• Authors:
    • Hoyt, G. D.
    • Walgenbach, J. F.
    • Hummel, R. L.
    • Kennedy, G. G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 93
  • Issue: 1-3
  • Year: 2002
  • Summary: Populations of foliar insect pests and natural enemies were monitored in vegetable production systems incorporating varying degrees of sustainable practices in Fletcher, NC, USA. Two types of tillage (conventional plow and disk, strip-tillage), two input approaches (chemically-based, biologically-based) and two cropping schedules (continuous tomato (Lycopersicon esculentum Mill.), 3-year rotation of corn (Zea mays L.), cucumber (Cucumis sativus L.) and tomato) were employed from 1995 to 1998. Tomato pest pressure was relatively low in all years, resulting in a limited impact of production systems on potato aphid, Macrosiphum euphorbiae (Thomas) (Homoptera: Aphididae), and its associated parasitoids and predators. Thrips (Frankliniella spp. (Thysanoptera)) populations were significantly higher in the biological input treatments in 3 of 4 years. Lepidopterous (primarily Helicoverpa zea Boddie (Lepidoptera: Noctuidae)) damage on tomato was significantly higher in biological treatments in all years, damage by thrips and pentatomids (Hemiptera: Pentatomidae) increasing each year in the continuous tomato crop schedule. Most insect populations were significantly influenced by type of insecticide input or ground cover. Few population measurements were affected by tillage type. Foliar insect problems in commercial vegetable production may be associated predominantly with insecticide input (i.e. more damage with biologically based insecticides) and use of intercropping (i.e. more damage in systems with living mulch); however, the long term effects of tillage and crop rotation remain to be seen. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Authors:
    • Hoyt, G. D.
    • Walgenbach, J. F.
    • Hummel, R. L.
    • Kennedy, G. G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 93
  • Issue: 1-3
  • Year: 2002
  • Summary: Populations of epigeal arthropods were monitored in vegetable production systems under varying degrees of sustainable agricultural practices in Fletcher, NC (USA). Two tillage types (conventional plow and disk, strip-tillage (ST)), two input approaches (chemically based, biologically based) and two cropping schedules (continuous tomato Lycopersicon esculentum Mill., 3-year rotation of sweet corn [Zea mays L.]/cabbage [Brassica oleracea L.], cucumber [Cucumis sativus L.]/cabbage and tomato) were employed from 1995-1998. A second study with tomatoes was performed in 1997-1998 to separate effects of pesticide use, intercropping and herbicide application. Pitfall traps (48-h sample period) were used at similar to25-day intervals to monitor relative activity of carabid beetles (Coleoptera: Carabidae), staphylinid (Coleoptera: Staphylinidae) beetles and lycosid spiders (Araneidae: Lycosidae). Carabids and lycosids appeared to be more active in systems with ground cover. Trap catches of carabid species were not significantly affected by insecticide input, but trap catches of lycosids were lower in plots with conventional insecticide use. No consistent effect of tillage was found over time, although Scarites spp. were more active in minimally disturbed habitats in 1998. Two distinct patterns of seasonal activity were observed for carabid beetles and lycosid spiders. Ground cover generally enhanced abundance of carabids and lycosids, while tillage type, pesticide use and crop rotation had different effects. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Authors:
    • Nielsen, G.
    • Mortensen, D.
    • McGinn, S.
    • Coen, G.
    • Caprio, J.
    • Waltman, S.
    • Padbury, G.
    • Sinclair, R.
  • Source: Agronomy Journal
  • Volume: 94
  • Issue: 2
  • Year: 2002
  • Summary: The northern Great Plains have long been dominated by conventional tillage systems and cereal-based rotations including summer fallow. Over the last decade, however, the use of conservation tillage systems has markedly increased and, through improved moisture storage, has provided an opportunity for more diversified extended rotations including oilseed, pulse, and forage crops throughout the region. Considerable research is being carried out to assess the adaptability of these new crops and to develop appropriate management strategies. Typically, this type of agronomic research is carried out at plot-sized research sites, with the findings then being extrapolated to surrounding regions where growing conditions are thought to be reasonably similar. Because the environment itself largely dictates the success of a particular cropping system, extrapolation requires knowledge of the environmental conditions of the region and, in particular, the interaction of environmental components of soil and climate in relation to specific crop requirements. This paper describes 14 agroecoregions in the northern Great Plains and provides an initial framework for extrapolating agronomic information at broad regional scales. Because climate is the dominant crop production factor in the region, most of the agroecosystems represent broad climatic zones. Each agroecoregion is described in terms of its soil and landscape characteristics, with a particular focus being given to likely key environmental parameters related to the production of the new oilseed, pulse, and forage crops being introduced in the region.
  • Authors:
    • Reeves, D. W.
    • Burmester, C. H.
    • Motta, A. C. V.
  • Source: Making Conservation Tillage Conventional: Building a Future on 25 Years of Research. Proceedings of 25th Annual Southern Conservation Tillage Conference for Sustainable Agriculture, Auburn, AL, USA, 24-26 June, 2002 - Special Report no. 1, Alabama Agricult
  • Year: 2002
  • Summary: A replicated cotton (Gossypium hirsutum) rotation experiment has been conducted for 22 years (1980-2001) on a Decatur silt loam (fine, kaolinitic, thermic, Rhodic Paleudults) in the Tennessee Valley of northern Alabama, USA. The highly productive soil with little disease and nematode problems resulted in cotton yield increases from rotations of generally less than 10% during the first 15 years of the study. A switch to no-tillage in all rotations except continuous cotton in 1995 greatly improved cotton yield response to rotations. From 1995 to 2001 cotton yield increases to rotation have averaged between 5% and 18%. In this study, yield increases due to rotations seem linked to increases in soil organic matter and consequent improvements in soil quality. From 1979 to 1994 using conventional tillage, the only rotation that produced a greater than 10% yield increase was cotton rotated with wheat ( Triticum aestivum) and double-cropped soyabean ( Glycine max). This rotation was also the only rotation that significantly increased organic matter levels under conventional tillage. From 1995 to 2001, all rotations were no-tilled and the greater yield increases to rotations can also be associated with higher soil organic matter levels. Wheat as a grain rotation or cover crop often produced the greatest yield increases to the following cotton crop. Under conventional tillage the wheat residue provided increased organic matter residue. With no-tillage the wheat cover crop reduced surface soil compaction. No-tillage and rotations that increased residue production were linked to increased cotton yields on this soil.
  • Authors:
    • Wuest, S. B.
  • Source: Applied Soil Ecology
  • Volume: 18
  • Issue: 2
  • Year: 2001
  • Summary: Dryland fanning in the Mediterranean climate of the Pacific Northwest, USA supports extremely low earthworm populations under conventional tillage. Increases in earthworm populations are being observed in fields under no-till cropping systems. A 30+ year experiment with four tillage levels in a pea (Pisum sativum L.)-winter wheat (Triticum aestivum L.) rotation was evaluated for earthworm populations and ponded infiltration rates. Where tillage has been limited to 2.5 cm depth, Apporectodea trapezoides (Duges) mean population was 25 m(-2). Plots subject to tillage by plow (25 cm depth) or chisel (35 cm depth) averaged less than 4 earthworms m-2. The shallow tillage treatment also had the highest average infiltration rate of 70 mm h(-1) compared to 36 for chisel, 27 for spring plow, and 19 mm h(-1) for fall plow treatments. The highly variable nature of earthworm counts and infiltration measurements prevented conclusive correlation between the two, but increases in both can be attributed to minimum tillage.
  • Authors:
    • Wagoner, P.
    • Drinkwater, L. E.
    • Douds, D. D.
    • Galvez, L.
  • Source: Plant and Soil
  • Volume: 228
  • Issue: 2
  • Year: 2001
  • Summary: Low-input agricultural systems that do not rely on fertilizers may be more dependent on vesicular-arbuscular mycorrhizal [VAM] fungi than conventionally managed systems. We studied populations of spores of VAM fungi, mycorrhiza formation and nutrient utilization of maize (Zea mays L.) grown in moldboard plowed, chisel-disked or no-tilled soil under conventional and low-input agricultural systems. Maize shoots and roots were collected at four growth stages. Soils under low-input management had higher VAM fungus spore populations than soils under conventional management. Spore populations and colonization of maize roots by VAM fungi were higher in no-tilled than in moldboard plowed or chisel-disked soil. The inoculum potential of soil collected in the autumn was greater for no-till and chisel-disked soils than for moldboard plowed soils and greater for low-input than conventionally farmed soil. The effects of tillage and farming system on N uptake and utilization varied with growth stage of the maize plants. The effect of farming system on P use efficiency was significant at the vegetative stages only, with higher efficiencies in plants under low-input management. The effect of tillage was consistent through all growth stages, with higher P use efficiencies in plants under moldboard plow and chisel-disk than under no-till. Plants grown in no-tilled soils had the highest shoot P concentrations throughout the experiment. This benefit of enhanced VAM fungus colonization, particularly in the low-input system in the absence of effective weed control and with likely lower soil temperatures, did not translate into enhanced growth and yield.
  • Authors:
    • Choudhary, A.
    • Akramkhanov, A.
    • Pulatov, A.
  • Source: Conservation agriculture, a worldwide challenge. First World Congress on conservation agriculture, Madrid, Spain, 1-5 October, 2001. Volume 2
  • Year: 2001
  • Summary: This paper describes the status of agriculture and environmental issues in Uzbekistan and other Central Asian states. The paper also outlines the recent research and development project being conducted in Uzbekistan to promote conservation agriculture technologies for wheat and cotton production. No-tillage and bed planting technologies were trialled for the first time in Uzbekistan to grow winter wheat at the Tashkent Institute of Irrigation and Agricultural Mechanisation Engineers Research Farm. These were compared to conventionally grown wheat. Wheat yield obtained was 3.44, 3.96 and 3.57 t/ha in no-till, bed planting and conventional fields respectively. These results suggest a high potential for irrigated wheat crop production with the use of such technologies in Uzbekistan.
  • Authors:
    • Harwood, R. R.
    • Paul, E. A.
    • Robertson, G. P.
  • Source: Science
  • Volume: 289
  • Issue: 5486
  • Year: 2000
  • Summary: Agriculture plays a major role in the global fluxes of the greenhouse gases carbon dioxide, nitrous oxide, and methane. From 1991 to 1999, we measured gas fluxes and other sources of global warming potential (GWP) in cropped and nearby unmanaged ecosystems. Net GWP (grams of carbon dioxide equivalents per square meter per year) ranged from 110 in our conventional tillage systems to 2211 in early successional communities. None of the annual cropping systems provided net mitigation, although soil carbon accumulation in no-till systems came closest to mitigating all other sources of GWP. In all but one ecosystem, nitrous oxide production was the single greatest source of GWP. In the late successional system, GWP was neutral because of significant methane oxidation. These results suggest additional opportunities for lessening the GWP of agronomic systems.
  • Authors:
    • Rossoni-Longnecker, L.
    • Janke, R. R.
    • Drinkwater, L. E.
  • Source: Plant and Soil
  • Volume: 227
  • Issue: 1
  • Year: 2000
  • Summary: Abstract In 1988 an experiment was established at the Rodale Institute Experimental Farm to study weed control and nitrogen (N) management in rotations with grain crops and N-fixing green manures under reduced tillage without the use of herbicides. Tillage intensities ranging from moldboard plow (MP) to continuous no-till (NT) were compared. We present results for maize production in 1994, the seventh year of the experiment. Our goal was to further investigate reduced tillage regimes that alternated no-till with different forms of primary tillage in legume-based systems. In the chisel-disc (CD) and MP treatments comparable yields were achieved under so-called organic (weeds controlled with cultivation and green manure N source) and conventional management (weeds controlled with herbicides and mineral N fertilizer applied). Weed competition in these treatments was minimal and the N status of maize plants was essentially the same regardless of the N source (fertilizer or green manure). Of the four organic no-till maize treatments, only the mixed-tillage system with cultivation for weed control (CD-NTc) produced yields comparable to conventional NT maize. The fate of vetch N as well as temporal N dynamics were largely determined by tillage intensity and the handling of the vetch residues at maize planting. Treatments with primary tillage (CD and MP) had extremely high levels of mineral N early in the season and had greater average net N-mineralization, even though N content of hairy vetch in these treatments was equal to or lower than that in treatments with mow-killed vetch. In terms of soil mineral N concentrations, the CD-NTc treatment was similar to the other mow-killed vetch/no-till maize treatments. However, N availability in this treatment was greater, probably due to more complete decomposition of green manure residues. Cultivation for weeds not only helped control weeds but also increased mineralization of the vetch residues, which in turn increased the N supply during the period of maximum N demand by the maize. Carefully designed rotations combining tillage reductions with the use of leguminous N sources can have multiple benefits, including improved timing of N availability, reduced herbicide applications, and improved soil quality in the long term.
  • Authors:
    • Pannkuk, C. D.
    • McCool, D. K.
  • Source: 2000 ASAE Annual International Meeting, Technical Papers: Engineering Solutions for a New Century. 
  • Year: 2000
  • Summary: Burn/low-till management of winter wheat is being practiced by some growers in the higher rainfall areas of the Pacific Northwest Wheat Region. The burning eliminates the numerous seedbed tillage operations that are normally required to reduce residues and control weeds and diseases in continuous winter wheat production. Detrimental effects of burn and till systems are well documented. However, there is little or no data on the effects of burning with no or low-till annual cropping on either erosion or soil quality. A three-year field study comparing 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 from the CM fields with various crops preceding winter wheat. For the BLT fields, soil loss was as closely related to soil disturbance (tillage operations) as to 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. The results of this study indicate no adverse effects on soil loss from using the BLT with one or two-pass seeding of winter wheat following winter wheat.