Scientia Agropecuaria

Floristic study of weeds in watermelon crops in Savannah of Roraima, Brazil

O município de Bonfim é considerado o segundo maior produtor de melancia do Estado e a incidência de plantas daninhas encontra-se como um dos fatores que mais afetam a qualidade e produtividade da cultura. Objetivou-se com este trabalho estudar floristicamente as plantas daninhas em cultivos de melancia no município de Bonfim, na savana Roraimense. A pesquisa foi realizada em 10 propriedades, com uma área em torno de 40 ha de plantio comercial de melancia. Para a coleta das plantas daninhas utilizou-se um quadrado de ferro vazado com dimensão de 0,50 x 0,50 m, sendo lançado aleatoriamente na área. Foram identificadas a nível de gênero, espécie, família e classe botânica. Foram calculados os parâmetros fitossociológicos: frequência, densidade, abundância, frequência relativa, densidade relativa, abundancia relativa e índice de valor de importância relativo. Foram ainda avaliadas o ciclo de vida, hábito de crescimento, método de propagação e a rota fotossintética das espécies invasoras. A composição da comunidade infestante de plantas daninhas na área levantada foi considerada heterogênea, apresentando 17 espécies distribuídas em 10 famílias botânicas. As famílias com maior ocorrência foram as Poaceae e Fabaceae. Os gêneros Digitaria e Sida apresentaram o maior número de espécies. A maioria das plantas daninhas identificadas propaga-se exclusivamente por sementes, apresentam ciclo de vida anual e a rota fotossintética C3

The municipality of Bonfim is the second largest watermelon producer in the state and the incidence of weeds is as one of the factors that most affect the quality and crop productivity. The objective of this work was to study floristically weeds in watermelon crops in the municipality of Bonfim, in Roraimense savannah. The survey was conducted in 10 properties with an area of around 40 ha commercial planting watermelon. To collect the weeds used a square cast iron with dimensions of 0.50 x 0.50 m, being released randomly in the area. They were identified to genus, species, family and botany class. the phytosociological parameters were calculated: frequency, density, abundance, relative frequency, relative density, relative abundance and relative importance value index. There were also evaluated the life cycle, growth habit, propagation method and the photosynthetic pathway of invasive species. The composition of the infesting weed community in the raised area was considered heterogeneous, with 17 species in 10 plant families. Families with higher incidence were Poaceae and Fabaceae. The Digitaria and Sida genres had the highest number of species. Most of the identified weed spreads only by seed have annual life cycle and the C3 photosynthetic pathway

Anticipation and harvest delay in oil and protein contents of soybean seeds, grow crops Valiosa RR

Objetivou-se com este trabalho avaliar a qualidade fisiológica e os teores de óleo e proteína de sementes de soja colhidas em diferentes estádios de desenvolvimento da planta e diferentes períodos de retardamento de colheita. A cultivar estudada foi a BRS Valiosa RR e o delineamento experimental foi de blocos casualizados, com três repetições. Foram estabelecidos 11 tratamentos, constituindo épocas diferentes de colheita nos estádios: R5.1, R5.3, R5.5, R6, R7.1, R7.3, R8.1, R9, R9+10 dias, R9+20 dias e R9+30 dias. A antecipação da colheita foi viabilizada por meio da aplicação, do herbicida Diquat (400 g ha-1) com pulverizador costal manual provido de bico "tipo leque" regulado para volume de calda de 300 L ha-1. Após a colheita, procedeu-se à avaliação da qualidade das sementes e à determinação dos teores de óleo e proteína. Constatou-se que o estádio R7.1 foi a época de colheita que apresentou maior porcentagem de germinação, demonstrando que a antecipação da colheita não provocou perda no vigor das sementes. Na fase de enchimento de grãos, os teores de óleo foram menores e os de proteína maiores. Ambos se estabilizaram a partir do estádio R7.1 até o R9 e apresentaram tendência de queda com o retardamento da colheita da soja

The objective of this work was to evaluate the physiological quality and oil and protein content of soybean seeds harvested in different stages of plant development and different periods of harvest delay. The cultivar studied was BRS Valiosa RR and the experimental design was of randomized blocks with three replications. Eleven treatments were established, constituting different times of harvest in the following stages: R5,1, R5,3, R5,5, R6, R7,1, R7,3, R8,1, R9, R9+10days, R9+20 days and R9+30 days. The anticipation of the harvest was made possible through the application in predetermined stages, of herbicide Diquat (400 g ha-1) with manual coastal spray with nozzle "type fan" set to volume of 300 L ha-1. After the harvest it was done the evaluation of physiological quality of seeds and the determination of the levels of oil and protein. It was noted that the stadium R7.1 was the harvest season that showed the highest percentage in the germination test, demonstrating that the anticipation of the harvest did not caused significant loss in seed vigor. At the grain filling stage, oil levels were lower and protein larger. Both stabilized from R7.1 to the R9 stadium and showed downward trend with the harvest delay

Producción de polihidroxialcanoatos por bacterias halófilas nativas utilizando almidón de cáscaras de Solanum tuberosum L

El objetivo del presente estudio fue determinar la concentración de almidón de cáscaras de Solanum tuberosum L. "papa" para la producción de polihidroxialcanoatos, PHA, por bacterias halófilas nativas, como una alternativa para disminuir los costos de producción de estos biopolímeros, posibles reemplazantes de los plásticos provenientes del petróleo. Las bacterias fueron aisladas de muestras de agua de ocho salinas y fueron enriquecidas en caldo HM1 a 30 °C, con 5, 10, 15, 20, 25 y 30 g 100 mL-1 de NaCl. A continuación, se realizaron diluciones, se tomaron alícuotas y se sembraron en agar HM1, obteniéndose 203 aislados de bacterias halófilas que fueron cultivados en caldo HM2 con 10 g.L-1 de glucosa como fuente de carbono y entre las que el 38,92% presentó gránulos de PHA teñidos por Sudan Negro B. Los 20 aislados con gránulos de PHA en el 65 95 % de las células nuevamente fueron llevadas a fermentación, alcanzando 0,174 0,889 g.g-1 de rendimiento Y (p/x). Se seleccionaron tres aislados con los mayores valores entre los que Halomonas sp. M4C1 desarrolló y sintetizó PHA en caldo HM2 con 5, 10, 15 y 20 g.L-1 de almidón como fuente de carbono, alcanzando 0,019; 0,016; 0,007 y 0,006 g.L-1 de PHA, con 0,177; 0,111; 0,056 y 0,066 g.L-1 de biomasa, después de 20, 40, 24 y 16 horas respectivamente. El mayor rendimiento de 0,144 g.g-1 le correspondió a 10 g.L-1 de almidón demostrándose que con esta concentración es factible la producción de PHA por las bacterias halófilas nativas

The aim of this study was to determine the concentration of starch Solanum tuberosum L. "potato" peels for the production of polyhydroxyalkanoates, PHA, from native halophilic bacteria as an alternative to reduce production costs of these biopolymers, possible replacements for petrochemical plastics. The bacteria were isolated of water samples of eight saline Lambayeque region and were enriched in HM1 broth at 30 °C with 5, 10, 15, 20, 25 and 30 g 100 mL-1 NaCl. Dilutions were performed subsequently, aliquots were taken and plated on HM1 agar, 203 isolates of halophilic bacteria were obtained, they were grown in HM2 broth with 10 g.L-1 glucose as carbon source and the 38.92% of the isolates showed PHA granules stained by Sudan Black B. Twenty bacteria with PHA granules in 65 - 75% over carried to fermentation, reaching between 0.174 to 0.889 g.g-1 of yield Y (p / x). Three isolates were selected with the highest values among which Halomonas sp M4C1 grew and synthesized PHA in HM2 broth with 5, 10, 15 and 20 g.L-1 of starch as carbon source, reaching 0.019; 0.016; 0.007 y 0.006 g.L-1 of PHA, with 0.177; 0.111; 0.056 and 0.066 g.L-1 of biomass after 20, 40, 24 and 16 hours respectively. The highest yield of 0.144 g.g-1 corresponded to 10 g.L-1 of starch demonstrating that this concentration is feasible PHA production by native halophilic bacteria

Influence of seed size on germination and vigor of seedlings of Camu-Camu

O camu-camu (Myrciaria dubia) é uma espécie frutífera nativa da Amazônia e sua importância econômica é comprovada devido ao fruto conter elevado teor de ácido ascórbico. O trabalho foi realizado com objetivo de avaliar a germinação e vigor de plântulas obtidas de sementes de diferentes tamanhos de duas populações de camu-camu. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial de 2 x 3 (duas procedências: rio Anauá e rio Urubu e três tamanhos de sementes: pequeno, médio e grande) com 5 repetições de 20 sementes por parcela. As sementes da procedência do rio Anauá, apresentaram maior massa (1,46 g) comparada com a procedência do rio Urubu (0,78 g). O percentual de emergência e velocidade de emergência de plântulas apresentaram melhores valores para a população do rio Anauá, justificando-se a adoção de escolha de procedência para a formação de mudas. Para comprimento do sistema radicular, massa seca da parte aérea e massa seca do sistema radicular, as sementes classificadas como média e grande oriundas do rio Anauá apresentaram maiores valores. As classes de massa das sementes apresentam um caractere importante para ser utilizado na produção de mudas de Myrciaria dubia. As sementes da procedência do rio Anauá são potencialmente mais vigorosas sendo indicadas para a produção de mudas de camu-camu (Myrciaria dubia)

Camu-camu (Myrciaria dubia) is a fruit species native to the Amazon and its economic importance is proven because the fruit contains high content of ascorbic acid. The objective of this work was to evaluate the germination and vigor of seedlings obtained from seeds of different sizes of two camu-camu populations. The experimental design was completely randomized in a factorial scheme of 2 x 3 (two provenances river Anauá and river Urubu and three seed sizes, small, medium and large) with 5 replicates of 20 seeds per plot. The seeds of the origin of the Anauá river presented higher mass (1.46 g) compared to the origin of the Urubu river (0.78 g). The speed and emergence of seed germination presented better values for the population of the Anauá river, justifying the adoption of choice of origin for the formation of seedlings. For root length, dry shoot mass and dry mass of the root system, the seeds classified as medium and large originated from the Anauá river presented higher values. The size of the seeds is an important character to be used in the production of Myrciaria dubia seedlings. The seeds of the origin of the Anauá river are potentially more vigorous are indicate for the production of camu-camu (Myrciaria dubia) seedling

Forage maize nutritional quality according to organic and inorganic fertilization

The research was conducted on a commercial land plot from the ejido Granada, municipality of Matamoros, Coahuila, situated inside the Comarca Lagunera, from April to August 2015, in order to establish the effect of two fertilization sources - organic and inorganic, upon the nutritional quality of forage maize during the spring-summer cycle with a randomized block experimental design. T1= Acadian soil +Acadian foliage (marine algae extracts) and T2= Regional control, with 16 replications. The evaluated variables were the nutritional quality of forage maize and the milk production (L•t-1 dry matter and L•ha-1). Due to the effect of the evaluated treatments, statistical differences were registered, both for, nutritional values of forage maize, such as: neutral and acid detergent fiber, non-fiber carbohydrates, total digestible nutrients, total net energy for lactation and for milk production, in favor of organic fertilization. Therefore, it can be concluded that fertilizers of marine origin applied to forage maize increased both nutritional quality of forage maize and milk yield per ton of dry matter and per hectare of this forage

**Desempeño del Phaseolus vulgaris bajo riego parcial cultivado en un sistema de respuesta hidrogravitrópica**

En el área experimental de la UNALM (Lima-Perú) se evaluó sobre tratamientos de riego parcial (RPR300 y RPR500, ml) y riego completo (RC300 y RC500, ml control), el impacto del potencial xilemático (Yx) y la conductancia estomática (gs) en plantas de frijol común (Phaseolus vulgaris L.) cultivadas en sistemas (maceteros) de respuesta hidrogravitrópica. Se utilizó un diseño de bloques completos al azar con 12 plantas/maceteros por tratamiento en tres repeticiones. Para controlar la aplicación del riego y mantener el Yx en condiciones no letales (<-15 bar), se generó una curva de retención agua-suelo. Los valores de gs antes del riego (entre 217,18 y 268,67 mmol m-2 s-1) mostraron que únicamente en RPR500 las plantas se mantenían en óptimas condiciones hídricas, a pesar de los bajos valores de Yx (entre -9,92 y -7,33 bar); situación que pudo atribuirse a la capacidad de las raíces de sopesar los momentos en que la mitad de estas estructuras se encontraban en la sección del macetero donde la humedad del suelo estaba en un nivel bajo, mientras que la otra mitad se encontraba en la sección del macetero con un adecuado nivel hídrico del suelo

In the experimental area of the UNALM (Lima-Perú) was evaluated on partial root-zone drying irrigation treatments (RPR300 and RPR500, ml) and full irrigation (RC300 and RC500, ml control), the impact of xylem potential (Yx) and stomatal conductance (gs) in common bean plants (Phaseolus vulgaris L.) cultivated in systems (pots) of hydrogravitropic response. A randomized complete block design with 12 plants/pots per treatments was used in three replicates. To control the irrigation application and manage to maintain the Yx nonlethal conditions (<-15 bars), a water-soil retention curve was generated. The values of gs before irrigation (between 217.18 and 268.67 mm m-2 s-1) showed that only RPR500 plants were maintained under optimal water conditions, despite low levels of Yx (between -9.92 and -7.33 bar); situation that could be attributed to the ability of the roots to balance those moments when half of these structures were inside soil with low humidity, while the opposite half was favorable soil water level

**Reserva de carbono en un sistema silvopastoril compuesto de Pinus patula y herbáceas nativas**

La investigación tuvo como objetivo determinar la reserva de carbono retenida bajo un sistema silvopastoril con Pinus patula, localizado en Amazonas, Perú. Para la estimación de carbono se utilizaron 06 plantas mediante el método directo, los fustes fueron seccionados cada 2 metros y a partir de estos se obtuvieron muestras de 5 cm de espesor previo al pesaje total. Para las ramas y hojas se realizó el pesaje total y se seleccionaron muestras de 200 g. Para la recolección de muestras de hojarasca y herbáceas nativas, se utilizó el método del cuadrante y las muestras de suelo se recolectaron alrededor de cada planta. Los datos fueron obtenidos mediante la formulación de ecuaciones alométricas y selección de la mayor correlación estimada, a partir de variables como diámetro a la altura del pecho (DAP) y altura del fuste (AF). Como resultado, se encontró 92,13 t/ha de carbono almacenado y 337,20 t/ha de carbono equivalente. Además, la investigación permitió establecer una ecuación que ayudó a estimar la cantidad de carbono y CO2 en pino pátula: Biomasa seca = 0,6575*DAP1,1794 (r2 = 0,91)

The objective of the research was to determine the carbon reserve retained under a silvopastoral system with Pinus patula, located in Amazonas, Peru. For the carbon estimation, 06 plants were used by the direct method, the shafts were sectioned every 2 meters and from these were obtained samples of 5 cm of thickness prior to the total weighing. For the branches and leaves the total weight was weighed and samples of 200 g were selected. For the collection of leaf litter and native herbaceous samples, the quadrant method was used and soil samples were collected around each plant. The data were obtained through the formulation of allometric equations and selection of the highest correlation estimated, based on variables such as diameter at chest height (DAP) and height of the stem (AF). As a result, 92.13 t / ha of stored carbon and 337.20 t / ha of carbon equivalent were found. In addition, the research allowed to establish an equation that allows estimating the amount of carbon and CO2 in the pine tree: Dry biomass = 0.6575 * DAP1,1794 (r2 = 0.91)

Vulnerability to soil loss in the Lajeado Pessegueiro watershed, Brazil

As geotecnologias se apresentam como ferramenta na identificação de áreas vulneráveis, auxiliando nos mapeamentos de vulnerabilidade do solo, permitindo a espacialização dos riscos causados por perdas de solo. Objetivou-se identificar e diagnosticar a vulnerabilidade do solo na microbacia Lajeado Pessegueiro, Guarujá do Sul, Santa Catarina, Brasil, com base nas potencialidades e fragilidades do ambiente, visando fornecer subsídios para o planejamento e gestão ambiental e econômica. O mapeamento de vulnerabilidade foi desenvolvido por meio de análise ambiental integrada com diversas variáveis e com a utilização de um sistema de informação geográfica que permite a espacialização dos riscos por meio de mapas temáticos, o que pode auxiliar no planejamento e ordenamento da bacia hidrográfica e das propriedades agrícolas inseridas nela. A metodologia utiliza a delimitação por unidades de paisagem, e atribui para cada variável temática um valor de estabilidade (que varia de 1 a 3) nos mapas temáticos (fisiográfico, pedológico, uso e ocupação das terras e declividade). O mapa de vulnerabilidade à perda de solo foi elaborado a partir da integração dos mapas temáticos. Os resultados obtidos indicaram a predominância com 51,98% de áreas medianamente estável/vulnerável na microbacia e essa ocorrência está associada principalmente pela presença de um equilíbrio entre os processos de morfogênese e pedogênese. O resultado obtido pode ser utilizado na elaboração de medidas de prevenção e aplicação de práticas e manejo do solo que visam a diminuição da perda do solo.

Geotechnologies present as an important tool in identifying vulnerable areas, assisting in land vulnerability mapping, allowing the spatial distribution of risks caused by soil loss. This study aimed to identify and diagnose the vulnerability of the soil in the Lajeado Pessegueiro watershed, Guarujá do Sul, Santa Catarina State, Brazil, based on the strengths and weaknesses of the environment, to provide input for the planning and environmental and economic management. The vulnerability mapping was developed through integrated environmental analysis with many variables and with the use of a geographic information system that allows the spatial distribution of risk through thematic maps, which can assist in the planning and management of the river basin and farms placed in it. The methodology uses the delimitation of landscape units, and assigns to each thematic variable a value of stability (ranging from 1 to 3) in thematic maps (physiographic, pedological, use and occupation of land and slope). The vulnerability map of soil loss was drawn from the integration of physiographic maps, slope, soil conditions and use and occupation of land. The results showed the predominance with 51.98% of averagely stable/vulnerable areas in watershed and this occurrence is associated mainly by the presence of a balance between the morphogenesis and pedogenesis processes. The results obtained can be used in the development of prevention and enforcement practices and soil management aimed at decreasing soil loss.

Prediction of beef marbling using Hyperspectral Imaging (HSI) and Partial Least Squares Regression (PLSR)

The aim of this study was to build a model to predict the beef marbling using HSI and Partial Least Squares Regression (PLSR). Totally 58 samples of longissmus dorsi muscle were scanned by a HSI system (400 - 1000 nm) in reflectance mode, using 44 samples to build the PLSR model and 14 samples to model validation. The Japanese Beef Marbling Standard (BMS) was used as reference by 15 middle-trained judges for the samples evaluation. The scores were assigned as continuous values and varied from 1.2 to 5.3 BMS. The PLSR model showed a high correlation coefficient in the prediction (r = 0.95), a low Standard Error of Calibration (SEC) of 0.2 BMS score, and a low Standard Error of Prediction (SEP) of 0.3 BMS score