Conservation systems for less soil movement and when associated with previous crops may reduce the effects of soil compaction. The objective of this work was to evaluate soil mechanical resistance penetration (MRP) in different cropping systems associated with previous corn crop after fifteen years. The experimental design was composed of experimental strips with subdivided plots, combining three soils management systems: CC- conventional cultivation, MC- minimum cultivation and NT- no-tillage, and four species of crops antecedent to maize for the production of commercial ears of green corn. In the determination of soil MRP, the electronic penetrometer (FALKER model SoloTrack PLG 5200) was used, with readings up to a depth of 400 mm. The results showed that there was a significant effect on the MRP values of the soil when submitted to the different cropping systems and previous crops at the end of fifteen years. The lowest MRP values were located in the superficial layers in the CC and MC. The NT cultivar system showed higher MRP values, at depth 0-100 mm. At conditions of tableland, after fifteen years, it was observed that the NT system provides better corn productivity levels combined with lower MRP values along the profile.

Soil quality, measured through its chemical, physical and microbiological attributes, changes as a result of anthropic sensations and becomes an important tool to assess environmental quality. The objective of this study was to determine and evaluate the Quality Index of an Ultisol in a long-term (17-yr) plots under different management systems in the Coastal Tablelands of Sergipe State, in Northeastern, Brazil. Main effects were conventional tillage (CT), no-tillage (NT), and minimum tillage (MT) distributed cultivated strips with corn as the main crop. Split-range treatments were randomly distributed and cultivated with cowpea beans (Vigna unguiculata), sunn hemp (Crotalaria juncea), pigeon pea (Cajanus cajan), and millet (Pennisetum glaucum). A forest soil was used as reference, compared to the soil samples of the cultivated area. The Soil Quality Index (SQI) for the 0-0.10 m layer was calculated by the additive method. There were changes in soil properties between the different management systems, and between the experimental soil and the reference area. The highest SQI was obtained from the forest area (67.1) followed by the NT treatment (65.5), MT (65.1) and CT treatment (61.0). The lowest SQI was observed in the CT treatment previously cultivated with pigeon pea (56.5). Among the evaluated soil functions, maintenance of homeostasis had the greatest influence on the SQI. The higher acidity of the forest soil helps to explain the origin of the limitations of the soil in the cultivated area that occupies the same type of soil, tolerated by the adoption of conservationist managements.

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The aim of this work was to compare and analyze three different methods of the sustainability evaluation in agricultural systems, such as the Indicateurs de Durabilité des Exploitations Agricoles (IDEA), the weighted Assessment of environmental impact of New Rural activities (APOIA Novo-Rural), and the indicators of sustainability in Agroecosystem (ISA). Those methods were comparied by two criteria. The first one relates to the distribution of sustainability indicators into categories (Endogenous System Operation, Endogenous Resources, Exogenous Systems Operation, and Exogenous Resources) and elements (technical, socioeconomic, natural and cultural resources). The second one involves the conceptual approaches of each method towards the concept of sustainability, objective and target audience, adoption of the systemic approach, level of stakeholder’s participation, level of adequacy, and method flexibility in different realities. The indicators set of each method, although quantitatively different, consider the diversity of elements that involve the agricultural systems. The IDEA method concentrates its indicators on the Endogenous System Operation category, while the APOIA Novo-Rural and the ISA methods concentrate their indicators on the Endogenous Resources category. The IDEA method directs the assessment to the awareness of the environmental processes that surround the agricultural activity in the property. On the other hand, in the APOIA Novo-Rural and the ISA methods, the reflective practice is fostered from impacts on the environment, and can be improved by extension actions. The main difference presented among those methods is the integrative evaluation of the indicators as well as trade-offs involved.

The present work had an objective to compare the stable infiltration rate obtained by infiltrometers with reduced dimensions and varied forms in different land uses. The infiltration tests were carried out in areas planted with cowpea, crotalaria, pigeon pea and millet, as crops previous corn planting, and managed with no-tillage, minimum tillage and conventional tillage and native forest area. In order to compare and analyze the results of the stable infiltration rates obtained between the alternative infiltrometers and the considered standard, the criteria involving the standard error of estimation (EPE), the standard error of estimation adjusted (EPEa), the standard error of estimation adjusted by origin (EPEao) and coefficients of adjustments of the linear equations with their respective determination coefficients (R2) were used. It was verified that the double-ring reduced, single-ring and double square infiltrometers provided a water saving of 57.06%, 66.19% and 38.54% respectively, relative to the standard. The alternative infiltrometers overestimated the stable infiltration rate in relation to the standard. The single-ring infiltrometer obtained a stable infiltration rate correction equation that showed results very close to the standard and the best statistical indices of stable infiltration rate results were obtained by the reduced double-ring infiltrometer.