Vermicompost and millicompost as a resource in sustainable agriculture in semiarid: decomposition, nutrient release, and microstructure under the action of nitrogen and organic-mineral fertilizers.

With the expansion of organic agriculture, research is needed to indicate economically and ecologically viable fertilizer options, especially in semiarid regions, with low soil organic matter and nitrogen content. In the Brazilian semiarid region, vermicomposts are widely used by farmers and are scientifically investigated; however, there is no information for millicompost, a new type of organic compound that has shown very promising results in other regions. Thus, this study aimed to analyze the decomposition rate, nutrient release, and microstructure evaluation of vermicomposts from different sources and of millicompost produced from plant residues, with the application of mineral nitrogen-urea and organo-mineral fertilizer in the Brazilian semiarid region. The experimental design was a randomized block in a 4 × 3 factorial scheme, with four replicates; four organic composts (millicompost, commercial vermicompost, vermicompost from bovine manure, vermicompost from goat manure); and three types of fertilization (without fertilizer, with mineral-urea and organo-mineral fertilizer). The organic composts were decomposed using litterbags at the soil surface. The variable's decomposition rate and the nutrient release were evaluated at six-time intervals (0, 30, 60, 90, 120, and 150 days), and microstructure was evaluated at the beginning and the end of the experiment, with scanning electron microscopy (SEM). The highest decomposition was verified for commercial vermicompost rich in macro and micronutrients and with lower P contents. The lignin:N ratio and the initial P content were more important in the permanence of the organic compost in the field than the C:N ratio. Regardless of the organic composts, the use of urea as a mineral fertilizer stimulated decomposition more than the organo-mineral fertilizer. The initial composition of the nutrients was decisive in the dynamics of nutrient release, mass loss, and decomposition of C. There was no pattern in the release order of macronutrients. However, for the micronutrients, the release order was Cu > Fe > Mn, in all treatments. Microstructure analysis is a visual analysis where differences are detected through microphotographs and the biggest difference occurred with millicompost, which showed elongated fibers and fiber bundles, forming a relatively open structure characteristic of the presence of fulvic acid. However, the addition of organo-mineral fertilizer formed agglomerates in compacted micro-portions, helping the mineralization of C and N.

Efficiency of Nitrogen Use in Sunflower.

The large variation in the response of sunflower to nitrogen fertilization indicates the need for studies to better adjust the optimum levels of this nutrient for production conditions. Our objectives were to analyze the agronomic yield of sunflower cultivars as a function of nitrogen fertilization; indicate the cultivar with high nitrogen use efficiency; and measure the adequate N dose for sunflower through nutritional efficiency. The completely randomized block design with split plots was used to conduct the experiments. The treatments included five nitrogen rates being allocated in the plots and the four sunflower cultivars. To estimate the nutrient use efficiency in the sunflower, we measured agronomic efficiency (AE), physiological efficiency (PE), agrophysiological efficiency (APE), apparent recovery efficiency (ARE), and utilization efficiency (UE). The results indicate that all cultivars had a reduction in AE due to the increase in N doses in the first crop. For PE, the highest values were observed for Altis 99 during the 2016 harvest. In that same harvest, Altis 99 had the highest APE. The dose of 30 kg ha-1 provided greater ARE for all cultivars in both crops, with greater emphasis on BRS 122 and Altis 99. The cultivation of cultivars Altis 99 and Multissol at a dose of 30 kg ha-1 in is recommended semiarid regions.

Interaction between herbicides applied in mixtures alters the conception of its environmental impact.

Herbicide mixtures have often been used to control weeds in crops worldwide, but the behavior of these mixtures in the environment is still poorly understood. Laboratory and greenhouse tests have been conducted to study the interaction of the herbicides diuron, hexazinone, and sulfometuron-methyl which have been applied alone and in binary and ternary mixtures in the processes of sorption, desorption, half-life, and leaching in the soil. A new index of the risk of leaching of these herbicides has also been proposed. The sorption and desorption study has been carried out by the batch equilibrium method. The dissipation of the herbicides has been evaluated for 180 days to determine the half-life (t1/2). The leaching tests have been carried out on soil columns. The herbicides isolated and in mixtures have been quantified using ultra-high performance liquid chromatography coupled to the mass spectrometer. Diuron, hexazinone, and sulfometuron-methyl in binary and ternary mixtures have less sorption capacity and greater desorption when compared to these isolated herbicides. Dissipation of diuron alone is slower, with a half-life (t1/2) = 101 days compared to mixtures (t1/2 between 44 and 66 days). For hexazinone and sulfometuron-methyl, the dissipation rate is lower in mixtures (t1/2 over 26 and 16 days), with a more pronounced effect in mixtures with the presence of diuron (t1/2 = 47 and 56 and 17 and 22 days). The binary and ternary mixtures of diuron, hexazinone, and sulfometuron-methyl promoted more significant transport in depth (with the three herbicides quantified to depth P4, P7, and P7, respectively) compared to the application of these isolated herbicides (quantified to depth P2, P4, and P5). Considering the herbicides' desorption and solubility, the new index proposed to estimate the leaching potential allowed a more rigorous assessment concerning the risk of leaching these pesticides, with hexazinone and sulfometuron-methyl presenting a higher risk of contamination of groundwater.

Machine learning models as an alternative to determine productivity losses caused by weeds.

BACKGROUND: Weed control can be economically viable if implemented at the necessary time to minimize interference. Empirical mathematical models have been used to determine when to start the weed control in many crops. Furthermore, empirical models have a low generalization capacity to understand different scenarios. However, computational development facilitated the implementation of supervised machine learning models, as artificial neural networks (ANNs), capable of understanding complex relationships. The objectives of our work were to evaluate the ability of ANNs to estimate yield losses in onion (model crop) due to weed interference and compare with multiple linear regression (MLR) and empirical models. RESULTS: MLR constructed from non-destructive and destructive methods show R2 and root mean square error (RMSE) values varying between 0.75% and 0.82%, 13.0% and 19.0%, respectively, during testing step. The ANNs has higher R2 (higher than 0.95) and lower RMSE (less than 6.95%) compared to MLR and empirical models for training and testing steps. ANNs considering only the coexistence period and system have similar performance to MLR models. However, the insertion of variables related to weed density (non-destructive ANN) or fresh matter (destructive ANN) increases the predictive capacity of the networks to values close to 99% correct. CONCLUSION: The best performing ANNs can indicate the beginning of weed control since they can accurately estimate losses due to competition. These results encourage future studies implementing ANNs based on computer vision to extract information about the weed community.

Impact of Pyrolysis Temperature on the Properties of Eucalyptus Wood-Derived Biochar.

Pyrolysis conditions directly influence biochar properties and, consequently, influence the potential use of biochar. In this study, we evaluated the effects of different pyrolysis temperatures (450, 550, 650, 750, 850, and 950 °C) on the hydrogen potential, electrical conductivity, ash content, yield, volatile matter content, elemental analysis, Fourier-transform infrared spectroscopy results, X-ray diffraction results, scanning electron microscopy results, specific surface area, and micropore volume of eucalyptus wood-derived biochar. The degree of linear association between pyrolysis temperatures and biochar properties was examined using the Pearson correlation coefficient. The results showed a positive correlation of the pyrolysis temperature with the hydrogen potential value, electrical conductivity, and elemental carbon. There was a negative correlation of the pyrolysis temperature with the yield, volatile matter content, elemental oxygen, elemental hydrogen, surface area, aromaticity, hydrophilicity, and polarity indexes. The Fourier-transform infrared spectroscopy data indicated an increase in aromaticity and a decrease in the polarity of high-temperature biochar. The increased pyrolysis temperature caused the loss of cellulose and crystalline mineral components, as indicated by X-ray diffraction analysis and scanning electron microscopy images. These results indicated that changing the pyrolysis temperature enables the production of biochar from the same raw material with a wide range of physicochemical properties, which allows its use in various types of agricultural and environmental activities.

Influence of Glyphosate Formulations on the Behavior of Sulfentrazone in Soil in Mixed Applications.

The selection of weed biotypes that are resistant to glyphosate has increased the demand for its use mixed with other herbicides, such as sulfentrazone. However, when chemical molecules are mixed, interactions may occur, modifying the behavior of these molecules in the environment, such as the sorption and desorption in soil. In this study, we hypothesized that the presence of glyphosate-formulated products might increase the sorption or decrease the desorption of sulfentrazone, thereby increasing the risk of the contamination of water resources. Therefore, our work aimed to evaluate the sorption, desorption, and leaching of sulfentrazone in the soil in an isolated and mixed application with different glyphosate formulations. The sorption coefficients (Kfs) for the sulfentrazone, sulfentrazone + Roundup Ready, sulfentrazone + Roundup Ultra, and sulfentrazone + Zapp Qi foram were 1.3, 2.1, 2.3, and 1.9, respectively. The desorption coefficients (Kfd) for the sulfentrazone, sulfentrazone + Roundup Ready, sulfentrazone + Roundup Ultra, and sulfentrazone + Zapp Qi foram were 65.7, 125.2, 733.3 and 239.8, respectively. The experiments demonstrated that the sorption and desorption of sulfentrazone in combination with the other formulated glyphosate products are altered, supporting the hypothesis suggested by this work, i.e., that the presence of other molecules is a factor that affects the behavior of herbicides in the soil. This phenomenon altered the vertical mobility of sulfentrazone. Situations involving mixtures of pesticides should be evaluated in order to improve our understanding of the dynamics of these molecules and thus avoid environmental contamination.

Adsorption mechanisms of atrazine isolated and mixed with glyphosate formulations in soil.

In Brazil, the atrazine has been applied frequently to join with glyphosate to control resistant biotypes and weed tolerant species to glyphosate. However, there are no studies about atrazine's behavior in soil when applied in admixture with glyphosate. Knowledge of atrazine's sorption and desorption mixed with glyphosate is necessary because the lower sorption and higher desorption may increase the leaching and runoff of pesticides, reaching groundwaters and rivers. Thereby, the objective of this study was to evaluate the adsorption mechanisms of atrazine when isolated and mixed with glyphosate formulations in a Red-Yellow Latosol. The maximum adsorbed amount of atrazine in equilibrium (qe) was not altered due to glyphosate formulations. The time to reach equilibrium was shortest when atrazine was mixed with the Roundup Ready® (te = 4.3 hours) due to the higher adsorption velocity (k2 = 2.3 mg min-1) in the soil. The highest sorption of atrazine occurred when mixed with the Roundup WG®, with the Freundlich sorption coefficient (Kf) equal to 2.51 and 2.43 for both formulation concentrations. However, other glyphosate formulations did not affect the sorption of atrazine. The desorption of atrazine was high for all treatments, with values close to 80% of the initial adsorbed amount, without differences among isolated and mixed treatments. The change in the velocity and capacity of sorption for the atrazine mixed with some glyphosate formulations indicates that further studies should be conducted to identify the mechanisms involved in this process.

Caracterização do fruto de Morinda citrifolia L. (noni) / Characterization of Morinda citrifolia L. (noni) fruit

Introdução: a Morinda citrifolia L. (noni) é uma fruta que foi recentemente introduzida no Brasil, como uma matéria-prima com forte apelo comercial devido a todas as características benéficas a ele atribuídas e os benefícios relacionados ao seu consumo. Objetivo: o presente trabalho teve como objetivo caracterizar frutos de noni em três estádios de maturação. Métodos: os frutos foram colhidos em pomares domésticos no município de Mossoró-RN, em três estádios de maturação, conforme a cor: verde (casca verde), de vez (verde esbranquiçado) e maduro (amarelo esbranquiçado). Para a caracterização do fruto, realizaram-se as seguintes análises: massa fresca, comprimentos longitudinal e transversal, DL/DT, firmeza e rendimento de polpa, vitamina C, sólidos solúveis (SS), acidez titulável (AT), pH e relação SS/AT. Adotou-se o delineamento inteiramente casualizado, com três tratamentos e doze repetições de um 1 fruto para cada parcela. Resultados: o fruto do noni é de formato ovóide, suculento e apresenta várias sementes triangulares de coloração vermelha. Considerando a polpa, ocorre mudança de coloração, passando da cor verde para a amarela esbranquiçada, à medida que o fruto amadurece. De acordo com os resultados obtidos, os estádios apresentam variabilidade para quase todos os caracteres físicos e físico-químicos. Conclusões: os frutos que apresentaram as melhores características físicas de massa e firmeza da polpa, tanto para consumo in natura, como para processamento agroindustrial são os de vez e verdes, com valores de 56,33 g e 128,41 N, respectivamente. Este fruto é considerado rica fonte de vitamina C, apresenta elevados teores de sólidos solúveis quando maduro (10,33 °Brix) e alta relação sólidos solúveis/acidez titulável em todos os estádios avaliados.

Introduction: a Morinda citrifolia L. (noni) is a fruit that was recently introduced in Brazil, as a raw material with fort I appeal advertising due to all the beneficial characteristics attributed to it and the related benefits of its consumption. Objectives: the objective of the present paper was to characterize noni fruits in three stages of maturation. Methods: the fruits had been harvested in domestic orchards in the city of Mossoró-RN, in three stages of maturation, according to the color: green (green rind), breaker stage (yellowish green) and mature (yellowish white). For the characterization of the fruit, the following analyses were performed: fresh matter, longitudinal and transversal length, DL/DT, firmness and income of pulp, acid ascorbic, soluble solids (SS), titratable acidity (AT), pH and SS/AT ratio. The experimental design was in randomized blocks, with three treatments and twelve repetitions of one (1) fruit for each parcel. Results: the noni fruit has ovoid format, is succulent and presents several triangular red seeds. Considering the pulp, coloration change occurs, going from green to yellowish white color according to the ripeness of fruits. Regarding the obtained results, the stages present variability for almost all the physical and physical chemical characters. Conclusions: the fruits that presented the best physical characteristics of mass and firmness of pulp, both for natural consumption and for agro-industrial processing are breaker stages and green fruits, with values of 56.33 g and 128.41 N, respectively. Noni is considered a rich source of vitamin C, presents high value of soluble solid when mature (10.33 Brix) and high soluble solids/titratable acidity ratio in all of the evaluated stages.

Avaliação de cultivares de alface adubadas com silicato de cálcio em casa-de-vegetação / Evaluation of lettuce cultivars fertilized with calcium silicate in greenhouse

O experimento foi conduzido no Departamento de Ciência do Solo da Universidade Federal de Lavras - UFLA, no período de junho a agosto de 2002. Objetivou-se avaliar a produtividade, o estado nutricional e a qualidade (classe de tamanho) de cultivares de alface cultivadas com doses de silicato de cálcio em vasos sob casa-de-vegetação. O delineamento experimental foi em blocos casualizados, com quatro repetições, com 1 planta/vaso, em esquema fatorial 3 x 4 + 3, sendo três cultivares de alface (Raider, Regina e Vera) e quatro doses de silicato de cálcio (0, 410, 1,000 e 2,000 mg dm-3); os tratamentos adicionais foram compostos pela aplicação de 820 mg dm-3 de carbonato de cálcio, para as três cultivares. O estado nutricional das plantas de alface foi avaliado pelo Sistema Integrado de Diagnose e Recomendação (DRIS). A aplicação da fonte silicato de cálcio não aumentou o crescimento das plantas e não aumentou o teor dos nutrientes nas plantas de alface, mas melhorou a nutrição das plantas para Si e aumentou a porcentagem de plantas sadias. A aplicação também aumentou a concentração de Mn, devido ao alto conteúdo de Mn no fertilizante aplicado (Silifértil®). As três variedades de alface comportaram-se como plantas não acumuladoras de Si.

The experiment was carried out at the Department of Soil Sciences of the Universidade Federal de Lavras - UFLA, from June to August 2002, with the objective to evaluate the productivity, the nutritional state and the quality (size class) of lettuce cultivars grown with calcium silicate in greenhouse. The experimental design was disposed in blocks with four replicates, in factorial arrangement with additional treatments: 3 x 4 +3, composed by three lettuce cultivars: Raider (group crisphead lettuce); Regina (group butterhead lettuce) and Vera (group looseleaf lettuce) and four calcium silicate rates (0, 410, 1.000 and 2.000 mg dm-3), additional treatments were composed of the application of calcium carbonate of 1.000 mg dm-3 for the three cultivars. The nutritional status of lettuce was evaluated by Diagnosis and Integrated Recommendation System. The application of calcium silicate fertilizer did not increase the growth of the plants and did not improve the concentration of nutrients in lettuce plants; but improved the lettuce nutritional status for Si and increased the percentage of leaves healthy. The application also increase Mn concentration, due to high content of Mn in the silifértil® fertilizer. The three varieties of lettuce behaved as non-accumulation plants of Si.

Composição de substratos e tamanho de recipientes na produção e qualidade das mudas de maracujazeiro 'amarelo' / Composition of substrates and volume of recipients in the production and quality of yellow passion fruit seedlings

A produção de mudas de maracujazeiro 'amarelo' (Passiflora edulis Sims. f. flavicarpa Degener) de boa qualidade genética, fitossanitária e bem nutridas é de suma importância. A multiplicação rápida depende de alguns fatores preponderantes, relacionados com a produção de mudas, ligados especificamente aos substratos e recipientes. Este experimento foi realizado visando à avaliação da produção de mudas em diferentes substratos e dois tamanhos de recipientes, em viveiro de produção de mudas da Universidade Estadual de Mato Grosso do Sul (UEMS), Cassilândia/MS. Foram testados quatro substratos: solo puro, solo + esterco (2:1 v:v), Plantmaxâ e solo + 150 mg.dm-3 de superfosfato simples e dois tamanhos de recipientes de polietileno preto: 14x20 cm (1000 mL) e 10x20 cm (700 mL). Utilizou-se o delineamento experimental em blocos casualizados, em esquema fatorial 4 (substratos) x 2 (tamanhos de recipientes), com 4 repetições e dez plantas por parcela. Avaliaram-se as características: índice de velocidade de emergência (IVE), altura da muda (cm), comprimento de raiz (cm), diâmetro do colo (mm), número de folhas/planta, índice de clorofila foliar (ICC), massa seca da parte aérea, massa seca da raiz e massa seca total. Os resultados para as variáveis analisadas indicaram que apenas para o número de folhas/planta houve diferença significativa para o tamanho de recipiente utilizado. O solo + esterco e o Plantmax® favoreceram todos os parâmetros de crescimento nos recipientes de 700 mL. O solo puro não é recomendado para a produção de mudas de maracujazeiro 'amarelo' em ambos recipientes; pois favoreceu apenas o comprimento de raiz e massa seca da parte aérea.

The production of yellow passion fruit seedlings (Passiflora edulis Sims. f. flavicarpa Degener) with genetic and phytosanitary quality, well-nourished and precocious, is of great importance. Fast multiplication depends on some preponderant factors related to seedling production, substrate and recipient. The experiment was realized to evaluate the production of seedlings in different substrates and two bulks recipients, in a seedling nursery at the Universidade Estadual do Mato Grosso do Sul, city of Cassilândia. Four substrates were evaluated: pure soil, soil + manure (2:1), Plantmax® and soil + 150 mg.dm-3 of simple super phosphate and two recipient sizes made of black polystyrene: 14 x 20 cm (1000 mL) and 10 x 20 cm (700 mL). We used a completely randomized experimental design in a 4 (substrates) x 2 (recipients volume) factorial outline, with four replications and ten seeds per plot. The characteristics evaluated were: index of emergency speed (IVE), seedlings height (cm), root length (cm), lap diameter (mm), number of leaves/plant, chlorophyll index (ICC), shoot and root dry mass and total dry mass. The results for the analyzed variables indicated that only for the number of leaves/plant there was a significant difference depending on the size of the recipient. The soil + manure and Plantmaxâ improved all growth parameters in the recipients of 700 mL. Pure soil is not recommended for yellow passion fruit seedlings in both recipients, because they improved only root length and shoot dry mass.

Esterco caprino na composição de substratos para formação de mudas de mamoeiro / Goat manure used in substrate composition for formation of papaya seedlings

Conduziu-se este trabalho, com o objetivo de avaliar a utilização de esterco caprino na composição de substratos para a formação de mudas de mamoeiro. O delineamento experimental adotado foi o de blocos casualizados com cinco tratamentos e quatro repetições, sendo cada parcela constituída por oito plantas. Os tratamentos constaram de misturas composta por: 100 por cento plantmax; 50 por cento terra, 25 por cento plantmax, 25 por cento de esterco bovino; 50 por cento terra, 25 por cento plantmax, 25 por cento esterco caprino; 30 por cento terra, 35 por cento plantmax, 35 por cento esterco bovino; 30 por cento terra, 35 por cento plantmax, 35 por cento esterco caprino. As variáveis analisadas foram: altura de planta; diâmetro do colo; número de folhas, comprimento de raiz; matéria seca da parte aérea e matéria seca da raiz. Os dados demonstram que a mistura mais eficiente para a formação de mudas de mamoeiro foi de 30 por cento terra, 35 por cento Plantmax, 35 por cento esterco caprino.

The objective of this work was to evaluate the utilization of goat manure in the substrate composition of papaya seedling formation. The experimental design used was of complete randomized blocks, with five treatments and four replications, and having eight plants per plot. The treatments consisted of substrate mixtures composed of: 100 percent Plantmax; 50 percent soil, 25 percent Plantmax, and 25 percent cattle manure; 50 percent soil, 25 percent Plantmax, and 25 percent goat manure; 30 percent soil, 35 percent Plantmax, and 35 percent cattle manure; 30 percent soil, 35 percent Plantmax, and 35 percent goat manure. Plant height and diameter, number of leaves per plant, root length, and shoot and root dry mass were evaluated. Substrate composed of 30 percent soil, 35 percent Plantmax, and 35 percent goat manure was most efficient for promoting growth.

Adubação nitrogenada em cobertura e substratos na produção de mudas de mamoeiro 'Formosa' / Nitrogen fertilization as top dressing and different substrates on the production of 'Formosa' papaya (Carica papaya L. ) seedlings

Objetivando-se avaliar a produção de mudas de mamoeiro em diferentes substratos com adubações de nitrogênio em cobertura, conduziu-se um experimento em viveiro de formação de mudas no pomar da Universidade Federal de Lavras (UFLA), Minas Gerais. Foram testadas cinco doses de nitrogênio 0; 400; 800; 1600 e 3200 mg de N dm-3 de substrato, aplicados cinco vezes, sendo que em cada aplicação foram adicionados aos sacos de polietileno (capacidade de 500 mL) 20 mL de solução contendo o N e duas composições de substratos: A (composto orgânico + areia + solo na proporção de 1:1:3 em volume) e B (Plantmax® + areia + solo na proporção de 1:1:3 em volume). Foi utilizado o delineamento experimental em blocos ao acaso em esquema fatorial 5 x 2, com 4 repetições e cinco plantas por parcela. Após 150 dias da semeadura avaliaram-se as seguintes variáveis: comprimento da parte aérea (cm); comprimento de raiz (cm), número de folha/muda, matéria seca da parte aérea, da raiz e total (g/planta). Verificou-se que dosagem de até 1.800 mg de N dm-3 em cobertura, foram as que proporcionaram melhor qualidade na formação das mudas. Em relação aos substratos verificou-se que o substrato B (Plantmax® + areia + solo na proporção de 1:1:3 em volume) foi o que promoveu os melhores resultados na produção das mudas do mamoeiro 'Formosa'.

Aiming at evaluating the seedling production of papaya (Carica papaya L.) on different substrates and nitrogen fertilization as top dressing, an experiment was carried out at the plant formation area of Federal University of Lavras orchard. Five doses of nitrogen were tested, viz.: 0; 400; 800; 1600, and 3200 mg N dm-3 substrate, applied five times, and in each application, 20 mL of the solution containing the N was added to the polyethylene bags (500 mL capacity). Two substrate composition were tested, namely A (organic compost + sand + soil at 1:1:3 volume proportion) and B (Plantmax + sand + soil at 1:1:3 volume proportion). A randomized block design was used with factorial scheme 5x2, with four replications and five plants per plot. One hundred and eighty days after the sowing the following characteristics were evaluated: height of the aerial parts (cm), length of roots (cm), number of leaves/plant, dry matter of aerial part, root, and total plant (g/plant). It was observed that the doses up to 1.800 mg N dm-3 as top dressing promoted better quality in the formation of seedlings. The substrate B promoted the best results in the production of 'Formosa' papaya plants.

Adubação nitrogenada em cobertura no girassol irrigado nas condições de Cassilândia-MS / Nitrogen side dressing fertilization in irrigated sunflower under conditions of Cassilândia-MS

O nitrogênio é o nutriente mais requerido pelas plantas por assumir funções importantes no metabolismo vegetal. Na cultura do girassol, sua deficiência causa desordem nutricional, sendo o nutriente que mais limita a produção. Além disso, doses elevadas podem aumentar a incidência de pragas e doenças afetando a produção de grãos. Conduziu-se o experimento com o objetivo de avaliar a resposta da cultura do girassol (Helianthus annuus L.) irrigado, submetido a diferentes doses de nitrogênio aplicado parceladamente, em cobertura. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições. Os tratamentos consistiram de quatro doses de nitrogênio (0, 20, 40 e 80 kg ha-1), na forma de uréia. A adubação nitrogenada em cobertura proporcionou um aumento em todas as características estudadas, sendo que a dose de N de máxima eficiência técnica para se ter uma boa produtividade é de 55 kg ha-1 de N para o cultivo do girassol, na região de Cassilândia-MS.

Nitrogen is the most required nutrient by plants for exerting important functions in the vegetable metabolism. In sunflower crop, its efficiency causes nutritional disorder, being the nutrient that most limits the yield. Besides, high doses may increase the incidence of pests and diseases, affecting the yield. Hereafter, this experiment was carried out with the aim of evaluating the response of the irrigated sunflower crop (Helianthus annuus L.) submitted to different doses of side dressing nitrogen fertilization applied uncovered nitrogen in small parts. A randomized complete block design, with four replications was used. The constituted by four doses of nitrogen (0, 20, 40, and 80 kg ha-1), as urea. Side dressing nitrogen fertilization provides increase in all characteristics studied, and the dose of N of maxim suitable technical efficiency to have a good yield is of 55 kg ha-1 of N for the cultivation of the sunflower irrigated in the region of Cassilândia, Mato Grosso do Sul State.

Prolongamento do período de colheita da tangerineira Ponkan com aplicação de GA3 e 2,4-D / Harvest season extent of tangerin 'Ponkan' fruits with the application of GA3 AND 2,4-D

Conduziu-se, este experimento em pomar comercial, dez anos após o plantio, localizado no município de São João Del Rei - MG, visando ampliar o período de colheita de frutos da tangerineira 'Ponkan' (Citrus reticulata Blanco). Foram avaliados os efeitos do ácido giberélico (GA3) à 0, 10, 20 e 30 mg.L-1 e do Ácido 2,4-diclorofenoxiacético (2,4-D) à 0 e 10 mg.L-1 aplicados em duas vezes: 24/4 e 17/5 quando os frutos apresentavam-se com coloração verde da casca e foram realizadas duas avaliações sendo a primeira no dia 25/7, quando já se aproximava a fase final de colheita da região, e a segunda 30 dias após. O delineamento experimental utilizado foi em blocos casualizados, em esquema fatorial 4 x 2 x 2, com quatro repetições em parcelas subdivididas. Os resultados mostraram que o 2,4-D, à 10 mg.L-1 influenciou na textura dos frutos, propiciando o prolongamento da colheita de tangerina 'Ponkan'; ¹ aumentou a acidez dos frutos e reduziu a relação sólidos solúveis totais /acidez; que a utilização de 20 mg.L-1 de GA3 promoveu incremento no diâmetro e no peso dos frutos; que o maior rendimento foi obtido no mês de agosto e que não houve diferença no teor de sólidos solúveis nas diferentes épocas de colheita.

This experiment was carried out on a ten year-old commercial orchard in São João Del Rei county-MG in order to extend the harvest season of tangerine Ponkan (Citrus reticulate Blanco). One evaluated the effects of Giberelic Acid (GA3) at 0, 10, 20 and 30 mg.0L-1 and Diclorofenoxiacetic acid (2,4- D) at 0 and 10 mg.L-1 applied two times: on 4/24 and 5/17 when the fruits still had a green peel color the evaluations were made: the first one on 7/25, when the harvest time in the region was ending, and the second 30 days after. The experimental design adopted was the one of randomized blocks, with a factorial of 4 x 2 x 2, with four split-plot replicates. The results showed that 2,4-D at 10 mg.L-1 influenced fruits texture and extended the harvest and also increased fruit acidity and reduced the ratio; GA3 at 20mg.L-1 increased the diameter and weight of the fruits harvested in August and presented higher juice rate and there was no difference on total soluble sugar in solid solute tenor.

Diferentes ambientes e Osmocote® na produção de mudas de tamarindeiro (Tamarindus indica) / Different ambient and Osmocote® for growth of tamarind (Tamarindus indica) fruits seedlings

Objetivou-se com este trabalho avaliar os efeitos de diferentes ambientes e doses de Osmocote® na produção de mudas de tamarindeiro (Tamarindus indica L). Um experimento foi instalado no Pomar da Universidade Federal de Lavras-MG, empregando-se delineamento experimental em blocos casualizados, em esquema fatorial 3 x 4, com quatro repetições e cinco plantas por parcela. Os tratamentos se constituíram dos diferentes ambientes de formação de mudas (casa de vegetação, telado e a céu aberto) e de quatro doses de Osmocote®: 0; 3; 6 e 9 kg m-3 de substrato. Avaliaram-se a altura da muda (cm), comprimento da raiz (cm), número de folhas/planta, matéria seca da parte aérea (g), matéria seca da raiz (g) e a matéria seca total (g). Os resultados demonstraram que o Osmocote® (15-10-10) pode ser recomendado para a formação de mudas de tamarindo, em doses de até 6,0 kg.m-3. O ambiente a céu aberto foi o que proporcionou melhor qualidade às mudas.

This work aimed to evaluate the effect of ambient and Osmocote® (15-10-10) doses on the production of tamarind fruits seedlings. An experiment was carried out in a nursery at Universidade Federal de Lavras, Brazil, arranged in a randomized complete block outline and a 3x4 factorial scheme, with four replications and five plants per plot. The treatments were constituted by greenhouse, nursery and exposed sky, using different dosages of Osmocote® (15-10-10) were 0; 3; 6 e 9 kg m-3 of substrate. Seedling growth, height, number of leaves, aerial part, root and total dry matter were evaluated. The results showed that of Osmocote® (15-10-10) can be recommended for the formation of tamarind seedlings, at doses of until 6 kg m-3. Sky exposing was the one which provided better quality to the seedlings.

Produção da tangerineira 'ponkan' após poda de recuperação / Production of 'ponkan' tangerine tree after pruning recovery

Objetivou esta pesquisa testar o efeito da poda de topo no rebaixamento da copa e poda da saia, na recuperação da tangerineira 'Ponkan' com 12 anos de idade, altura de 4 metros, espaçadas de 6 x 4 m e enxertadas sobre limoeiro 'Cravo'. O experimento foi conduzido na Fazenda Vito Crincoli localizada no município de Perdões, MG. O delineamento experimental utilizado foi em blocos ao acaso, em esquema fatorial 4 x 2, sendo poda do topo (sem poda, poda a 3,0; 2,5 e 2,0m) e poda da saia (sem e com a poda) com quatro repetições. A parcela útil foi constituída de três plantas. As podas drásticas de topo prejudicaram a primeira produção, contudo a partir do segundo ano após a poda, as plantas apresentaram boa recuperação. Esse comportamento foi confirmado na terceira colheita, quando os diferentes tipos de podas do topo não se diferenciaram na produtividade, sendo que o tratamento com poda da saia foi superior ao sem poda.

This research aimed to test top pruning effect on the lowering of plant canopy, pruning the lower canopy on the recover of 12 years old 'Ponkan' tangerine tree, 4 meters height, 6 x 4 spaced and grafted on 'Cravo' lemon rootstock. This experiment was carried out at Vito Crincoli's Farm in Perdões, MG. It was carried out under randomized plots in a factorial scheme of 4x2, top pruning (without pruning, pruning at 3.0; 2.5 and 2.0 m) and skirt pruning (with and without pruning) with 4 replications. Plot size was composed by three plants. Heavy pruning of the top canopy lowered the first tree yield, however, and in the begining of the second year, the plants showed a very good recover. The same behavior was seem for the third harvest when several kinds of top pruning did not differ in the yield. Skirt pruning treatment was superior to that without any pruning.

Adubação nitrogenada e substratos na produção de mudas de maracujazeiro doce / Nitrogen fertilization and substrates in the production of 'sweet' passion fruit seedlings

Com o objetivo de avaliar diferentes substratos e doses de nitrogênio na produção de mudas de maracujazeiro doce, conduziu-se um experimento no Setor de Fruticultura do Departamento de Agricultura da Universidade Federal de Lavras. Foram estudadas cinco doses de nitrogênio 0; 400; 800; 1600 e 3200 mg de N/dm³ e duas composições de substratos: A (composto orgânico + areia + solo na proporção de 1:1:3 em volume) e B (Plantmax® + areia + solo na proporção de 1:1:3 em volume ). Foi utilizado o delineamento experimental em blocos casualizados em esquema fatorial 5 x 2, com quatro repetições e cinco plantas por parcela. Foi observado que doses elevadas de adubação de cobertura com N podem promover efeitos depressivos nas mudas. E que o melhor substrato foi o B, contendo: Plantmax® + areia + solo na proporção de 1:1:3 em volume.

With the objective to evaluate different substrata and doses of nitrogen in the production of maracujazeiro doce, an experiment was conducted in fishery of formation of changes in the didactic orchard of the Federal University of Lavras. It was tested five doses of nitrogen 0; 400; 800; 1600 e 3200 mg N dm-3 and two substrate composition: A (organic compost + sand + soil at 1:1:3 volume proportion) and B (Plantmax + sand + soil at 1:1:3 volume proportion). A randomized block design was used with factorial scheme 5x2, with four replications and five plants by plot. It was observed that the elevated doses to seedling of 'sweet passion fruit' seedlings may be hurtful. The substrate B promoted best results in production of 'sweet passion fruit' seedlings.

Fertilizante de liberação lenta na formação de mudas de maracujazeiro 'amarelo' / Fertilization of low liberation in cutting formation of yellow passion fruits

A prática de adubações, além de se constituir num fator indispensável para o desenvolvimento das mudas, acelera consideravelmente o crescimento das mesmas, reduzindo assim os custos de produção. Com o objetivo de avaliar a produção de mudas de maracujazeiro 'Amarelo' com adubações com o fertilizante Entec®, conduziu-se um experimento em viveiro de formação de mudas a céu aberto no setor de produção da Universidade Estadual de Mato Grosso do Sul (UEMS), Mato Grosso do Sul. Foram testadas cinco doses de Entec® 0; 3; 6; 9 e 12 kg m-3 de substrato. Foi utilizado o delineamento experimental em blocos ao acaso com cinco tratamentos, quatro repetições e cinco plantas por parcela. Após 120 dias da semeadura avaliaram-se as características: altura de plantas (cm); número de folha/planta, matéria seca da parte aérea, da raiz e total (g/planta). Foi observado que a utilização de adubações nitrogenada com Entec® em dosagem de até 6,0 kg m-3 de substrato garante melhor qualidade na formação e no desenvolvimento das mudas de maracujazeiro 'amarelo'.

Aiming to evaluate the production of yellow passion fruits cuttings with covering Entec® fertilization an experiment was carried out in exposed sky condition at orchard of Universidade Estadual de Mato Grosso do Sul (UEMS), Mato Grosso do Sul. It was tested five Entec® dosages: 0; 3; 6; 9 and 12 kg m-3. A randomized block design was used with five treatments, with four replications and five plants per plot. After 120 days of seed germination it was evaluated the following characteristics: plant high (cm), number of leaves/plant, dry weight of aerial part, roots and total (g/plant). It was observed that the utilization of Nitrogen fertilization with Entec® until 6,0 kg m-3 warranty best quality and better development of stem and of passion fruit.

Superfosfato simples e cloreto de potássio na formação de porta-enxerto de sapotizeiro [Manilkara zapota (L.) Von Royen] / Simple superphosphate and potassium hydrochloride in the formation of sapodilla rootstocks [Manilkara zapota (L.) Von Royen]

Objetivou-se com este estudo avaliar o efeito da aplicação de superfosfato simples e cloreto de potássio no desenvolvimento de porta-enxerto de sapotizeiro até a época de enxertia. O delineamento experimental utilizado foi em blocos casualizados em esquema fatorial 4 x 4, sendo quatro doses de superfosfato simples (0; 2,5; 5 e 10 kg m-3 de substrato) e quatro doses de cloreto de potássio (0; 1; 2 e 4 kg m-3 de substrato) com quatro repetições e duas plantas por parcela. Os porta-enxertos foram avaliados quando atingiram o ponto de enxertia, nas seguintes características: altura da muda (cm); comprimento de raiz (cm); número de folhas; matéria seca da raiz, da parte aérea e total (g). Pelas respostas obtidas verificou-se que na formação de porta-enxerto de sapotizeiro há necessidades de aplicação dos fertilizantes cloreto de potássio e, principalmente, o superfosfato simples. Doses de superfosfato simples de até 5 kg m-3 com 4 kg m-3 de cloreto de potássio proporcionaram, a essa frutífera, ganhos em matéria seca.

The objective of this research was to verify the effect simple superphosphate and potassium hydrochloride doses on the growth of sapodilla rootstocks. The experimental design was a randomized block, with four replications in a (4 x 4) factorial scheme, being four doses of simple superphosphate (0; 2,5; 5 and 10 kg m-3 of substrate) and four levels of potassium hydrochloride (0; 1; 2 and 4 kg m-3 of substrate) and two plant per plot. The rootstocks were evaluated when they reached the graft point, by the following characteristics: length of the aerial part; root length; leaf number; dry matter of the roots, aerial and total part. The result showed that for formation of sapodilla rootstocks, it is necessary the application of simple superphosphate and potassium hydrochloride the substrate and that, level of simple superphosphate of up to 5 kg m-3 with 4 kg m-3 of potassium hydrochloride, provided, to increase, advantage in dry matter production.