A eficiência do sistema de rotação de cultura requer, entre outros tratamentos, a escolha adequada das espécies a serem instaladas. Culturas vegetais podem apresentar compostos aleloquímicos, os quais são liberados por meio de pelos radiculares, sementes, raízes, colmos e folhas, em quantidades variáveis, capazes de interferir nas culturas subsequentes, comprometendo a produção. Assim, este estudo analisou o potencial alelopático de aveia-preta (Avena strigosa Schreb) (AP), nabo forrageiro (Raphanus sativus L.) (NF), ervilhaca (Vicia sativa L.) (ER), azevém (Lolium multiflorum Lam.) (AZ) e consórcio (CO-AP+ER+NF) na germinação de sementes e crescimento de plântulas de soja. O experimento foi em laboratório, com substrato de areia, onde foram cultivadas plantas de cobertura, por 30 dias, mantendo os restos radiculares das plantas com e sem restos de parte aérea. Observou-se redução na emergência de plântulas de soja sob CO, AZ e AP. O índice de velocidade de emergência (IVE), a porcentagem de emergência em areia (EA) e a massa fresca de hipocótilo (MFH) foram afetados negativamente pelas plantas de cobertura. Palavras-chave: rotação de cultura, culturas de inverno, alelopatia. ABSTRACT. Soybean (Glycine max L. Merrill) seed germination and plantlet growth under vegetation cover. In order to be efficient, the crop rotation system requires, among other factors, an adequate choice of species to be installed. Vegetal cultures can feature allelochemical compounds, released by root hairs, roots, stems and leaves in variable amounts, which are able to interfere on subsequent cultures, as well as cause a delay in their production. Thus, this study analyzed the allelopathic potential of black oat (Avena strigosa Schreb) (BO), forage turnip (Raphanus sativus L.) (FT), vetch (Vicia sativa L.) (V), ryegrass (Lolium multiflorum Lam.) (RG) and consortium (CO-BO+V+FT) on soybean seed germination and plantlet growth. This trial was carried out in a laboratory, with sand substrate, where coverage plants were grown, during 30 days. The remaining root portions of plants were kept with and without the remaining aerial part portions. A reduction was observed on the emergence of soybean plantlets under CO, RG and BO. The emergence speed index (ESI), emergence percentage on sand (ES) and the green mass of hypocotyls (GMH) were negatively affected by coverage plants, and due to this, another study is essential to verify whether there is an indication of the allelopathic effect.

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R ESU M OThe objective of this study was to evaluate the application of wastewater from swine manure (ARS) and chemical fertilization on foliar concentrations of macronutrients and micronutrients, and its relationship with the growth of babycorn. An experiment was conducted in completely randomized design with eight treatments and three replications in 4 x 2 factorial arrangement, which consisted of the application of four doses of swine wastewater (0, 40, 80 and 120 kg N ha ). The results indicated that the increase in fertilization using swine wastewater manure resulted in significant differences for babycorn's foliar concentrations of N and P, promoting levels below the adequate for N and K, appropriate levels of Cu, Zn, Mn and Fe, and levels above the adequate for P, Ca, Mg and S. For growth variables, results indicated significant differences and the increased use of fertilizer with swine wastewater promoted higher plant height, leaf area, leaf area index, number of leaves per plant and absolute growth rate. Key words: Zea mays L., leaf content, nutrientsComposição mineral e crescimento do minimilho sob água residuária de suinocultura combinada com adubação química A B ST R A C T Objetivou-se, com este trabalho, avaliar a aplicação de águas residuárias de suinocultura (ARS) e adubação química sobre os teores foliares de macronutrientes e micronutrientes e sua relação com o crescimento do minimilho. Conduziu-se um experimento em delineamento inteiramente casualizado, com oito tratamentos e três repetições dispostos em esquema fatorial 4 x 2, os quais consistiram da aplicação de quatro doses de água residuária de suinocultura (0, 40, 80 e 120 kg ha -1 de N) e duas doses de adubação química (0 e 40 kg ha -1 ). Os resultados indicaram que o incremento na adubação com uso de águas residuárias de suinocultura favoreceu diferenças significativas para as concentrações foliares no minimilho para N e P, proporcionou teores abaixo dos adequados para N e K, teores adequados de Cu, Zn, Mn e Fe e teores acima dos adequados para P, Ca, Mg e S. Para as variáveis de crescimento os resultados indicaram que houve diferenças significativas e que o incremento da adubação com uso de ARS proporcionou maiores estaturas de plantas, área foliar, índice de área foliar, número de folhas por planta e taxa de crescimento absoluto.

Soil is a complex and dynamic system in constant change due to its natural processes, as well as interaction among physical, chemical and biological characteristics that take part in it. However, the greatest transformation occurred due to the farm business and the adopted management system. Thus, man can manipulate some soil characteristics and make it more suitable for cropping development. Although anthropic action cannot fully control how soil characteristics interact, it is possible to track them. The action of chemical substances should not be disregarded, a product of the secondary metabolism of plants, since they interfere with plant's ability to compete and survive. Such substances can act out as protectors against herbivores and pathogens. They can be attractive or repellent agents in plant-plant competition and plant-microorganism symbiosis. They can also influence the interaction between plant matter and soil organisms. Among these substances, terpenoids are highlighted as the most structurally diverse chemical family in the class of secondary metabolites that are part of natural products. This knowledge allows a better understanding of nutrient decomposition and cycling processes, the influence of environmental factors on production and terpenoid variability in some plants with medicinal and economic importance.