EFEITOS DA FERTIRRIGAÇÃO DE N E K2O NA DISTRIBUIÇÃO DO SISTEMA RADICULAR DA GRAVIOLEIRA

Abstract

The objective of this work was to evaluate the effect of different doses of nitrogen and potassium applied through the irrigation water by micro-sprinkler in the space distribution of the root system of the soursop (Annona muricata L.), through digital images. The study was conducted at the experimental field of Embrapa - North, in Teresina - PI (05th 05 ' S and 42 and 48 ' W). The treatments consisted of the combination of five doses of nitrogen (20, 120, 200, 280 and 380 kg ha-1 year-1) with five potassium doses (30, 180, 300, 420 and 570 kg ha-1 year-1), besides the witness, applied every fifteen days. The evaluation of the length of roots was accomplished being used the software SIARCS and the results were analyzed through graphs of contour and columns. The largest concentrations of roots in relation to horizontal distance happened inside of the projection of the cup. The treatment whose doses of N and K2O were 380 kg ha-1 year-1 of N and 420 kg ha-1 year-1 of K2O it presented the best vertical profile of root distribution and it was also verified that dose high of potassium they inhibit the root development.