Banca de DEFESA: FERNANDA VITORIA SILVA DO NASCIMENTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FERNANDA VITORIA SILVA DO NASCIMENTO
DATE: 01/09/2022
TIME: 08:30
LOCAL: Google Meet
TITLE:

INFLUENCE OF SALINITY ON THE PERFORMANCE OF NATIVE SPECIES SEEDLINGS IN A CAATINGA RESTORATION PROGRAM

KEY WORDS:

Soil fertility; Salinity; Caatinga; Restoration; Native trees.

PAGES: 50
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

The Caatinga is characterised by a semi-arid climate, high temperatures, high evaporation rates and geological conditions that favour greater soil fertility and rapid plant growth in the rainy season, but also a greater accumulation of salts in the soil, which can impair plant development. To increase the efficiency of restoration in degraded areas, studies of plant responses to both soil fertility and salinity are necessary. This study was conducted in a restored area of Caatinga and aims to: 1) Characterize the levels of salinity and fertility of the soil in this restored area; 2) Test how salinity and fertility contribute to the success of restored communities, in terms of  survival; 3) Test how different compositions of restored communities could influence soil parameters after 5 years of restoration. The study was conducted at FLONA de Açu-RN, in an experiment established 2016 in a degraded Caatinga area. The site was divided into 155 plots, where native seedlings were planted with five different levels of richness (1, 2, 4, 8 and 16). The work was carried out in all monocultures and in the plots where all tree species were planted together (16 species). In these plots soil samples were collected and analysed for fertility and salinity parameters that were calculated according to the Embrapa methods manual. To test whether soil salinity and fertility characteristics (explanatory variables X) influence the survival of tree communities (response variable Y), we used Mixed Models in R software, observing how the continuous parameters of salinity, fertility and the two levels of vegetation diversity (1 and 16 species) affect the survival of planted tree species. To test whether the species composition of monoculture and polyculture (explanatory variable X) has any effect on soil parameters (response variables Y) a MANOVA was performed using the soil parameters that were not previously correlated. The results showed that the soils are not saline and that several plots show good fertility. For salinity-related parameters, increasing Electrical Conductivity reduced species  survival in mono and polycultures, whereas high potassium (K) availability generated higher survival rates in the plots. For fertility parameters, high availability of potassium (K) was also observed in higher survival plots, while high availability of Organic Matter generated lower survivals. No significant difference was found in soil arameters for both salinity and fertility in relation to monocultures and polycultures in these first 5 years of restoration demonstrating that tree species, in this space of time, are not yet able to alter the quality of the soil. The work also demonstrates that a greater amount of potassium in the soil can lead to an increase in seedling survival in Caatinga restoration programmes.

COMMITTEE MEMBERS:
Interno - 1718346 - EDUARDO MARTINS VENTICINQUE
Presidente - 1677189 - GISLENE MARIA DA SILVA GANADE
Externa à Instituição - MARINA VERGARA FAGUNDES