Zone Tillage Research Articles

Conservation tillage systems for cotton advance in the San Joaquin Valley

Cotton production in the San Joaquin Valley has traditionally relied heavily on tillage for its presumed benefits to plant establishment, yields and insect management. Research in the 1960s and 1970s demonstrated the potential of precision or zone tillage, which foreshadowed the introduction of a variety of minimum tillage implements in the early 1990s. During a 3-year comparison study from 2001 to 2003, cotton yields in strip tillage plots matched or exceeded yields of standard tillage plots in all 3 years. In a 12-year study from 1999 to 2011, tillage costs were lowered an average of $70 per acre in 2011 dollars using no-tillage compared to standard tillage while achieving statistically comparable yields, provided that adequate crop stands were achieved. If bottom-line profitability can be maintained, conservation tillage may become increasingly attractive to cotton producers in the San Joaquin Valley.

Genesis, stability and preservation potential of large lateral moraines of Alpine valley glaciers – towards a unifying theory based on Findelengletscher, Switzerland

Lateral moraines are prominent features of glaciated landscapes in high-mountain environments and key landforms in glacier and palaeoclimatic reconstructions, yet, compared to smaller moraines, they have been little studied and several aspects are not well understood. We here present detailed sedimentological results from the lateral moraines of Findelengletscher in SW Switzerland to gain new insights into the formation of these landforms. The lateral moraines studied here stand up to 140 m above the valley floor, are over 3 km long and strongly asymmetrical in cross-profile, with distal slopes between 29 and 36° and proximal slopes that are commonly 41–64°, but locally reach angles of up to 80°. Recorded lithofacies comprise loose clast and matrix-supported, stratified diamicts and intercalated sorted sediments in the distal slopes and near the crestline; overconsolidated matrix-supported, massive and weakly stratified diamicts and streaked-out sorted sediment lenses in the core and proximal slopes; and partly intercalated dark-brown layers overlain by loose and consolidated diamicts exposed in near-vertical walls in the proximal flank. These are interpreted as supraglacial debris flow units with intercalated fluvial ‘wash’ horizons; glaciotectonised and subglacial traction till with boudinaged and streaked-out sediment lenses; and palaeosoils overlain by sediment produced by overtopping of the former moraine surface during a subsequent advance of the glacier. Clast shape analysis and process observations reveal that the dominant mode of transport is subglacial and glaciofluvial, and that the main mode of sediment delivery to the moraines is by debris flows after the material has been transferred from the bed via englacial debris bands and meltout at the surface. This differs from previous studies that found that a supraglacial source was dominant. Sedimentary structures, clast fabric and process observations during the 1979/1980 readvance of Findelengletscher strongly suggest that proximal layers of reworked pre-existing sediments and/or basal traction zone till have been plastered onto the moraine core in several locations, causing a high degree of overconsolidation and strongly-clustered fabric eigenvalues (S1 ≤ 0.94) with clustering parallel to the moraine crestline. This suggests that a combination of basal-lateral drag and lateral plastering produces the observed proximal stability and ensures a high preservation potential. We develop a conceptual model that describes Alpine lateral moraines as structurally complex landforms that do not just record a single event as often surmised, and we discuss implications for palaeo-glacier reconstruction and the application of numerical dating methods.

Conservation tillage for organic agriculture: Evolution toward hybrid systems in the western USA

AbstractOrganic farming has been historically dependent on conventional tillage operations to convert perennial pasture leys to annual crop rotations, incorporate crop residues, compost and cover crops, as well as to mechanically kill existing vegetation. Conventional tillage, however, has long been known to lead to soil degradation and erosion. A recently developed no-till organic production system that uses a roller–crimper technology to mechanically kill cover crops was evaluated in two states in the western United States. In Washington, pumpkins (Cucurbitaspp.) grown in a no-till roller–crimper (NT-RC) system produced yields 80% of conventional tillage, but with fewer weeds. However, in California on-farm research trials in organic cotton (Gossypium barbadenseL.), tomato (Lycopersicon esculentumMill.), eggplant (Solanum melongenaL.) and cowpea (Vigna unguiculata(L.) Walp.), the no-till system produced virtual crop failure, or yields less than 20% of the standard production method. The major problems associated with rolled cover crops in California included reduced crop seedling emergence, planter impediment with excessive residue, lack of moisture and delay in transplanting of vegetable crops due to continued growth of cover crops, in-season crop competition from cover crop regrowth and impracticability of using cultivators. Further, excessive dry residue during summer in California can present the risk of fire. In both California and Oregon, considerable success has been demonstrated with zone tillage (strip tillage) in conventionally produced field and vegetable crops. In a replicated Oregon trial, the organic strip tillage treatment produced 85% of the broccoli (Brassica oleraceaL.) yield compared to a conventional tillage treatment. Our studies suggest that the zone tillage concept may offer opportunities to overcome many of the agronomic challenges facing no-till.

Use of a partial-width tillage system maintains benefits of no-tillage in increasing total soil nitrogen

Tillage treatments had impact on total soil nitrogen (N) storage and consequently on soil carbon (C) sequestration. The objective of this study was to assess effects of long-term (1992–2010) tillage practices, including a partial-width tillage system (paraplow) on N concentration and stratification. The tillage treatments were: no-tillage (NT), minimum tillage (18–22 cm depth) with chisel plow (MT), conventional tillage (25–30 cm depth) with mouldboard plow (CT) and zone-tillage subsoiling (25–30 cm) with a paraplow (ZT) applied in alternate years in rotation with NT. The soil was a Calcic Haploxeralf from Central Spain. The crop rotation was chick pea ( Cicer arietinun L.) cv. Inmaculada/barley ( Hordeum vulgare L.) cv. Volley. The equivalent mass approach was used to compare N stocks in the various tillage methods. Tillage treatments had significant effects on soil bulk density and no-till increased soil bulk density of the top layer. At the end of 19 years, the stocks of N had increased under NT compared with MT and CT. Most changes occurred within the 0–5 cm layer, where plots under NT had 0.48 Mg N ha −1 and 0.53 Mg N ha −1 greater than in MT and CT, respectively. Zone tillage maintained most of the long-term benefit of NT in increasing N stocks in the top layer (0–5 cm). At the end of the experiment, total N concentration in the 0–5 cm depth under ZT was 42% and 53% higher that under MT and CT, respectively. Stratification ratios of N from 1992 to 2000 showed no significant differences between NT, MT and CT. In contrast, from 2001 onwards, all stratification ratios were significantly higher in NT than in the other two tillage systems. In addition, in 2010 the stratification ratio of N in NT was >2 and more than 2-fold those obtained in MT and CT. Values of stratification ratios under ZT followed the same trend than under NT and were significantly greater than under MT or CT. These greater stratification ratios of N observed under NT and ZT confirm, in the soil studied, not only the benefits associated with the long-term application of no-till in increasing total N in the top layer, but also the positive impact of the use of a paraplow as a rotational tillage system.

Zone Tillage Impacts on Organic Carbon of a Clay Loam in Southwestern Ontario

No-till (NT) management can reduce corn (Zea mays L.) yields relative to moldboard plow tillage (MP) on fine-textured soils in cool humid climates. Zone tillage (ZT) consists of tilling the corn row only (zone in, ZI) and leaving the interrows uncultivated (zone out, ZO) and has increased corn yields relative to NT. In this study, soil organic C (SOC) content, bulk density, and penetration resistance were compared among ZT, ZI, ZO, MP, and NT for a Brookston clay loam soil (Typic Argiaquoll) in southern Ontario, Canada. Relative to MP, NT produced SOC stratification, with significantly greater SOC in the surface soil (0-5 cm) but lower SOC in the subsurface soil (10-30 cm). Zone tillage produced SOC and total soil N levels that were similar to NT near the soil surface but similar to MP in the subsurface. On an equivalent soil mass basis (4570 Mg ha ―1 ), ZT increased SOC storage (80.6 Mg C ha ―1 ) by 11.2 and 12.5% compared with NT and MP, respectively. Penetration resistance and bulk density at the 0- to 20-cm depth were lower in ZI than the other tillage treatments. Soil moisture content at the 0- to 12-cm depth under ZO was similar to NT and both were greater than ZI and MP. Zone tillage did not reduce stratification of SOC or total soil N; however, ZI decreased bulk density stratification. We concluded that ZT has the potential to improve both SOC sequestration and selected soil properties relative to NT and MP on fine-textured soils in cool, humid climates.

Effect of direct incorporation of poultry litter on phosphorus leaching from coastal plain soils

Management of poultry litter on the Delmarva Peninsula is critical to reducing phosphorus losses to the Chesapeake Bay. New poultry litter incorporation technologies have shown promise at reducing phosphorus losses, but their effectiveness has not been tested in this environmentally sensitive region. This study evaluates subsurface leaching losses of three litter application methods, including surface broadcast, surface broadcast with disking, and subsurface litter incorporation with a novel litter incorporator developed by the USDA Agricultural Research Service. Cube-shaped soil lysimeters (61 × 61 × 61 cm (24 × 24 × 24 in)) were extracted from high phosphorus (P) (Mehlich-3 P is greater than 500 mg kg -1 ) agricultural soils on the University of Maryland Eastern Shore Research Farm near Princess Anne, Maryland, and were subjected to two rainfall simulation events that were separated by 11 semiweekly soaking-type irrigation events. The average cumulative total phosphorus loss was highest for the subsurface litter incorporation method (0.48 kg ha -1 (0.43 lb ac -1 )) and was lowest for the no litter control (0.19 kg ha -1 (0.17 lb ac -1 )). Particulate P loss among manure treatments ranged from 58% to 64% of total P loss. Total phosphorus losses were strongly correlated to total phosphorus concentration in the leachate (coefficient of determi- nation (r 2 ) ≥ 0.84), indicating availability of P in applied litter to be the primary control of P in leachate. Soil properties also impacted P leaching losses, with the soils possessing a higher sand content and having a shallower depth to the sandy subsoil, yielding higher cumulative total P losses (0.64 kg ha -1 (0.57 lb ac -1 )). Although the subsurface litter incorporator increased total P leaching losses, a concern on the Delmarva Peninsula, opportunity exists to modify the subsurface incorporator design using zone tillage, potentially reducing the leaching losses.

Zone Tillage Depth Affects Yield and Economics of Corn Silage Production

Increasing numbers of dairies in northeastern United States are classified as confined animal feeding operations (CAFOs). Many dairy farmers in New York (NY) abandoned conventional and adopted zone tillage (ZT) in 4‐yr corn (Zea mays L.) silage‐alfalfa (Medicago sativa L.) rotations on highly erodible land to comply with NY CAFO plans. Farmers now question optimum ZT depth because of increased diesel costs. The objective of this 2‐yr NY study was to determine optimum ZT depth for corn silage in continuous corn and first‐year corn following alfalfa. The ZT depth (with attached Aerway implement), evaluated at 0, 18, and 36 cm, did not affect surface residue (∼34%), plant densities (71,605–73,998 plants ha−1), and dry matter (DM) accumulation at the 12th leaf stage (334–365 g m−2). Significant contrasts were observed between 18 vs. 0 cm for DM yield (19.9 and 18.7 Mg ha−1) and N uptake (236 and 219 kg ha−1, respectively), but not between 18 vs. 36 cm (19.7 Mg ha−1 and 237 kg ha−1).The ZT depth did not affect silage quality. Partial budget analyses indicate that reducing ZT depth from 36 to 18 cm increases profit by ∼$30 ha−1 because of decreased labor ($1.48 ha−1), fuel ($5.88 ha−1), and equipment repair and maintenance costs ($3.01 ha−1) and increased return from higher yield ($21.98 ha−1, offset by $2.57 ha−1 increased harvest cost). We recommend an 18‐cm ZT depth for corn silage in a 4‐yr corn silage‐alfalfa rotation on silt loam soils in northeastern United States.

Use of an integrative soil health test for evaluation of soil management impacts

AbstractUnderstanding the response of soil quality indicators to changes in management practices is essential for sustainable land management. Soil quality indicators were measured for 2 years under established experiments with varying management histories and durations at four locations in New York State. The Willsboro (clay loam) and Aurora (silt loam) experiments were established in 1992, comparing no-till (NT) to plow-till (PT) management under corn (Zea maysL.)–soybean (Glycine maxL.) rotation. The Chazy (silt loam) trial was established in 1973 as a factorial experiment comparing NT versus PT and the crop harvesting method (corn silage versus corn grain). The Geneva (silt loam) experiment was established in 2003 with vegetable rotations with and without intervening soil building crops, each under three tillage methods (NT, PT and zone-till (ZT)) and three cover cropping systems (none, rye and vetch). Physical indicators measured were wet aggregate stability (WAS), available water capacity (AWC) and surface hardness (SH) and subsurface hardness (SSH). Soil biological indicators included organic matter (OM), active carbon (AC), potentially mineralizable nitrogen (PMN) and root disease potential (RDP). Chemical indicators included pH, P, K, Mg, Fe, Mn and Zn. Results from the Willsboro and Aurora sites showed significant tillage effects for several indicators including WAS, AWC, OM, AC, pH, P, K, Mg, Fe and Mn. Generally, the NT treatment had better indicator values than the PT treatments. At the Chazy site, WAS, AWC, OM, AC, pH, K and Mg showed significant differences for tillage and/or harvest method, also with NT showing better indicator values compared to PT and corn grain better than corn silage. Aggregate stability was on average 2.5 times higher in NT compared to PT treatments at Willsboro, Aurora and Chazy sites. OM was also 1.2, 1.1 and 1.5 times higher in NT compared to PT treatments at Willsboro, Aurora and Chazy sites, respectively. At the Geneva site WAS, SH, AC, PMN, pH, P, K and Zn showed significant tillage effects. The cover crop effect was only significant for SH and PMN measurements. Indicators that gave consistent performance across locations included WAS, OM and AC, while PMN and RDP were site and management dependent. The composite soil health index (CSHI) significantly differentiated between contrasting management practices. The CSHI for the Willsboro site was 71% for NT and 59% for PT, while at the Aurora site it was 61% for NT and 48% for PT after 15 years of tillage treatments.

Is Deep Zone Tillage Agronomically Viable in Minnesota?

Deep zone tillage is a strategy used to alleviate compaction problems, including plow pans, and to improve internal drainage. Midwestern soils do not typically form a defined plow pan under normal production practices. Despite lack of scientific evidence for yield benefits associated with deep tillage, it is still used in Minnesota as a low cost alternative to tile drainage. To evaluate the soil and economic impact of deep zone tillage on crop yield when a restrictive layer is lacking, a 20-acre field was deep zone tilled to a 20-inch depth, every other 12 rows at 30-inch spacing. After zone tilling, the entire field was ridge tilled. Ridge tillage confines wheel traffic to the same rows, reducing the percent of the field trafficked. All crop and soil measurements were collected in the depressional and upland areas of the field to distinguish if zone till is of benefit in different landscape areas. Crop yields were measured for two seasons following zone tilling a ridge-tilled field. Zone till failed to increase corn and soybean yields. A restrictive layer was not observed in this field and as a result, potential economic losses occurred due to deep zone tillage.

Zonejection: Conservation Tillage Manure Nutrient Delivery System

Manure application in minimum till (MT) systems is a challenge worthy of attention because residue cover is a keystone for environmental protection. To develop a system combining zone tillage and manure application into one operation (zonejection), two experiments were conducted. In Exp. 1, liquid swine manure (LSM) was applied in fall or spring for two site years (A, B). In Exp. 2, LSM was zone‐applied either all preplant (PP) or split between preplant and sidedress (SP) for three site years (C, D, E). In both experiments, dietrich (DMI), vibro shank (VS), or subsurface deposition (SSD) applied the LSM, corn (Zea mays L.) was seeded in the manured zone, and NO3–N movement was monitored. Nutrients were supplied by inorganic fertilizer (IF) in control treatments under conventional till (CT), no till (NT), and zone till (ZT). With fall‐applied LSM, after a mild winter, more N was lost from the soil–plant system (i.e., 35 kg ha−1 soil NO3–N) than after a cold winter with snow cover (18 kg ha−1), and corn grain yield was reduced (by 1.2 Mg ha−1), even though supplemental fertilizer N was sidedressed. In Exp. 2, with LSM zoned all PP or SP, grain yield and N use efficiency were comparable to that with IF, except when double the crop N requirement was zoned all PP (Site D). Planting into a zone of concentrated LSM (3.4 S m−1) reduced grain yield when the LSM was injected by VS. With careful management, zonejection allows efficient utilization of manure nutrients while preserving residue cover.

Cover Crop Effects on the Activity-Density of the Weed Seed PredatorHarpalus rufipes(Coleoptera: Carabidae)

Cover crop systems were investigated in 2004 and 2005 for their effects on the activity-density (a function of movement and density) of a promising group of weed biocontrol organisms, the ground beetles collectively known as carabids, with particular emphasis on a beneficial carabid speciesHarpalus rufipesDeGeer. MarkedH. rufipesreleased into pea/oat–rye/vetch cover crop plots were more than twice as likely to be recaptured within the same plots as beetles released in nonvegetated fallow plots (18 and 8%, respectively). Marked beetles released into fallow plots were more than twice as likely to leave their plots and be recaptured in pea/oat–rye/vetch plots as vice versa (13 vs. 5%), indicating a clear preference for habitat with vegetative cover. Overall recapture rates were not different between treatments. UnmarkedH. rufipesactivity-density was also higher in pea/oat–rye/vetch compared to fallow plots. Additionally, five cover crop systems, including the fallow and pea/oat–rye/vetch treatments, and two residue management methods (conventional and zone tillage) were investigated from June to August in 2005 for their effects onH. rufipesactivity-density. Corn was planted in 2005 into residues of the five cover crop systems grown in 2004.H. rufipesactivity-density was higher in zone and conventionally tilled corn planted in pea/oat–rye/vetch residues and conventionally tilled corn planted in red clover/oat residues than in any other cover crop and residue management combination. Pea/oat–rye/vetch cover crop systems are apparently beneficial forH. rufipesduring the cover crop year as well as in subsequent crops planted into this cover crop's residues. This system was not the least disturbed system but, based on the number of tillage events, represented a medium level of disturbance among the various systems. Thus, some level of disturbance might be beneficial forH. rufipes, but how and when that soil disturbance occurs requires further research to determine the best means of conserving this species.

Deposition of Ti–6Al–4V using a high power diode laser and wire, Part I: Investigation on the process characteristics

In this paper the deposition of Ti–6Al–4V wire with High Power Diode Laser was investigated by producing single tracks. The effect of the wire feeding direction and angle was firstly studied. The influence of laser power, traverse speed and wire feed rate on the weight and dimension of the deposited single tracks was then investigated. The microstructure and hardness of the single tracks were examined. Deposition with diode laser and wire was proved to provide a high deposition rate with good quality. Columnar grains were found in the deposits. Wire feeding orientation, laser power, traverse speed and wire feed rate were verified as factors which influenced the quality of the deposit. With similar energy level, different power/traverse speed produced deposits with different hardness value. Hardness values tended to increase from the deposit, via the re-melted zone till to the heat affected zone, and then decrease again when the measurements were taken in the unaffected base material.

Energy Inputs for Conservation and Conventional Primary Tillage Implements in a Clay Loam Soil

An instrumented research tractor was used to determine the energy inputs for eight primary tillage implements applied to a Brookston clay loam soil in southwestern Ontario, Canada. The energy measurements included draft, fuel consumption (L ha-1), and specific fuel consumption (L GJ-1), which is an indicator of tractor-implement match. Implements included moldboard plow, chisel plow, disk ripper, combination chisel sweep, disk harrow, fluted coulter, deep zone till, and shallow zone till. The study was conducted over four years (2002-2005) using a randomized complete block design with fall primary tillage occurring in the wheat phase of a corn-soybean-winter wheat rotation. The disk harrow and fluted coulter were not effective primary tillage implements due to penetration of only 50 to 60 mm into the clay loam soil. Operating depth for the other six implements was 170 to 190 mm, except for deep zone till which was designed to operate at about 340 mm depth to loosen compacted subsoil and break up plow pans. The mean drafts for these implements ranged from 16.3 kN m-1 for the deep zone till to 5.0 kN m-1 for the shallow zone till. Fuel consumption ranged from 21.6 L ha-1 for the moldboard plow to 6.5 L ha-1 for the shallow zone till. Specific fuel consumption ranged from 110 L GJ-1 for the deep zone till to 204 L GJ-1 for the disk harrow. The large ranges in implement draft, fuel consumption, and tractor efficiency indicate that substantial energy savings can be readily obtained by selecting energy-efficient tillage implements and by proper matching of the tractor size and operating parameters to the tillage implement.

Overcoming Compaction Limitations on Cabbage Growth and Yield in the Transition to Reduced Tillage

Vegetable producers are increasingly interested in adopting conservation tillage practices to maintain or enhance productivity and soil health, but reducing tillage may reduce yields in cool climates. Strategies to transition from full-width tillage to zone tillage systems for cabbage (Brassica oleracea L. Group capitata) were tested with the goals of overcoming soil temperature and compaction limitations and producing crop yield and quality equivalent to conventionally tilled. Designed to achieve differential soil temperature and compaction levels, the treatments were factorial combinations of two widths of zone tillage (15 and 30 cm) and two depths of zone tillage (10 and 30 cm) plus a conventional rototilled treatment (full width and 20-cm depth) as a control. To assess the effect of treatments in the transitional year to reduced tillage, the experiment was conducted in 2003 and 2004 at different fields that were previously conventionally tilled. Increasing tillage width from 15 cm to 30 cm increased soil temperature by 1 °C in both years but had a limited effect on cabbage growth and no effect on yield. Tillage width and soil temperature may have greater impact on an earlier planting. By contrast, increasing tillage depth from 10 cm to 30 cm reduced soil penetrometer resistance by up to 1 MPa, increased plant growth by 28%, and increased yield by 22%. Growth and yield in 30-cm depth treatments were similar to conventional tillage, indicating the undisturbed, between-row areas in zone tillage treatments did not restrict growth. Zone tillage did not affect cabbage maturity or quality. Tillage depth was more important to the success of this system than tillage width; vertical tillage to 30-cm depth left between 60% and 80% of the soil surface area undisturbed and can be an effective transition to conservation tillage for transplanted cabbage.

Response of potatoes to reduced tillage and different nitrogen fertility levels

Conventional tillage in potato production can reduce organic matter levels and cause soil loss. This study compared effects of conventional tillage and zone tillage on plant emergence, weed control, and yield parameters of Russet Burbank potato at nitrogen rates of 0, 50, 100 and 150 kg ha-1. Inconsistent plant emergence across years was likely due to variable weather and planting dates rather than tillage treatment. There were no significant differences between conventional and zone tillage on weed species, weed numbers, weed biomass, or tuber French fry colour. Marketable tuber numbers and total yield were reduced by zone tillage. Nitrogen rate had no effect on any of the variables with the exception that 150 kg ha-1 nitrogen reduced tuber specific gravity compared to the lower rates. Key words: Potato, zone tillage, conventional tillage, nitrogen fertility, tuber number, tuber yield

Corn and Soybean Production as Affected by Tillage Systems

Although continuous no‐till (NT) cropping systems are appropriate on highly erodible land, concern among producers about potential yield reductions has limited NT adoption in the northern Corn Belt, especially on poorly drained soils. The objectives of this 4‐yr study were to quantify the effects of rotational full‐width tillage compared with long‐term NT and zone‐tillage (ZT) systems with and without in‐season row cultivation (RC) on corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] yield and economic return. The study was conducted on a tile‐drained Nicollet–Webster clay loam soil complex. Sixteen of the 18 treatments comprised a factorial arrangement of three factors: (i) tillage for corn following soybean [NT, 38‐cm deep fall ZT, 20‐cm deep fall strip‐tillage (ST), or spring field cultivate (SFC)], (ii) tillage for soybean following corn [NT or fall chisel plow (CP) plus SFC], and (iii) in‐season RC for corn (with or without). Four‐year average corn grain yields were greater for ST and ZT (10.1 Mg ha−1) compared with SFC (9.7 Mg ha−1) and NT (9.6 Mg ha−1) tillage for corn. No‐tillage for the previous year's soybean crop reduced corn yields in two of 4 yr compared with full width (CP+SFC) tillage. Moreover, when full‐width tillage for soybean was rotated with ZT or ST for corn, these treatments produced greater corn yields and economic returns than annual full‐width tillage systems. Soybean yields were maximized by rotational tillage; however, the small differences in yields found among the tillage systems did not result in an economic return to full‐width tillage practices. When both corn and soybean production was considered, rotational tillage practices were likely to maximize yields but not economic return.

Soybean Response to Zone Tillage, Twin‐Row Planting, and Row Spacing

Although zone tillage can result in favorable in‐row seedbed environments for high crop yield while providing soil conservation characteristics similar to no‐till, it necessitates a wide row width planting system. The objective of this study was to evaluate various zone‐till systems for soybean [Glycine max (L.) Merr.] production. This study was conducted in southwestern Ontario from 1998 to 2000 on nine fields with clay contents between 133 and 354 g kg−1 and a minimum 5‐yr continuous no‐till history. Tillage systems evaluated were fall moldboard, fall zone‐till 15‐ and 30‐cm deep, spring coulter tillage, and no‐till. The no‐till and moldboard systems were planted in equally spaced 19‐, 38‐, 57‐, and 76‐cm rows plus a twin‐row configuration consisting of two 19‐cm rows centered 76 cm apart. Only single 76‐cm and twin‐row configurations were planted in the zone‐till and coulter‐till systems, where tillage was conducted in strips centered 76 cm apart. Twin‐row configurations in no‐till, spring coulter‐till, and fall zone‐till systems often increased yields over those obtained with single 76‐cm rows, with yields that were always similar to those obtained with no‐till planted in 38‐ or 19‐cm rows. Depth of fall zone tillage did not affect soybean yield. Fall zone‐till yields never exceeded those obtained with no‐till, even in environments where no‐till yields were less than those obtained with fall moldboard systems. Spring coulter tillage did not increase yields over those obtained with no‐till. Future research evaluating zone‐till systems for soybean should consider using twin‐row planting configurations.

Improving Root Health and Yield of Dry Beans in the Nebraska Panhandle with a New Technique for Reducing Soil Compaction.

A field study conducted during the 2001 and 2002 growing seasons investigated the integration of fungicide applications and tillage methods for reducing root health problems in dry bean (Phaseolus vulgaris) plants by alleviating soil compaction and its potential exacerbation of root disease. Several cultural practices were combined with applications of the strobilurin fungicide azoxystrobin. Soil compaction was created artificially throughout the entire plot area. Six treatments, consisting of four tillage treatments and two combinations of tillage or applications of azoxystrobin, were tested to alleviate the compaction and enhance root health. Tillage treatments included a compacted control with no additional tillage, formation of beds approximately 10 cm above soil surface, zone tillage with an implement using in-row shanks, and both zone tillage and bedding combined. Fungicide treatments utilized the combination of both zone tillage and bedding with fungicide applications, and a fungicide treatment singly. Effects of compaction on plant vigor and disease development and severity were evaluated 67 and 83 days after planting in 2001 and 2002, respectively, by a visual estimation of plot vigor and by destructively sampling and making root and hypocotyl disease ratings on dry bean plants from nonharvest rows. Soil resistance and moisture were measured in plots 80 and 104 days after planting in 2001 and 2002, respectively, to estimate degree of compaction. In both years, Fusarium root rot, caused by Fusarium solani f. sp. phaseoli, was determined to be the main root disease impacting plant health in studies. All measured variables (root disease index, plant vigor ratings, total seed yield, seed size, and soil resistance) were significantly improved by any treatment that included zone tillage prior to planting. No added advantages were observed for decreasing disease or improving root health and plant performance with the use of azoxystrobin or by planting on raised beds. This is the first study to evaluate zone tillage as a method of reducing plant stress and root disease in dry bean plants.

Zone tillage systems for onion and carrot production on muck soils

This study examined whether zone tillage was a viable alternative to conventional tillage for carrot [Daucus carota L. var. sativus (Hoffm.) Arcang.] and onion (Allium cepa L.) production on muck soils. Total and marketable yields under zone tillage were e qual to (carrot) or greater than (onion) yields under conventional tillage. Carrot yields did not differ between raised and flat bed treatments. Key words: Reduced tillage, conventional tillage, Daucus carota L. var. sativus (Hoffm.) Arcang.); Allium cepa L.

Reduced Tillage Alternatives for Machine-harvested Cucumbers

Cucumber (Cucumis sativus L.) is grown using intensive tillage practices, which increase the cost of production and may lead to an increase in soil and water erosion. Research on alternative tillage practices for cucumber production has been limited primarily to exploring the benefits of no tillage. Alternative tillage practices, such as disking (one pass with a tandem disk) and zone tillage (one pass with a Trans-till) have not been investigated. Thus, the objective of this study was to compare the influence of reduced tillage practices on the growth, development, and yield of cucumbers. Seedling emergence varied between years, but was unaffected by a reduction in tillage, while cucumber leaf number, leaf area index, and vine growth were reduced by no tillage (P ≤ 0.05). Total dry matter accumulation and days to 50% open flower varied with tillage. No-tillage plots produced an average of 34 g·m-2 of dry matter compared to 47 g·m-2 for conventional tillage plots and took 1 day longer to reach 50% flower. Although growth differences were observed under all reduced tillage treatments, no reduction in total yield was observed when compared with conventional tillage yields. Alternative reduced tillage practices, such as disking or zone tillage, were found to be viable options for successful cucumber production. These alternative practices will reduce the cost of production, provide growers with greater time flexibility and ease of land preparation, and reduce the potential for water and wind erosion.