C and P pool restoration by a no-tillage system on Brazilian Cerrado Oxisol in Piaui State.

The Cerrado soil is under constant modification, especially because of the use of agricultural systems, which affect soil carbon (C) and phosphorus (P) functioning. Thus, the objective of this study was to determine the C and P dynamics in Brazilian Cerrado Oxisol in Piaui State under natural and anthropic conditions, considering that conservational agricultural management and no-tillage systems can restore the C and P pools in that soil. Four soil samples with distinct characteristics (native Cerrado, NC; burned native Cerrado, BNC; conventional tillage agricultural system, CTS; and no-tillage agricultural system, NTS) were collected in the study area for chemical and physical laboratory analysis. The total organic carbon (TOC) concentrations found were 33 g kg(-1), 27 g kg(-1), 26 g kg(-1), and 20 g kg(-1) for CTS, NTS, NC, and BNC, respectively. The NTS had a total nitrogen (TN) concentration of 2.0 g kg(-1). The CTS had 33.4 g kg(-1) of soil-oxidizable C, followed by the NTS with 27.2 g kg(-1). In both studied layers, the NTS had an organic P concentration > 200 mg kg(-1). The higher TOC concentration in the CTS was because of the higher content of clay in comparison with that in the NTS. The organic P in the NTS was associated with a less labile fraction of C. Thus, despite the disturbance caused by agricultural systems, the adoption of the NTS could be an influential strategy in agricultural systems to restore soil organic functioning in the Brazilian Cerrado Oxisol in Piaui State.