Fallow is a practice in which the soil is left uncultivated for a period of time and is used less due to the pressure on agricultural land, which impairs soil regeneration. The cultivation of legumes, such as peanuts, is a viable alternative that leads to an improvement in the soil chemistry and grain capacity. Despite their importance, there are gaps regarding the use of peanuts for land reclamation and their importance for enzymatic activity in the soil. Therefore, the aim of this study was to evaluate the effects of straw incorporation and peanut cultivation in fallow land on the soil’s chemical and biological quality and to determine whether the introduction of these elements contributes to an improvement in the soil fertility parameters and enzymatic activity. To achieve these objectives, experimental plots were established in fallow soils with different amounts of straw (0; 5 and 10 t ha⁻¹), with and without herbicide application and with peanut incorporation. The soil chemistry and enzymatic activity, plant biometrics and productivity were evaluated. The results showed that the straw treatment resulted in better plant development and increased productivity by up to 80%. The pH, soil organic matter, soil organic carbon, P, K, sum of bases and cation exchange capacity variables increased significantly with the presence of the plant and the incorporation of straw compared to uncovered soil, by 10%, 86%, 80%, 68%, 42%, 38% and 27%, respectively. For the enzymatic activity, the values showed that straw and peanut management affects the higher activity of β-glucosidase and arylsulfatase, with differences of 75 and 74% compared to the control. The incorporation of straw and peanuts in fallow land improves the chemical and biological quality of the soil. The use of herbicides has no effect on the soil dynamics or peanut development in the presence of straw and the presence of peanuts provides a better soil quality index and increases the β-glucosidase and arylsulfatase activity in the soil.

The present work aims at evaluating the initial development of two Eucalyptus urograndis (eucalypt) clones (H017 and H1069) consorted with maize in six plants per meter; soy in eighteen plants per meter; beans in ten plants per meter; and signal-grass, with 0.5 kg m-2 of seeds. The eucalypt planting was upheld in cement vases-70 L of capacity, filled with red oxisol-in the center of the vase. The crops were sown equidistant from the border, in one or two sowing lines. A randomized block design was used, in a 5x2 factorial scheme, using five crops (maize, bean, soy, signal grass and control treatment) in two densities (one and two sowing lines), all with three repetitions. Ninety days after planting, eucalypt height, diameter, foliar area, dry matter of leaves and stem and crops aerial parts dry matter were evaluated. Consort crops negatively affected the initial development of both clones, especially in the density of two sowing lines. Bean and soy were the least harmful crops and maize and signal-grass were the most harmful crops.

As atividades agrícolas e não agrícolas na Amazônia são os meios econômicos que garantem segurança alimentar e nutricional da sociedade do campo. Logo esse trabalho tem como objetivo geral analisar os arranjos adotados pelas Unidades de Produção Agrícola (UPAs), na comunidade São Pedro no município de Limoeiro do Ajuru/PA, na Amazônia Tocantina. Para a coletas dos dados utilizou-se a caminhada transversal, entrevistas diretivas e aplicação de um roteiro semi-estruturado, com a finalidade de compreender as escolhas dos agricultores, para a obtenção do sustento das unidades familiares. No sistema de produção os destaques foram para os cultivos da mandioca, da pimenta-do-reino e do açaí nativo, enquanto as criações se caracterizam pela pequena escala e destinação para o autoconsumo. O estudo relata que os agricultores possuem inúmeras estratégias e possibilidades para manter o sustento de suas famílias, no qual refirma que a agricultura familiar não é apenas uma forma de fazer agricultura e sim parte de uma categoria social.

O cultivo de raízes de mandioca é muito importante nas regiões do Brasil, principalmente por pessoas de baixa renda. Apesar do aumento da área plantada, a produtividade desta cultura é baixa, devido principalmente a baixa fertilidade e manejo dos solos utilizados para o plantio. Este trabalho teve como objetivo avaliar a influencia do calcário na cultura da mandioca no Nordeste Paraense (Amazônia Tocantina). O experimento foi realizado sob condições de campo, no período de novembro de 2015 a setembro de 2016, em uma propriedade rural de caráter familiar no município de Cametá, estado do Pará. O experimento foi conduzido em delineamento em blocos casualizados – DBC, com quatro repetições. Os tratamentos utilizados foram dosagens crescentes de calcário: 500 kg ha-1; 750 kg ha-1; 1.000 kg ha-1; 1.500 kg ha-1, mais uma testemunha sem aplicação. A cultura foi conduzida de acordo com os produtores familiares da Amazônia Tocantina, sem irrigação e adubação complementares. Foram avaliados: comprimento, diâmetro, número e peso de raízes por planta, produção total de raízes e também a quantificação de ácido cianídrico. Verificou-se que o maior peso de raízes por planta e a máxima produção foram obtidos utilizando a menor dosagem. A quantidade de ácido cianídrico nas raízes não foi diminuída com o aumento das doses de calcário, sendo a cultivar utilizada, classificada como mandioca mansa ou de mesa.

The aim of this study was to evaluate the effects of selenium (Se) biofortification on growth, biomass accumulation, and micronutrient composition of industrial hemp (Cannabis sativa L., cv. Finola) microgreens, with emphasis on Se uptake and its distribution among leaves, stems, and roots. Microgreens were subjected to four Se treatments (Se_0, Se_2, Se_4, and Se_6 µmol Se/L), and changes in morphological traits, micronutrient status (Mn, Fe, Cu, Zn), and Se accumulation were assessed. Selenium biofortification had a marked impact on plant morphology and biomass. Stem length decreased by 12–18% under Se treatments compared with the control, whereas root length increased slightly, particularly at Se_2 and Se_4 (up to +6%). Fresh industrial hemp microgreens biomass responded strongly to Se supply, with the highest stem, root, and total fresh mass recorded at Se_4—representing an increase of 15–22% relative to control plants. At the highest Se level (Se_6), biomass declined by approximately 10–14%, indicating potential growth inhibition at excessive Se concentrations. Micronutrient concentrations were significantly affected by Se. Leaf Mn increased from 152 mg kg⁻¹ at Se_0 to 175 mg kg⁻¹ at Se_6 (+15%), while leaf Zn decreased by 20–25% at higher Se exposure. Stems and roots showed similar antagonistic interactions, with Fe and Zn decreasing by up to 30% at elevated Se levels. Conversely, Mn in stems and roots increased with Se up to Se_4, reaching 400 mg kg⁻¹ in roots. Selenium accumulation exhibited a strong linear response to biofortification, with high coefficients of determination (R² = 0.9685–0.9943), confirming predictable and efficient Se uptake. Correlation analysis revealed strong positive associations among biomass-related traits and distinct interactions among micronutrients, especially the near-perfect correlation between Se and Cu in roots (r ≈ 0.99). Overall, industrial hemp microgreens demonstrate potential for selenium biofortification, provided that selenium application levels remain within safe dietary limits.

EFEITOS DA ÉPOCA RELATIVA DE EMERGÊNCIA DE PICÃO-PRETO (Biden pilosa L.) COM A CULTURA DO FEIJÃO (Phaseolus vulgaris L.)