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Provider: - Institution: Internet Culturale / Biblioteca di Storia Moderna e Contemporanea - Roma; Museo Centrale del Risorgimento - Roma - Data provided by Europeana Collections- In basso a sinistra ...:"Pinelli inv. e inc."; a destra:" Roma 1823". In basso:"Due pensionati francesi paesisti lasciati in camicia da Massaroni nelle vicinanze di Genzano"- I due artisti francesi, in camicia e senza scarpe, accanto ai fogli dei disegni; nella destra Massaroni e i briganti- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain ...Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
After recalling the major importance of weed control and herbicide use in cultivated fields, the authors present an analysis of the efficiency and the effect of chemical weed control on the weed ...flora composition and emergence density in field crops in the Noyonnais. The estimation of weed population densities was done on plots without chemical control. The number of seedlings varied from 20 to 300 m-2 with a median of 125. The most common and frequent species were annual weeds ; perennials were generally frequent but with a low density. For the main species, some environmental requirements were noted. In maize fields, systematic surveys showed the presence of triazine-resistant populations of Chenopodium album (in a quarter of the fields) and Solanum nigrum.
Après avoir rappelé l’importance prépondérante du désherbage et du rôle des herbicides en régions de grande culture, les auteurs se proposent d’étudier l’efficacité des moyens de lutte utilisés et leur incidence sur la densité d’infestation parcellaire. L’importance de l’infestation est estimée à partir d’observations sur la végétation adventice de parcelles mises en défens de traitements herbicides. Elle est quantitativement très variable, de 20 à 300 levées de plantules au m2 avec une médiane à 125. Les mauvaises herbes majeures et quelques caractéristiques de leur biotope sont indiquées. Les espèces les plus fréquentes et abondantes sont des annuelles ; les vivaces sont généralement fréquentes mais peu abondantes. Enfin, la prospection systématique de cultures de maïs a mis en évidence la présence de populations de chenopodium album (sur le quart des parcelles visitées) et de Solanum nigrum résistantes à l’atrazine.
