Do planting methods and nitrogen management interfere with the economic viability of the melon crop?

Proper crop management results in higher profitability and the verification of economic viability is paramount to the definition of the methodologies used. This study aimed to verify the economic viability of seedlings or seeds use, associated with the inoculation with Azospirillum brasilense and nitrogen in topdressing fertilization in Cantaloupe melon production. The experiment was designed in randomized blocks with eight treatments. The treatments were composed of planting methods (seedling or seed), inoculation with Azospirillum brasilense (with or without), and partial application of 120 kg ha-1 of nitrogen as topdressing fertilization (with and without). It was verified that operations and seed acquisition represent the major cost factors. As for treatments, the use of seedling transplants with topdressing fertilization with nitrogen results in an increase of up to 37.01% in fruit production and, consequently, increases the indicators of economic viability. Also, A. brasilense, although not resulting in significantly higher production, raises the profitability. In this way, the seedling transplant, combined with the nitrogen in topdressing fertilization, results in higher profitability, and the use of A. brasilense is a technique with the potential for use in melon cultivation.Proper crop management results in higher profitability and the verification of economic viability is paramount to the definition of the methodologies used. This study aimed to verify the economic viability of seedlings or seeds use, associated with the inoculation with Azospirillum brasilense and nitrogen in topdressing fertilization in Cantaloupe melon production. The experiment was designed in randomized blocks with eight treatments. The treatments were composed of planting methods (seedling or seed), inoculation with Azospirillum brasilense (with or without), and partial application of 120 kg ha-1 of nitrogen as topdressing fertilization (with and without). It was verified that operations and seed acquisition represent the major cost factors. As for treatments, the use of seedling transplants with topdressing fertilization with nitrogen results in an increase of up to 37.01% in fruit production and, consequently, increases the indicators of economic viability. Also, A. brasilense, although not resulting in significantly higher production, raises the profitability. In this way, the seedling transplant, combined with the nitrogen in topdressing fertilization, results in higher profitability, and the use of A. brasilense is a technique with the potential for use in melon cultivation

Profundidade de semeadura e tipo de palhada influenciam a produtividade da soja

Implementing a crop such as a soybean requires favorable sowing conditions so that uniform and healthy seedlings emerge. This study aimed to evaluate the yield of soybeans crop concerning the type of soil cover and sowing depth. The experiment was conducted at the State University of Mato Grosso do Sul - University Unit of Cassilândia. A Completely randomized design with four replications in a 3x5 factorial scheme was used. Three cropping systems (without soil cover, millet straw, and brachiaria straw) and five sowing depths (2, 4, 6, 8, and 10 cm) were evaluated. The emergence speed index, plant height, stem diameter, first pod insertion height, number of branches, number of pods per plant, number of grains per pod, and grain yield per plant were assessed. The highest yield per plant was obtained with millet straw and a sowing depth of 6 cm. It can be concluded that the sowing depth and type of straw influence the soybean grain yield.A implantação de uma cultura como a soja exige que na semeadura ocorram condições propícias, para que se obtenha uma emergência de plântulas uniformes e sadias. O objetivo do trabalho foi avaliar a produtividade da cultura de soja em relação ao tipo de cobertura vegetal e profundidade de semeadura. O experimento foi realizado na Universidade Estadual de Mato Grosso do Sul – Unidade Universitária de Cassilândia. O delineamento utilizado foi inteiramente casualizado, com 4 repetições em esquema fatorial 3x5, sendo três sistemas de cultivo (convencional, com palhada de milheto e palhada de braquiária) e cinco profundidades de semeadura (2, 4, 6, 8 e 10 cm). Avaliou-se o índice de velocidade de emergência, altura de planta, diâmetro, altura de inserção primeira vagem, número de ramificações, vagens por planta, grãos por vagem e produtividade por planta. Obteve-se maior produtividade por planta no tratamento associado a palhada de milheto e profundidade de semeadura de 6 cm. Conclui-se que a profundidade de semeadura e o tipo de palhada influenciam na produtividade da cultura de soja

Dessecação em pré-colheita no potencial fisiológico de sementes e desenvolvimento inicial de trigo

Apesar de ser o segundo cereal mais produzido no mundo, ainda não existem herbicidas registrados para dessecação ou antecipação e uniformização da colheita do trigo no Brasil. O potencial de conservação de sementes é diretamente proporcional à qualidade fisiológica, ou seja, desde o início do armazenamento até a maturação fisiológica ainda no campo. O presente trabalho tem como objetivo avaliar o efeito da aplicação de doses de amônio-glufosinato, glifosato e paraquat como herbicidas dessecantes em pré-colheita de trigo, sobre a qualidade fisiológica de sementes. A germinação, comprimento radicular, massa de matéria fresca não sofrem influencia da dessecação de herbicidas, independente da dose. Há incremento de parte aérea utilizando o dobro da dose recomendada de glifosato para a maioria das culturas. O amônio-glufosinato no dobro da dose apresenta condutividade elétrica menos prejudicial às sementes do trigo. O paraquat apresenta melhor desempenho na dose recomendada para a maioria das culturas. Em geral, o uso da dose média recomendada para a maioria das culturas não prejudicam a qualidade fisiológica de sementes de trigo em dessecação pré-colheita

Aplicação exógena de tiamina ameniza os efeitos da baixa saturação de bases do solo sobre plantas de pimentão?

O uso intensivo do solo para a produção de hortaliças resulta em elevada degradação do solo e da área de cultivo. A utilização de técnicas e recursos que viabilizem a produção sob condições desfavoráveis pode ser decisiva para agricultura. Desta maneira, o objetivo deste trabalho foi avaliar os efeitos isolados e conjuntos da correção do solo e da aplicação de tiamina sobre o desenvolvimento das plantas de pimentão. Os tratamentos foram compostos por três diferentes saturações de base do solo (36, 60 e 80%), combinadas à aplicação de tiamina via foliar (com e sem) na concentração de 100 mg L-1. Verificou-se que a tiamina ameniza os efeitos da baixa saturação por base do solo sobre as características fisiológicas das plantas de pimentão. Os incrementos relativos à eficiência do uso da água e da eficiência instantânea de carboxilação, possibilitaram maior desenvolvimento das plantas tratadas com tiamina. Em complemento, a aplicação da tiamina é vantajosa para casos em que o plantio é realizado em condições de baixa saturação por bases, seguida da oferta adequada de nutrientes ou sistemas em que há parcial ou total correção das características químicas do solo, promovendo o desenvolvimento das plantas e aumento da atividade fisiológica.The intensive use of land to produce vegetables results in high soil degradation and cultivated area. The use of techniques and resources that make production possible under unfavorable conditions can be decisive for agriculture. Thus, this study aimed to evaluate the isolated and joint effects of liming and thiamine application on the development of bell pepper plants. The treatments consisted of three different soil base saturation (36, 60, and 80%), combined with foliar application of thiamine (with and without) at a concentration of 100 mg L-1. It was found that thiamine mitigates the effects of low base saturation on the physiological traits of bell pepper plants. The increments related to the water use efficiency and instantaneous carboxylation efficiency allowed greater development of plants treated with thiamine. In addition, the application of thiamine is advantageous in cases where planting is carried out under conditions of low base saturation, followed by an adequate supply of nutrients or systems in which there is a partial or total correction of the soil chemical characteristics, promoting the development of plants and increased physiological activity

SOYBEAN GRAIN YIELD IS IMPACTED BY THE SOWING DEPTH AND THE TYPE OF SOIL COVER

Implementing a crop such as a soybean requires favorable sowing conditions so that uniform and healthy seedlings emerge. This study aimed to evaluate the yield of soybeans crop concerning the type of soil cover and sowing depth. The experiment was conducted at the State University of Mato Grosso do Sul - University Unit of Cassilândia. A Completely randomized design with four replications in a 3x5 factorial scheme was used. Three cropping systems (without soil cover, millet straw, and brachiaria straw) and five sowing depths (2, 4, 6, 8, and 10 cm) were evaluated. The emergence speed index, plant height, stem diameter, first pod insertion height, number of branches, number of pods per plant, number of grains per pod, and grain yield per plant were assessed. The highest yield per plant was obtained with millet straw and a sowing depth of 6 cm. It can be concluded that the sowing depth and type of straw influence the soybean grain yield

Composted sewage sludge as an alternative substrate for forest seedlings production

The production of forest seedlings with adequate morphological and physiological characteristics is essential for the success of plantations. Substrates and irrigation are the major factors determining seedlings’ growth. Substrates made of urban and agricultural residues are a sustainable alternative to peat-based substrates. In this study, we evaluated how composted sewage sludge substrates affect the growth and gas exchange in seedlings of Cedrela fissilis Vell. Seedlings were produced under daily irrigation depths of 6, 9, and 12 mm, and on different substrates. The substrates were based on sewage sludge composted with Eucalyptus bark or sugarcane bagasse, and a commercial substrate based on peat, involving a double factorial design with 12 treatments (3 irrigation depths × 3 substrates). Both physical and chemical characteristics of substrates were analyzed, and morphological traits and gas exchanges of seedlings were measured. Sewage sludge-based substrates presented different characteristics according to the material it was mixed. Eucalyptus bark provided higher bulk density (0.19 g cm-3) and lower total porosity (75%) to the substrate, while sugarcane bagasse increased macroporosity up to 60%. Seedlings produced in sewage sludge-based substrates presented a height up to 17.8 cm and stem diameters of between 8.39-10.29 mm. Higher shoot and root dry mass was obtained in sewage sludge-based substrates with irrigation depth of 9 mm, which were 3.71 and 2.01 g, respectively. Photosynthetic carbon assimilation varied between 2.26 and 3.23 µmol CO2 m-2 s-1, and water use efficiency varied from 2.058 to 3.395 µmol CO2 (mol H2O)-1, with the highest values being obtained in seedlings produced in sewage sludge-based substrates with irrigation depth of 6 mm. Our results demonstrate that sewage sludge-based substrates are an efficient alternative to commercial peat-based substrates for seedling production

Caracterização de linhagens de cártamo (Carthamus tinctorius L.) em condições de deficiência hídrica e reidratação

Safflower is barely known and explored in Brazil, but has been shown as an interesting alternative for inclusion in crop rotation systems in the Cerrado region. The culture is rustic, tolerant to cold and water deficiency, what make it an option for cultivation in the off-season. The objective of this work was to evaluate the morphology and physiology of six safflower lines under water deficit. The experiment was carried out in a greenhouse in pots contend approximately 300 L of soil. The treatments were arranged in a randomized block design in factorial scheme 6 x 2. The first factor was composed of six lines of safflower (IMA 02, IMA 04, IMA 10, IMA 14, IMA 16 e IMA 21), and the second was the two water regimes (without and with water deficiency). All the boxes were kept at field capacity (FC) to 55 days after seeding (DAS), after the plants were exposed to water deficiency stress for a period of 30 days. The treatment without deficiency (-D) plants were hydrated in 100 field capacity (FC), while in the treatment with deficiency (+D) plants were maintained with 50% FC. After the period of 30 days, the plants were rehydrated for 18 days, in this period were carried out evaluations of leaf water potential, chlorophyll content, relative water content, protoplasmic tolerance, dry mass of root, shoot and flowers, root/shoot ratio, plant height, number of flowers per plant, harvest index, weight of thousand grains and grain yield. There is genetic variability among the six safflower lines for all traits evaluated. The lines IMA 04, IMA 10 and IMA 21 had better recovery of morpho-physiological characteristics after the water deficit and rehydration, in that, the line IMA 14 had better values of number of chapters per plant, relative water content in leaf, and dry matter of the shoot and root; and the line IMA 10 stood out in the variables contents of chlorophyll a, b, total, carotenoids and SPAD index ...Pouco conhecido e explorado no Brasil, o cártamo (Carthamus tinctorius L.) é uma alternativa interessante para ser incluída em sistemas de rotação de cultura na região do cerrado. A cultura é rústica, tolerante à deficiência hídrica e ao frio, tornando-se uma opção para cultivo de safrinha, porém pouco ainda se conhece sobre a variabilidade genética das linhagens introduzidas no país. O objetivo do trabalho foi avaliar a morfologia e a fisiologia de seis linhagens de cártamo em condições de deficiência hídrica seguida de reidratação. O experimento foi realizado sob cultivo protegido em caixas contendo aproximadamente 300 L de solo. Os tratamentos foram arranjados em um delineamento de blocos ao acaso em esquema fatorial 6 x 2. O primeiro fator foi composto por seis linhagens de cártamo (IMA 02, IMA 04, IMA 10, IMA 14, IMA 16 e IMA 21), e o segundo por dois regimes hídricos (sem e com deficiência hídrica). Todas as caixas foram mantidas em capacidade de campo (CC) até os 55 dias após a semeadura (DAS), depois as plantas foram expostas ao estresse por deficiência hídrica por um período de 30 dias. No tratamento sem deficiência (-D) as plantas foram hidratadas em 100% da capacidade de campo (CC), enquanto que no tratamento com deficiência moderada (+D) as plantas foram mantidas com 50% CC. Após o período de 30 dias de deficiência hídrica, as plantas foram reidratadas por 18 dias, neste período foram realizadas avaliações de potencial hídrico foliar, teor de clorofila, conteúdo relativo de água, tolerância protoplasmática, massa seca de raízes, parte aérea e capítulos, razão raiz/parte aérea, altura de planta, número de capítulos por planta, índice de colheita, peso de mil grãos e produtividade de grãos. Há variabilidade genética entre as seis linhagens de cártamo para todas as características avaliadas. As linhagens IMA 21, IMA 10 e IMA 04 ..

Increased hormetic dose of glyphosate causes oxidative stress and reduces yield in common bean

Glyphosate can alter several physiological and biochemical processes and even plant nutrient absorption. This study aimed to verify whether biochemical and non-biochemical variables of the antioxidant complex are affected by low doses, considered hormetic, of glyphosate herbicide. Two experiments were conducted in the field, one in the winter and the other in the wet season, with the early cycle common bean cultivar IAC Imperador. The experimental design was in a randomized block, consisting of applying low doses of glyphosate (0.0, 1.8, 7.2, 12, 36, 54, and 108 g a.e. ha–1) in the phenological stage V4, with four replicates. Environmental conditions, such as air temperature, interfered in the early cycle common bean response to low doses of glyphosate. Lower doses of glyphosate did not alter the gas exchange of bean plants. However, the increase in the glyphosate doses reduced the net CO2 assimilation rate, stomatal conductance, and transpiration rate while increasing the SOD and CAT activity, and MDA and proline content. In the winter season, the dose 7.2 g a.e. ha–1 increased bean productivity, while the dose 36 g a.e. ha–1 induced oxidative stress in bean plants and reduced productivity. In the wet season, doses 36 and 54 g a.e. ha–1 increased bean productivity, and the dose 108 g a.e. ha–1 decreased grain yield. Thus, the more favorable climatic conditions in the wet season enhance plant metabolism, subsequently increasing plant tolerance to higher glyphosate doses

Physiological changes associated with antioxidant enzymes in response to sugarcane tolerance to water deficit and rehydration

Water deficit is the main limiting factor for sugarcane yield worldwide. Under this stress, the crop develops adaptive mechanisms that participate in maintaining the plants’ water status. A better understanding of these mechanisms may contribute to differentiating tolerant cultivars to be used in genetic improvement programs. Therefore, this study aimed to assess the physiological responses of sugarcane cultivars subjected to water deficit and rehydration. Cultivars RB92579, SP81-3250, SP83-2847 and IAC91-5155 were grown in pots in a greenhouse. These plants were physiologically and biochemically evaluated at three intervals: 0 (before stress), 15 (water deficit) and 27 days (rehydration) after the onset of treatment (DAT) at 85 days after planting. Cultivars RB92579 and SP81-3250 had greater reductions in stem height, number of green leaves, leaf area, relative water content, leaf water potential (Ψw), leaf temperature, stomatal conductance (gs), maximum photochemical efficiency of photosystem II (Fv/Fm), SPAD index and photosynthetic pigments, and inhibited catalase enzyme activity when subjected to water stress. Furthermore, SP81-3250 showed no recovery after rehydration. Water deficit also increased the levels of proline and the enzymes superoxide dismutase and ascorbate peroxidase in all cultivars. We also found increased carbohydrates under stress, except in the cultivar SP81-3250, which had a reduced content. Due to the minor damage caused by drought in the physiology and biochemistry of cultivars SP83-2847 and IAC91-5155, they have higher potential for tolerance and can acclimate to drought. Consequently, oxidative stress can be largely avoided in the chloroplasts of these cultivars by maintaining the balance of antioxidant enzyme activity, photosynthetic efficiency, stomatal control and water status.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Productivity and Quality Sugarcane Broth at Different Soil Management

The quality of sugarcane broth can be affected by soil management. In compacted soils the productivity is reduced, and the raw material is poor. This research aimed to evaluate productivity and quality of sugarcane for four soil management types: (CT) heavy harrow + light harrow; (CTI) Subsoiler + light harrow; (MT) Subsoiler and (NT) no soil movement. The variables investigated were resistance to soil penetration (SPR), the chemical raw material quality (broth) and crop yield. In crop rows, SPR did not reach severe levels up to 0.3 m for sugarcane root development. However, below this layer, MT, NT, and CTI reached SPR limiting values of 2.50, 2.35 and 1.95 MPa, respectively. In inter-crop rows, compaction was concentrated in soil surface layers (0–0.3 m). In addition, all adopted managements presented SPR above the critical value (2 MPa). The soil preparation forms qualitatively affected the sugarcane broth, showing higher fiber and protein contents in NT, MT, and CT. The PS, Brix, TRS, and Pol were not affected by soil management. Still, higher absolute values were found in the NT, indicating an increase in broth quality when applying conservation management. The highest yields were obtained by reduced tillage (MT), surpassing the lowest yield management (NT) with an increase of 10.5 Mg ha−1