A condutividade elétrica aparente do solo (CEa) é uma medida que permite avaliar a variabilidade da parcela agrícola de forma rápida e expedita, tornando possível a identificação de zonas com propriedades semelhantes, a delimitação de unidades de gestão diferenciada e a orientação estratégica na colheita de amostras de solo. O presente trabalho pretende contribuir para uma melhor compreensão das relações entre a CEa e algumas características do solo e teve como principal objetivo perceber se a avaliação da CEa do solo é uma ferramenta importante na gestão da rega de culturas plurianuais. O estudo foi efetuado no âmbito do projeto H2Oliva – Eficiência do uso da água na cultura do olival, financiado pela Fundação Calouste Gulbenkian, numa parcela de olival, localizada na Quinta do Juncal, região de Pernes, Santarém. A recolha de dados georreferenciados de CEa foi efetuada por um sensor de indução eletromagnética, sem contacto com o solo, às profundidades de 50 e 100 cm, propriedade da empresa TERRAPRO. As cartas de altimetria e de CEa a 50 e 100 cm foram elaboradas recorrendo ao software ArcGISTM (ESRI, 2019). Os resultados permitiram identificar i) zonas que deverão ser alvo de distinta gestão de rega; ii) zonas com textura arenosa, com valores mais elevados de CEa devido à presença de água em profundidade; iii) zonas de textura mais argilosa com menores valores de CEa devido à diferenciação de camadas em profundidade (abaixo dos 40 cm).

Em consequência do aumento populacional esperado para os próximos anos e dos desafios da PAC, a agricultura tem hoje um papel protagonista na produção suficiente de alimentos de forma a garantir a alimentação da população e em simultâneo contrariar a degradação ambiental e as alterações climáticas. Este trabalho incidiu sobre uma parcela agrícola localizada na Herdade dos Boicilhos, concelho de Coruche, que recebeu a cultura do milho em 2021. O estudo teve como objetivo perceber se se justifica o tratamento diferenciado dos fatores de produção, com base no ano cultural antecedente (2021). Para alcançar este objetivo recorreu-se a: condutividade elétrica aparente do solo; imagens de satélite; compactação do solo; produtividade da cultura milho e ferramentas de sistemas de informação geográfica através do software ArcGISTM (ESRI, 2019). Este trabalho permitiu delimitar diferentes zonas candidatas à implementação de práticas agrícolas diferenciadas. Desta forma foi possível obter uma melhor perceção das zonas da parcela, em termos espaciais, o que permitirá a dinamização de boas práticas agrícolas, a fomentação de práticas mais sustentáveis e consequentemente melhorar a gestão da parcela.

This work presents the study of the relationship between soil apparent electrical resistivity ρa and the moisture content, clay content and soil compaction, for use of the ρa as a mapping tool of spatial soil variability. The values of apparent electrical resistivity are obtained by geoelectrical prospecting methods that detect the effects produced by the flow of electrical current in the soil. It is used the Wenner array and the technique of Lateral Profiling for data collection. It was held measures of ρa in different soil types, varying moisture content gradually while maintaining a constant compaction, and then varying the compaction and relating it to a constant humidity. To the study of spatial variability, it was chose two areas that would enable the change of moisture and compaction content, in order to verify the measurement capacity of ρa as methodology of identification of change in soil dynamics. The results obtained are presented and discussed.

The objective of this work was to delineate irrigation management zones using geostatistics and multivariate analysis in different combinations of physical and hydraulic soil properties, as well as to determine the optimal number of management zones in order to avoid overlaping. A field experiment was carried out in a Quartzipsamment, for two years, in an irrigated orchard of table grape, in the Senador Nilo Coelho Irrigation Scheme, in the municipality of Petrolina, in the state of Pernanbuco, Brazil. Soil samples were collected for the determination of soil physico-hydraulic properties. A portable meter was used to measure soil apparent electrical conductivity. Spatial distribution maps were generated using ordinary kriging. Management zones for five different combinations of soil properties were defined using the fuzzy c-means clustering algorithm, and two indexes were applied to determine the optimal number of management zones. Two combinations of soil properties can be used in the management zone planning in order to monitor soil moisture.

The constant increase in the world population is making more and more crops with the versatility of their products take more space in the market. The cultivation of soybean, which is of great expression in the Brazilian territory, fits these requirements, making it very important to study and search for the measurement of all its technical recommendations. In this way, Precision Agriculture, which seeks to identify and delimit sub-areas of cultivation within a pattern of physical-chemical soil characteristics and apply specific management to them, becomes a crucial agronomic strategy that aims to achieve maximum productive and financial performance of this soil. productive sector allied to a lower environmental impact, without disregarding its practicality of adoption in the field. With this in mind, effective and agile ways of measuring and mapping characteristics of the cultivation area, such as soil apparent electrical conductivity (AEC), become the target of study. In this work, the AEC was effective on delimiting management zones for the area. The higher AEC management zone showed a positive response to the increase in plant population, meanwhile in the lower AEC management zone higher yield was obtained at the intermediate plant population. With the suggested population settlement was estimated a potential productivity gain of 157,07 kg ha-1.

In an increasingly competitive system, optimizing the use of available resources and obtaining profitability with sustainability in your rural business must be the focus of rural producers, research and rural extension. When we use the expression “physical soil quality”, we are referring to the physical capacity of the soil to sustain the full development of plants. The main cause of compaction in agricultural soils is the traffic of machines in operations of preparation, sowing, cultivation and harvesting, especially when the soil is too humid. Knowing the variability of soil attributes is an important tool in the context of precision agriculture. In this work, the delimitation of management zones was studied based on the mapping of the spatial variability of the apparent electrical conductivity of the soil as a tool for decision making for soil unpacking operation. Management zones were defined based on the spatial variability of the apparent electrical conductivity of the soil and the resistance to penetration in each defined management zone was characterized. The work was carried out in the municipality of Cachoeira do Sul, in a commercial area for the cultivation of grains under no-tillage system, under central pivot. A sample grid composed of 95 points with a regular spacing of 50 x 50 meters was established. These points served as a basis for collecting altitude data in relation to sea level, measuring soil resistance to penetration (RP, MPa) and samples for textural characterization (0-20 cm). The apparent electrical conductivity of the soil was measured using Falker Automação Agrícola's Terram® equipment. Based on CEa data, mangrove zones were delimited and soon afterwards, PR was measured within each zone in order to characterize each zone and identify the correlation between the CEa and PR measurements. It was possible to differentiate RP values from the zones generated based on the CEa variability. It was identified that the minimum number of zones should be three and the measurement of CEa should be performed when the soil has low moisture content.