ABSTRACT Nutrients present in soil aggregates are essential for maintaining the productive capacity of agroecosystems and environmental quality. The aim of this study was to evaluate the chemical properties of macroaggregates of a Humic Dystrudept cultivated with onions under a no-till vegetable system (NTVS) compared to the conventional tillage system (CTS) and a forest area in Ituporanga, SC, Brazil. The treatments consisted of the following single and mixed cover crops with onion under the NTVS: spontaneous vegetation, 100 % black oats, 100 % rye, 100 % oilseed radish, intercropped oilseed radish (14 %) + rye (86 %), and intercropped oilseed radish (14 %) + black oat (86 %). Additionally, we evaluated two areas, one with onion grown under the CTS for ±37 years and an area under forest for ±30 years, both adjacent to the experiment. Five years after implementation of the treatments with cover crops, we collected undisturbed soil samples at depths of 0.00-0.05, 0.05-0.10, and 0.10-0.20 m, and we obtained macroaggregates (8.00 mm > Ø ≥ 2.0 mm). We analyzed total organic carbon (TOC), pH in water, Ca2+, Mg2+, Al3+, H+Al, K+, and P in the macroaggregates. The conversion of onion-growing areas from the CTS to the NTVS after five years increases TOC, pH, Ca, Mg, and K in soil macroaggregates at the depth of 0.00-0.05 m. There is increased K content in the macroaggregates of soil under the NTVS at all depths evaluated in this study compared to the CTS. The use of millet in the CTS increases P content at depth (0.05-0.10 and 0.10-0.20 m). Intercropping black oat + oilseed radish increases Ca content at the 0.10-0.20 m depth in comparison to the black oat, rye + oilseed radish, and control treatments, and increases Mg content as well, compared to the other cover crops at the depths of 0.05-0.10 and 0.10-0.20 m.

O cultivo e a deposição de resíduos de plantas de cobertura em sistema plantio direto podem afetar os atributos químicos do solo e a produção de cebola. O trabalho objetivou avaliar a interferência do cultivo de plantas de cobertura sobre a produção de cebola e sobre os atributos químicos do solo em sistema plantio direto (SPD) agroecológico. O experimento foi conduzido na EPAGRI, em Ituporanga (SC), em um Cambissolo Húmico, nas safras de 2010 e 2011. Em abril, foram implantados os tratamentos: testemunha com vegetação espontânea (T1); cevada (2010)/aveia-preta (2011) (T2); centeio (T3); nabo-forrageiro (T4); centeio + nabo-forrageiro (T5); e cevada (2010)/aveia-preta (2011) + nabo-forrageiro (T6). Aos 60, 80 e 95 dias após a semeadura (DAS) das espécies de inverno, coletou-se a parte aérea das plantas e determinou-se a produção de matéria seca por hectare. Em julho, foram transplantadas mudas de cebola e, em novembro, avaliou-se a produção. Após o acamamento das plantas de cobertura de inverno e a colheita da cebola, foi coletado solo na camada de 0-10 cm e submetido à análise de atributos químicos. O cultivo e a deposição dos resíduos de matéria seca das espécies de plantas de cobertura em SPD contribuíram para o aumento e a manutenção da produção total de cebola ao longo dos anos. Os atributos químicos do solo, com exceção do K trocável, P disponível e valores de saturação da CTCpH7,0 por bases não foram afetados pelo cultivo de plantas de cobertura.

The cultivation and deposition of waste from cover crops in no-tillage can affect soil chemical attributes and onion yield. The aim of this study was to evaluate the dry matter yield of plant species from winter cover crops, onion yield and chemical attributes of soil in agroecological no-tillage system. The experiment was carried out at EPAGRI Experimental Station in Ituporanga (SC) under Humic Haplumbrept in the agricultural years of 2010 and 2011. The following treatments was implanted in April: weed vegetation (T1), Hordeum vulgare L. (2010)/Avena strigosa L. (2011) (T2), Secale cereale L. (T3), Raphanus sativus L. (T4), Secale cereale L + Raphanus sativus L. (T5) e Hordeum vulgare L. (2010)/Avena strigosa L. (2011) + Raphanus sativus L. (T6). At 60, 80 and 95 days after sowing (DAS) of winter species, the cover crops were collected to determine the dry matter yield. In July the onion seedlings were transplanted and in November the yield was evaluated. After the rolling of winter cover crops and after onion harvest, soil was collected at 0-10cm for the evaluation of chemical attributes. The cultivation and deposition of waste from cover crops in no-tillage contributed to the growth and maintenance of the total production of onion over the years. The soil chemical attributes in 0-10cm layer, with the exception of exchangeable K, available P and CTCpH7,0 saturation values for bases, were not affected by cover crops cultivation and deposition of waste.

Exposure to indoor allergens is an important risk factor for sensitisation and respiratory allergy. The aim of this paper was to evaluate the levels of mite, cat and latex allergens in dust collected from an indoor workplace and to assess whether the exposure to these allergens was associated with the allergy symptoms reported by employees. Sixty dust samples were collected. Allergen concentrations were measured with antibody based ELISAs. All 144 participants compiled a questionnaire exploring possible symptoms of allergy. No association between latex allergen exposure and symptoms was found in spite of the high frequency of latex allergens. Mite allergens were detected in a minority of rooms. Cat allergen was the most important indoor allergen in the sampled workplace and exposure to this allergen could represent a risk for employees.

L'esposizione agli allergeni indoor costituisce un importante fattore di rischio per lo sviluppo di allergie. L'obiettivo di questo articolo è valutare i livelli degli allergeni degli acari, del gatto e del lattice in campioni di polvere raccolti in un ambiente lavorativo, al fine di stabilire una eventuale relazione tra l'esposizione a questi allergeni ed i sintomi di allergia manifestati dai dipendenti. La concentrazione degli allergeni è stata analizzata in sessanta campioni e 144 dipendenti hanno compilato un questionario avente lo scopo di valutare eventuali sintomi di allergia. Nonostante l'elevata frequenza degli allergeni del lattice, non esiste associazione tra sintomi ed esposizione a questi allergeni. La presenza di allergeni degli acari è stata riscontrata in una minoranza di ambienti. L'allergene del gatto è l'allergene indoor più diffuso nell'ambiente lavorativo esaminato e l'esposizione a tale allergene può costituire un rischio per i dipendenti.

Exposure to indoor allergens can occur both at home and in public places such as schools and workplaces. To investigate and compare the presence of indoor allergens in different kind of environments (schools, offices and homes), dust samples were collected from furniture, desks, mattresses and floors with a standardized procedure. Samples were analyzed for Der p 1, Der f 1, Mite group 2 (mites) and Fel d 1(cat) by monoclonal antibody ELISA assay. Mite allergens were detected with low frequencies in schools and workplaces and with high frequency in homes. Fel d 1 was found with high frequency in every examined environment. Homes rather than public places can represent the environment where people can easier incur in mite allergy. All environments could be at risk for cat allergen exposure.

L'esposizione agli allergeni indoor può avvenire sia nelle abitazioni che nei luoghi pubblici. Per effettuare un confronto relativo alla presenza di allergeni indoor in differenti ambienti (scuole, uffici e abitazioni) sono stati raccolti campioni di polvere da mobili, scrivanie, materassi e pavimenti mediante procedura standardizzata. I campioni sono stati analizzati per il contenuto di Der p 1, Der f 1, Mite group 2 (acari) e Fel d 1 (gatto) mediante saggi ELISA. Gli allergeni degli acari sono stati riscontrati raramente nelle scuole e negli uffici, ma frequentemente nelle abitazioni. Fel d 1 è stato rilevato con elevata frequenza in ogni ambiente esaminato. In conclusione le abitazioni, piuttosto che i luoghi pubblici, possono rappresentare l'ambiente più a rischio per l'esposizione agli allergeni degli acari, mentre tutti gli ambienti possono costituire un rischio per l'esposizione agli allergeni del gatto.