Sazonalidade de artrópodes edáficos, taxa de decomposição foliar e redistribuição de nutrientes em Spondias cytherea Sonn no Semiárido da Paraíba

Abstract

Nutrient cycling involves the stages of deposition of organic material, its decomposition and availability of nutrients, which are fundamental for the maintenance of plants in the ecosystem. The biotic and abiotic factors regulate these stages, determining the sustainability of the environment. Thus, the objective of this work was to study the distribution, diversity and abundance of the edaphic fauna, as well as its influence on the rate of leaf decomposition and the redistribution of nutrients in Spondias cytherea Sonn., in the semiarid region of Paraíba. The work was developed in the Campo Comprido Settlement, in the municipality of Patos-PB, covering the period from July/2020 to July/2021. Samplings of edaphic macrofauna and mesofauna were carried out using adapted “Provid” traps and metallic rings, respectively. The leaf decomposition rate was estimated using nylon bags, distributed at different distances from the stem, both on the soil surface and in depth. The levels and percentage of redistribution of macronutrients and sodium were evaluated at different leaf stages, divided into four treatments equivalent to young, intermediate, mature and deciduous leaves, in five replicates and four plants per replicate. As a result, it was observed that the highest number of edaphic macrofauna individuals was found in the riparian forest area, while mesofauna organisms were more abundant in the Caatinga area. The highest leaf decomposition rate occurred in the first 120 days, in which the Spondias leaves that were buried and close to the trunk were influenced by rainfall peaks and, consequently, by the water content and greater activity of decomposers; the treatment in which the nylon bags were placed on the surface of the soil and farther from the stem, was more influenced by the increase in temperature and photodegradation recorded during this period. The highest levels of N, P, K, Mg and Na occurred in young leaves.