Crescimento de plantas jovens de Euterpe edulis Martius em resposta a diferentes doses de fósforo

Abstract

The knowledge about palm (Euterpe edulis Mart.) mineral nutrition are important in the commercial scale of biomass of this specie, but there is a lack about nutritional necessities from the nursery to the production phase. The phosphorus is found in small concentrations in forest soils, affecting the vegetal species growth and production. So, the objective of this study was to evaluate the effect of phosphorus doses in the growth of young palm plants, as well as, determine the content of macro and micronutrients from the below and above ground biomass through a tissue analysis. The assay was conducted in a greenhouse. The seeds of Euterpe edulis Mart. were collected in the county of Venâncio Aires-RS. The substrate was Yellow-Reddish Argisoil collected on the first superficial layer (0 20 cm). As complement fertilizer were add 10mg Kg -1 of N and 12,5mg Kg-1 of K., the sources were (NH4)SO4 and KCL, respectively.Polypropylene vases with the capacity of 2,0 dm3 were used, which were sealed, to minimize the loss of water and nutrients. The statistical design was completely randomized with 8 treatments and 8 replicates, totalizing 64 plots. The treatments were quantitative and equidistant, constituted by: T1- control (soil without P); T2-90mg Kg-1; T3-180mg Kg-1 ; T4-270mg Kg -1;T5-360mg Kg-1; T6-450mg Kg-1; T7-540mg Kg-1; T8-630mg Kg-1 of P, respectively, using CaHPO4 as salt. The phosphorus was mixed to the soil before the sowing. After 12 months after sowing, the following variables were evaluated: above ground height, stem diameter, above ground biomass, below ground biomass, total biomass and roots length. The nutritional analysis from below and above ground biomass was done to obtain the amount of macro and micronutrients. The results show that the growth of young palm plants was achieved to the analyzed parameters, except stem diameter and root length, ranging between 450 and 540 mg de P kg-1 to the above ground height, above ground biomass and total biomass, and between 360 and 450 mg de P kg-1 to the below ground biomass. Due to the macro and micronutrients amount in the above and below ground biomass, the following sequence was established: N > Ca > K > Mg > P>S; Fe > Mn > Zn > B > Cu ; N > Ca > Mg > S > K > P; Fe > Mn > Zn > B > Cu.