Integration of forage grasses with grain crops, such as maize, allows maintaining soil cover. The objective of this study was to evaluate the tensile strength, friability, and stability of soil aggregates in the maize and forage grass intercropping under no-tillage system. The study used a completely randomized block design with seven treatments and three replications. Undisturbed soil samples were collected in two seasons (2015 and 2016) at 0-0.10 m and 0.10-0.20 m soil depth. The following properties of soil aggregates were measured: tensile strength (TS), friability (F), gravimetric moisture (GM), weighted mean diameter (WMD), geometric mean diameter (GMD), and aggregate stability index (ASI). The intercropping of maize with Urochloa ruziziensis presented higher WMD and GMD at 0.10-0.20 m soil depth. Moreover, TS at 0.10-0.20 m soil depth was lower in maize without intercropping. The effects of the intercropping system on soil aggregates were better detected by aggregate stability than by TS or F. The intercropping of maize and U. ruziziensis improved soil aggregation to a higher extent than those systems with other forage grasses.

Intensive exploitation of soils has resulted in physical, chemical, and biological degradation as the demand for agricultural commodities, including cotton, has grown. Physical characteristics of the soil are those that are directly linked to the supply of water, nutrients, and air, as well as the establishment of roots for good agricultural crop development and yield. In this context, soil compaction is one of the most serious environmental issues caused by conventional agriculture. Cotton plant, which is highly sensitive to water stress and lack of soil aeration, is directly impacted by this type of degradation, which results in reduced root system development, affecting water and nutrient absorption, and causing damage to overall plant and crop yield. Soil compaction has been shown to reduce cotton yield in several studies; for example, the majority of the southeastern cotton-growing regions in the United States, which make up the majority of the U.S. Cotton Belt, have compacted soils and 66 % of cotton farmers in Australia were affected by soil compaction, while other research shows a 27 % yield loss for the crop in these conditions. On the other hand, most studies carried out in systems that aim to reduce soil compaction, have shown that improvements in soil physical properties related to decompaction result in an increase in cotton plant yield.

No abstract

Direitos para esta edição cedidos à Atena Editora pelos autores. Todo o conteúdo deste livro está licenciado sob uma Licença de Atribuição Creative Commons. Atribuição-Não-Comercial-NãoDerivativos 4.0 Internacional (CC BY-NC-ND 4.0).O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores, inclusive não representam necessariamente a posição oficial da Atena Editora. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais. Todos os manuscritos foram previamente submetidos à avaliação cega pelos pares, membros do Conselho Editorial desta Editora, tendo sido aprovados para a publicação com base em critérios de neutralidade e imparcialidade acadêmica.A Atena Editora é comprometida em garantir a integridade editorial em todas as etapas do processo de publicação, evitando plágio, dados ou resultados fraudulentos e impedindo que interesses financeiros comprometam os padrões éticos da publicação. Situações suspeitas de má conduta científica serão investigadas sob o mais alto padrão de rigor acadêmico e ético.

The objective of this study was to automate the acquisition of water travel time, as well as the computation of hydraulic conductivity of saturated soil by the falling head method, using water sensors and the Arduino platform. To automate the measurement of travel time, the Arduino Uno board was used, and two water sensors were installed at the initial (h0) and final (h1) heights of the water inside the core. When the water flows across the soil and the water level passes the bottom part of the initial sensor (h0), the time recording starts; it ends when the water is absent from the final height of the second sensor (h1). The equation for calculating the hydraulic conductivity was inserted into the algorithm so the calculation was automatic. Undisturbed soil samples were taken in a long-term no-tillage area. There were no significant differences for the time and hydraulic conductivity means between the permeameters. The coefficient of the residual mass index showed an overestimation of the time variable; thus, the automated permeameter improves the precision of time recording and saturated hydraulic conductivity estimated by the falling head method.