Author(s): BERNARDI, A. C. de C.; SEGNINI, A.; PRIMAVESI, O. M. A. S. P. R.; OLIVEIRA, P. P. A.; PEZZOPANE, J. R. M.; BERNDT, A.; BAYER, C.; MILORI, D. M. B. P.; SILVA, W. T. L. da; SIMOES, M. L.; MARTIN NETO, L.

Summary: This study case aimed to evaluate the impact of liming and mineral fertilization of a Signalgrass pasture on C accumulation in surface and deeper layers of a Brazilian Oxisol. A 27-yr old Signalgrass pasture ((Urochloa decumbens cv. Basilisk Stapf (Syn: Brachiaria)) was used in the trial. This pasture has been grazed in a stocking rate of one animal per ha and did not receive any liming and fertilizer until the beginning of the experiment. Treatments used in a 6-year trial are described in Table 129, and both limestone and fertilizers were applied to the soil surface with no soil plowing or disc-harrowing. Soil C stocks were calculated in equivalent soil mass, taking the native Cerrado (Savanna forest) soil mass as reference. Limed soil (0-100 cm) under non-fertilized pasture showed an annual increase of 1.71 tC/ha after 6 years over the soil under native vegetation. In contrast, fertilization of low productive and degraded pasture resulted in C accumulation rates varying from 5.4 to 7.2 t/ha/yr. The results illustrate that despite the C saturation in the surface soil layer, as evidenced by a sigmoid relationship between C contents in the whole soil and the clay fraction through the soil profile, the large proportion of C accumulation (from 55 to 68 percent) in deeper soil layers makes tropical pasture soils suitable long-term C sinks.

Publication year: 2021

Types of publication: Book sections

Unit: Embrapa Southeastern Livestock

Keywords: Adaptation to climate change, Grasslands, Greenhouse gas emissions, ILPF, Liming, Mineral fertilization, Mitigation to climate change, No-tillage, Potential drawbacks, Soil management, Soil organic carbon stocks