Atributos químicos e estoques de carbono e nitrogênio em argissolo vermelho-amarelo sob sistemas agroflorestais e agricultura de corte e queima no norte do Piauí

摘要

Slash and burn farming practices have caused land degradation in the state of Piauí. This problem has stimulated the adoption of land use sustainable alternatives such as agroforestry systems. This work aimed to evaluate changes in the chemical characteristics and carbon and nitrogen stocks in Acrisol under six (SAF6) and ten year (SAF10) old agroforestry systems, agriculture with a three year (SE3) ecological basis, slash and burning practices (ACQ), and native forest (FN) in the northern state of Piauí. Soil samples, in the dry and humid periods, were collected in the 0-10 cm depth. Chemical soil properties, total organic carbon (TOC) and total nitrogen (TN) were evaluated. SAF10 showed lower Al +3 content (0.02 cmolc dm-3) in relation to the other systems. In the dry season, P content in SAF10 (12.27 mg dm-3) was six to seven times larger than ACQ and FN, respectively. The highest values of TOC and TN were observed, in the dry season, respectively, in the SAF10 (48.54 Mg ha-1 and 4.43 Mg ha-1) and SAF6 (43.30 Mg ha-1 and3.45 Mg ha-1). Agroforestry systems improved soil quality and can be considered conservation strategy for northern Piaui.