GROWTH OF JACARANDA-DA-BAHIA (Dalbergia nigra((Vell.) Fr. All. ex Benth)) UNDER DIFFERENT LEVELS OF NPK

Abstract

The use of well-nourished and quality seedlings is one of the factors that contribute to the successful implementation of forest plantations. The present study aimed to verify, by means of morphological characteristics, the effects of nitrogen, phosphorus and potassium on the growth of jacarandá-da-bahia seedlings (Dalbergia nigra ((Vell.) Fr. All. in order to establish the optimal dose of each nutrient to be added in different substrates thus aiming to ensure the production of seedlings with better quality. The seedlings were produced in three types of soils: mesotrophic Ultisol (PVAm), Alic Oxisol (LVAa) and distrofic Oxisol (LVAd). The experiment was conducted under greenhouse conditions from February to June of 2006. 11 treatments were defined according baconian matrix, in which the nutrients (N, P and K) ranged in three different doses and two additional treatments (Zero and Reference). A completely randomized design with four replications was adopted. The seedlings were planted in pots with a capacity of 2.1 dm3 and 120 days after sowing the data was collected. After analyzing the data, it was concluded that for the production of jacarandá-da-bahia seedlings it is recommended an addition of dosages greater than or equal to 600 mg.dm-3 of P and 200 mg.dm-3 of N when using underground earth in the production of seedlings, from distrofic Oxisol and 300 mg.dm-3 of P and 90 mg.dm-3 of N when using mesotrophic Ultisol. As for the addition of K, since the seedlings were undemanding or the available contents in the soil were sufficient to supply their needs, it is recommended the application of the minimum tested dose of 50 mg.dm-³ of soil until further studies with lower doses is tested.