• Authors:
    • Anderson, R. L.
  • Source: Weed Technology
  • Volume: 22
  • Issue: 1
  • Year: 2008
  • Summary: Producers are interested in tactics for managing crop residues when growing maize after spring wheat. We compared five systems of managing spring wheat residues: conventional tillage, no-till, strip-till, cover crop (hairy vetch) with no-till, and cover crop with strip-till following spring wheat. Conventional tillage consisted of chisel ploughing and discing, whereas strip-till consisted of tilling a 15-cm band centred on maize rows, which were spaced 76 cm apart. Plots were split into weed-free and weed-infested subplots. Grain yield in weed-free conditions did not differ among treatments. However, weed-free yield was nearly 40% greater than weed-infested maize in conventional tillage. In contrast, weeds reduced yield only 15% with strip-till. Weed density and biomass was two-fold greater with conventional tillage compared with the no-till and strip-till treatments. Weed seedlings also emerged earlier with conventional tillage. Increased weed tolerance with strip-till may be related to fertilizer placement. Maize growth and tolerance to weeds in no-till systems may be improved if a starter fertilizer is placed in the seed furrow.
  • Authors:
    • Correia, M. E. F.
    • Mercante, F. M.
    • Silva, R. F. da
    • Aquino, A. M. de
    • Guimaraes, M. de F.
    • Lavelle, P.
  • Source: European Journal of Soil Biology
  • Volume: 44
  • Issue: 2
  • Year: 2008
  • Summary: This work was aimed at evaluating the invertebrate macrofauna community in the soil, by means of its abundance and richness of groups under different plant covers in the no-till system. Evaluations were performed at the experimental field of Embrapa Agropecuaria Oeste, in the municipal district of Dourados-MS, on a Typic Hapludox under conventional, no-till, and natural systems. Samplings were performed in December 2000, June 2001, January 2002, and June 2002. Five soil monoliths measuring 0.25*0.25 m width and 0.30 m depth were sampled along a transect. Turnip residues before a corn crop (turnip/corn) and soybean residues before wheat and turnip crops (soybean/wheat and soybean/turnip) provided positive effects on the density and diversity of the edaphic macrofauna community.
  • Authors:
    • Brenzil, C. A.
    • Hall, L. M.
    • Thomas, A. G.
    • Leeson,J. Y.
    • Beckie, H. J.
  • Source: Weed Technology
  • Volume: 22
  • Issue: 4
  • Year: 2008
  • Summary: Agricultural practices, other than herbicide use, can affect the rate of evolution of herbicide resistance in weeds. This study examined associations of farm management practices with the occurrence of herbicide (acetyl-CoA carboxylase or acetolactate synthase inhibitor)-resistant weeds, based upon a multi-year (2001 to 2003) random Survey of 370 fields/growers from the Canadian Prairies. Herbicide-resistant weeds Occurred in one-quarter of the surveyed fields. The primary herbicide-resistant weed species was wild oat, with lesser occurrence of green foxtail, kochia, common chickweed, spiny sowthistle, and redroot pigweed. The risk of weed resistance was greatest in fields with cereal-based rotations and least in fields with forage crops, fallow, or where three or more crop types were grown. Weed resistance risk also was greatest in conservation-tillage systems and particularly low soil disturbance no-tillage, possibly due to greater herbicide use or weed seed bank turnover. Large farms (> 400 ha) had a greater risk of weed resistance than smaller farms, although the reason for this association Was unclear. The results of this study identify cropping system diversity as the foundation of proactive weed resistance management.
  • Authors:
    • Claupein, W.
    • Lewandowski, I.
    • Boehmel, C.
  • Source: Agricultural Systems
  • Volume: 96
  • Issue: 1/3
  • Year: 2008
  • Summary: Given the political targets, it can be expected that in Europe, energy production from agricultural land will increase and that improved systems for its production are needed. Therefore, a four year field trial was conducted on one site in south-western Germany to compare and evaluate the biomass and energy yield performance of important energy crops. Six energy cropping systems with the potential to produce biomass for first and second-generation biofuels were selected. The systems were short rotation willow coppice, miscanthus, switchgrass, energy maize and two different crop rotation systems including winter oilseed rape, winter wheat and winter triticale. The two crop rotation systems were managed in either conventional tillage or no-till soil cultivation systems. The second test parameter was three different crop-specific nitrogen application levels. The performance of the energy cropping systems was evaluated by measuring the biomass yields and calculating the energy yields, as well as through an energy balance and nitrogen budget. Results show the superiority of the annual energy crop maize in dry matter yield (DMY) and primary net energy yield (PNEY=difference between the primary energy yield (DMY * lower heating value) and the energy consumption) performance with peak values at the highest N-application level of 19.1 t DM ha -1 a -1 and 350 GJ ha -1 a -1, respectively. The highest yielding perennial crop was miscanthus with 18.1 t ha -1 a -1 DMY and a PNEY of 277 GJ ha -1 a -1, followed by willow with 15.2 t ha -1 a -1 and 258 GJ ha -1 a -1, at the highest N-application level. Switchgrass showed the lowest yields of the perennial crops with 14.1 t ha -1 a -1 DMY at the highest N-application level. The yields of the two crop rotation systems did not differ significantly and amounted to 14.6 t ha -1 a -1 DMY of both grain and straw at the highest N-application level. Willow showed the significantly highest energy use efficiency (output (PNEY):input (energy consumption)-ratio) with 99 GJ energy output per GJ fossil energy input at the lowest N-application level (no fertilizer). The two crop rotation systems had the lowest energy use efficiency with 20 GJ GJ -1 for the production of total aboveground biomass. Energy maize gave the best energy yield performance but at a relatively high energy input, whereas willow and miscanthus as perennial energy crops combine high yields with low inputs. Results suggest that no-till systems had no negative impact on biomass and energy yields, but that there was also no positive impact on energy saving.
  • Authors:
    • Buschiazzo, D. E.
    • Alvarez, R.
    • Bono, A.
    • Cantet, R. J. C.
  • Source: Soil Science Society of America Journal
  • Volume: 72
  • Issue: 4
  • Year: 2008
  • Summary: Tillage systems may affect soil C sequestration, with a potential impact on crop productivity or organic matter mineralization. We evaluated crop yield, C inputs to the soil, and in situ CO 2-C fluxes under no-till and conventional tillage (disc tillage) during the 3- to 6-year period from the installation of an experiment in an Entic Haplustoll of the Semiarid Pampean Region of Argentina to elucidate the mechanisms responsible for possible management-induced soil organic matter changes. Yield and biomass production were greater under no-till than disc tillage for all the crops included in the rotation (oat + hairy vetch ( Vicia villosa ssp. villosa), maize, wheat and oat). This result was attributed to the higher soil water content under no-till. Carbon inputs to the soil averaged 4 Mg C ha -1 year -1 under no-till and 3 Mg C ha -1 year -1 under disc tillage. Soil temperature was similar between tillage systems and CO 2-C emission was approximately 4 Mg C ha -1 year -1, with significant but small differences between treatments (~0.2 Mg C ha -1 year -1). Carbon balance of the soil was nearly equilibrated under no-till; meanwhile, greater C losses as CO 2 than inputs in crop residues were measured under conventional tillage. Organic C in the soil was 5.4 Mg ha -1 higher under no-till than the disc tillage treatment 6 years after initiation of the experiment. Results showed that in our semiarid environment, C sequestration occurred under no-till but not conventional tillage. The sequestration process was attributed to the effect of the tillage system on crop productivity rather than on the mineralization intensity of soil organic pools.
  • Authors:
    • Heitman, J. L.
    • Gaur, A.
    • Horton, R.
    • Jaynes, D. B.
    • Kaspar, T. C.
  • Source: Soil Science Society of America Journal
  • Volume: 71
  • Issue: 2
  • Year: 2007
  • Summary: Management of chemicals in soil is important, yet the complexity of field soils limits prediction of management effects on transport. To date, few methods have been available for field measurement of chemical transport properties, but a recently developed dripper-time domain reflectometry technique allows rapid collection of data for determining these properties. The objective of this work was to apply this technique for comparison of chemical transport properties for different soil management zones. Experiments were conducted in Iowa, USA, comparing four interrow management zones: no-till non-trafficked, no-till trafficked, chisel plough non-trafficked, and chisel plough trafficked. Drip emitters were positioned at 12 locations in each zone and used to apply water followed by a step input of CaCl 2 tracer solution. Breakthrough curves were measured via electrical conductivity with time domain reflectometry probes. The mobile-immobile model was fit to the breakthrough curves to determine chemical transport properties. Mean chemical transport properties were 0.34, 0.11 h -1, 10 cm h -1, 164 cm 2 h -1, and 5 cm, for the immobile water fraction, mass exchange coefficient, average pore-water velocity, mobile dispersion coefficient, and dispersivity, respectively. All five properties showed significant differences between management zones. Differences in mass exchange and mobile dispersion coefficients coincided with differences in tillage, while differences in mean pore water velocities coincided with differences in traffic. The immobile water fraction was largest for the no-till non-trafficked zone. These results represent one of very few reports for field measurement of chemical transport properties and the first application of this approach for comparison of chemical transport properties across management zones.
  • Authors:
    • Jia, H.
    • Ma, C.
    • Yang, Q.
    • Liu, Z.
    • Li, G.
    • Liu, H.
  • Source: Nongye Jixie Xuebao = Transactions of the Chinese Society for Agricultural Machinery
  • Volume: 38
  • Issue: 12
  • Year: 2007
  • Summary: The present status of dry farming in northern China was analyzed and a three-year rotation tillage method suitable for the ridged cultivation region of northeastern China and the techniques for efficient utilization of natural rainfall in the Loess Plateau region of northwestern China was put forward. The tests conducted in the northeast showed that stalk mulching increased the percentage of soil moisture content by 10% and the content of soil organic matter by 0.06 percentage point after three years, decreased the volume density of soil by 0.09 g/cm 3, chiseling increased the percentage of soil moisture content by 26.2%, and less tillage increased the percentage of soil moisture content by 3 percentage point. The tests conducted in the northwest showed that for winter wheat, the percentage of water storage increased by 18-5%; for spring corn, the percentage of soil moisture content increased by 30%. The stalk mulching tests for two years showed that the content of soil organic matter increased by 0.05%-0.1% and the content of total nitrogen increased by about 0.1 g/kg.
  • Authors:
    • Lenssen, A. W.
    • Johnson, G. D.
    • Carlson, G. R.
  • Source: Field Crops Research
  • Volume: 100
  • Issue: 1
  • Year: 2007
  • Summary: Available water is typically the biggest constraint to spring wheat production in the northern Great Plains of the USA. The most common rotation for spring wheat is with summer fallow, which is used to accrue additional soil moisture. Tillage during fallow periods controls weeds, which otherwise would use substantial amounts of water, decreasing the efficiency of fallow. Chemical fallow and zero tillage systems improve soil water conservation, allowing for increased cropping intensity. We conducted a field trial from 1998 through 2003 comparing productivity and water use of crops in nine rotations under two tillage systems, conventional and no-till. All rotations included spring wheat, two rotations included field pea, while lentil, chickpea, yellow mustard, sunflower, and safflower were present in single rotations with wheat. Growing season precipitation was below average most years, resulting in substantial drought stress to crops not following fallow. Preplant soil water, water use, and spring wheat yields were generally greater following summer fallow than wheat recropped after wheat or alternate crops. Water use and yield of wheat following summer fallow was greater than for chickpea or yellow mustard, the only other crops in the trial that followed summer fallow. Field pea performed best of all alternate crops, providing yields comparable to those of recropped spring wheat. Chickpea, lentil, yellow mustard, safflower, and sunflower did not perform well and were not adapted to this region, at least during periods of below average precipitation. Following summer fallow, and despite drought conditions, zero tillage often provided greater amounts of soil water at planting compared to conventional tillage.
  • Authors:
    • Lenssen, A. W.
    • Waddell, J. T.
    • Johnson, G. D.
    • Carlson, G. R.
  • Source: Soil & Tillage Research
  • Volume: 94
  • Issue: 2
  • Year: 2007
  • Summary: Improved nitrogen use efficiency would be beneficial to agroccosystem sustainability in the northern Great Plains of the USA. The most common rotation in the northern Great Plains is fallow-spring wheat. Tillage during fallow periods controls weeds, which other-wise would use substantial amounts of water and available nitrogen, decreasing the efficiency of fallow. Chemical fallow and zero tillage systems improve soil water conservation, and may improve nitrogen availability to subsequent crops. We conducted a field trial from 1998 through 2003 comparing nitrogen uptake and nitrogen use efficiency of crops in nine rotations under two tillage systems, conventional and no-till. All rotations included spring wheat, two rotations included field pea, while lentil, chickpea, yellow mustard, sunflower, and safflower were present in single rotations with wheat. Growing season precipitation was below average in 3 of 4 years, resulting in substantial drought stress to crops not following fallow. In general, rotation had a greater influence on spring wheat nitrogen accumulation and use efficiency than did tillage system. Spring wheat following fallow had substantially higher N accumulation in seed and biomass, N harvest index, and superior nitrogen use efficiency than wheat following pea, lentil, chickpea, yellow mustard, or wheat. Preplant nitrate-N varied widely among years and rotations, but overall, conventional tillage resulted in 9 kg ha(-1) more nitrate-N (060 cm) for spring wheat than did zero tillage. However, zero tillage spring wheat averaged 11 kg ha(-1) more N in biomass than wheat in conventional tillage. Nitrogen accumulation in pea seed, 45 kg ha(-1) was superior to that of all alternate crops and spring wheat, 17 and 23 kg ha(-1), respectively. Chickpea, lentil, yellow mustard, safflower, and sunflower did not perform well and were not adapted to this region during periods of below average precipitation. During periods of drought, field pea and wheat following fallow had greater nitrogen use efficiency than recropped wheat or other pulse and oilseed crops.
  • Authors:
    • Radford, B. J.
    • Yule, D. F.
    • McGarry, D.
    • Playford, C.
  • Source: Soil & Tillage Research
  • Volume: 97
  • Issue: 2
  • Year: 2007
  • Summary: Heavy wheel traffic causes soil compaction, which adversely affects crop production and may persist for several years. We applied known compaction forces to entire plots annually for 5 years, and then determined the duration of the adverse effects on the properties of a Vertisol and the performance of maize and sorghum crops under no-till dryland cropping with residue retention. For up to 5 years after a final treatment with a 10 Mg axle load on wet soil, soil shear strength at 70-100 mm and cone index at 180-360 mm were significantly ( P<0.05) higher than in a control treatment, and soil water storage and grain yield were lower. We conclude that compaction effects persisted because (1) there were insufficient wet-dry cycles to swell and shrink the entire compacted layer, (2) soil loosening by tillage was absent and (3) there were fewer earthworms in the compacted soil. Compaction of dry soil with 6 Mg had little effect at any time, indicating that by using wheel traffic only when the soil is dry, problems can be avoided. Unfortunately such a restriction is not always possible because sowing, tillage and harvest operations often need to be done when the soil is wet. A more generally applicable solution, which also ensures timely operations, is the permanent separation of wheel zones and crop zones in the field-the practice known as controlled traffic farming. Where a compacted layer already exists, even on a clay soil, management options to hasten repair should be considered, e.g. tillage, deep ripping, sowing a ley pasture or sowing crop species more effective at repairing compacted soil.