Serapilheira e teores de nutrientes em argissolo sob diferentes manejos no norte do Piauí

摘要

This work aimed to evaluate litter deposition and quantify contents of N, P, K, Ca and Mg in agroforest systems six (AFS6) and ten (AFS10) years after implantation, in three-year old ecological based systems (ES3), slash-and-burn agriculture (SBA) and native forest (NF), all located in Esperantina, northern region of Piauí, Brazil. Collections were carried out in the wet and dry seasons of 2007. The litter was separated into leaves and branches and weighted to estimate the deposition on the soil. The highest leaf depositions were found in NF (3.8 Mg ha-1), in the dry season, whereas for branches, in the AFS10 (2.2 Mg ha-1), in the wet season. AFS showed the highest nutrient contents in the litter fractions, and, among them the N concentration was higher than the others, in both seasons. The estimate transfer of nutrients by the litter followed the sequence N>Ca>K>P>Mg. The values for litter deposition and contents and input of nutrients in the AFS systems show the contribution of the agroforest management to soil quality and the economic sustainability of the system.