Carbon and phosphorus stocks of clayey Ferralsols in Cerrado native and agroecosystems, Brazil

Abstract In the central part of Brazil, the native savannah known as Cerrado has undergone a rapid conversion into agricultural land. This study assessed carbon and phosphorus reserves in Latosols under different types of savannah and in derived pastures. Average total phosphorus (Pt) concentrations were 360 mg Pt kg −1  soil in A horizons and 212 mg Pt kg −1  soil in Bw layers. Organic phosphorus (Po) contents ranged from 86 to 194 mg Po kg −1  soil in topsoils and Po levels decreased in BA and Bw horizons, showing a similar pattern to the soil organic carbon depth distribution. The organic P represented 26–75% of the total P forms in the soil surface layers. Carbon (C) and P-stocks ranged from 23 to 30 kg C m −2 and 357 to 442 g Pt m −2 , respectively, in the 0–200 cm profile. The 0–100 cm layer contained more than 60 and 50% of C- and P-stocks, respectively. Higher values of C- and P-stocks for topsoils were observed under natural vegetation dominated by Graminaceae. Highly significant and positive linear relationships were observed between organic or total P- and C-contents, and these highlighted the role of organic matter in soil P cycling in the Cerrado ecosystems. Pastures were found to increase the storage of C in topsoils as compared to the native ecosystems.