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Agriculture depends on biotic and abiotic factors, and one of them is allelopathy, defined as the chemical interference that one plant has on others, which can negatively affect germination. The objective of this work is to evaluate the allelopathic effects of Sorghum bicolor and Digitaria insularis on seed germination and initial development of canola seedlings (Brassica napus L.). A completely randomized design was used in a 2x5 factorial scheme (two extracts: D. insularis and S. bicolor) and five concentrations (0, 25, 50, 75, and 100%), with four replicates of fifty seeds, the plot being constituted by a 'gerbox' box containing 50 seeds evenly distributed. The variable analyzed were germination percentage (G), abnormal seedlings (AS), dead seeds (DS), length of the shoot (SL) and primary root (RL), total length (TL) of the seedling, shoot ratio (S/T), and root ratio (R/T). The aqueous extracts of D. insularis interfere in all variables studied, which compromises the formation of normal seedlings, regardless of concentration. The extract of S. bicolor expressed allelopathic effects only in concentrations above 75%. Both species can inhibit the initial development of canola plants.

Efficient Microorganisms are shown to be an effective, alternative, sustainable, safe, and low-cost technique to increase the productivity of organic foods, and their use is a good option for agroecological management. Based on this context, this work had as main objective to evaluate the efficiency of the application of a biological cocktail from Efficient Microorganisms in the cultivation of lettuce. In the capture of the Efficient Microorganisms and the manufacture of the biological cocktail, a methodology proposal in the agroecology used by Brazilian Ministry of Agriculture, Cattle and Supplying (MAPA, in Portuguese, Ministério da Agricultura, Pecuária e Abastecimento). The adopted experimental design was randomized blocks containing 8 blocks and 3 treatments. The T1 treatment, application of the Efficient Microorganisms, obtained a greater fresh mass of the aerial part of the plants sampled in the two cycles, resulting in a higher productivity in tons/hectare. The results proved to be advantageous for the productivity of the lettuce that received application of the biological cocktail from Efficient Microorganisms, when the biomass parameters were analyzed.

Este estudo teve como objetivo avaliar os efeitos da inoculação das sementes de trigo com microrganismos eficientes, testando diferentes concentrações e produtos comerciais, afim de obter o controle da contaminação de possíveis agentes patogênicos associados a semente da cultura, assim como, um efeito positivo na germinação destas sementes. Utilizou-se o delineamento inteiramente casualizado em esquema fatorial 2 x 5 + 1, sendo o primeiro fator composto por dois produtos contendo microrganismos eficientes (EM comercial e EM convencional), o segundo fator foi constituído por cinco níveis da concentração dos produtos (20, 40, 60, 80 e 100%), adicionando mais um tratamento contendo somente água deionizada, com quatro repetições, totalizando 44 parcelas experimentais. Os produtos contendo microrganismos eficientes e as concentrações apresentaram interação significativa somente para as variáveis porcentagem da presença de fungos e porcentagem da ausência de fungos. No teste de germinação, verificou-se uma interação significativa nas variáveis porcentagem de germinação e índice de velocidade de germinação. Os resultados obtidos permitem concluir que ambos os produtos utilizados (comercial e convencional), apresentaram eficiência no controle de fungos infectantes nas sementes de trigo, assim como, incrementaram o desenvolvimento inicial das plântulas.

The objective of this work was to evaluate the nutrition and agronomic characteristics of common bean and castor bean under intercropping subject of nitrogen fertilization in top dressing. A randomized block design in a 2×2×4 + 4 factorial scheme was used, and there were three replicates. The treatments consisted of two common bean cultivars (Pontal and Pérola), which were intercropped with two castor bean cultivars (Energia and Paraguaçu), and combined with four nitrogen treatments (0, 50, 100 and 200 kg ha-1). Four additional treatments involved bean and castor bean cultivars at a single dosage of 40 kg ha-1 nitrogen. The nitrogen, potassium, calcium, magnesium and sulfur contents in castor bean intercropped with common bean leaves were influenced by nitrogen treatments. For common bean applied as top dressing, the maximum grain yields were 1,122 and 1,024 kg ha-1 for cultivars (cvs.) Pontal and Pérola, respectively, with a dose of 100 kg ha-1 nitrogen. Similar results were observed for castor bean, for whom 100 kg ha-1nitrogen provided the largest number of bunches and number of berries per bunch and the highest grain yield. The maximum values observed were 38 and 27 bunches per plant, 27.6 and 35.4 berries per bunch and 1,474 and 1,286 kg ha-1 grain yield for cvs. Paraguaçu and Energia, respectively.

Pasture leafhoppers are considered highly important pests in forage grasses in Brazil due to their widespread occurrence. This insect is one of the most relevant pests in pasture degradation. In order for the control of spittlebugs to be efficient, it is important to know the population behavior of the species of this insect, identify the period of greatest occurrence, as well as the climatic and environmental conditions that favor the development of the pest. Thus, this study aimed to evaluate the population dynamics of spittlebugs, at a quantitative level, in Brachiaria decumbens and Panicum maximum pastures, associating the results with meteorological data from the municipality of Conceição do Araguaia, Southeast Pará. To study the population dynamics of spittlebugs, samples were taken every two weeks, in two types of pastures aged between 5 and 7 years, kept under rotational grazing, with a stocking of 1.5 animal units. The method of monitoring nymphs and adults of leafhoppers was adopted, through walking within the observation area. The level of infestation of spittlebugs in both forage species was evaluated and all results were submitted to analysis of variance by the F test. It was found that the species B. decumbens had a greater number of adults and nymphs when compared to the forage species P. maximum. The population dynamics of spittlebugs occur gradually according to climatic conditions, and the period with not-so-high temperatures (22 ºC to 34 ºC) and good rainfall provide an infestation of this insect pest in the pasture.

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The response capacity of the bean to fix atmospheric nitrogen is questionable, mainly due to its inability to supply all the nitrogen in the flowering and grain filling phases when the crop needs it most. Thus, a new application of inoculant can keep the population of rhizobia in the soil at adequate levels, meeting all the nitrogen demands of the plant. This study aimed to investigate the nodulation capacity and the production of beans submitted to doses and reinoculation of Rhizobium in topdressing under field conditions in two growth stages. For this, an experiment was conducted using a randomized block design with four replicates in a 4 × 2 + 2 factorial scheme. The treatments consisted of the application of four doses of liquid inoculant containing Rhizobium tropici (SEMIA 4088), in the concentration 2 × 109 CFU g-1, in topdressing (0, 100, 200 and 400 mL ha-1), in two development stages (V4 and R5) of plants, and two additional treatments (inoculation via seed at a dose of 100 g of the product per 50 kg of seeds and mineral nitrogen fertilization at a dose of 16 kg ha-1 applied at sowing and 60 kg ha-1 in topdressing, divided into two stages, with half being applied at the stage V3 and the other half in V4 stage).The inoculant application increased the nodulation rates of bean cultivar BRS Cometa and the dry biomass produced by plants, using doses of 232 and 221 mL ha-1, respectively. The dose of 257mL ha-1 of the liquid inoculant applied in topdressing at the V4 stage, and the inoculation via seed provide greater common bean yield without supplementing mineral nitrogen.