Comparação de métodos para extração da fase aquosa de solos de mineralogias distintas de Pernambuco

Abstract

The soil solution characterization is of fundamental importance to evaluate a series of processes inherent to the soil-plant system. In this sense, research comparing soil solution extraction methodologies and at the same time presenting practical and financial feasibility are required in the literature. The objective of this study was to compare the efficiency of different soil solution extraction methods in Soil classes representing representative mineralogical assemblages in the state of Pernambuco. The soil solution extraction methods were carried out using saturation paste, centrifugation, porous capsules and suspensions of soil: water (1: 2, 1: 5 and 1:10) in soils (Neossolo Regolítico (RR), Luvissolo Háplicco (TX), Gleissolo Háplico (GX), Nitossolo Háplico (NX) and Latossolo Amarelo (LA)) for the horizon horizons (A horizon) and diagnoses. Relations between the five methods were established for the parameters: pH, electrical conductivity (CE), osmotic potential (Ψo), Ca 2+, Mg 2+, Na+, K+ soluble, chloride, carbonate and bicarbonate. Data analysis was performed using Pearson correlation, analysis of variance and fit of the linear model. For the soils TX, GX, NX and LA, it was possible to find regressions with good adjustments for the methods (centrifugation and porous capsule) with the standard method (pulp extract) for the variables, CE, Ψo, Ca2 +, Mg2 +, Na + and K +, Cl-. The smallest adjustments were found in ratios 1: 5 and 1:10. When the purpose is to perform a rapid method for the determination of Na +, Ca + 2, K +, Na +, Cl -, for the soils TX, GX, NX and LA and RR, the use of the 1: 2 dilution is recommended. For the analysis of the electrical conductivity and determination of the ions (Na +, Ca + 2, K +, Na +, Cl-) more commonly found in saline soils, it was possible to establish regressions with high adjustments among the evaluated methods: centrifugation, porous capsule, different proportions (1: 2; 1:5; 1:10) when related to the standard methods, for the main classes of soils and mineralogical assemblages of the State of Pernambuco.