• Authors:
    • Ellert, B. H.
    • Janzen, H. H.
    • Carefoot, J. M.
    • Chang, C.
    • Hao, X.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 60
  • Issue: 1
  • Year: 2001
  • Summary: Nitrous oxide (N2O) emission from farmland is a concern for both environmental quality and agricultural productivity. Field experiments were conducted in 1996-1997 to assess soil N2O emissions as affected by timing of N fertilizer application and straw/tillage practices for crop production under irrigation in southern Alberta. The crops were soft wheat (Triticum aestivum L.) in 1996 and canola (Brassica napus L.) in 1997. Nitrous oxide flux from soil was measured using a vented chamber technique and calculated from the increase in concentration with time. Nitrous oxide fluxes for all treatments varied greatly during the year, with the greatest fluxes occurring in association with freeze-thaw events during March and April. Emissions were greater when N fertilizer (100 kg N ha-1) was applied in the fall compared to spring application. Straw removal at harvest in the fall increased N2O emissions when N fertilizer was applied in the fall, but decreased emissions when no fertilizer was applied. Fall plowing also increased N2O emissions compared to spring plowing or direct seeding. The study showed that N2O emissions may be minimized by applying N fertilizer in spring, retaining straw, and incorporating it in spring. The estimates of regional N2O emissions based on a fixed proportion of applied N may be tenuous since N2O emission varied widely depending on straw and fertilizer management practices.
  • Authors:
    • Hnatowich, G.
    • Hultgreen, G.
    • Lafond, G.
    • Johnston, A.
  • Source: Canadian Journal of Plant Science
  • Volume: 81
  • Issue: 1
  • Year: 2001
  • Summary: The development of successful no-till crop production systems has led to the practice of applying all the seed and fertilizer in a single field operation. This study was initiated to assist producers in the selection of commercially available bolt-on side banding openers. Field trials were conducted at 10 locations in Saskatchewan, Canada, over a 2-year period (1995 and 1996) to evaluate the performance of five bolt-on side band openers on the establishment and yield of spring wheat ( Triticum aestivum) and rape ( Brassica rapa [ B. campestris]). Trial locations were selected to provide a range of soil and environmental conditions. The openers tested included the Flexi-coil Stealth, Dutch-Vern Eaglebuster, Swede SW470, GEN 200 and Morris Edge-On. Fertilizer nitrogen (N) as urea was applied in the side band at rates of 0, 40, 80 and 120 kg N ha -1 with a side banded starter fertilizer blend of phosphorus, potassium and sulfur. When properly adjusted for individual site soil conditions at sowing, no difference was recorded between the side band openers tested in the establishment and grain yield of spring wheat. Averaged across all N rates, three of the five openers showed poor rape seedling emergence, indicating inadequate seed-fertilizer separation. However, the ability of the rape crop to branch and compensate for poor crop establishment prevented any significant grain yield loss in this study. In cases where differences between openers were observed, the Flexi-Coil Stealth and GEN 200 openers provided the best crop establishment. Given the importance of crop establishment to achieving optimum grain yields, the bolt-on side band openers that provided good crop establishment should be recommended to producers.
  • Authors:
    • Morse, R. D.
    • Miyao, E. M.
    • Temple, S. R.
    • Lanini, W. T.
    • Mitchell, J. P.
    • Herrero, E. V.
    • Campiglia, E.
  • Source: California Agriculture
  • Volume: 55
  • Issue: 1
  • Year: 2001
  • Summary: The efficacy of no-till systems in conserving soil moisture and improving water infiltration under furrow irrigation was evaluated during 1997 and 1998 in California, USA. Two grass/legume mixtures, i.e. triticale/lana woolypod vetch (* Triticosecale/ Vicia dasycarpa [ V. villosa]) and rye/lana woolypod vetch ( Secale cereale/ V. dasycarpa), were used as cover cop mulches in no-till treatments, and compared with a winter fallow treatment with pre-plant herbicide (fallow +h) and a fallow control treatment with no herbicide (fallow -h). Tomato cv. Halley 3155 plants were transplanted in April 1997 and 1998, sprinkle irrigated during the first 6 weeks after transplanting, and furrow irrigated thereafter until 3 weeks before harvest. During 1997, soil water content between 0 and 78 inches did not differ among treatments, while soil water content during the 1997/98 winter was higher under the fallow +h than the cover crop treatments until cover crop termination. Soil water content of cover crop treatments in shallower soil layers (18 and 42 inches) was significantly lower than fallow treatments at the end of the winter. During the 1998 tomato crop season, soil water content between 0 and 90 inches was greater under the triticale and rye mulches than the fallow +h, beginning the 3rd week after furrow irrigations were started. Soil moisture in the shallower layers was also affected by cover crop mulches. In the 42-inch depth increment, there was significantly higher water content under the cover crops than under the fallow +h from about 1 month after the first furrow irrigation until 2 weeks before the last irrigation. Changes in soil water content during furrow irrigation under the fallow +h treatment appeared to be more pronounced than under the triticale or rye surface mulches. Soil compaction in the fallow +h treatment was higher than under the cover crop mulches for most of the 0.6-inch intervals, especially below 1 foot, but differences were significantly higher only for the 3, 3.6, 4.2, 17, 18, and 24-inch depth, but lower from the surface to 2.4 inches. Soil carbon was significantly higher (by 14 and 18%) under triticale and rye, respectively, compared with the fallow +h treatment. The number of earthworms was also higher in no-till (2.1 earthworms per square foot) than in the fallow treatments (0.6 earthworms). Tomato canopy growth did not reach 100% cover in either 1997 or 1998, while tomato plant growth, assessed by measuring the photosynthetically active radiation intercepted by the canopy, did not differ in the triticale, rye, and fallow +h system in either 1997 or 1998. Results showed that the no-till mulch system enhanced water infiltration and soil water conservation.
  • Authors:
    • Morse, R. D.
    • Miyao, E. M.
    • Temple, S. R.
    • Lanini, W. T.
    • Mitchell, J. P.
    • Herrero, E. V.
    • Campiglia, E.
  • Source: HortTechnology
  • Volume: 11
  • Issue: 1
  • Year: 2001
  • Summary: No-tillage processing tomato production in four winter cover crop-derived mulches was evaluated in 1997 and 1998 in Five Points, California, USA. The effectiveness of two medics, 'Sava' snail medic ( Medicago scutellata), and 'Sephi' barrel medic ( Medicago truncatula), and two cereal/legume cover crop mixtures, triticale/'Lana' woolypod vetch ( Triticum x Secale/ Vicia dasycarpa [ Vicia villosa]) and rye/'Lana' woolypod vetch ( Secale cereale/ V. dasycarpa), was compared with two conventionally tilled fallow controls (with and without herbicide) (fallow+h and fallow-h) in suppressing weeds and maintaining yields with reduced fertilizer inputs. The comparison was conducted as a split plot, with three N fertilization rates (0, 100, and 200 lb/acre; 0, 112, and 224 kg/ha) as main plots and cover crops and fallow controls as subplots. Tomato seedlings were transplanted 3 weeks after the cover crops had been mowed and sprayed with herbicide. There were no significant differences in weed cover in the no-till cover crop treatments relative to the fallow controls in 1997. Early season weed suppression in rye/vetch and triticale/vetch plots was similar to herbicide-treated fallow (fallow+h) in 1998, however, later in the 1998 season weed suppression was best in the fallow+h. Tissue N was highest in the fallow treatments in both 1997 and 1998. Yields were highest in the triticale/vetch and fallow and lowest in sephi treatments in 1997, but there were no differences among treatments in 1998.
  • 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:
    • Santos, H. P. dos
    • Roman, E. S.
  • Source: Pesquisa Agropecuária Gaúcha
  • Volume: 7
  • Issue: 1
  • Year: 2001
  • Summary: Field experiments were conducted in Passo Fundo (1984-89) and in Coxilha (1996-97), Rio Grande do Sul, and in Guarapuava (1984-90 and 1990-94), Parana, Brazil, to study the effects of winter crop residues on soyabean grown in succession, under no-till system. Winter crops were white oats knife rolled for mulching purposes, white oats, barley, rapeseed, flax, and wheat for grain yield. In these cropping systems, soyabean was grown in the summer in monoculture and in rotation with maize and pearl millet. Soyabean grown after flax and rape showed lower yield and plant height than soyabean after barley and wheat. Yields of soyabean grown in monoculture were moderate compared with yields of soyabean grown in crop rotation and soyabean grown after rape or flax. Soyabean grown after barley and wheat may be included in the different systems studied without yield losses. Volunteer white oat seeds may reduce soyabean yield and plant height.
  • Authors:
    • Christoffoleti, P. J.
    • Shiratsuchi, L. S.
  • Source: The BCPC Conference: Weeds, 2001, Volume 1 and Volume 2. Proceedings of an international conference held at the Brighton Hilton Metropole Hotel, Brighton, UK, 12-15 November 2001
  • Year: 2001
  • Summary: Weed control represents a high percentage of the production costs in no-till systems in Brazil, and chemical control using herbicides is by far the most important method used. However, the weeds are not uniformly or randomly distributed but have a patchy distribution such that the broadcast application of herbicides can spray post-emergence herbicides in areas where there are no weeds. Therefore, this work had the objective of demonstrating the potential of saving of herbicides in the no-till production system of the Brazilian agriculture, based on weed seed bank and weed seedling maps. The density of several weeds was mapped using a backpack DGPS and laptop computer. Experiments were conducted in Sao Paulo [date not given] in a 17.7-ha field of no-till maize under centre pivot irrigation. Seed bank data was determined from soil cores collected from a depth of 0.05 m in the centre of a 20*20 m grid and emergence assessments in a greenhouse. On the same grid size, weed seedlings were counted in 0.25 m 2 quadrats. Resultant maps showed a high weed density in the seed bank over just 4.67 ha, which was only 26% of the field area. The seedling maps demonstrated that grasses and broadleaf weeds had different distributions with broadleaf weeds occupying 12.6% of the field and grasses 87.4%. The targeting of herbicide to weed patches using pre- and postemergent herbicides has the potential to reduce herbicide use compared to broadcast application giving both environmental and economic advantages.
  • Authors:
    • Duarte, G. A.
    • Diaz-Zorita, M.
  • Source: Siembra Directa II
  • Year: 2001
  • Summary: Notes are given on the effects of incorporation of direct grazing in systems of continuous zero tillage in western Buenos Aires, Argentina. It is concluded that incorporation of grazing with direct sowing practices in mixed production systems is feasible, with the aim of maintaining high levels of stubble cover. The removal of crop residues reduces the potential for conservation of soil water and attenuates the impact of trampling by animals.
  • Authors:
    • Follett, R. F.
  • Source: Soil & Tillage Research
  • Volume: 61
  • Issue: 1/2
  • Year: 2001
  • Summary: One of the most important terrestrial pools for carbon (C) storage and exchange with atmospheric CO 2 is soil organic carbon (SOC). Following the advent of large-scale cultivation, this long-term balance was disrupted and increased amounts of SOC were exposed to oxidation and loss as atmospheric CO 2. The result was a dramatic decrease in SOC. If amounts of C entering the soil exceed that lost to the atmosphere by oxidation, SOC increases. Such an increase can result from practices that include improved: (1) tillage management and cropping systems, (2) management to increase amount of land cover, and (3) efficient use of production inputs, e.g. nutrients and water. Among the most important contributors is conservation tillage (i.e., no-till, ridge-till, and mulch-tillage) whereby higher levels of residue cover are maintained than for conventional-tillage. Gains in amount of land area under conservation tillage between 1989 and 1998 are encouraging because of their contributions to soil and water conservation and for their potential to sequester SOC. Other important contributors are crop residue and biomass management and fallow reduction. Collectively, tillage management and cropping systems in the US are estimated to have the potential to sequester 30-105 million metric tonnes of carbon (MMTC) year -1. Two important examples of management strategies whereby land cover is increased include crop rotations with winter cover crops and the conservation reserve programme (CRP). Such practices enhance SOC sequestration by increasing the amount and time during which the land is covered by growing plants. Crop rotations, winter cover crops, and the CRP combined have the potential to sequester 14-29 MMTC year -1. Biomass production is increased by efficient use of production inputs. Optimum fertility levels and water availability in soils can directly affect quantity of crop residues produced for return to the soil and for SOC sequestration. Nutrient inputs and supplemental irrigation are estimated to have the potential to sequester 11-30 MMTC year -1. In the future, it is important to acquire an improved understanding of SOC sequestration processes, the ability to make quantitative estimates of rates of SOC sequestration, and technology to enhance these rates in an energy- and input-efficient manner. Adoption of improved tillage practices and cropping systems, increased land cover, and efficient use of nutrient and water inputs are examples where such information is necessary.
  • Authors:
    • Sojka, R. E.
    • Bjorneberg, D. L.
    • Aase, J. K.
  • Source: Transactions of the ASAE
  • Volume: 44
  • Issue: 3
  • Year: 2001
  • Summary: Zone subsoiling on irrigated land has been successfully used to improve potato ( Solanum tuberosum) yield and quality. Zone subsoiling under furrow irrigation may disrupt water flow and influence infiltration and soil erosion. We hypothesized that zone subsoiling, done appropriately, will maintain integrity of irrigation furrows, improve small grain (barley) and dry bean ( Phaseolus vulgaris) growth and yield, and not adversely affect water flow, infiltration, or erosion on furrow-irrigated soils. The experiment, which started in 1995, was conducted at the USDA-ARS Northwest Irrigation and Soils Research Laboratory in Kimberly, Idaho, USA. The soil is a Portneuf silt loam (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcids). Tillage treatments were disc, disc+paratill, paratill, and no-till. There were no differences in water infiltration, runoff, or soil erosion among treatments. Bulk density differences among treatments were largest at the 0.15 to 0.20-m depth, and bulk density was ~16 to 18% greater on disc and no-till treatments than on paratill treatments. The highest frequency of low cone index (CI) values belonged to paratill treatments (65 to 80% frequency of CI values less than 2 MPa); the lowest frequency of low CI values belonged to no-till treatment (20% frequency less than 2 MPa). Cone index versus bulk density relationships depended on soil water content with a slope of 5.81 (r 2=0.70) in the wetter year of 1997, and 2.90 in the drier year of 1995 (r 2=0.60). Subsoiling can be accomplished on furrow-irrigated lands with no adverse effects on runoff, infiltration, and erosion, but under our conditions did not improve crop growth and yield.