Banca de DEFESA: BEATRIZ GASPAR DE AGUIAR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : BEATRIZ GASPAR DE AGUIAR
DATE: 26/09/2024
TIME: 09:00
LOCAL: Sala da Fitotecnia/IA/UFRRJ
TITLE:

Agronomic efficiency of remineralizers in corn cultivation under an organic management system and potential for K solubilization by organic acids

KEY WORDS:

 Remineralizers; Potassium; Organic acids; Phonolite, Hydrothermalized phonolite; Glauconitic siltstone; Rock Powder. 

PAGES: 60
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Manejo e Tratos Culturais
SUMMARY:

Brazil is the fourth largest consumer of fertilizers in the world and 96% of potassium fertilizers are imported, resulting in a strong external dependence. Decree No. 10,605 was created, which deals with the National Fertilizer Plan, with the purpose of strengthening policies to promote the production and distribution of fertilizers in Brazil in a sustainable way, increase national production, develop technologies aimed at the tropical conditions of Brazilian agriculture and train technicians, as well as economic policies and actions.

A possible alternative to reduce external dependence is soil remineralizers. These come from the mining industry as a waste and present slow solubilization of nutrients. However, adequate doses, efficiency and factors that accelerate their solubilization still require research. Thousands of scientific articles on the use of remineralizers can be found in the literature; however, due to the diversity of rocks and crops, there is no consensus in the scientific community on the efficiency of these products. Based on this premise, this study has two hypotheses: 1) remineralizers are efficient sources of K for corn crops under organic production management and 2) the use of organic acids (the same acids produced by microorganisms and the root system) increases the solubility of K contained in remineralizers. Thus, this study aimed to determine the agronomic efficiency of remineralizers in corn crops and the potential for K solubilization through organic acids.

The experimental activities are divided into two stages. The first stage aims to determine the agronomic efficiency of remineralizers in corn crops under organic management. The experiment was carried out in the experimental area of Embrapa Agrobiologia, Seropédica-RJ. The experimental design was randomized blocks, with 20 treatments and 4 replicates. The treatments consisted of different doses of 3 types of remineralizers (hydrothermalized phonolite with total K2O of 12%; phonolite with total K2O of 8% and glauconitic siltstone with total K2O of 10%) combined with different doses of potassium sulfate (K2SO4). An experiment was also carried out in a greenhouse with corn with different doses of two remineralizers (hydrothermalized phonolite and phonolite) from 0 to 100% of the total substrate of the pot. The second stage aimed to test the solubility of the remineralizers in different organic acids. The experiment was carried out at Embrapa Agrobiologia, Seropédica, RJ. The experimental design used was completely randomized with four replicates in a 3x1x5 factorial scheme, where the first factor corresponds to the remineralizers (phonolite, hydrothermalized phonolite and glauconitic siltstone), the second represents the solvent and the third represents 5 agitation times (1; 3; 5; 8 and 16 hours at 80 oscillations per minute). The experiment was performed four times, once for each type of solvent: citric acid (0.02 mol L-1); acetic acid (0.02 mol L-1); lactic acid (0.02 mol L-1); and water. Samples of 0.500 g of each of the remineralizers were weighed. After agitation, the K contents were determined. It is concluded that the phonolite and hydrothermalized phonolite present more promising results than the glauconitic siltstone regarding corn productivity. Furthermore, the use of mixed fertilization (remineralizer + potassium sulfate) appears to be a viable practice. Fertilization of remineralizers alone did not increase corn productivity. It is also concluded that it is possible to increase the availability of K present in the phonolite with organic acids.

COMMITTEE MEMBERS:
Presidente - ***.960.133-** - EDNALDO DA SILVA ARAÚJO - EMBRAPA
Externo ao Programa - 2213075 - EVERALDO ZONTA - UFRRJExterno à Instituição - DAVID VILAS BOAS DE CAMPOS - EMBRAPA