Influence of Nitrogen Fertilizer on Seedling Production of CUPUAÇUZEIRO (Theobroma grandiflorum Schum.)

Abstract

The Cupuaçuzeiro (Theobroma grandiflorum Schum.) is widely cultivated in tropical regions of Brazil but has a few recommendations and requirements. The quality and growth of seedlings can be improved by nitrogen fertilization. The objective of this work was to evaluate the influence of different dosages of urea applied and coverage in the substrate for the seedling production of the Cupuaçu tree. The experiment was installed in the University campus of Gurupi from Universidade Federal the Tocantins in the first half of 2010. The experimental design used was the random blocks with four repetitions and five treatments, being 0, 20, 40, 60 e 80 mg dm−3 the basis of urea nitrogen. Each parcel consisted of five seedlings queued. Were measured weekly the diameter and height of the aerial part. The 72 DAE, the seedlings were collected for the evaluation of the following biometric data: average leaf area (cm2), average leaf area, and total and total (g), the relationship APA/DC, APA/ MSPA and the Dickson quality index (IQD). The results were subjected to polynomial regression analysis to evaluate the effects of doses of nitrogen, testing the linear and quadratic models. The relation and height of the aerial part by the diameter of the stem and height of the aerial part by the dry mass of the aerial part showed that fertilizations between 74 and 80 mg.dm−3 of N should provide Cupuaçu seedlings more balanced. The IQD indicated that doses of 66 mg.dm-3 of N may promote a better quality standard of Cupuaçu tree seedlings.