggregates. Our objective was to develop a whole soil stability index (WSSI) by combining data from dry aggregate size distribution and water-stable aggregation along with a 'quality' constant for each aggregate size class. The quality constant was based on the impact of aggregate size on soil quality indicators. Soil quality indicators can be loosely defined as those soil properties and processes that have the greatest sensitivity to changes in soil function. The WSSI was hypothesized to have a better relationship to the impacts of aboveground management than other soil aggregation indices such as a mean weight diameter (MWD), geometric mean diameter (GIVID), and the normalized stability index (NSI). Soil samples used in this study were collected from sites established on the same or similar soil types at the Northern Great Plains Research Laboratory in Mandan, ND. By utilizing dry aggregate size distribution, water-stable aggregation, and the quality constant, the WSSI detected differences in soil quality due to management (such as amount of disturbance, plant cover, and crop rotation) with the highest values occurring for the undisturbed, native range and the lowest values for conventional tillage, fallow treatments. The WSSI had the best relationship with management and is recommended as a standard measurement for soil aggregation. Published by Elsevier B.V.
  • Authors:
    • Nonnecke, G. R.
    • Portz, D. N.
  • Source: HortScience
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: Yield of strawberry grown continuously on the same site often declines over time as a result of proliferation of weed seeds and pathogenic organisms in the soil. Plots were established and maintained in seven different cover crops and as continuous strawberry or continuous tillage for 10 years (1996 to 2005) in a site that was previously in strawberry production for 10 years (1986 to 1995). Cover crops included blackeyed Susan (Rudbeckia hirta L.), sorghum Sudangrass [Sorghum bicolor (L.) Moench], marigold (Tagetes credo L.), big bluestem (Andropogon gerardii Vitman), perennial ryegrass (Lolium permute L.), switchgrass (Panicum virgatum L.), and Indiangrass [Sorghastrum nutans (L.) Nash]. Treatments were ended in 2005 and plots were planted with 'Honeoye' strawberry in a matted row. Effectiveness of soil pretreatments in reducing weed populations and enhancing strawberry production was evaluated for four growing seasons by quantifying weed growth by type and biomass and strawberry plant density and yield. The results indicate that matted-row strawberry production plots that were either in continuous tillage or established in S. bicolor, P. virgatum, or A. gerardii before planting strawberry had lower weed biomass and greater strawberry plant establishment and yield than plots established in L. permute or R. hirta or that had supported continuous strawberry production.