• 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:
    • 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.
  • Authors:
    • Hill, J. E.
    • Scow, K. M.
    • Fitzgerald, G. J.
  • Source: Global Biogeochemical Cycles
  • Volume: 14
  • Issue: 3
  • Year: 2000
  • Summary: In response to legislative mandate to reduce postharvest straw burning and environmental concerns to restore wetland habitat for Pacific fly-way waterfowl, California rice growers are incorporating straw into soil and flooding rice fields in winter. These changes were hypothesized to alter soil carbon cycling pathways across the region. The principal objective of this study was to determine how various winter fallowed straw and water management changes would affect year-round methane emissions. Main plots were winter flood and nonflood, and subplots had straw treatments: burned, soil incorporated, or rolled (partially soil incorporated). Results showed the principal factor controlling methane emissions was the interaction of flooding and straw amendments. The presence of either water or straw alone led to low emissions. Winter emissions accounted for 50% of annual totals in straw-amended treatments despite lower temperatures and the presence of plants in summer. Summer emissions were significantly influenced by winter straw amendments but not by winter flood. Postdrain peaks after winter drain accounted for 10-13% of annual emissions in treatments with amended straw. Although rolled and incorporated treatments had similar straw inputs, methane fluxes from rolled treatments were higher than from incorporated treatments. Measurements of methane should be conducted year-round to capture fallow and postdrain fluxes and improve global emission estimates. Regional emission estimates showed that 2.6 times more methane was emitted after flooding plus incorporation was implemented than before the legislative mandate was enacted.
  • 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.
  • Authors:
    • Nacci, S.
    • Ramos, M. C.
    • Pla, I.
  • Source: Soil Science
  • Volume: 165
  • Issue: 5
  • Year: 2000
  • Summary: In the vineyards of the Anoia-Alt Penedes region of NE Spain, erosion problems arising from a combination of soil and climate characteristics and their relief have been accelerated in the last few decades as a consequence of new cropping/planting patterns and soil management practices involving continuous tillage, which leaves the soil bare most of the time. In the rain-fed vineyards of the area, rainfall water conservation in situ has also become a problem that influences the production of high quality wine. The determination of the actual and potential erosion processes required for rational selection, design, and application of soil and water conservation practices requires identification and quantification of the hydrological properties and processes that induce runoff and soil erosion. Laboratory studies in 10 representative surface soils of the region, using simulated rainfall, proved that erosion losses were highly related to the surface sealing susceptibility of the soils, which reduced minimum rainfall water intake rates to 1 to 7 mm h(-1) or less after only 10 minutes of rainfall. This susceptibility was highly correlated with the high silt and low organic matter content of the soils. In most of the soils, surface protection by a cover was found to increase the minimum rainfall water intake rate 50 to 200 times. A simple laboratory test, based on the measurement of saturated hydraulic conductivity and the time to reach its minimum value, measured efficiently the sealing susceptibility of the studied soils and the relative effect of a protective cover. The minimum value of saturated hydraulic conductivity was highly correlated to runoff and soil erosion losses in soil boxes under simulated rainfall.
  • Authors:
    • Ray, D. E.
    • Slinsky, S. E.
    • Graham, R. L.
    • Becker, D. A.
    • de la Torre Ugarte, D.
    • Turhollow, A.
    • Perlack, R. L.
    • Walsh, M. E.
  • Year: 1999
  • Authors:
    • Peters, M.
    • House, R.
    • Lewandrowski, J.
    • McDowell, H.
  • Source: Agricultural Outlook
  • Year: 1999
  • Authors:
    • Parker, J. P.
    • Scott, A.
    • Ball, B. C.
  • Source: Soil & Tillage Research
  • Volume: 53
  • Issue: 1
  • Year: 1999
  • Summary: Tillage practices and weather affect the release of greenhouse gases but there have been few integrated studies of the quantities released or the mechanisms involved. No-tillage may increase emissions of nitrous oxide (N2O) and the fixation of carbon by decreasing carbon dioxide (CO2) emissions. Tillage may also decrease the oxidation rate of atmospheric methane (CH4) in aerobic soil. These effects are partly due to compaction and to the lack of both soil disturbance and residue incorporation. Our objective was to investigate how tillage practices, soil conditions and weather interact to influence greenhouse gas emissions. Here we present early measurements of N2O and CO2 emission and CH4 oxidation in two field experiments in Scotland under a cool moist climate, one involving soil compaction plus residue incorporation and the other involving no-tillage and two depths of mouldboard ploughing of a former grass sward. The experiments were located 10-15 km south of Edinburgh on a cambisol and a gleysol. In order to monitor emissions regularly, at short intervals and over long periods, a novel automatic gas sampling system which allows subsequent automated determination of both N2O and CO2 fluxes was used. Both N2O and CO2 fluxes were episodic and strongly dependent on rainfall. Peak N2O emissions were mainly associated with heavy rainfalls after fertilisation, particularly with no-tilled and compact soils. In the tillage experiment, N2O fluxes and treatment differences were greater under spring barley (Hordeum vulgare L.) (up to 600 g N ha-1 per day) than under winter barley. CO2 emissions in the few weeks after sowing were not strongly influenced by tillage and diurnal variations were related to soil temperature. However, periods of low or zero CO2 fluxes and very high N2O fluxes under no-tillage were associated with reduced gas diffusivity and air-filled porosity, both caused by heavy rainfall. Early results show that CH4 oxidation rates may best be preserved by no-tillage. The quality of the loam/clay-loams and the climate in these experiments makes ploughing, preferably to 300 mm depth, and the control of compaction necessary to minimise soil N2O and CO2 losses. The gas exchange response of different soil types to tillage, particularly methane oxidation rate which is affected by long-term soil structural damage, is a potentially useful aspect of soil quality when taken in conjunction with other qualities.
  • Authors:
    • Camp, C. R.
  • Source: Transactions of the ASAE
  • Volume: 41
  • Issue: 5
  • Year: 1998
  • Summary: A comprehensive review of published information on subsurface drip irrigation was performed to determine the state of the art on the subject. Subsurface drip irrigation has been a part of drip irrigation development in the USA since its beginning about 1960, but interest has escalated since the early 1980s. Yield response for over 30 crops indicated that crop yield for subsurface drip was greater than or equal to that for other irrigation methods, including surface drip, and required less water in most cases. Lateral depths ranged from 0.02 to 0.70 m and lateral spacings ranged from 0.25 to 5.0 m. Several irrigation scheduling techniques, management strategies, crop water requirements, and water use efficiencies were discussed. Injection of nutrients, pesticides, and other chemicals to modify water and soil conditions is an important component of subsurface drip irrigation. Some mathematical models that simulate water movement in subsurface drip systems were included Uniformity measurements and methods, a limited assessment of root intrusion into emitters, and estimates of overall system longevity were also discussed. Sufficient information exists to provide general guidance with regard to design, installation, and management of subsurface drip irrigation systems. A significant body of information is available to assist in determining relative advantages and disadvantages of this technology in comparison with other irrigation types. Subsurface drip provides a more efficient delivery system if water and nutrient applications are managed properly. Waste water application, especially for turf and landscape plants, offers great potential Profitability and economic aspects have not been determined conclusively and will depend greatly on local conditions and constraints, especially availability and cost of water.
  • Authors:
    • Zalom, F. G.
    • van Bruggen, A. H. C.
    • Lanini, W. T.
    • Klonsky, K. M.
    • Ferris, H.
    • Clark, M. S.
  • Source: Agriculture, Ecosystems and Environment
  • Volume: 68
  • Issue: 1
  • Year: 1998
  • Summary: The effectiveness, economic efficiency, and environmental impact of pest management practices was compared in conventional, low-input, and organic processing tomato and field corn systems in northern California. Pests, including arthropods, weeds, pathogens, and nematodes, were monitored over an 8-year period. Although both crops responded agronomically to the production-system treatments, arthropods, pathogens, and nematodes were found to play a relatively small role in influencing yields. In contrast, weed abundance was negatively correlated with tomato and corn yields and appeared to partially account for lower yields in the alternative systems compared to the conventional systems. Lower pesticide use in the organic and low-input systems resulted in considerably less potential environmental impact but the economic feasibility of reducing pesticide use differed dramatically between the two crops. The performances of the organic and low-input systems indicate that pesticide use could be reduced by 50% or more in corn with little or no yield reduction. Furthermore, the substitution of mechanical cultivation for herbicide applications in corn could reduce pest management costs. By contrast, pesticide reductions in tomato would be economically costly due to the dependence on hand hoeing as a substitution for herbicides. Based on the performance of the low-input and organic tomato systems, a 50% pesticide reduction would increase average pest management costs by 50%.