Phosphorus fraction in a yellow latosol cropped under no-tilage system in the brazilian Amazon.
2020
BRASIL, E. C. | DANTAS, R. C. R. | SILVA JÚNIOR, M. L. da | GAMA, M. A. P. | EDILSON CARVALHO BRASIL, CPATU | RUBIA CARLA RIBEIRO DANTAS, UFRA | MÁRIO LOPES DA SILVA JÚNIOR, UFRA | MARCOS ANDRÉ PIEDADE GAMA, UFRA.
Phosphorus (P) deficiency is one of the main factors that limits productivity in Brazilian soils. However, soil management under no-tillage system (NT) may alter the availability of P in the soil. The objective of this study was to evaluate the dynamics ofP fractions in a dystrophic Yellow Latosol, cropped under no-tillage for a long period of time in the Amazon Biome. The study was conducted on a farm located in the municipality of Paragominas, southeastern Pará. This experiment evaluated plots cultivatedin plots at nine (NT9), 11 (NT11) and 13 (NT13) years of no-tillage system adoption, in one plot under conventional cultivation system (CS) and a surrounding area under native forest (NF) at depths of 0-10, 10-20, 20-30 and 30-40 cm. The soil samples weresubjected to P chemical fractionation to determine the different ractions. The soil management systems showed differential capacity of P accumulation. In the areas under no-tillage, P is accumulated in the toplayer and drastically reduced with depth, while in CS, this reduction is less pronounced. In the 0-20 cm depth layer during the adopted period of the no-tillage system, it was observed an increase in the content of inorganic phosphorus extracted by resin and 0.5 M NaHCO3(PiAERand PiBIC) and organicphosphorus extracted by 0.5 M NaHCO3(PoBIC), fractions considered as available for Biomass. Regardless of the year of adoption, the no-tillage system was superior to CS and NF. This was also observed for the inorganic and organic fractions extracted by NaOH 0.1M(PiHid-0.1and PoHid-0.1)and inorganic fraction extracted by HCl 1M (PiHCl).
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