Logo Locus

Communities in DSpace

Select a community to browse its collections.

Now showing 1 - 6 of 6

Recent Submissions

  • Thumbnail Image
    Item type:Item,
    Avocado: is it possible to produce two seedlings with one seed?
    (Revista Ceres, 2020) Souza, Jackson Aparecido Chaves; Prates, Guilherme Carvalho; Ferreira, Joseane Turquete; Castro, Guilherme Dumbá Monteiro de; Salomão, Luiz Carlos Chamhum
    It was evaluated the possibility to produce two seedlings per avocado seed, through the separation of cotyledons. Two seed lots from two different ungrafted trees were evaluated. From the first tree were obtained 60 seeds, and 50 from the second. Half the seeds of each lot had their cotyledons separated and then whole seeds and half-seeds were sown in river sand. At 90 days after sowing, percentage of germinated seeds, shoot height, main root length, fresh and dry mass of shoots, roots and cotyledons were evaluated. From the first lot of seeds, there was 100% germination, both for the whole seeds and for the half-seeds. For all traits evaluated, higher mean values were observed for seedlings formed from whole seeds. In the second lot of seeds, 88% of germination was observed for whole seeds and 82% of germination for half-seeds. In this second lot, there were no significant differences between the seedlings formed from whole seeds and half-seeds for any of the characteristics evaluated, except for fresh and dry mass of cotyledons. Thus, it is possible to produce two seedlings or rootstocks with a single avocado seed, although this may slightly delay the development of the seedlings.
  • Thumbnail Image
    Item type:Item,
    Pre-harvest desiccation in biomass sorghum with herbicides
    (Revista Ceres, 2020) Barros, Angélica Fátima de; Pimentel, Leonardo Duarte; Freitas, Francisco Cláudio Lopes de; Cecon, Paulo Roberto; Tomaz, Adriano Cirino; Biesdorf, Evandro Marcos
    The purpose of this study was to assess the effect of different herbicide treatments on moisture removal and calorific power of biomass sorghum for co-generation of electric energy through burning. The experiment was conducted in randomized complete block design with four replicates per treatment and a 6x4 factorial scheme (six herbicide treatments x four intervals between spraying and harvesting). The herbicide treatments were: two different doses of glyphosate (1.92 kg a.i. ha-1 and 3.84 Kg a.i. ha-1), paraquat (0.4 Kg a.i. ha-1), a commercial mixture of paraquat + diuron (0.6 + 0.3 Kg a.i. ha-1), glufosinate-ammonium (0.8 Kg a.i. ha-1) and control (unsprayed). The intervals between spraying and harvesting assessed were 7, 14, 21 and 28 days after desiccation (DAD). It was assessed: the number of leaves per plant, moisture content of leaves, panicles, culm and whole ground plants and Superior Calorific Power (SCP). The herbicides paraquat and paraquat + diuron promotes defoliation, after 14 DAD. Glyphosate, paraquat, paraquat + diuron and glufosinateammonium reduce leaf and panicle moisture, despite only glyphosate reduces moisture in the culm. The herbicides do not affect the SCP of biomass sorghum. Therefore, the herbicides, especially glyphosate, have high potential for preharvest desiccation in biomass sorghum.
  • Thumbnail Image
    Item type:Item,
    Foliar application of molybdenum on cover crops and response of common beans in successive cultivation
    (Revista Ceres, 2020) Brandelero, Fernanda Daniela; Kutz, Talita Slota; Vargas, Thiago de Oliveira; Modolo, Alcir José; Cassol, Luís César; Oliveira, Marisa de Cacia; Santos, Ricardo Henrique Silva
    The effects of foliar application of Mo and use of N from cover crops (Crotalaria juncea L. and Canavalia ensiformis (L.) DC) on the performance of common beans were investigated in this study. Field experiments were carried out in a succession planting system (cover crops – common beans), and nitrate reductase activities were evaluated in the laboratory. For the production of cover crops, a 2 x 4 factorial scheme was installed, with the two cover crops sunn hemp and jack bean, along with four doses of Mo (0, 40, 80, and 120 g ha-1) in the form of sodium molybdate (Na2MoO4 ) through foliar application in random blocks with four replications. For bean cultivation, an unfertilized control treatment was evaluated. Sunn hemp showed a linear positive response to Mo application in terms of shoot dry matter and N accumulation, while jack bean showed a quadratic negative response for shoot dry matter; for N accumulation, there was no adjustment of the regression models. Nitrate reductase activity in the common beans was up to three times higher at the Mo dose of 0 g ha-1 when compared to the treatments with Mo application to both cover crops. Cover crops or Mo doses had no significant effect on bean productivity.
  • Thumbnail Image
    Item type:Item,
    Interference of volunteer corn in growth and chlorophyll fluorescence of bean
    (Revista Ceres, 2019) Aguiar, Adalin Cezar Moraes de; Silva, Diecson Ruy Orsolin da; Basso, Claudir José; Soriani, Hilda Hildebrand; Novello, Bruna Dal’Pizol; Muraro, Dionei Schmidt
    Corn kernels or seeds that remain a( er harvest can germinate and become a troublesome volunteer plant where bean crops are grown.The objective of this study was to evaluate the e) ect of time of emergence of volunteer corn on growth parameters, photosynthetic pigments and chlorophyll fluorescence in bean plants, competition for soil and light and light resources. The study was conducted in completely randomised experimental design, in 2×2×2+2 factorial scheme with four replications, involving two bean cultivars in competition with volunteer corn, emerging seven days before and simultaneously with beans, besides the partitioning of the competition by soil and light, just light and two controls without competition. We measured the levels of chlorophyll a, b, total and carotenoids, parameters related to chlorophyll fluorescence and bean growth variables. Volunteer corn was more competitive when it emerged seven days before the beans. When competition was established by light resource, there was a reduction in photosynthetic pigments and morphological variables of the bean plants. When competition by soil and light resources occurred, there was a reduction not only in photosynthetic pigments and morphological characteristics, but also in the chlorophyll fluorescence variables. There were signi" cant correlations between the growth variables of the bean plants and chlorophyll fluorescence, which makes it an important analytical tool for quantifying the stress caused by weeds.
  • Thumbnail Image
    Item type:Item,
    The automatic selection of hydraulic spray nozzles based on the psychrometric air conditions in hydropneumatic sprayers
    (Revista Ceres, 2020) Sasaki, Robson Shigueaki; Brito, Ana Cláudia de; Alvarenga, Cleyton Batista de; Teixeira, Mauri Martins; Rocha, Helton John Alves
    The aim of the current study is to develop an electronic system capable of automatically replacing hydraulic spray nozzles, based on psychrometric air conditions such as temperature and relative air humidity, in order to help improving the efficiency of application technologies. The system comprised one microcontroller, two solenoid valves, one temperature and relative humidity sensor, and a control algorithm. The system was installed in a hydropneumatic sprayer adapted with two semi-arcs. One semi-arc was equipped with JA-2 and other semi-arc with CVIA-015 hydraulic nozzles. After the algorithm interpreted the momentary psychrometric air conditions, it activated the JA-2 (when VPD < 20 hPa) or the CVIA-015 nozzle (when VPD > 20 hPa). The system was evaluated based on technical spraying parameters and on the response time to replace the hydraulic nozzle. Based on the results, the smallest-diameter droplets were the most influenced by psychrometric air conditions. VPD > 20 hPa tended to increase the VMD values and to reduce droplet density, although it did not change the SPAN index. The necessary mean time to switch from the JA-2 to the CVIA-015 nozzle was 0.742 s, whereas the necessary mean time to switch from the CVIA-015 to the JA-2 nozzle was 0.684 s.