Growth and quality of Microdesmia rigida (benth.) Sothers & Prance seedlings in response to potassium fertilization and watering schedule

Abstract

The research aimed to evaluate the effects of water deficiency on growth and quality of Microdesmia rigida seedlings, as well as the ability of potassium fertilization to attenuate these effects. The experiment was conducted in a shaded environment, with 50% light interception, in the Forest Nursery of UAEF/UFCG. The treatments were distributed in an entirely randomized design (DIC), consisting of a 4x4 factorial, with four levels of potassium (K) (0, 50,100 and 150 mg dm-3 K) and four irrigation shifts (ID - daily irrigation (control), and every 5 (5D), 10 (10D) and 15 days (15D)), with five repetitions and two plants per sampling unit, totaling 160 plants. Absolute growth rate (TCA), plant height, stem diameter, height/diameter ratio (HDR), plant dry mass and Dickson Quality Index (DQI) were evaluated. Except for the HDR and DQI variables, which were not affected by the imposed treatments, the other variables suffered significant effect of irrigation shift, without having a significant effect for potassium fertilization. Increase in irrigation shift negatively affected the growth and dry mass production of plants. Potassium fertilization did not mitigate the negative effects of irrigation shifts on the growth and dry mass production of M. rigida seedlings. The quality of seedlings was not affected by the potassium fertilization and irrigation shift factors.