1,721,021 research outputs found
Possibilità di controllo meccanico delle piante infestanti nel mais
No full textIn questo lavoro vengono illustrati i principali mezzi di controllo meccanico delle piante infestanti utilizzabili nella coltura del mais. Questi sono stati suddivisi, in funzione della diversa localizzazione dell’azione di controllo, in tre diversi gruppi: 1) mezzi meccanici a prevalente azione di controllo nell’interfila della coltura; 2) mezzi meccanici a prevalente azione di controllo nella fila della coltura; 3) mezzi meccanici a duplice azione di controllo (fila ed interfila). Si riportano, inoltre, i risultati di un triennio di sperimentazione (2002-2004), svolta in Italia centrale, su mais in pieno campo, per la valutazione dell’efficacia erbicida di alcuni mezzi meccanici tradizionali (sarchiatrice, rincalzatrice, erpice strigliatore) ed innovativi (sarchia-separatrice “split-hoe” e sarchiatrice a dita rotanti o diserbatore a dita “finger-weeder”), impiegati da soli e in aggiunta al diserbo chimico. Dai risultati è possibile evidenziare come il diserbo chimico (metolachlor 1449 g ha-1 + terbuthylazine 725 g ha-1, in pre-emergenza) ha fornito sempre un'efficacia erbicida del 100%, sia quando distribuito a pieno campo che quando localizzato sulla fila (50% della superficie totale) e seguito dalla sarchiatura dell’interfila. La sarchiatura abbinata alla rincalzatura ha fornito un'efficacia erbicida media del 92%, che è migliorata quando i due interventi anzidetti sono stati preceduti da un passaggio con l'erpice strigliatore. Quest’ultimo impiegato da solo ha fornito una scarsa efficacia erbicida e pari in media al 42%. La sarchia-separatrice e la sarchiatrice a dita rotanti hanno mostrato valori di efficacia compresi tra 71%-90% e 49%-84%, rispettivamente; impiegando queste due macchine insieme non sempre si è ottenuto un miglioramento significativo dell’efficacia rispetto alla sola sarchia-separatrice. Tutti i trattamenti hanno mostrato una buona selettività nei confronti della coltura, la cui produzione è risultata correlata negativamente con il peso secco delle infestanti non controllate
Il diserbo del mais in post-emergenza
No full textArticolo pubblicato su "Contoterzismo e Agricoltura" da FRIMA Marche facente parte del Gruppo UNIMA della quale "il Contoterzista" è l'organo ufficial
Optimization of foramsulfuron doses for post-emergence weed control in maize (Zea mays L.)
Full text linkFour field experiments were carried out from 2011 to 2014 in order to evaluate the effects of foramsulfuron, applied at the recommended (60.8 g a.i./ha) and reduced doses (1/3 and 2/3), on the efficacy against several of the most important weeds in maize. For each “year-weed” combination, dose-response curves were applied to estimate the dose of foramsulfuron required to obtain 90% and 95% weed control (ED90 and ED95). Foramsulfuron phytotoxicity on maize and crop yield were assessed. Foramsulfuron at 1/3 of the recommended dose (20.3 g a.i./ha) provided 95% efficacy against redroot pigweed (Amaranthus retroflexus L.), green foxtail (Setaria viridis (L.) Beauv.), wild mustard (Sinapis arvensis L.) and black nightshade (Solanum nigrum L.). Velvetleaf (Abutilon theophrasti Medik.), common lambsquarters (Chenopodium album L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv.) were satisfactorily controlled (95% weed efficacy) with ED95 ranged from 20 to 50 g/ha of foramsulfuron (about from 1/3 to 5/6 of the recommended dose) depending on growth stage. The recommended dose was effective against pale smartweed (Polygonum lapathifolium L.) at 2-4 true leaves (12-14 BBCH scale), but this dose did not kill plants larger than 2-4 true leaves. The ranking among weed species based on their susceptibility to foramsulfuron was: redroot pigweed = green foxtail = wild mustard = black nightshade > velvetleaf = common lambsquarters = barnyardgrass > pale smartweed. Dose of foramsulfuron can be reduced below recommended dose depending on weed species and growth stage. Foramsulfuron showed a good crop selectivity and had no negative effect on maize yield
Spreadsheet tools for biometry classes in crop science programmes
No full textTeaching biometry to undergraduate students in crop science or similar programmes may be a challenging task, as these students show a small background in mathematics and computer programming and are mainly interested in practical applications. It is therefore fundamental to use ‘realistic’ case-studies and provide the students with statistical software that does not overload them with a steep learning curve. This paper wishes to bring to the attention of readers two new EXCEL macro addins (DSAASTAT and BIOASSAY97), which have been extensively tested, validated and used as teaching aids in biometry courses. They only require a basic knowledge of spreadsheet environments and may also be useful for technicians and practitioners for general data analyses of ‘routine’ field experiments
Effetto di due substrati e livelli di concimazione azotata sulla crescita del tappeto erboso
No full textValutazione dell'efficacia di mezzi meccanici tradizionali e innovativi nel controllo delle piante infestanti il girasole
No full textIntegrated weed management systems in vegetables: current status and perspectives
No full textMost vegetable crops are characterised by a low plant density, a wide row distance, a slow initial growth and, as a consequence, by a poor competitive ability. Taking into consideration that most vegetables are high-income crops, the threshold weed densities are very low and the critical periods of weed competition are pretty long. Most vegetables are minor crops, thus the availability of approved herbicides for use is scarce due to the low economic interest by the chemical industries. Special projects for supporting the registration of pest control products on minor or specialty crops (e.g. the IR-4 in USA) or for coordinating scientific and regulatory decisions on pesticides were established to alleviate the problem. In EU the already difficult situation has been worsening by the application of the directive 91/414/EEC concerning the authorization, placing on the market, use and control of plant protection products in commercial form. This directive has already caused the expiration of the authorisation of several herbicides largely used in vegetables and other ones will be withdrawn within few years. Chemical weed control in vegetables shows peculiar environmental and health concerns due to the relatively short growth cycle, fresh edible parts of vegetables, and a coarse soil texture found in the main production areas; moreover, a repeated use of herbicides with similar mode of action may lead to a strong and quick selection of weed flora. So an Integrated Weed Management System (IWMS) in vegetables, like in any other crops, should be based on: 1) weed population management strategies by sound cultural weed control methods, i.e. any aspect of crop management that favours the crop relative to the weeds, reduces the weed seed-bank, regulates weed communities and prevents the build-up of adapted species; 2) an integration of non-chemical and chemical weed control methods characterised by a low selection pressure on weed communities, an environmental sustainability and an economic feasibility.
Regarding preventive (indirect) weed control methods, it should be pointed out that: although the crop rotation was crucial for an IWM, in practice a sound crop rotation frequently is not applied due to economic and market constraints; the strategic importance of the cover crops seems low in environments characterised by limited availability of irrigation water or high water cost; intercropping, thanks to new technical solutions for mechanical harvest, is increasing in interest in organic and low input farming systems; a stale seedbed preparation is widely applied in several vegetable crops throughout the world; the breeding of competitive cultivars is not yet enough developed even if experimental results seem to be encouraging; the transplanting instead of the direct sowing is commonly applied in order to give a higher competitive ability to the crop, shorten the critical period of competition and facilitate direct weed control; the increase of crop plant density and the adoption of a narrower row distance or twin rows in order to increase the crop competitivity offers interesting applications but in some crops the cost of transplants, the negative effects of a higher crop density on quality product and the need to have well-spaced crop rows for the application of mechanical weed control limit the use of those cultural practices; the effect of different localised fertilisation and/or irrigation methods (e.g. starter fertilisation, band fertilisation, fertigation) on crop competitive ability against weeds should be better studied.
Regarding curative (direct) weed control methods: non-degradable black PE mulches are widely used in several vegetable crops; non-degradable photo-selective coloured plastic mulches, that combine the thermal properties of transparent films with the weed control ability of black films, show a good efficacy but not always an economic feasibility; starch-based biodegradable mulches are more and more used both in conventional and organic farming systems where they show a mulching activity for 2-4 months, that is enough to cover the critical period of competition of most vegetable crops; inter-row weeds are easily removed by inter-row cultivation (i.e. hoeing, harrowing, brushing) while intra-row weeds still constitute a major challenge aimed at minimising laborious hand weeding although new implements (i.e. finger weeder, torsion weeder, split hoe, steering hoe) show a pretty good efficacy if their application is included in a sound IWM programme; physical and mechanical weed control methods are widely used in organic farming systems and in conventional systems where the availability of approved herbicides for use is scarce; at present, biological control does not seem to be applicable on large scale and successfully in European vegetable crops systems characterised by small fields, a high number of crop species, and pluri-specific weed infestations; chemical control still is the main weed control method in conventional and low input vegetable production systems even if concerns about food safety, environmental sustainability, weed population dynamics and application cost are increasing among public opinion and technicians, particularly because the global market shows a huge variability in crop management and regulatory decisions on pesticides
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