ABSTRACT The intercropping of corn with forage grasses increases soil cover and may improve soil structural quality. The objective of the study was to evaluate the soil structural properties and the development of second-crop corn intercropping with forage grasses under no-tillage system. The experiment was carried out in an area of Sítio Santo Antônio, located in the municipality of Borrazópolis, Paraná state, Brazil, on a Red Latosol with a very clayey texture. The experiment consisted of five treatments: corn + Urochloa brizantha cv. Marandu (T1), corn + Urochloa brizantha cv. Piatã (T2), corn + Urochloa brizantha cv. Xaraés (T3), corn + Urochloa ruziziensis (T4), and non-intercropping corn (T5). In the corn crop, the following characteristics were evaluated: plant height, first ear in insertion height, stem diameter, corn yield, dry mass of corn straw mulch, dry mass of grasses shoots and dry mass of grasses root. Dry mass of the aerial part and roots of the grasses were evaluated. In the 0–0.10 and 0.10–0.20-m soil depth, soil physical properties were also determined: tensile strength and friability, stability of aggregates, bulk density and total porosity, and degree of compactness. The treatments of corn in intercropping with grasses showed positive results regarding the stability of aggregates, reduction of bulk density and increase of total porosity in the 0–0.10-m soil depth. The intercropping of corn + U. ruziziensis showed the lowest values of degree of compactness and higher production of dry mass of the aerial part.

Abstract The objective was to undertake the visual evaluation of soil structure in maize and forage grasses intercropping under no-tillage. The experiment was carried out in a rural property located in North Paraná State, Brazil, where there were five parallel areas with the following treatments: maize + Urochloa brizantha cv. Marandu (T1), maize + Urochloa brizantha cv. Piatã (T2), maize + Urochloa brizantha cv. Xaraés (T3), maize + Urochloa ruziziensis (T4), and non-intercropping maize (T5). Seeds of forage grasses were sown in April 5th, 2018 and sampling was carried out in December, 30th, 2018. Samples of 0.10 m width, 0.20 m length, and 0.25 m thickness were collected from five random locations of each experimental area and, for the visual evaluation of soil structural quality, a soil evaluation (VESS) chart was used so that visual scores were attributed to each sample. Treatments 1 and 5 received the highest scores, while treatment 3 had the lowest score and showed good structural quality and great root presence. At the superficial layer, treatment 2 had the lowest score (0.8) among treatments. For the subsuperficial layer, the scores obtained were higher than those found for the superficial layer: T3 had the lowest mean (1.5) and was significantly similar to T4 that presented a mean score of 1.7. Except for T1, which showed a similar score to non-intercropping maize (T5), the forage grasses had better visual scores. The visual evaluation of soil structure indicated that maize and forage grasses intercropping improves soil structural quality.