Title:	Mineral nitrogen dynamics, mineralization and nitrification in soybean fields under No-Tillage and conventional tillage in Amazonian tropical soils.
Authors:	RODDRIGUES, N. E. OLIVEIRA JUNIOR, R. C. de SANTOS, D. B. OLIVEIRA, D. R.
Affiliation:	NIELI ELOINE RODDRIGUES, UNIVERSIDADE FEDERAL DO OESTE DO PARÁ; RAIMUNDO COSME DE OLIVEIRA JUNIOR, CPATU; DARLISSON BENTES SANTOS; DANIEL ROCHA OLIVEIRA, AGÊNCIA DE DEFESA AGROPECUÁRIA DO ESTADO DO PARÁ.
Date Issued:	2026
Citation:	Ambiente e Água: An Interdisciplinary Journal of Applied Science, v. 21, e3115, 2026.
Description:	This study evaluated mineral nitrogen (NH₄⁺ and NO₃⁻) concentrations and potential mineralization and nitrification rates in soils under No-Tillage (NT) and Conventional Tillage (CT) in soybean fields in the Santarém Plateau, Pará, Brazil. Soil samples were collected at three phenological stages (R1: flowering; R5: grain filling; R8: physiological maturity) and four depths (0 – 10, 10 – 20, 20 – 30, 30 – 40 cm). No significant differences were observed between NT and CT for mineral N concentrations or transformation rates, suggesting that after two years of NT adoption, short-term effects on N dynamics are minimal. Mineral N concentrations decreased significantly (p< 0.05) from R1 to R8, mainly in deeper layers (10 – 40 cm), likely due to intense N uptake by soybean during early reproductive stages. The highest daily mineralization and nitrification rates occurred in the 0 – 10 cm layer, associated with greater organic matter and microbial activity. Positive transformation rates at all depths indicate continuous conversion of organic N into plant-available forms throughout the crop cycle. Results suggest that NT benefits on soil N cycling in Amazonian agricultural systems may become more evident over longer adoption periods, particularly when integrated with crop rotation and permanent soil cover.
Thesagro:	Nitrato
Keywords:	Ciclagem Agricultura tropical Amônio Sistemas de manejo agrícola
ISSN:	1980-993X.
DOI:	https://doi.org/10.4136/ambi-agua.3115
Type of Material:	Artigo de periódico
Access:	openAccess
Appears in Collections:	Artigo em periódico indexado (CPATU)