Dinâmica de serapilheira e produção de raízes finas em plantios de Paricá (Schizolobium Parahyba Var. Amazonicum) e floresta sucessional em Aurora do Pará, Amazônia Oriental

Abstract

The establishment of silviculturals and agroforestry systems with the paricá (Schizolobium parahyba var. amazonicum) expanded in the state of Pará, brazil, usually as alternative to reforestation of degraded areas (abandoned pasture). However lacking basic studies on the cycling of organic matter to understand the potencial of paricá to recover degrades areas. Set up an experiment on the farm Tramontina, Aurora do Pará, to evaluate process connected with cycling of organic matter, how the litter production (litterfall), litter stock, production of fine root during 12 months (October 2007 and September 2008), in treatments with plantations of paricá with five years, in the following arrangement: paricá single (PS), consortium paricá + freijó (Cordia goeldiana) (PF), Agroforestry systems with paricá, freijó and curauá (Ananas comusus var. erectifolius) (PFC). This treatments with paricá was compared with an area of reference (successional forest ecosystem with 25 years of age) (SUC). The treatments of paricá presented annual litter production under SUC (8,79 ± 0,08 Mg ha-1 yr-1), no significant difference between treatments PS (6,05 ± 0,15 Mg ha-1), PF (6,08 ± 0,13 Mg ha-1 yr-1) and PFC (6,63 ± 0,13 Mg ha-1 yr-1). The monthly production of litter was significativety major in dry season than wet season. The largest stock of litter has been identified in treatments with paricá PS (7,7 ± 1,0 Mg ha-1) and PF (7.4 ± 0,1 Mg ha-1), while the SUC presented an stock of 5.9 ± 1,3 Mg ha-1. This results is related to the lower rate of decomposition found in treatments with paricá. The production of total fine roots (live + dead) was significativelly major in the treatments PS (380,3 ± 20,6 g m-²), PF (343,0 ± 18,4 g m-²) and PFC (265,5 ± 9,9 g m-²) than SUC (107,2 ± 2,7 g m-²), the variation of fine roots production in the period of study is associate with a seasonality of pluviometric precipitation; the fine roots production decreases during the period of increased precipitation and increases with the arrival of the dry period. Treatments with paricá showed good ability to provide organic material above and below the ground. More specifically, the paricá presented high production and storage of litter on soil, which are desirable attributes in systems for recovery of degraded areas.