Banca de DEFESA: MARCONDES DE SÁ SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARCONDES DE SÁ SOUZA
DATE: 24/01/2025
TIME: 09:00
LOCAL: Auditório do Prédio Mateus Rosas Ribeiro em formato on-line
TITLE:

Nutritional status of mango trees and soil relationships in the Sub-Middle Sao Francisco

Valley

KEY WORDS:

Mangifera indica L. DRIS. CND. Multivariate analysis.

PAGES: 83
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Fertilidade do Solo e Adubação
SUMMARY:

The objective of this research was to evaluate the nutritional status of the mango cultivars

Tommy Atkins, Kent and Palmer using the DRIS and CND methods, and to verify the

correlation of the DRIS indices with attributes of different soil types in the Sub-Middle region

of the Sao Francisco Valley. The study was carried out in commercial mango orchards on five

farms of the company Agrobras Agricola Tropical do Brasil Ltda. 85 mango plots were

selected, 33 of which were from Tommy Atkins, 32 from Kent and 20 from Palmer. The

database consisted of productivity and leaf contents of the nutrients N, P, K, Ca, Mg, S, B, Cu,

Fe, Mn, Zn, Mo and Ni. To separate the reference population, three criteria were used as the

database cutoff point, based on the mean productivity + standard deviation: criterion 1

(mean); criterion 2 (mean + 0.5 standard deviation); and criterion 3 (mean + standard

deviation). The high-productivity population was used to establish the DRIS standards. The

means, standard deviations and variances of each nutrient and of all possible bivariate

relationships between nutrients were calculated. All variance ratios between low and high

productivity groups were also calculated. The bivariate relationship with the highest variance

ratio was selected as the DRIS norm. After establishing the DRIS norms, the DRIS functions

and finally the DRIS indices were calculated. To use the CND method, the following were

calculated: the filling value, the geometric mean of the nutrients studied, the multivariate

relationship between nutrients, the CND norms and the CND indices. The average nutritional

balance index (IBNm) was also calculated. The DRIS and CND indices were interpreted

according to the Fertilization Response Potential (FRP). Optimal levels of each nutrient were

estimated by regression analysis between the nutrient concentration in the leaf and its

respective DRIS and CND index. The optimal ranges were established based on the optimal

content ± 2/3 of the standard deviation of the nutrient in the reference population. The chi-

square test was applied to assess whether there was an association between the DRIS and

CND diagnoses. Principal component analysis (PCA) was used to verify the relationship

between DRIS indices and soil attributes of three farms. Criterion 2 proved to be the best

method for dividing the database. Specific DRIS standards for each of the studied cultivars

were established. Optimal nutrient contents and optimal ranges, at the leaf level, were

established for each cultivar. The DRIS and CND methods showed high agreement in

nutritional diagnosis, but the DRIS method proved to be more sensitive in detecting

nutritional imbalances, since it was more correlated with the nutritional indices compared to

CND. The most limiting nutrients by deficiency were Cu, Mn, Zn and Mo, while the most

limiting nutrients by excess were Cu and Mn. The DRIS indices ICu and IK, IS, IMn and INi

showed positive and negative correlations with the P, K, Ca, Mg, Cu, Mn, Zn and T contents,

respectively, for the more clayey (Agrobras 01) and more sandy (Hidrotec) soil conditions.

Future studies should be conducted with the aim of establishing specific DRIS standards

considering not only the cultivar, but also each soil type. Experiments should focus on

validating the established DRIS standards.

COMMITTEE MEMBERS:
Presidente - FERNANDO JOSE FREIRE
Externo à Instituição - EDUARDO CEZAR MEDEIROS SALDANHA
Externo à Instituição - JAILSON CAVALCANTE CUNHA
Externo à Instituição - JEFREJAN SOUZA REZENDE
Externo à Instituição - ÍTALO CARVALHO CAVALCANTI