Carbono orgânico e nutrientes em solos antrópicos e adjacentes sob floresta secundária na Amazônia Central

Abstract

Most soils in the Amazon, land is usually weathered and have low chemical fertility. However, there are also anthropogenic A horizon soils, dark colored, popularly called "Terra Preta" (ICC), which generally have high fertility with high levels of P, Ca, Mg, Mn, Zn and organic matter , high pH (5.5 to 6.5), high cation exchange capacity, low potential acidity (H + Al) and high base saturation, when compared to adjacent soils. The Terra Preta in Amazonia have elevated levels of carbon, with concentrations up to 150 g C kg-1 soil, compared to the surrounding soils with 20-30 g C kg-1 soil. The ability of TPIs to store and retaining stable carbon are high, it is potentially an important mechanism for mitigating the greenhouse effect and needs to be better assessed and understood. This study aimed to estimate the levels and dynamics of dissolved organic carbon (DOC) and nutrient content in soil profiles and anthropogenic soils adjacent secondary forest in central Amazonia. The experimental design was a randomized block design with three replicates each block being a trial site: Autazes Mirim (ATM) Meeting of the Waters (EA), Rio Preto da Eva (RPE). Collections were made in two soils at each site: soil horizon with man-made and man-made adjacent without horizons. We are the anthropogenic Terra Preta (TP) and Land Mulatas (TM) in the adjacent Oxisols Yellow (LA) in three locations. In each area three systems were installed to extract soil solution, each system consisted of three extractants at different depths up to 1m. Were also made to retrieve samples of soil up to 1m for determination of chemical and physical characteristics. There was significant difference in carbon stocks between the soils and sites studied: Carbon stocks were Autazes Mirim (ATM) in TP 172 Mg C/ha-1 in TM 192 Mg C/ha-1 and LA C/ha-1 of 233 Mg. In as found in Waters (EA) for TP was 213 Mg C/ha-1 in TM C/ha-1 112 Mg and 77 Mg C/ha-1 LA, and finally in Rio Preto da Eva (RPE) values were in the TP C/ha-1 165 Mg, 151 Mg C/ha-1 in TM and LA 179 Mg C/ha-1. The highest values of DOC mobilized were found in adjacent soil (624, 297 and 662 mg L-1 for ATM, EA and RP, respectively), are intermediates for the Lands Mulatas (511, 371 and 634 mg L-1 for ATM EA and EPR, respectively) and lowest for Black Earth (464, 189 and 465 mg L-1 for ATM, EA and EPR, respectively). Once knowing the relationship between chemical and physical properties of soils and its relationship with the DOC could improve the understanding of leaching processes in soils with anthropogenic A horizon and soil without these horizons.