• 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:
    • Williams, S.
    • Schuler, J.
    • Killian, K.
    • Kautza, T.
    • Elliott, T.
    • Easter, M.
    • Cipra, J.
    • Bluhm, G.
    • Paustian, K.
    • Brenner, J.
  • Year: 2001
  • Summary: Land managers have long known the importance of soil organic matter in maintaining the productivity and sustainability of agricultural land. More recently, interest has developed in the potential for using agricultural soils to sequester C and mitigate increasing atmospheric carbon- dioxide by adopting practices that increase standing stocks of carbon in soil organic matter and vegetation. Practices that increase the amount of CO2 taken up by plants (through photosynthesis), which then enter the soil as plant residues, tend to increase soil C stocks. Likewise, management practices that reduce the rate of decay or turnover of organic matter in soils will also tend to increase carbon stocks.
  • 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:
    • Schillinger, W. F.
  • Source: Soil Erosion Research for the 21st Century, Proc. Int. Symp. (3-5 January 2001, Honolulu, HI, USA). Eds. J.C. Ascough II and D.C. Flanagan. St. Joseph, MI: ASAE.701P0007
  • Year: 2001
  • Summary: Water runoff and soil loss from wheat fields in the inland Pacific Northwest (PNW) USA is often severe during the winter when rain or snow melt occur on frozen soils. Annual precipitation in this region varies from 150 to 600 mm and characteristically 60% occurs between November and March. Water erosion in the wheat-fallow rotation is most severe during the winter of the crop year because of the winter precipitation pattern, long steep slopes, very little ground cover from crop residue or wheat seedlings, and low water infiltration rates through frozen soil. Additional management practices are needed to combat erosion events associated with frozen soil. Research was conducted at 9 on-farm sites in eastern Washington state from 1993 to 1999 to determine the effects of subsoiling fall-sown wheat on 15 to 40% slopes prior to soil freezing on soil loss, water infiltration into the soil, and grain yield. The experimental design at each site was a randomized complete block with 6 replications of 2 treatments: subsoiled and control. Two types of subsoilers were used over the 6-yr period: (i) a 5-cm-wide shank operated 40 cm deep on the contour with shanks spaced 4 or 6 m apart to cut a continuous groove in the soil, and (ii) a rotary 'sharks tooth' implement which creates a 40 cm deep, 4-litre-capacity hole every 0.7 m 2. The sharks tooth subsoiler causes less soil disturbance and less damage to wheat plants than continuous shank channels. Results show that, when water runoff on frozen soils occurs, tillage channels or holes (i) reduce soil loss by retarding rill erosion, (ii) increase water infiltration, and (iii) do not reduce or increase grain yield. Many wheat growers have started to adopt these, or similar, soil conservation practices on their farms.
  • Authors:
    • Spurlock, S. R.
    • Elmore, C. D.
    • Wesley, R. A.
  • Source: Agronomy Journal
  • Volume: 93
  • Issue: 1
  • Year: 2001
  • Summary: Deep tillage (subsoiling) of clayey soils in the fall when the profile is dry is a new concept that results in increased yields and net returns from soyabean (Glycine max) grown without irrigation. Crop rotation may also result in increased crop yields. Field studies were conducted on Tunica clay (clayey over loamy, smectitic, nonacid, thermic, Vertic Haplaquept) near Stoneville, Mississippi, USA (33degrees 26′ N lat), during 1993-97, to determine the individual and combined effects of fall deep tillage and crop rotations on crop yields and net returns. Treatments included monocrop cotton (Gossypium hirsutum cultivars DES 119 and Suregrow 125), soyabean (cultivars Pioneer 9592 and DPL 3588), and grain sorghum ( Sorghum bicolor cv. Pioneer 8333), and biennial rotations of cotton with grain sorghum and soyabean with grain sorghum grown without irrigation and in either a conventional-till (CT) or deep-till (DT) production system. Yields from all cotton and soyabean crop sequences grown in the DT respectively averaged 541 kg ha -1 and 525 kg ha -1 greater than comparable cotton (2184 kg ha -1) and soyabean (2983 kg ha -1) crop sequences grown in the CT. Net returns from monocrop cotton ($552 ha -1) and soyabean ($462 ha -1) in the DT respectively averaged $392 ha -1 and $121 ha -1 more than similar crop sequences in the CT. Rotations increased cotton and soyabean yields but not net returns because of the low value of the grain sorghum component. These data indicate that fall deep tillage should be incorporated into monocrop cotton and soyabean crop sequences to maximize and stabilize net returns from these crops on Tunica clay.
  • 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.
  • Authors:
    • Rivero, M. L.
    • Sasal, C.
    • Andriulo, A.
  • Source: Siembra Directa II
  • Year: 2001
  • Summary: Notes are given on the role of conservation production in the reduction of greenhouse gases. Responses of soil carbon to agricultural practices, the introduction of agriculture to native vegetation, and conversion of cultivated land to perennial vegetation are discussed. The effects of tillage, integration of residues, mulching and cover crops are also considered. Emissions and capture of carbon dioxide in rough pampas are described, with reference to continuous agriculture, conservation production and potential for capture of carbon by conservation production systems.
  • Authors:
    • Kayisoglu, B.
    • Yalcn, H.
    • Koc, F.
    • Gonulol, E.
    • Bayhan, Y.
  • Source: Farm work science facing the challenges of the XXI century. Proceedings XXIX CIOSTA-GIGR V Congress, Krakow, Poland, 25-27 June, 2001, p. 30-35
  • Volume: 10
  • Year: 2001
  • Summary: The effect of different tillage methods on silage quality in second crop maize for silage was determined in this study. For this purpose, second crop maize was planted by using the following tillage methods: (1) Direct drilling (no-till) (DRD); (2) Heavy duty disc harrow+pneumatic precision drill (DIS); (3) Plough+disc harrow+roller+pneumatic precision drill (PLO); (4) Rotary tiller+pneumatic precision drill (ROT); (5) Tillage combination+pneumatic precision drill (TIC); and (6) Irrigation+Plough+disc harrow+roller+pneumatic precision drill (conventional) (CON). After harvesting, plant samples were filled into PVC silos (with three replication for each treatment) for fermentation and kept in these silos for 75 days. Significant statistical differences were found between treatments (tillage methods) according to pH, DM (dry matter), CA (crude ash), CF (crude fibre), WSC (water soluble carbohydrate), NH 3-N 3 and LAB (lactic acid batteries). Quality parameters in all treatments remained between the desired levels. No-tillage method with DRD and minimum tillage methods with ROT and TIC can be suggested.