In-row Cultivation Research Articles

FLUE-CURED TOBACCO IN A STRIP-TILL PRODUCTION SYSTEM

Abstract A four-year study was conducted to compare the effects of strip-till tobacco production under crop rotation to conventional-till tobacco on a South Carolina Coastal Plain soil. A separate two-year study was conducted to define the impact of in-row cultivation and nitrogen application rate on conservation-till tobacco production. Flue-cured tobacco was planted into strip-till without bedding or into a conventional bedded production system. All plants received in-row sub-soiling. In-row cultivation of strip-till tobacco and conventional-till tobacco were evaluated under three nitrogen levels: 78.4, 95.2, and 112.0 kgN/ha. Strip-till tobacco production resulted in a negative impact on tobacco yield, quality, and lodging. The negative attributes of strip-till tobacco production can be partially overcome by cultivation. Increased nitrogen tended to improve yields, but at the expense of leaf quality and chemistry. Crop rotation resulted in significantly improved tobacco yields and value, and reduced ro...

Mechanical In-Row Weed Control in Transplanted and Direct-Sown Bulb Onions

ABSTRACT Different strategies for mechanical in-row weed control were evaluated in direct-sown and transplanted bulb onions (Allium cepa) in terms of in-row weeds, labour requirements for hand weeding and marketable yield. Transplanted onions generally performed much better than direct sown onions. The best strategies in transplanted onions decreased the hand weeding time by 70% and increased marketable yield by 96% compared with the best strategies in direct-sown onions. In transplanted onions, one weed harrowing and three in-row cultivations with torsion weeders reduced in-row weed numbers by 85%, reduced hand weeding time by 73%, and caused no yield reduction compared with the normal strategy of one weed harrowing and ordinary inter-row cultivation. In direct-sown onions, pre-emergence flame weeding and repeated torsion weeding reduced hand weeding time by 40% and caused no yield reduction compared with flame weeding and inter-row cultivation. The effectiveness of in-row cultivation was very dependent on the timing of treatments. Using transplanted onions and in-row weed control is a way to ensure high yields and reduce labour requirements for hand weeding compared with direct-sown onions and inter-row cultivation.

Mycorrhizal Colonization in Dryland Vineyards of the Willamette Valley, Oregon

Abstract Arbuscular mycorrhizal fungi (AMF) enhance the growth of numerous plants, including grapevines, by increasing the absorptive surface area between roots and soil. A survey of commercial vineyards in Oregon was conducted to assess the levels of root colonization by AMF at two times during the growing season. Grapevines sampled, ranged in age from 2 to 29 years old and were growing in 10 different soil types from 3 soil orders. AMF colonization of fine (feeder) roots of vines was generally high, averaging 73% and 69% of root length colonized at bloom and veraison, respectively. Vine age, soil type, cultivar, trellis type and vine row aspect did not influence colonization of roots by AMF. In-row cultivation reduced AMF colonization at bloom, and foliar application of soluble phosphorus fertilizers reduced arbuscules (the site of nutrient transfer in mycorrhizas) in roots at veraison. The proportion of roots colonized by AMF at bloom was negatively correlated to leaf N concentrations and positively co...

Effect of in-row cultivation, herbicides, and dry bean canopy on weed seedling emergence

Field experiments were conducted in 1996 and 1997 to evaluate the effect of EPTC (S-ethyl dipropyl carbamothioate) plus ethalfluralin at 2.4 plus 0.83 kg ai ha−1, rotary hoeing, in-row cultivation, rotary hoeing plus in-row cultivation, and dry bean canopy on weed seedling emergence. Cumulative weed emergence in 1996 and 1997 was similar in cropped and noncropped areas. Herbicides were more effective than mechanical cultivation in reducing weed emergence 91% in 1996 and 88% in 1997. Weed emergence was similar in both rotary hoed area and cultivated area in 1996 but weed emergence was 44% lower in rotary hoed plots than in cultivated plots in 1997. The Gompertz equation did not adequately predict weed seedling emergence in the untreated control and with in-row cultivation in 1996. Initial weed seedling emergence was observed at about 120 growing degree-days with 3 to 9% cumulative emergence among treatments. In 1997, the Gompertz equation adequately described weed seedling emergence in plots with or without disturbed soil. Weed emergence was first observed at 80 growing degree-days with 6 to 16% cumulative emergence among treatments. Predicted percent weed emergence closely approximated observed emergence in 1996 and 1997. Rotary hoeing plus in-row cultivation reduced maximum percent emergence rate 37% on an average. The greater maximum percent emergence rate obtained with in-row cultivation suggests that this treatment increased weed seedling emergence in 1997. On average, weed seedling emergence in the untreated check was lower in cropped areas than in noncropped areas, implying a competitive effect by the dry bean crop. Although weed seedling emergence occurred throughout the growing season, more weed seedlings emerged in June and early July than in late July and August.

Weed Control and Dry Bean (Phaseolus vulgaris) Response to In-Row Cultivation, Rotary Hoeing, and Herbicides1

Field experiments were conducted in 1996 and 1997 to evaluate weed control and dry bean response to mechanical tillage and herbicide treatments. Herbicide treatments were EPTC plus ethalfluralin, dimethenamid, and imazethapyr plus bentazon. Herbicides were applied alone or combined with rotary hoeing and in-row cultivation. Differences in dry bean yields between years were due to differences in weed density. Weed species included redroot pigweed, common lambsquarters, hairy nightshade, wild proso millet, and green foxtail. Weed density in the untreated check plots at the end of the growing season was 35 plants/m2 in 1996 and 134 plants/m2 in 1997. Dry bean stands were not reduced by rotary hoeing, in-row cultivation, and herbicides in 1996, but in-row cultivation reduced dry bean populations 27% compared to the hand-weeded check in 1997. In-row cultivation and rotary hoeing provided similar weed control in both years. At low weed densities, either mechanical tillage or herbicides alone were effective in suppressing weeds, whereas at higher densities, herbicides combined with mechanical tillage were required for effective control.Nomenclature: Bentazon; dimethenamid; EPTC; ethalfluralin; imazethapyr; common lambsquarters, Chenopodium album L. #3 CHEAL; dry bean, Phaseolus vulgaris, Great Northern ‘Beryl’; green foxtail, Setaria viridis L. Beauv. # SETVI; hairy nightshade, Solanum sarrachoides Sendt. # SOLSA; redroot pigweed, Amaranthus retroflexus L. # AMARE; wild proso millet, Panicum miliaceum L. # PANMI.Additional index words: Combinations, herbicides and mechanical tillage, postemergence herbicides, preemergence herbicides, preplant-incorporated herbicides.Abbreviations: DAP, days after planting; IR, in-row cultivation; POST, postemergence; PRE, preemergence; RH, rotary hoeing.

Impact of Timing and Frequency of In-Row Cultivation for Weed Control in Dry Bean (Phaseolus vulgaris)

Effectiveness of rotary hoeing with cultivation and comparison of an in-row cultivator with a standard row-crop cultivator were determined in dry edible bean. The effectiveness of in-row cultivation conducted at various timings and frequencies was examined. The in-row cultivator was more effective in reducing weed populations than the standard cultivator, although at least two mechanical weeding operations were needed to reduce weed populations to levels of the herbicide check (EPTC [S-ethyl dipropyl carbamothioate] plus ethalfluralin). When the in-row cultivation was delayed until the second trifoliolate stage or later, weed populations were greater than those in the herbicide check. In situations with high weed populations, rotary hoeing prior to cultivation was required to reduce weed populations to levels similar to the herbicide check. An in-row cultivator has potential to improve mechanical weed control options in a crop such as dry edible bean. The types of adjustments made in combination with soil textures, soil moisture, and operator experience affect overall weed control. Thus, it is expected that the level of weed control will vary from year to year and even field to field for the same operator.

The Lodi-Woodbridge Winegrape Commission: a Framework for Implementing IPM

The Lodi-Woodbridge Winegrape Commission Crush District 11 was created by referendum during the summer of 1991. The commission conducts extensive on-farm research trials and demonstration projects in cooperation with the University of California, the California State University system and local growers. The results have been disseminated through a series of regular grower meetings, seminars and an IPM newsletter sponsored by the commission and widespread coverage in the agriculture and general media. Several pest management practices which could reduce pesticide inputs have been promoted by the commission's IPM Program, and others are being further validated or are being researched for applicability to growers in the area. The research falls into two distinct categories. The first category of research is evaluation of the efficacy of recommended practices and includes economic analysis and the collection of biological data to evaluate performance from the perspectives of vineyard ecology, input use, and profitability. Intensive study of 10 growers over 2 years showed a highly variable level of adoption. The yield response to pest control inputs showed increasing returns up to the level of inputs of $375 per hectare after which returns leveled off. The second category of research is the development of alternative practices through on-farm controlled trials. The results of 3 on-farm trials are reported. A cover crop trial showed a reduction of pests in 1995 but no difference in 1994 between the cover cropped and bare soil blocks. Yellow sticky bands significantly reduced the number of leafhoppers in a trial vineyard, but was not as effective as pesticide treatments. The comparison of four alternative weed management techniques demonstrated that the use of an in-row cultivator is more effective than preemergent herbicides or mulch placed along the vine row in controlling weeds. A visual sprayer was shown to reduce the use of contact herbicide. The on-farm approach to all of the research and the ‘in your own backyard’ nature of the meetings has created the sense of ownership for the growers that has been instrumental in achieving grower support. The public nature of the information provided by the commission and grower members to all winegrape producers implies a recognition among members of their interdependence and the long-term benefits of reducing pesticide use as a group. The recognition of interdependency is crucial for any group trying to form an IPM district.

Evaluation of Mechanical Weed Management Programs for Corn (Zea mays)

Eight cultivation programs with several equipment combinations were compared with each other and with an atrazine plus pendimethalin herbicide program with and without supplemental cultivation from 1992 to 1994. In two of the three years, cultivation with a rotary hoe or tine weeder reduced weed seedling density by 39 to 74%. Tine weeding was more effective than rotary hoeing in 1992. Rotary hoeing or tine weeding reduced corn populations by an average of 6%. Weed control by different types of inter-row cultivators varied little, except that an in-row cultivator provided better control than a rolling cultivator in two years and better control than a shovel cultivator in one year. Weeds establishing from seeds were better controlled by herbicides in all three years, but weeds establishing from roots, rhizomes, and tubers were controlled as well or better by cultivation. Weed control was sometimes better using herbicides plus cultivation than with herbicides alone, but the combination damaged the crop in two of the three years. Cost of mechanical treatments which combined inter-row cultivation with rotary hoeing or tine weeding differed from that for the herbicide treatment by less than 2%. Yields of the best mechanical treatment and the herbicide treatment were nearly equal in all years, but the best mechanical regime varied between years. Consequently, mean net return was moderately higher for the herbicide treatment.

Compatibility and Efficiency of In-Row Cultivation for Weed Management in Corn (Zea mays)

Information on the effects of multiple weed management tactics in corn is needed to develop integrated weed management systems. The effectiveness and compatibility of an in-row cultivator as compared to a standard interrow cultivator used with reduced rates of a soil-applied herbicide, rotary hoeing, and/or a bioeconomic model for POST herbicide selection was examined. Weed control with a single rotary hoeing at corn emergence controlled annual weeds similarly to two rotary hoeings. One-third recommended use rate of alachlor controlled weeds similarly to a two-thirds rate. Reduced rates of alachlor controlled more weeds than rotary hoeing over 2 yr. The in-row cultivator required early-season weed control (rotary hoeing or reduced alachlor rate) for optimum efficacy. The in-row cultivator provided better weed control than the standard cultivator while the cost of operating the two cultivators was similar. Thus, the in-row cultivator was more efficient than the standard cultivator. Furthermore, less intensive early-season weed control was required with the in-row cultivator for maximum weed control as compared to the standard cultivator. Rotary hoeing plus the in-row cultivator provided similar weed control to other weed management tactics that required both soil-applied and POST herbicides. Gross margin was influenced more by corn yield than cost of weed management tactics.

Controlling Weeds in Corn (Zea mays) Rows with an In-Row Cultivator Versus Decisions Made by a Computer Model

A 3-yr field study was conducted to compare an in-row cultivator versus a standard row-crop cultivator to decisions made with WEEDCAM, a weed/corn management computer decision aid, for controlling annual weeds within the row in irrigated corn. In the absence of herbicides, weeds were always controlled better with the in-row cultivator than with the standard row-crop cultivator. However, grain yield and gross margin were affected only in 1991 when weeds emerged simultaneously with corn, and rain delayed the first cultivation 10 d. The in-row cultivator plots not only averaged 34% more grain ha-1than the standard row-crop cultivator plots, but gross margin was $143 ha-1more. Weed densities each year were about 95% less in plots managed in accordance with the computer model WEEDCAM simulations than in the non-herbicide treated post-planting tillage plots. Grain yields and gross margins were not affected by weed seedbank density, pre-cultivation tillage, or type of cultivator when weed management decisions were based on WEEDCAM simulation ranking. In the absence of herbicides, weeds can be controlled successfully in corn with an in-row cultivator, but success will depend on such factors as weed seedbank density, cultivation timeliness, and relative time of weed and corn emergence.

Control of Ivyleaf Morningglory (Ipomoea hederacea) in Cotton (Gossypium hirsutum) by Combinations of Methods

Various combinations of methods were evaluated for the control of ivyleaf morningglory growing in cotton. The combinations included chemicals incorporated to two depths or tanked-mixed as postemergence treatments and cultural methods that included in-row cultivation and hand weeding. The most effective combinations of methods included a herbicide such as cyanazine or prometryn in some treatments resulting in reduced ivyleaf morningglory population and improved cotton yields. Cultural methods without chemical assistance gave little or no control of ivyleaf morningglory based on weed populations and cotton yield. Statistically the best combinations had lint yields equal to the weed-free treatment, but the yields were reduced from 114 to 372 kg/ha. Also, most combination treatments had enough plant debris in the lint to reduce fiber grade.