Weed control in no-till organic soybean in southern Brazil

Weed control has always been an important issue in agriculture. With the advent of no-till systems, soil erosion was reduced but herbicide use was increased. Organic no-till systems try to adjust reduced erosion to the no use of herbicides. Nevertheless, this adjustment is limited by the cost of mechanical weed control. This cost may be reduced by improved cultural weed control with cover crops mulches. In this paper we report a study on the application of compost manure on an oats winter cover crop, preceding soybean, instead of on the soybean summer crop. Treatments comprised a control without compost manure, and compost manure doses of 4 and 8 Mg ha-1 applied either on oats in winter or soybean in summer, organized in a randomized block design, with five replications. In summer, plots were split into weed-controlled or not controlled subplots. The timing of application and the manure doses did not affect the oats biomass or the soybean performance. However, in summer, without water stress, the application of manure at 8 Mg ha-1 directly on soybean has reduced weed biomass in this crop.

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“…This correlation has been reported for several species (Bond & Grundy, 2001;Khatounian, 2004;Melander et al, 2005;Charles et al, 2006).…”

Section: Introductionsupporting

confidence: 57%

“…Other authors (Theisen et al, 2000;Khatounian, 2004) who studied this subject used artificial doses of oats mulches to assess Effects of early compost application on no-till organic soybean its suppressive effects, while we attempted to use natural mulch production under different managements.…”

Section: Oats Biomassmentioning

confidence: 99%

Effects of early compost application on no-till organic soybean

2012

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“…Since the early 2000s in the USA and early 1970s in Brazil (Khatounian, ), no‐till soyabean production systems featuring rolled‐crimped cover crops have attracted farmers who wish to balance soil conservation and weed management benefits (Wells et al ., ). The roller‐crimper, a heavy metal cylinder with protruding fins that rotates on a lengthwise axis as it is drawn over the soil, is commonly used to kill winter annual cover crops before no‐till planting of cash crops and deposits residues uniformly on the soil surface (Ashford & Reeves, ; Kornecki et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Weed interference with no‐till soyabeans influenced by fine‐scale covariation between soil properties and cover crop performance

Eslami

Davis

2018

Weed Research

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Summary Balancing trade‐offs in conservation agriculture between the conflicting impacts of soil disturbance on crop yield and soil quality is complicated by the need for adequate weed management, especially in production systems with low, or no, reliance upon herbicides. Production of soyabeans no‐till planted into a rolled‐crimped cereal rye cover crop is attracting increasing farmer interest. Experimental work on this approach to date has provided inferences at the field scale and above, helping to identify broad recommendation domains for best management practices. For individual growers, however, fine‐scale information may also be helpful for making in‐field adjustments to refine the system. In a three‐year field study in Illinois, USA, we quantified key associations among no‐till soyabean performance in a rolled rye system and decametre‐scale variation in soil characteristics, cover crop performance and weed growth. Subfield variation in soil properties had both direct and indirect effects on soyabean yield. Local soil potassium limitation was linked to reduced rye height, which in turn indirectly reduced soyabean yields through decreased weed suppression by the cover crop. Slow‐draining field areas that were still moist at the time of cover crop termination were associated with lower soyabean stands, directly reducing yields. Although the subfield characteristics influencing soyabean and cover crop performance may vary from farm to farm, this study highlights potential gains to be realised in this production system from a better understanding of how such properties covary at fine spatial scales and taking steps to create an environment conducive to maximising cover crop establishment and growth.

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“…In terms of control strategies for aircraft S/G system, there are several papers reporting on this [9][10][11] [12]. Based on variable speed drive application, a control strategy of the doubly fed induction generator is achieved by inner flux control loop and stator-voltage outer loop in [9].…”

Section: Introductionmentioning

confidence: 99%

“…Based on variable speed drive application, a control strategy of the doubly fed induction generator is achieved by inner flux control loop and stator-voltage outer loop in [9]. A control methodology which utilizes angle and speed estimation algorithm is presented [10].…”

Section: Introductionmentioning

confidence: 99%

Control Design for PMM-Based Generator Fed by Active Front-End Rectifier in More-Electric Aircraft

Yin

Bozhko

Yeoh

2016

SAE Int. J. Aerosp.

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(2016) Control design for PMM-based generator fed by active front-end rectifier in more-electric aircraft. SAE International Journal of Aerospace, 9 (1). pp. 23-29. ISSN 1946-3901 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/44373/1/Control%20Design%20for%20PMM-based %20Generator%20fed%20by%20Active%20Front-End%20Rectifier%20in%20More-Electric %20Aircraft.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractThe future aircraft electrical power system is expected to be more efficient, safer, simpler in servicing and easier in maintenance. As a result, many existing hydraulic and pneumatic power driven systems are being replaced by their electrical counterparts. This trend is known as a move towards the More-Electric Aircraft (MEA). As a result, a large number of new electrical loads have been introduced in order to power many primary functions including actuation, de-icing, cabin airconditioning, and engine start. Therefore electric power generation systems have a key role in supporting this technological trend. Advances in modern power electronics allow the concept of starter/generator (S/G) which enables electrical engine start and power generation using the same electrical machine. This results in substantial improvements in power density and reduced overall weight. One of the potential S/G solutions is to employ a permanent magnet machine (PMM) controlled by active front-end rectifier (AFE). Operation of the PMM as a generator at wide range of speed that is dictated by the engine and electrical loads connected to the aircraft bus require careful design of the controllers. Corresponding plant models are derived and verified with simulations using developed models in Matlab/Simulink. The relevant controllers are designed based on the derived plants and operating points. The controllers are tested with Simulink models and experimentally using a scaled prototype of the investigated generator system.

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Weed control in no-till organic soybean in southern Brazil

Cited by 3 publications

References 2 publications

Effects of early compost application on no-till organic soybean

Effects of early compost application on no-till organic soybean

Weed interference with no‐till soyabeans influenced by fine‐scale covariation between soil properties and cover crop performance

Control Design for PMM-Based Generator Fed by Active Front-End Rectifier in More-Electric Aircraft

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