The production of biochar from organic residues promises to be an interesting strategy for the management of organic waste. To assess the effect of biochar on soil properties and the production and nutrition of common bean (Phaseolus vulgaris L.), three simultaneous experiments were conducted in a greenhouse with different biochar from organic residues (rice husk, sawdust, and sorghum silage) used as filtration material for swine biofertilizer. In each experiment the treatments consisted of five different biochar concentrations (0, 25, 50, 75 and 100 L m⁻³), arranged in a completely randomized design, with four repetitions. In the experiments, the use of biochar increased soil pH, cation exchange capacity, nutrient availability in the soil, and nutrient accumulation in grains. The biochar concentrations corresponding to the maximum production of grain dry matter of bean plants were 100, 68, and 71 L m⁻³ for biochar from rice husk filter (BRHF), biochar from sawdust filter (BSF), and biochar from sorghum silage filter (BSSF), respectively.

Production systems that promote the accumulation of soil organic matter (SOM) must be implemented to maintain the sustainability of agriculture, livestock, and forestry. Since increases in MOS content contribute to improving the chemical, physical, and biological quality of the soil, as well as helping to reduce carbon emissions to mitigate climate change. Therefore, the objective of this study was to evaluate soil organic carbon (SOC) and nitrogen (N) stocks after the implementation of agrosilvopastoral (ASP) systems in a Cerrado-Caatinga transition zone in Brazil. Native vegetation of Cerrado-Caatinga (NV), regenerating stratum of Cerrado-Caatinga (RS), two arrangements of ASP systems cultivating Cenchrus ciliaris L. intercropped with Eucalyptus camaldulensis Dehnh. × Eucalyptus tereticornis Sm. hybrid (ASP1 and ASP2), and intercropped with Eucalyptus urophylla S.T. Blake × Eucalyptus grandis W. Mill ex Maiden hybrid (ASP3 and ASP4) were evaluated. Soil C and N stocks and the C content in the humic fractions of SOM were evaluated at 0–10, 10–20, and 20–30 cm soil depths. The introduction of ASP2, ASP3, and ASP4 systems in an area previously occupied by low productivity pasture increased and restored SOC stocks to levels found in NV, at a depth of 0–30 cm. N stocks were higher in ASP systems, regardless of the arrangement studied. As a result, the ASP systems provided accumulations that ranged from 1.0 to 4.31 Mg SOC ha⁻¹ yr⁻¹ and from 0.33 to 0.36 Mg N ha⁻¹ yr⁻¹. The carbon contents in humic fractions remained higher in NV. The hierarchical grouping and principal component analysis showed that the implementation of the ASP systems was efficient in increasing soil C and N stocks over time. In conclusion, the present study identified that integrated production systems can support land use intensification strategies based on sustainable and low-carbon agriculture in a transition area between the Cerrado and Caatinga biomes in Brazil.

C3 plants tend to present more evident responses in their growth when there is an increase in CO₂ in the environment. Such observations are not so evident in plants with C4 metabolism, which are considered more naturally evolved due to their functional anatomy, which is capable of concentrating a greater amount of CO₂ in their cells, making photosynthesis a more efficient process. Several studies are found that suggest greater growth of plants that use both C3 and C4 metabolism when subjected to higher CO₂ concentrations than current environmental conditions. The objective of the present work was to carry out a review of the influence of atmospheric CO₂ concentration on the growth of cultivated plants with emphasis on the cultivation of beans and corn and weeds. The increase in carbon dioxide benefits the growth of both C3 metabolism and C4 metabolism plants. Knowing that the future trend is that the concentration of carbon dioxide is increased in the atmosphere, due to emissions mainly from fossil fuels, it will become appropriate to invest in more inputs and technologies to reduce competition with weeds, as their growth also it will be favored and may interfere with competition for nutrients, and thus reduce crop productivity.

Com o objetivo de avaliar o crescimento do abacaxizeiro 'Vitória' irrigado, submetido ao aumento da densidade populacional, e doses de N na região norte de Minas Gerais, foi instalado um experimento em esquema fatorial 5 x 4 x 4, correspondendo a cinco doses de N (0; 5; 10; 15 e 20 g planta-1), quatro populações de plantas (51.282; 76.923; 90.909 e 126.984 plantas ha-1) e quatro épocas de avaliação (270; 360; 450 e 540 dias após o plantio - DAP), utilizando ureia ou esterco bovino como fonte de N. Aos 540 dias após o plantio - DAP (época de indução floral), foi avaliado o efeito das fontes de N por meio do fatorial 2 x 5 x 4, que consistiu em : duas fontes N (ureia e esterco bovino), cinco doses de N e quatro populações de plantas, conforme estudo anterior. Utilizou-se o delineamento em blocos casualizados, com três repetições, com mudas micropropagadas da cultivar Vitória. Avaliaram-se as características de crescimento da planta (número de folhas emitidas, comprimento e peso da folha "D" e diâmetro do caule), além do peso dos frutos com e sem coroa no final do cultivo. Não foi observada interação entre densidade de plantio, doses de N e dias após o plantio (DAP). O aumento da densidade de plantio reduziu o diâmetro do caule do abacaxizeiro, no entanto não interferiu no peso dos frutos, indicando a possibilidade de aumento da população de plantas para o incremento da produtividade. A utilização de ureia como fonte de N promoveu maior crescimento e peso dos frutos do abacaxizeiro. A utilização de doses de N na forma de ureia e esterco promoveu maior crescimento do abacaxizeiro e incremento linearmente no peso dos frutos, indicando a dose de 20 g planta-1 na forma de ureia, como recomendação de adubação nitrogenada para o cultivo do abacaxizeiro 'Vitória' irrigado.

O efeito da mistura de fibra de coco (FC) e resíduo compostado de algodão (RA) foi avaliado na formação de substrato para produção de mudas de tomateiro Kada Gigante. O experimento foi conduzido em casa de vegetação no ICA da UFMG em Montes Claros-MG. Utilizou-se o delineamento experimental em blocos ao acaso, com quatro repetições. Os tratamentos avaliados foram: T1) Substrato comercial Hortimix®; T2) 100% massa seca de resíduo algodão proveniente da compostagem do resíduo da industria têxtil (RA); T3) 20% FC+80% RA; T4) 40% FC+60% RA; T5) 60% FC+40% RA; T6) 80% FC+20% RA; T7) 100% FC+% RA. Foram avaliados o diâmetro do caule, a altura da planta, o índice de velocidade de emergência, a porcentagem de germinação, a massa fresca da parte aérea e a massa fresca da raiz, a massa seca da aérea seca e a massa da matéria seca da raiz. Observou-se que o aumento da proporção de fibra de coco verde em relação ao resíduo compostado de algodão proporcionou maior emergência, e índice de velocidade de emergência, entretanto, o diâmetro do caule, a altura da planta, a massa fresca e seca da parte aérea e do sistema radicular diminuíram com o aumento dessa proporção. O resíduo de algodão proveniente da compostagem do resíduo da industria têxtil, constitui-se em um material útil na produção de substratos comerciais.

Chickpea is the third most cultivated legume in the world. In Brazil, cropping of this legume is recent and definitions of fertilizer management techniques are scarce. In this study, the objective was to evaluate chickpea (BRS Aleppo) production and soil chemical attributes with and without phosphorus fertilization and leaf-applied molybdenum. A randomized block experimental design was used, with four replications. A 2 x 5 factorial arrangement was used to evaluate production, consisting of two molybdenum fertilization management practices (with and without molybdenum) and five application rates of P₂O₅ (0, 60, 120, 180, and 240 kg ha^-1) in the form of single superphosphate. Soil sampling for evaluation of soil chemical attributes in the crop row and between rows was also considered. Molybdenum fertilization brought about greater stem and aboveground dry matter. Phosphorus fertilization increased stem, leaf, and seed yield, yielding a maximum of 2.83 t ha^-1 seed at the rate of 200 kg ha^-1 P₂O₅. However, maximum agronomic efficiency (8.30) was observed with the addition of 150 kg ha^-1 P. Soil in the crop row attained higher concentrations of P, K, H+Al, and P-rem and reduction in pH, Ca concentration, SB, T, and V compared to between rows. Phosphorus rates reduced soil pH and increased T and the P concentrations, though only in the plant row. Between the rows, no changes were observed in soil chemical attributes, indicating low mobility of P and the acidification capacity of superphosphate in alkaline soils.