Pedotransfer carbon stock of agroforestry systems in different soil classes in the South Western Amazon

Abstract

Land use practices such as logging and burning are among the main emitters of CO2 carbon dioxide in the atmosphere. Agroforestry systems (SAF´s) emerge as alternative practices for the use of natural resources, because in addition to generating various products of animal and vegetable origin, they are potential promoters of ecosystem services. Methodologies that are suitable for measuring soil carbon stocks are expensive and require technical rigor. Pedotransfer equations can be used to estimate the soil density and consequently the carbon stock of the soil, as they are easy to apply. Thus, the objective this work is evaluate and compare the C stock obtained through different formulas / methods in agroforestry systems at 28 years of implantation and in the native forest, in three classes of soil. Areas were evaluated with: Argilúvico Dystrophic Argilúvico Plintossolo (FTd), Plintossolic Dystrophic Red Yellow Argisol (PVAf), and Typical Concretary Dystrophic Red Latosol (LVd), in the Baixa Verde, Nova California (Rondônia) branch. In each soil type, SAF’s and adjacent forest areas were evaluated. In each area, a 1 x 1 x 1.5 m trench was opened to collect soil samples, profile description and soil classification. In the trench the soil was collected at six depths of 0-10, 10-20, 20-40, 40-60, 60-80 and 80-100 cm. Pedotransfer equation (BENITES et al., 2007) was used for the estimated density calculations. It was used to estimate the carbon stocks in the different areas of use and correction of the carbon stock was made. The estimated density ranged from 1.04 to 1.33 g.com-3 for the SAF’s areas and 1.03 to 1.33 g.com-3 for the native forest. In the estimates of carbon stored without correction, the area of Forest LVd obtained the highest absolute value of C 120.36 Mg.ha-1, for values of carbon corrected the SAF 2 LVd obtained the greatest stock 121.81 Mg.ha-1 in absolute values . However, there was no statistical difference between them (p <0.05). The class of the Red Latosols was the one that obtained the highest average of corrected stored carbon up to 1 m 115.64 Mg.ha-1, followed by the Argilúvico Plintossolo with 82.21 Mg.ha-1 and Red Yellow Argisol with 69.28 Mg. ha-1. Among the areas of use, SAF’s stocked carbon in a similar way to that of a native forest, demonstrating their potential as CO2 capture and storage.