Produção de serapilheira e variação dos macronutrientes sob o plantio de hibridos de Eucalyptus, Aliança do Tocantins - Tocantins

Abstract

This study aimed to quantify the total deposition of litter and analyze the return of nutrients N, P, K under the planting of hybrids of Eucalyptus inserted in the Cerrado Biome, Tocantins State. Ten collectors of 1 x 1 m were installed in each plantation, with a 50% shading screen background and depth of 0.10 m. The collectors were supported by 0.80 m height piles, which were monitored monthly during the period from May 2015 to April 2016. The samples were dried and separated into leaf and timber material fractions, which were therefore sent to the Federal University of Tocantins Soils Laboratory, Gurupi Campus - TO, where the routine analysis for macronutrients N, P and K took place. The highest rainfall period occurred during the months of November 2015 to April 2016. The average production of total litter between the two stands showed quite varied with an annual production of 3274.5 kg ha-1 in the E. urocam stand and 3523 kg ha-1 in the E. urograndis stand. E. urocam hybrid planting is suffering from edge effects, ie adverse weather conditions with higher incidence of wind and rainfall besides excessive heat at the edges while E. urograndis planting is protected by legal reserve and hybrid E. urocam. The most representative fraction of the total litter found in both stands studied consisted of leaves that make up 51.2% of the material deposited in the collector while the timber material fraction contributed 48.8%. In both stands, the greatest contribution of leaves occurred in the period of highest rainfall (May, November and December 2015 and January to April 2016). The leaf fraction in both stands showed the highest levels of the elements (N, P and K), being 78.5, 57.3 and 65.5% respectively.