Soil organisms in organic and conventional cropping systems.

Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponíveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos,bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivíduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior índice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamília Oribatuloidea. Indivíduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas

Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.

The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by the altitude and position of the area relative to the sun

Natural Availability of Oak Wilt Inocula

IN the past 10 years, oak wilt, caused by Endoconidiophora fagacearum Bretz, has become increasingly important as a destroyer of oak trees in the eastern half of the United States. It was first described about 13 years ago as a fungus disease in Wisconsin (Anonymous 1942), but earlier reports of dying oaks indicate that it probably has been present there for the past 20 years. The studies reported herein are intended mainly to supply information concerning the availability of oak wilt inocula and the relative importance of Illinois environmental conditions at different times of the year on the longevity of the causal fungus in nature. It seems that such information would be applicable in finding the means of spread of the disease beyond root graft distances and in selecting and developing effective control measures.published or submitted for publicationis peer reviewe

Natural Availability of Oak Wilt Inocula

95 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1954.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

The communicative functions of final rises in Finnish intonation

This paper considers the communicative function of final rises in Finnishconversational talk between pairs of teenage girls. Final rises are fairly common,occurring approximately twice a minute, predominantly on declaratives and in nar-rativesequences. We briefly consider the interplay between voice quality (known tobe a marker of transition relevance) and rising intonation in Finnish. We argue that innarrative sequences, rising terminals manage two main interactional tasks: they pro-videa place for a coparticipant to mark recipiency, and they project more talk by thecurrent speaker. Using a methodology which combines phonetic observation withconversation analysis, we demonstrate participants’ orientation to these functions