Correspondence between chemical analysis and biological evaluation of soil fertility

Abstract

At the National University of Loja, several investigations have been carried out on biological evaluation with the missing element technique, adapted and validated by Valarezo and Guayllas which uses tomato (Solanum lycopersicum L.) as an indicator plant, a relatively fast, efficient and effective in detecting nutrient deficiencies in the soil, by systematically eliminating one of the elements from a complete nutritional formula. In Ecuador, the Soil Laboratory Network (RELASE) uses the Modified Olsen extractant solution to determine the elements present in the soil; however, this solution is generally used for all soils. The results of chemical analyze should be correlated with dry biomass weight values; however, in general, they present a lack of correspondence. In these considerations, it was proposed to explore possible relationships through statistical analysis techniques between the laboratory results and the missing element method. Data was collected from 12 investigations carried out in the Ecuadorian provinces: Esmeraldas, Los Ríos, Zamora Chinchipe and Loja; correlation calculations were carried out between height and weight of the dry biomass of the indicator plant. A lack of correlation was evident between the results of the laboratory chemical analysis with the results of the biological evaluation; In the Pueblo Nuevo sector (Malacatos, Loja), a lack of correspondence was evident between the results of the chemical analysis and the technique of the missing element. Compared to the extractant solution, biological evaluation more reliably expresses the nutrient content of the soil.