Banca de DEFESA: WINKLER JOSE PINTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : WINKLER JOSE PINTO
DATE: 18/12/2020
TIME: 09:00
LOCAL: Universidade Federal de São João del-Rei - Vídeo conferência
TITLE:

ENVIRONMENTAL QUALITY IN EUCALYPTUS SPP. PLANTATIONS DETERMINED FROM FUNCTIONAL PROCESSES OF ITS LITTER

KEY WORDS:

Ecosystem Processes; Litter decomposition; Litter Water Retention; Nutritional Quality of Litter; Functional Processes of Litter

PAGES: 84
BIG AREA: Ciências Humanas
AREA: Geografia
SUMMARY:

Transformations in the planet's natural landscapes impact negatives the ecosystems. Intense anthropic actions accelerate habitats perturbances. Among these, it includes the activity of monoculture, which under the perspective of geoecology act as a factor in reducing biodiversity. In this context, analyzes related to the processes responsible for the functioning of ecosystems, appear as an alternative to assess the levels of disturbances in the environments. Thus, the main objective of the study was to understand the cultivation of Eucalyptus spp. about the quality of the environment where it is located. To this, analyzes were carried out on the functional structure of leaf litter, due to its functions exercised in ecosystems. Three eucalyptus areas located in the municipality of São João del-Rei-MG, and an area controlled by heterogeneous vegetation, located in the Ritápolis National Forest (FNR), were used. In these areas, were made measurements on the leaf litter mass loss, water retention capacity (WRC) tests, measurement of macronutrient concentration (N, P, K, Ca, Mg, S), micronutrients (B, Cu, Mn, Zn, Fe) and organic fractions (lignin, cellulose and polyphenols) in the litter, in addition to analyzes physics of the top of the soils. in the litter, in addition to analyzes physics of the top of the soils. The following hypotheses were tested: (1) The samples of Eucalyptus ssp., They would present lower rates of decomposition of leaf litter, lower WRC, as well as soils and litter with lower nutritional quality, in comparison with as derived from the control area (effect species-specific); (2) the sampled materials would present lower decomposition rates when deposited in eucalyptus areas (effect of the environment); (3) the litter decomposition and water retention rates would be statistically related to the physical and chemical characteristics of the top of the soil and the sampled plant material; (4) the relationship between effects species-specific and environmental effects on litter decomposition and WRC would be made. In the FNR (control area), the litter from this area presented decomposition coefficient (k) (k = 0.78; 0.82; 0.87), a greater significantly than that of Eucalyptus spp. (k = 0.62; 0.57; 0.58) (Student's t-test, p <0.05). Occurring in the same way with the samples deposited in the eucalyptus areas, with the species the of control area (k = 0.51; 0.52; 0.55), greater presenting decomposition coefficient in relation to the species of Eucalyptus spp. (k = 0.47; 0.48; 0.50). For a WCR, the samples from the control area, they indicated values between 161% and 339%, with an average value equal to 260%. These values being higher than the eucalyptus areas, which varied between 72% and 156%, appointing an average value equal to 112% (Student's t-test, p <0.05). Regarding the characteristics chemicals the of samples, the material collected in the control area presented a greater average value for the concentration of N, Mg, S, Cu and Fe, in comparison to samples of Eucalyptus spp. (Student's t-test, p <0.05). On the other hand, for the lignin and polyphenols, the samples of the eucalyptus area presenting greater concentration (Student's t-test, p <0.05). The results obtained showed a strong correlation statistic between the concentrations of N, Mg, S, lignin and polyphenols in the leaf material and the ecosystem processes obtained (Pearson's correlation, p <0.01). The soils the sample areas are acidic, dystrophic with values for the sum of exchangeable bases below 1.2 cmolc / dm³, and the base saturation index less than 25%. The soils of the control area, demonstrated high saturation of aluminum, feature of alic soils. While the soils of the eucalyptus areas presented low aluminum saturation, characteristic of acric soils. The soils sampled have low effective cation exchange capacity. The soils in the control area presented lower P retention capacity, demonstrating a high value for the rate of phosphorus remaining in the soil. As for the physical characteristics of the top of the soil, the control area presented sandy texture, and the samples eucalyptus areas, a clay texture. The control area presented more aggregates of soils larger than 2 mm (Student's t-test, p <0.05). As noted, the samples from the control area showed higher rates of decomposition and CRH than those from the eucalyptus areas, as well as the litter presented of better nutritional quality (species-specific effect). The samples when deposited in the control area showed higher decomposition rates than when incubated in the eucalyptus areas (Effect of the environment). Decomposition rates and CRH were influenced by the composition of the litter, seen statistical correlation between the variables. It was also pointed out a statistical relationship, of summation interaction, between the composition of plant material and the quality of the environment (Two-way ANOVA, p <0.01). In short, the decomposition of Eucalyptus spp. in this study, it corroborated a pattern presented in the literature, showing a slow decomposition, strongly linked to its chemical composition, which makes the action of decomposing agents difficult. The analyzes carried in this study proved to be useful for the understanding functioning of forest ecosystems. It indicated that ecosystems in areas of lesser human intervention function more efficiently. Highlighting the importance of protecting environments that present a greater diversity of fauna and flora species. The way in that it becomes essential to think about a less predatory environmental management, for as not to harm the functioning of ecosystems and consequently not bring future problems to society.

BANKING MEMBERS:
Presidente - 2029209 - ANDRE BATISTA DE NEGREIROS
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Externo à Instituição - ACHILLES D'ÁVILA CHIROL - UERJ