Banca de DEFESA: JÉSSICA FRANCIELE KAMINSKI RAMOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JÉSSICA FRANCIELE KAMINSKI RAMOS
DATE: 11/07/2023
TIME: 13:00
LOCAL: sala 24 do departamento de solos
TITLE:

Chemical and mineralogical characterization of diferente phosphates and their influence on agronomic efficiency

KEY WORDS:

Natural phosphates; Biophosphates; Phosphorus

PAGES: 82
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:

The high demand for phosphate fertilizers in Brazil and the external dependence on these inputs, mostly imported, highlight the need to develop domestic strategies to meet the P deficiency of Brazilian soils. The country has an enormous potential for exploiting these sources, both in terms of national reserves of phosphate rock and the use of agricultural waste. The origin of these materials and their chemical composition are directly related to agronomic efficiency. This work had the objective: (i) to characterize and (ii) to evaluate the agronomic performance of phosphates of different origins, including sedimentary phosphates (Arraias-TO; Bonito-MS; Pratápolis-MG; Algeria; Bayóvar; Morocco), igneous phosphates (Catalão-GO, Jacupiranga-SP, Registro-SP), biophosphates (Bonechar, digestate) and a reference phosphate, triple superphosphate (STP). Mineralogical and chemical analyses were performed to characterize the phosphates. A simplified methodology for determining total P and soluble P in 2% citric acid was addressed, comparing it with the official MAPA method. The soluble P content was extracted by different organic acids and then correlated with agronomic performance results in corn. The greenhouse experiment was conducted in an entirely randomized design, with 12 treatments and four repetitions, including the different phosphates and a control treatment (without P). Two corn crops were grown, each lasting 45 days. The aerial dry mass (ADM) and the foliar contents of P, N, K, Ca and Mg were evaluated. The results of the comparison between the methods for determining P showed excellent agreement, indicating that the simplified methodology is a viable alternative in the analysis of phosphate fertilizers. Biophosphates, from agricultural by-products, had high solubility in all organic extractors. Formic acid 2% had the highest capacity to solubilize reactive phosphates. Bonechar had equivalent agronomic efficiency to STP in both crops. Fertilization with biophosphates in the second crop resulted in higher P accumulation than STP. Reactive sedimentary phosphates were equivalent to STP in agronomic efficiency.  The national, sedimentary and igneous phosphates, considered of lower quality due to their low reactivity, showed higher agronomic efficiency in the second crop. The formic acid 2% and oxalic acid 2% were excellent indicators of the production of MSPA and the accumulated P in the first crop. Citric acid 2% was a reliable indicator of the production of DMPA. Fertilization with biophosphates and sedimentary phosphates for direct use in agriculture can be an alternative in supplying P in Brazilian soils.

COMMITTEE MEMBERS:
Interno - 1104775 - ADELSON PAULO DE ARAUJO
Presidente - ***.282.827-** - BRUNO JOSÉ RODRIGUES ALVES - EMBRAPA
Externo à Instituição - PAULO CÉSAR TEIXEIRA - EMBRAPA