Spatio-Temporal Disposition of Micronutrients in Green Bean Grown in Sandy Mulching Soils

Abstract

Currently, there is no information available about the spatio-temporal distribution of micronutrients in sandy mulching soils widely used in the southeast of Spain; therefore, in this experiment, we aimed to characterize the spatio-temporal distribution of micronutrients in the wet bulb zone in two sand-mulched soils. Four different factors were considered over the experiment: (a) soil model, (b) time sampling, (c) distance from the emitter, and (d) depth. Each soil was divided into four blocks and the soil sample per block was composed of 20 subsamples. The micronutrient concentration was determined in each soil sample through atomic absorption spectrometry determinations. To establish the relationship between factors, a multifactor ANOVA test analysis was conducted. The results obtained reported a higher micronutrient concentration in the soil profile than in the sand layer. Moreover, in the soil profile, there was a decrease in micronutrient concentration in distance for Fe (from 10.4 to 7.9 mg kg−1), Zn (from 4.0 to 3.5 mg kg−1), Mn (from 23.9 to 16.2 mg kg−1), and Cu forms (from 2.5 to 1.5 mg kg−1). Moreover, there was a decrease in micronutrients with depth for Fe (from 10.5 to 8.0 mg kg−1), Zn (from 4.0 to 3.7 mg kg−1), Mn (22.0 to 17.2 mg kg−1), and Cu (from 2.1 to 1.7 mg kg−1). Higher micronutrient concentration after green bean crop harvest was related to the highest organic matter content, with the following values for Fe (12.3 mg kg−1), Zn (4.0 mg kg−1), Mn (23.6 mg kg−1), and Cu (2.0 mg kg−1) in the soil profile. The fertigation management of the crop did not modify the micronutrient concentrations in distance in the sand layer due to the reduced exchange capacity of the sand with micronutrients.