43 resultados para aboveground
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This trial aimed to evaluate the effect of sequential applications of different plant regulators over growth and flower rachis emission of 'Meyer' zoysiagrass (Zoysia japonica). The study was conducted on 15-month old green turfgrass under a randomized complete block design with four replications. The following plant regulator and doses were tested: trinexapac-ethyl (113+113, 226+113, 226+226, 452+113, 452+226, 452+452, 678+339 e 904+452 g a.i./ha-1), prohexadione-calcium (100+100 e 200+200 g a.i. ha-1) and bispyribac-sodium (40+40 e 60+60 g a.i. ha-1), as well as an untreated control. The turfgrass was mowed again at 3.0 cm aboveground and the second plant regulator was applied when 'Meyer' zoysiagrass was between 5.0 and 6.0 cm high. The effect of the treatments was visually rated for visual injury, plant height, height and number of flower rachis, and total dry mass production of clippings. Only bispyribac-sodium had visual symptoms of injury on 'Meyer' zoysiagrass, and no intoxication was observed at 28 days after the second application (DAAB). The sequential applications of trinexapac-ethyl, prohexadione-calcium and bispyribac-sodium reduced by more than 80% the total clipping dry mass produced by 'Meyer' zoysiagrass. All the plant regulators tested also showed promising results in reducing the height and emission of rachis, especially when trinexapac-ethyl was applied at the doses 452+452, 678+339 and 904+452 g a.i. ha-1. 'Meyer' zoysiagrass turfgrass can be handled with the sequential application of a plant regulator, which reduces the need for mowing over a period up to 110 days after the application of the second plant regulator, and it also avoids deleterious visual effects over turfgrass.
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Lianas play a key role in many tropical forests ecosystems, contributing to community abundance, diversity and structure. Techniques to census lianas and estimate biomass have been used mainly in tropical forests. The aim of this study was to verify if different measurement location on the stem and inclusion criteria influence the estimations of liana abundance and biomass in Cerrado. The study was carried out at Itirapina fragment (ca 260 ha) located in Sao Paulo, Southeast Brazil. We measured all apparent ramets of rooted lianas by using different inclusion criteria: >= 0.5 cm in diameter at 30 cm basal area (D_30), and at 130 cm diameter breast height (DBH), in 36 transects (10 x 25 m). We compared the biomass using the allometric equation based on data from tropical florest take at 130 cm (DBH) and other The allometric biomass equation development to estimate the aboveground biomass of live lianas in tropical forests (DAP = 130 cm) was used. We tested the liana biomass, based on measurements taken at (D_30) using two different conversion equations. The results did not show significant differences in liana abundance and above ground biomass estimated applying the different criteria of inclusion However the biomass estimated from data collected at D_30 and converted into DAP showed a tendency to increase in biomass. Our findings suggest that the protocol used to the census of liana and the allometric biomass equation proposed to forests can be applied in the Cerrado.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aims of this study was evaluated the efficiency of nitrogen sufficiency index (NSI) calculated with base on the measures relative chlorophyll index (RCI) leaves, measured with portable chlorophyll meter, as an indicator of time of sidedressing N fertilization and verify which value of NSI (90% and 95%) is the most appropriate to indicate the moment of N fertilization on common bean cultivar IAC Alvorada. An experiment with five N managements (M1: 200 kg ha(-1) N (40 kg at sowing + 80 kg at 15 days after emergency (DAE) + 80 kg 30 DAE); M2: 100 kg ha(-1) N (20 kg at sowing + 40 kg at 15 DAE + 40 kg at 30 DAE); M3: 20 kg ha(-1) N at sowing + 30 kg ha(-1) when chlorophyll meter readings indicated NSI < 95%; M4: 20 kg ha(-1) N at sowing + 30 kg N ha(-1) N when chlorophyll meter readings indicated NSI <90% and, M5: control (without N application)) and four replications was carried out in the rainy and dry growing seasons of the agricultural year 2009/10, in Botucatu, Sao Paulo State, Brazil. The variables RCI, aboveground dry matter, leaf N concentration, yield components, grain yield, and N use efficiency were evaluated. The NSI of 90%, calculated based on monitoring of RCI in common bean leaves with chlorophyll meter, was more effective than 95% to define need for N sidedressing in common bean cultivar IAC Alvorada, reducing the N application and improving the use efficiency of applied N.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fire is a common event in different ecosystems and can both be caused by humans or have natural sources.. In many of these ecosystems, natural fires are an important factor that determines the vegetation. The reduction of tree cover by fire for example, resulted in the evolution of several species-rich ecosystems, dominated by C4 grasses. However, the fire caused by human actions may have greater intensity and lead to negative responses of vegetation, since man changed the fire regime in many parts of the world, such as in the Cerrado. The passage of fire can benefit herbaceous and woody seedlings that cannot compete with the dominant grass layer. It removes the dead biomass and litter (major components of the fuel load), opening up spaces within the grass matrix that allow the establishment of other species. After some time without fire, an increase in shrub cover and decrease herbaceous layer can be observed. One of the major consequences of the absence of fire in savanna and grassland ecosystems is the accumulation of flammable dead biomass (mainly composed of graminoids), which will probably be the fuel load of the next burning thus, fires will be more intense and hotter. Moreover, very frequent burns lead to a reduction in the frequency and density of grasses. Therefore, this study aimed to assess the quantity and quality of biomass in areas with different fire history (fire exclusion for 2 and 7 years) in areas of campo sujo in central Cerrado. Plots (1x1m) were established in both areas and all aboveground biomass of each plot was cut at ground level and put in paper bags in the field. In the laboratory, the material was sorted into live and dead biomass. In addition, live biomass was separated into different functional groups (graminoids, forbs, Vellozia spp, palm and shrubs). The material was oven dried for two days at 80°C and subsequently weighed. In both areas, we found a dominance of graminoid and dead biomass. The area...
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Pós-graduação em Ciência Florestal - FCA
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
