No abstract

The species that can be used as cover plants are many, which makes it difficult to make a choice, since there is no ideal plant, and it is necessary to make a survey of the most favorable species. The objective of this study was to evaluate the biomass productivity of cover crops in autumn and winter (Poaceaea and Fabaceae), and their effects on soil physical properties at different depths.The experimental design was of randomized blocks with subdivided plots, with six replications. The plots consisted of four cover crops in autumn and winter; two Poaceae (black oats and brachiaria) and two Fabaceae (fried pea and white lupine). The subplots were at different depths of evaluations; 0 -0.05; 0.05 -0.10 and 0.10 -0.15 m to determine the pore volume and soil density; and 0 to 0.40 m to resistance to penetration. Were evaluated: dry mass yield; soil surface cover index; volume of macropores, micropores, total porosity; soil density; and soil resistance to penetration. It was verified that the family of plants Fabaceae showed higher dry matter yield (4400 kg•ha −1 ), however, the lower soil cover rate (68.71%). The highest volume of macropores (0.05 m 3 •m −3 ) and the lowest soil resistance to penetration were observed in the soil cultivated with Poaceae family cover plants, in the respective depths of 0 -0.10 m and 0.05 -0.20 m.

Várias são as maneiras possíveis de se trabalhar o solo para melhorar suas propriedades físicas, amenizando os efeitos prejudiciais da compactação e aumentando a capacidade e eficiência de armazenamento de água no solo. O objetivo deste trabalho foi avaliar o efeito de plantas de cobertura cultivadas em plantio direto e preparo reduzido nas propriedades físicas do solo. O experimento foi conduzido na Estação Experimental da Universidade Estadual do Oeste do Paraná, em delineamento de blocos casualizados, em esquema de parcelas subdivididas, com quatro repetições. Nas parcelas principais foram alocados dois sistemas de manejo: plantio direto e preparo reduzido do solo com o uso de escarificador de hastes. As subparcelas constaram do cultivo de diferentes espécies vegetais de inverno: trigo; um mix de aveia preta com ervilha forrageira; e um mix de aveia preta com nabo forrageiro. O preparo reduzido com escarificador foi eficiente para descompactar o solo, promovendo aumento da porosidade de aeração e diminuição da densidade e resistência a penetração, mas não promoveu alterações na estabilidade dos agregados do solo. Os mix de plantas de cobertura com diferentes famílias aumentaram os macroporos na superfície do solo, mas atuaram igualmente na agregação do solo e na resistência do solo à penetração.

Soil organic matter is degraded and easily altered by the type of management. The objective of this work is to determine the total organic carbon and humic substance fractions in the organic matter of the soil with different management types and depths in the western region of Paraná, Brazil. The work was carried out in the Experimental Farm "Professor Antônio Carlos dos Santos Pessoa", belonging to the State University of the West of Paraná. Five soil management systems were evaluated: one area with corn cultivation for silage (CS); other area with succession of crops, with soybean in summer and corn in winter (SC); the next area also with succession of crops, with soy in the summer and oat in the winter (SO); the following area with permanent pasture with Tifton (PP); and the last area with crop-livestock integration (ILC). For each management system, four plots were randomly selected, in each plot three simple samples were collected in a diagonal direction to form a composite sample for the depth of 0.00-0.05 m, 0.05-0.10 m and 0.10-0.15 m. Total organic carbon, fractionation of the humic substances and the AH/AF and EA/HUM ratios were calculated. For most of the analyzed variables, it was verified that there were significant differences (P < 0.05) between the systems evaluated in the studied depths. In the evaluated areas, the PP, SO and ILC systems presented the highest carbon content for all attributes analyzed.