RESUMO Compostos derivados de petróleo presentes no solo podem comprometer o crescimento das plantas e inibir o desenvolvimento da população microbiana. Esses contaminantes diminuem a porosidade do solo, dificultam a absorção de água e podem interromper processos metabólicos das plantas. Assim, nesta pesquisa buscou-se avaliar os efeitos da presença no solo de três hidrocarbonetos no solo sobre o crescimento e desenvolvimento de espécies forrageiras e nos indicadores microbiológicos do solo. O experimento foi realizado em casa de vegetação no delineamento experimental de blocos casualizados, com quatro repetições. Os tratamentos foram dispostos em fatorial de 5×4, sendo o primeiro fator constituído pelas espécies avaliadas (Pennisetum glaucum, Zea mays, Brachiaria ruziziensis, Panicum maximum e Sorghum bicolor), e o segundo fator correspondendo a presença dos contaminantes: benzeno, tolueno ou xileno e solo sem contaminante. As espécies foram cultivadas por 42 dias. A tolerância das espécies dependeu do tipo de contaminante presente no solo. A massa seca total da P. glaucum foi reduzida em 26%, 10% e 32% para o tolueno, benzeno e xileno, respectivamente. Z. mays teve o crescimento reduzido na presença do tolueno (13%) e do benzeno (21%). S. bicolor teve sua matéria seca aumentada em 58% com o xileno. B. ruziziensis e P. maximum foram tolerantes para todos os contaminantes. A magnitude dos efeitos dos contaminantes nos indicadores microbiológicos do solo dependeu da espécie cultivada. A tolerância das plantas e da comunidade microbiana do solo aos contaminantes depende da espécie forrageira utilizada e deve ser aspecto importante para a seleção de plantas para recuperação de áreas degradadas. Assim buscouse buscou se casualizados repetições 54 5 4 5×4 Pennisetum bicolor, , bicolor) dias P 26 26% 10 32 respectivamente Z 13% 13 (13% 21%. 21 21% . (21%) S 58 B cultivada degradadas 5× 2 1 3 (13 (21% (1 (21 ( (2

ABSTRACT Oil-derived compounds present in the soil can compromise plant growth and inhibit the development of the microbial population. These contaminants reduce soil porosity, hinder water absorption, and can disrupt plant metabolic processes. The aim of this research was to evaluate the effects of the presence of three hydrocarbons in the soil on the growth and development of forage species and on soil microbiological indicators. The experiment was carried out in a greenhouse using a randomized block design with four replications. Treatments were arranged in a 5×4 factorial, with the first factor consisting of the species evaluated (Pennisetum glaucum, Zea mays, Brachiaria ruziziensis, Panicum maximum and Sorghum bicolor) and the second factor corresponding to the presence of contaminants: benzene, toluene or xylene and soil without contaminants. The species were grown for 42 days. The tolerance of the species depended on the type of contaminant present in the soil. The total dry matter of P. glaucum was reduced by 26%, 10% and 32% for toluene, benzene and xylene, respectively. Z. mays had its growth reduced in the presence of toluene (13%) and benzene (21%). S. bicolor had its dry matter increased by 58% with xylene. B. ruziziensis and P. maximum were tolerant to all contaminants. The magnitude of the effects of contaminants on soil microbiological indicators depended on the species grown. The tolerance of plants and soil microbial community to contaminants depends on the forage species used and should be an important aspect when selecting plants to restore degraded areas. Oilderived Oil derived population porosity absorption processes replications 54 5 4 5× factorial Pennisetum days P 26 26% 10 32 respectively Z 13% 13 (13% 21%. 21 21% . (21%) S 58 B areas 2 1 3 (13 (21% (1 (21 ( (2

Abstract: Background: Knowing the relationships between the soil's physical-chemical properties and herbicide behavior in the soil allows establishing strategies for the efficient control of weeds with less environmental risk. Objective: It carried this study to investigate the role of physical-chemical properties of Brazilian soils in the sorption-desorption and mobility of the herbicide saflufenacil. Methods: We used nine soils from different regions of Brazil in the study of sorption-desorption and mobility of 14C-saflufenacil. The herbicide sorption-desorption estimate was performed using the batch equilibrium method and mobility using soil thin-layer chromatography. Principal component analysis (PCA) and clustering were performed to evaluate the impact of soil properties on the sorption-desorption behavior of saflufenacil. Results: The results indicated that saflufenacil was weakly sorbed in different types of tropical soils, and the sorption process is reversible, with its mobility varied from mobile (Rf = 0.70) to very mobile (Rf = 0.99) in the different soils and indicates that the herbicide has leaching potential in these types of soils. The sorption-desorption capacity and mobility of saflufenacil depend mainly on pH, CEC, clay, and OC content, and therefore it is vital to analyze them to predict the impacts of herbicide application on the environment. The PCA is an essential tool that helps to clarify how the effects of soil properties influence herbicide behavior. Conclusions: The OC content in Brazilian soils has a direct role in saflufenacil sorption and desorption. BR3 soil (soil with highest organic carbon; OC = 2,1%) exhibits greater sorption (Kd = 1,85 L kg−1), value 5.5 times greater than the BR1 (soil with lower sorption; with OC = 0,6%). Therefore, the application of saflufenacil to tropical soils, especially those with low levels of CO (< 1%), may result in a greater potential risk of contamination of surface and groundwater in neighbouring agricultural and non-agricultural areas, particularly those with intensive use and ineffectiveness of saflufenacil. Future investigations could focus on integrating modeling approaches that incorporate soil variability to predict saflufenacil behavior accurately in diverse soil types, aiding in decision-making for sustainable herbicide use. Abstract Background s physicalchemical physical chemical Objective sorptiondesorption desorption Methods 14Csaflufenacil. 14Csaflufenacil Csaflufenacil 14C C 14C-saflufenacil thinlayer thin layer chromatography (PCA Results reversible Rf 0.70 070 0 70 0.99 099 99 pH CEC clay environment Conclusions BR carbon 2,1% 21 2 1 Kd 185 85 1,8 kg−1, kg1 kg kg−1 , kg−1) 55 5 5. 0,6%. 06 0,6% . 6 0,6%) Therefore < ( 1%, 1% 1%) nonagricultural non areas decisionmaking decision making 0.7 07 7 0.9 09 9 2,1 18 8 1, kg− 0,6 0. 2, 0,

RESUMO Em espécies fruteiras, é essencial considerar o gerenciamento da distribuição da luz nas copas das plantas, pois a quantidade de energia solar absorvida pode influenciar na qualidade dos frutos. Diante disso, os objetivos deste estudo foram: (i) analisar as variações das trocas gasosas ao longo do dia; (ii) identificar a densidade de fluxo de fótons fotossinteticamente ativos (PPFD) que promove maior fluorescência da clorofila e maior taxa de transporte de elétrons em mudas de jaboticaba. O delineamento experimental foi inteiramente casualizado, sendo os tratamentos compostos por 18 densidades de fluxo de fótons fotossinteticamente ativos (0; 25; 50; 75; 100; 125; 150; 175; 200; 400; 600; 800; 1.000; 1.200; 1.400; 1.600; 1.800 e 2.000 μmol m-2 s-1) e três horários de avaliação ao longo do dia (08:00, 12:00 e 16:00 h). Foram utilizadas seis repetições, considerando duas plantas por parcela útil. Trocas gasosas e fluorescência da clorofila a de P. peruviana foram alterados em virtude da PPFD e das condições ambientais ao longo do dia. A alta PPFD (1.384,6 μmol m-2 s-1) e temperatura do ar (39,74 °C) no horário de 12 horas favoreceu as trocas gasosas dessa espécie. O aumento da PPFD até 1.000 µmol m-2 s-1 influenciou positivamente as trocas gasosas e fluorescência da clorofila a de P. peruviana. fruteiras frutos disso i (i ii (ii (PPFD jaboticaba casualizado 1 0 (0 25 50 75 100 125 150 175 200 400 600 800 1000 000 1.200 1200 1.400 1400 1.600 1600 1800 1.80 2000 2 2.00 m2 m m- s1 s 0800, 0800 08 00, 00 (08:00 12:0 16 16:0 h. h . h) repetições útil P 1.384,6 13846 384 6 (1.384, 39,74 3974 39 74 (39,7 °C C espécie 1.00 s- ( 5 7 10 15 17 20 40 60 80 1.20 120 1.40 140 1.60 160 180 1.8 2.0 080 (08:0 12: 16: 1.384, 1384 38 (1.384 39,7 397 3 (39, 1.0 4 8 1.2 1.4 14 1.6 1. 2. (08: 1.384 138 (1.38 39, (39 (08 1.38 13 (1.3 (3 1.3 (1. (1

ABSTRACT In fruit species, the amount of solar energy absorbed can influence fruit quality; hence, ensuring optimal light distribution management in the canopy of plants is essential. Therefore, the objectives of this study were (i) to analyze the variations in gas exchange through the day and (ii) identify the photosynthetically active photon flux density (PPFD) that promotes higher chlorophyll fluorescence and electron transport rate in jaboticaba seedlings. The experimental design was completely randomized, with treatments consisting of 18 photosynthetic photon flux densities and three evaluations throughout the day. Six replicates were used, with two plants per plot. Gas exchange and chlorophyll a fluorescence in P. peruviana were altered due to fluctuating photosynthetic photon flux density (0; 25; 50; 75; 100; 125; 150; 175; 200; 400; 600; 800; 1,000; 1,200; 1,400; 1,600; 1,800; and 2,000 μmol m-2 s-1) and environmental conditions throughout the day (8:00 a.m., 12:00 and 4:00 p.m.). The higher PPFD (1,384.6 μmol m-2 s-1) and air temperature (39.74 °C) at noon (12:00 p.m.) favored gas exchange in this species. An increase in PPFD of up to 1,000 μmol m-2 s-1 positively influenced the gas exchange and chlorophyll a fluorescence of P. peruviana. species quality hence essential Therefore i (i ii (ii (PPFD seedlings randomized 1 used plot P 0 (0 25 50 75 100 125 150 175 200 400 600 800 1000 000 1,200 1200 1,400 1400 1,600 1600 1,800 1800 2000 2 2,00 m2 m m- s1 s 8 00 (8:0 am a.m. 12 12:0 4 4:0 p.m.. pm p.m. . p 1,384.6 13846 384 6 (1,384. 39.74 3974 39 74 (39.7 °C C (12:0 1,00 s- ( 5 7 10 15 17 20 40 60 80 1,20 120 1,40 140 1,60 160 1,80 180 2,0 (8: a.m 12: 4: p.m 1,384. 1384 38 (1,384 39.7 397 3 (39. (12: 1,0 1,2 1,4 14 1,6 16 1,8 2, (8 1,384 138 (1,38 39. (39 (12 1, 1,38 13 (1,3 (3 (1 1,3 (1,

Abstract Background The study of corn and palisade grass physiology may assist in determining the best arrangement of the plants and more efficient management of this intercropped system. Objective To evaluate the effects of different palisade grass plant arrangements and their control on physiological characteristics and corn yield. Methods Two trials in randomized complete block design with four replications were conducted in field conditions. In the first, corn was sown with 0.50 m row spacing, whereas the second had 1.00 m row spacing. All the treatments were arranged in the same way in both experiments, in a 2x4 factorial design. The first factor was the nicosulfuron dose applied (0 and 8 g a.i. ha-1), and the second, the forage seeding rates (0, 2, 4, and 6 kg of seeds per hectare). Sowing of both species was performed on the same day. Results The application of nicosulfuron negatively affected stomatal conductance, internal carbon concentration, and increased CO2 consumption and efficiency in water use. The photosynthetic rate was not affected by the herbicide application, however it presented lower values in the 0.50 m spacing. Although the yield was not affected by row spacing, it was higher when nicosulfuron was applied. Conclusions The increase in palisade grass density caused detrimental changes in the water use efficiency with direct consequences to the crop yield. The physiological response and corn yield depend on the arrangement of plants and the palisade grass management adopted.

RESUMO O déficit hídrico pode alterar funções fisiológicas vitais e afetar negativamente o crescimento das plantas. Esses efeitos podem ser intensificados pelas plantas daninhas que competem pela água disponível para as culturas. O objetivo foi avaliar os efeitos da competição e do déficit hídrico temporário do solo sobre a transpiração (E), condutância estomática (gs) e taxa fotossintética (A) do milho, da Urochloa decumbens e da Bidens pilosa L. O delineamento experimental foi em blocos casualizados, com oito repetições. Os tratamentos foram arranjados em esquema fatorial 5 x 2, com o primeiro fator correspondente às espécies milho + U. decumbens, milho + B. pilosa, e milho, U. decumbens e B. pilosa sem competição, e o segundo fator dois regimes hídricos, irrigação diária e restrição hídrica, que correspondeu à suspensão da irrigação desde o início do estágio V3 do milho até o momento em que seus estômatos ficaram totalmente fechados. As espécies B. pilosa e U. decumbens agravaram em diferentes intensidades os efeitos negativos sobre E, gs e A do milho em condição de restrição hídrica. A U. decumbens foi mais agressiva em relação a B. pilosa em competição com o milho, em ambos regimes hídricos. A competição com o milho afetou a E e gs da U. decumbens nos dois regimes hídricos, mas a A foi alterada sob déficit hídrico. Por outro lado, os componentes fisiológicos de B. pilosa não foram afetadas pela competição com o milho, nos dois regimes hídricos.

ABSTRACT Water deficits can alter vital physiological functions and negatively affect plant growth. These effects can be intensified by weeds competing for water available to crops. The objective of this study was to evaluate the effects of competition and temporary soil water deficit on the transpiration (E), stomatal conductance (gs) and photosynthetic rate (A) of corn, Urochloa decumbens, and Bidens pilosa L. The experimental design was in randomized blocks with eight repetitions. The treatments were arranged in a 5 x 2 factorial scheme, with the first factor corresponding to the species: corn + U. decumbens, corn + B. pilosa, and corn, U. decumbens, and B. pilosa without competition. The second factor was two water regimes: daily irrigation and water restriction, which corresponded to the suspension of irrigation from the beginning of the V3 stage of corn until the time when their stomata were completely closed. The species B. pilosa and U. decumbens worsened the negative effects on E, gs, and A of corn at different intensities under water restriction. The U. decumbens was more aggressive in relation to B. pilosa while coexisting with corn in both water regimes. The competition with corn affected the E and gs of U. decumbens in the two water regimes, but the A was altered under water deficit. On the other hand, the physiological components of B. pilosa were not affected by its coexistence with corn in the two water regimes.

RESUMO A germinação de sementes de espécies que se desenvolvem em regiões áridas e semiáridas pode ser afetada por fatores como deficiência hídrica e excesso de sais no solo, desta forma, o conhecimento sobre os limites de tolerância a esses fatores, é fundamental para compreender a sua capacidade de adaptação. Objetivou-se neste trabalho avaliar as alterações fisiológicas (germinação e vigor) de sementes de Mimosa caesalpiniifolia provenientes de diferentes regiões brasileiras (Sudeste, Centro-Oeste e Nordeste) e submetidas aos estresses hídrico e salino. Para simular o estresse hídrico foi utilizado o agente osmótico polietilenoglicol (PEG 6000), ajustado para os potenciais de 0; -0,2; -0,4; -0,6 e -0,8 MPa, enquanto para o salino utilizou-se as soluções de NaCl nos potenciais de 0; -0,1; -0,3; -0,5; -0,7; -0,9; -1,1 MPa. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 3 x 5 para estresse hídrico e 3 x 7 para estresse salino, com quatro repetições de 25 sementes. As variáveis analisadas foram: porcentagem de germinação, índice de velocidade de germinação, comprimento da parte aérea e da raiz e massa seca da parte aérea e da raiz de plântulas. As sementes de M. caesalpiniifolia, provenientes das diferentes regiões geográficas, respondem fisiologicamente de maneira semelhante ao estresse hídrico; já com relação ao estresse salino, a tolerância das sementes é variável em função da região de colheita, sendo as provenientes de Vazante, MG, mais tolerantes durante a germinação e o crescimento inicial das plântulas.

ABSTRACT Seed germination of species that develop in arid and semi-arid soils can be altered by water deficit and abundance of salts in the soil. Knowledge on tolerance limits is fundamental to understand the adaptive capacity of species under such conditions. The objective of this study was to evaluate the physiological changes (germination and vigor) of Mimosa caesalpiniifolia seeds from different regions and submitted to water and saline stresses. To simulate water stress, the osmotic agent polyethylene glycol (PEG 6000) was adjusted to the potentials of 0, -0.2, -0.4, -0.6 and -0.8 MPa, whereas for the saline stress, NaCl solutions were adjusted to the potentials of 0, -0.1, -0.3, -0.5, -0.7; -0.9 and -1.1 MPa. The experimental design was completely randomized, in a 3 x 5 factorial scheme for water stress and 3 x 7 factorial scheme for saline stress, with four replicates of 25 seeds. The variables analysed were: germination, germination speed index and seedling shoot length, root length, shoot dry matter and root dry matter. M. caesalpiniifolia seeds, coming from different geographic regions, showed similar physiological responses to water stress; with respect to salt stress, their tolerance varies according to the region of harvest, and those from Vazante, MG, Brazil were more tolerant during germination and initial growth of seedlings.

Intercropping is a common practice among farmers in tropical regions of the world and has persisted for years, not only for traditional reasons, but also for certain advantages that helped in its ecological adaptation. In regard to low income farmers with small areas for cultivation, more attention should be given to the cost of production and better land management. Thus, the aim of this work was to determine the best intercropping system of cassava with other crops. The experiment was conducted in an area belonging to the cassava (Manihot esculenta) producers of the Planalto de Minas district in Diamantina, Minas Gerais State, Brazil. The treatments comprised cassava intercropped with maize, beans and dwarf pigeon pea, as well as controls with and without weeding. The dry mass of shoots for maize, beans and dwarf-pigeon pea was affected by the presence of cassava. The productivity of cassava was dependent on cultivar and the intercropped crop. The highest harvest indexes were observed when cassava was intercropped with maize. In a general way, intercropping with maize and beans showed the highest area equivalence indexes and are recommended for the cassava crop.

Intercalar cultivos es una práctica común entre los agricultores de las regiones tropicales del mundo, que ha persistido a lo largo de los años, no sólo por tradición, sino también por la búsqueda de las ventajas que han ayudado en su adaptación ecológica.Cuando se considera a agricultores con pequeñas propiedades de cultivo y bajos ingresos económicos, se debe poner más atención en los costos de producción y en el mejor aprovechamiento de la tierra. Así pues, el objetivo de este trabajo fue determinar el mejor sistema de intercalar la yuca con otros cultivos. El experimento se realizó en un área perteneciente a los productores de yuca (Manihot esculenta) del distrito de Planalto de Minas en Diamantina, Minas Gerais, Brasil. Los tratamientos consistieron en intercalar la yuca con maíz, frijoles y guisantes enano paloma, así como los controles con y sin deshierbe. La producción de materia seca de rebrote de maíz, frijoles y guisantes enano paloma se vio afectada por la presencia de yuca. La productividad de la yuca depende de la variedad utilizada y de los cultivos intercalados. Los mayores índices de cosecha se observaron cuando la yuca se intercaló con maíz. De forma general se puede afirmar que el cultivo de la yuca, intercalado con maíz y frijol, muestra los índices de equivalencia área más altos, siendo el más recomendado para el cultivo de la yuca.

Competition between weeds and crops results in a lower availability of some resources to crop species, which causes deficiencies, such as water and nutritional deficiencies and low light quality or quantity. The aims of this study were to evaluate the effects of Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster, cv. Xaraes (brachiaria) emergence times comparing with corn (Zea mays L.), in addition to the fertilization and application of different nicosulfuron and atrazine herbicides levels, on the physiological characteristics of intercropped species. The physiological characteristics Brachiaria plants that were treated with herbicides were negatively affected. The emergence time of Brachiaria plants in comparison with corn altered the physiological characteristics of both. The Brachiaria plants that emerged before corn presented higher photosynthetic and transpiration rates and reduced the intensity of these characteristics in corn. Thus, the Brachiaria plants that emerged before the corn crop presented a higher physiological efficiency, and they were more competitive than the weeds that emerged during other seasons.