Corn is grown throughout the country, with its yields varying according to the technology investment. Among the technologies that seek to optimize productivity, the focus is on the use of improved seeds, which is associated with the properly integrated management of production factors such as pH adjustment and soil fertilization, irrigation, pest control and competitors, and more recently, the use of plant growth regulators. Analogous to synthetic growth regulators such as auxins, humic substances in organic matter have a stimulating effect on plants. However, the bioactivity and optimum concentration of humic substances vary with the type of plant and the type of raw materials used for their isolation. This work aimed to study the growth and development of maize in response to the treatment of seeds by different concentrations of humic acids. The treatments involved the application of two sources of humic acid (bovine manure and poultry litter) and five concentrations (0, 10, 20, 30, and 40 mmol L -1 of C) of humic acid solutions to seeds in a bioassay carried out in a greenhouse. At the end of the experiment (45 days after germination), plants were evaluated biometrically and nutritionally. The results showed a significant increase in the growth and development of shoots and roots, and there was a significant accumulation of N and P after the application of humic acid isolated from bovine manure. These effects did not occur with the application of humic acid isolated from poultry litter. Therefore, biostimulation by humic acids isolated from bovine manure showed positive results and was complementary as compared to the effects of other inputs commonly used in the treatment of maize seeds. Key words: Bioactivity, humic substances, soil chemistry and fertility, soil organic matter ResumoO milho é cultivado em todo o país, produzindo quantidades variáveis conforme o investimento em tecnologia. Dentre essas tecnologias, destaca-se o uso de sementes melhoradas, associadas com adequado manejo integrado dos fatores de produção, tais como a correção e fertilização dos solos, a irrigação, o controle fitossanitário e de competidores e, mais recentemente, o uso de biorreguladores, buscando otimizar a produtividade. De forma análoga aos reguladores de crescimento sintéticos, como as auxinas, as substâncias húmicas da matéria orgânica apresentam um efeito estimulante em plantas. Contudo, a bioatividade e a concentração ótima das substâncias húmicas variam de acordo com as espécies vegetais e com matérias primas das quais elas foram isoladas. Por essas razões, este trabalho teve como objetivo estudar o crescimento e desenvolvimento do milho, em resposta à aplicação de diferentes concentrações de ácidos húmicos, via tratamento de sementes. Os tratamentos constituíram-se de duas fontes de ácidos húmicos (esterco bovino e cama de aviário) utilizando cinco concentrações (0, 10, 20, 30 e 40 mmol L -1 de C) das respectivas soluções, aplicado via tratamentos de sementes em um bioensaio conduzido em casa de vegetação. Ao fi...

Corn cultivation continually demands new technologies, since average yields can still be increased. This study aimed to evaluate the response of high-yield corn to humic acids, isolated from organic manure compost, with or without the application of lime and fertilizer. The experiment was conducted at Milhão® (http://www.omilhao.com.br) in Florestal, Minas Gerais State, Brazil. Three treatments were used: (a) control, without liming, fertilization, or humic acids; (b) conventional farm cultivation, with liming and fertilization; (c) liming, fertilization, and humic acids applied to seeds. The experiment design was a randomized block with five replicates (fifteen experimental units). Lime was applied at 1.6 Mg ha-1, incorporated into total area. Fertilization treatments included 300 kg ha-1 NPK 08-28-16 at sowing, and 500 kg ha-1 NPK 20-00-20 in coverage. The concentration of humic acids used in both seed treatment was 10 mmol L-1 of C. Biometrics and biomass productivity were evaluated at harvest time. Humic acids, whether applied as a seed coating, increased yield by ~15% higher than conventional farm cultivation, and this difference was statistically significant. Therefore, the use of humic acids based plant regulators is positive and complementary to the inputs generally used for corn yield.

Sugarcane cultivation using pre-sprouted seedlings has decreased the number of stalks used per hectare, increased the multiplication rate, improved seedling health, and increased planting uniformity. However, because this system has been only recently proposed, the number of studies evaluating this new technology is still scarce, particularly those examining the effect of the application of growth-promoting substances on seedling characteristics during the production phase. Here, we hypothesized that it is possible to combine the plant growth-promoting activity of humic acid (HA) with the inoculation of selected strains of plant growth-promoting bacteria (PGPB) to improve the yield of sugarcane seedlings compared with the individual application of these two techniques. The potential of the combined use of HA and PGPB as agricultural inputs was evaluated by conducting an experiment with sugarcane micro cuttings in a greenhouse. Treatments included control, PGPB, HA, and PGPB with HA. At the end of the experiment (60 d after planting), the plants were subjected to biometric evaluation. The results indicated that it was possible to combine HA with selected strains of PGPB (Burkholderia sp.) to improve the yield of seedlings compared with individual HA and PGPB treatments. HA, PGPB, and HA + PGPB increased the total dry matter compared with the control by 23%, 25%, and 36%, respectively. Therefore, the use of HA-based plant regulators in combination with PGPB was more effective than the isolated use of these inputs for the treatment of micro cuttings and improvement of sugarcane seedling yield. Key words: Burkholderia sp. Diazotrophic bacteria. Humic substances. Saccharum officinarum. Soil organic matter. ResumoO cultivo da cana-de-açúcar com mudas pré-brotadas tem permitido a redução do volume gasto de colmos por hectare, o aumento da taxa de multiplicação, da sanidade das mudas e da uniformidade do plantio. Contudo, por ter sido proposto há pouco tempo, o número de trabalhos com essa nova tecnologia ainda é escasso, especialmente quanto ao comportamento dessas mudas frente à inoculação com bactérias promotoras de crescimento de plantas. Hipótese desse trabalho propõe que é possível

Physical exercise is a known preventive and therapeutic alternative for several cerebrovascular diseases. Therefore, the objective of the present study was to evaluate the motor performance and histomorphometry of the biceps brachii, soleus, and tibialis anterior muscles of rats submitted to a treadmill training program prior to the induction of cerebral ischemia via occlusion of the middle cerebral artery (OMCA). A total of 24 Wistar rats were distributed into four groups: Sham-Sed: sedentary control animals (n=6), who underwent sham surgery (in which OMCA did not occur); Sham+Ex: control animals exercised before the sham surgery (n=6); I-Sed: sedentary animals with cerebral ischemia (n=6); and I+Ex: animals exercised before the induction of ischemia (n=6). The physical exercise consisted of treadmill training for five weeks, 30 min/day (5 days/week), at a speed of 14 m/min. The results showed that the type-I fibers presented greater fiber area in the exercised ischemic group (I+Ex: 2347.96±202.77 µm2) compared to the other groups (Sham-Sed: 1676.46±132.21 µm2; Sham+Ex: 1647.63±191.09 µm2; I+Ex: 1566.93±185.09 µm2; P=0.0002). Our findings suggested that the angiogenesis process may have influenced muscle recovery and reduced muscle atrophy of type-I fibers in the animals that exercised before cerebral ischemia.

In tomato, foliar application of calcium-based nutrient solutions is used to complement soil fertilization. However, knowledge regarding the factors that influence the effectiveness of foliar fertilizer applications remains incomplete. The objective of this study was to evaluate the efficiency of foliar fertilization with calcium for improving production and quality of hydroponic Sweet Grape tomatoes. An experiment was conducted in a commercial hydroponic system in a splitsplit-plot scheme, with two calcium doses: 1,5 and 3 mmol L -1 of Ca. The solutions were sprayed on the leaves at intervals of 7 and 14 days, using commercial foliar fertilizers containing 0.3 g L -1 of calcium chloride or calcium acetate. The results indicate that the foliar application of calcium fertilizers, regardless of the amount of calcium provided in the nutrient solution and the frequency of applications, positively affects fruit production and quality. No difference was found between the effects of application of the two calcium sources, as well as the frequency of application.

O tratamento de sementes com inoculantes a base de bactérias promotoras de crescimento de vegetal (BPCV) ou a aplicação de ácidos húmicos (AH) podem aumentar a produtividade de plantas de interesse agrícola. A hipótese deste trabalho propõe que é possível combinar o efeito de promoção do crescimento vegetal característico dos AH com a inoculação de estirpes selecionadas de BPCV no tratamento de sementes de milho com vias a obtenção de respostas superiores à aplicação isolada de ambos no desenvolvimento inicial do milho. Para atender esse propósito foi feita a aplicação isolada de AH ou a inoculação de BPCV das espirpes Burkholderia gladioli e Rhizobium cellulosilyticum, e o uso conjunto de BPCV e AH através do tratamento de sementes de milho. Ao final do experimento (45 dias após a germinação), as plantas foram avaliadas biometricamente, nutricionalmente e foi realizada a contagem de bactérias nas plantas pela técnica do Número Mais Provável. Os resultados demonstraram ser possível combinar os efeitos dos AH com a inoculação de estirpes selecionadas de BPCV com vias a obtenção de respostas superiores à aplicação isolada de ambos. Assim o uso de bioestimulantes à base de AH, em combinação com BPCV é positivo e complementar comparativamente aos insumos geralmente usados no tratamento de sementes de milho.Palavras-chave: substâncias húmicas; bactérias diazotróficas; matéria orgânica do solo. ABSTRACT RESUMOInitial performance of maize in response to humic acids and plant growth-promoting bacteria 1 Seed treatment with inoculants based on plant growth-promoting bacteria (PGPB) or the application of humic acids (HA) may increase the productivity of plants of agricultural interest. The hypothesis of this work is that it is possible to combine the effect of plant growth promoting characteristic of HA with the inoculation of PGPB selected strains in the treatment of maize seeds. Thus, providing superior responses than in single applications of both in the initial maize development. To meet this purpose, we conducted isolated application of HA or PGPB inoculation of Burkholderia gladioli and Rhizobium cellulosilyticum, and the combined application of PGPB and HA for treatment of maize seeds. At the end of the experiment (45 days after germination), the plants were evaluated biometrically, nutritionally and a bacteria count was performed in plants using the Most Probable Number technique. The results showed that it is possible to combine the effects of HA with the inoculation of selected strains of PGPB, obtaining superior responses to the isolated application of both. Thus, the use of HA-based bio-stimulants in combination with PGPB is positive and complementary compared to inputs generally used in the treatment of maize seeds.

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Eucalyptus harvesting, forwarding and soil tillage operations are among the main causes for compaction of forest soils, with potential impacts on productivity. This concern is especially important in areas with soils that are naturally compacted (fragipans and duripans). In these soils, tillage operations include the use of subsoilers that can reach depths of more than one meter and require heavy tractors that exert high pressure on the soil. One of the ways to try to minimize the effect of this compaction is by retaining harvest residues. The objective of this study was to evaluate the impacts of eucalyptus harvesting on soil physical attributes, as well as to determine the potential of different types of residue management to reduce compaction from the soil tillage operation. Two experiments were conducted in the same area with a Yellow Argisol. In the first experiment, compaction caused by mechanized harvesting with harvester + forwarder was evaluated. In the second experiment, different managements of harvest residues were examined as potential modifiers of soil compaction during tillage for new plantings. For this, three managements systems were tested: (1) retention of all harvest residues and litter from the previous rotation (HR + L), (2) retention of litter from the previous rotation (L), and (3) removal of harvest residues and litter from the previous rotation (WR). Before and after harvest, sampling was carried out in the planting rows and inter-rows, and after tillage, samples were collected in the traffic line of the subsoiler-tractor set. In both experiments, undisturbed soil samples were collected from the center of the 0–10, 10–20, 20–40, 40–60, and 60–100 cm layers to determine soil density and total porosity. In each period and site of evaluation, mechanical resistance to penetration up to the 60-cm depth was also determined. The harvesting operation increased soil density at 0–10 and 60–100 cm depths only in the inter-rows. Retention of harvest residues and litter (HR + L) after harvesting avoided increases in soil density and penetration resistance caused by machine traffic during tillage. The results indicate the importance of retaining harvest residues on forest soils for achieving sustainable utilization and for conserving soil quality.